{"data":{"id":"610654","string_id":"0Hz7eNba","status":"1","parent_id":"0","slug":"0Hz7eNba","order":"2","name":"\u547c\u5438\u77e5\u8bc6","type":"1","cover":"","cover_alt":"","desc":null,"website":"","contact":"","seo_title":"","seo_keyword":"","seo_desc":"","author":"","published_time":"0","add_time":"1757139989","update_time":"1757655065","corp_auth_id":"0","verify_code_auth_id":"0","editor_type":"1","tags":[],"child":[{"id":"610660","string_id":"t6wrT2XK","status":"1","parent_id":"610654","slug":"2015-BTS-cheng-ren-jia-ting-yang-qi-shi-yong-zhi-nan","order":"0","name":"2015 BTS\u6210\u4eba\u5bb6\u5ead\u6c27\u6c14\u4f7f\u7528\u6307\u5357","type":"2","cover":"","cover_alt":"","desc":null,"website":"","contact":"","seo_title":"","seo_keyword":"","seo_desc":"","share_switch":"0","share_code":"","author":"","published_time":"1757143078","add_time":"1757143010","update_time":"1757143078","corp_auth_id":"0","verify_code_auth_id":"0","editor_type":"4","file_type":"pdf","auth_id":"[\"610660\", \"610654\"]","content":{"content_id":"610660","content":"British Thoracic Society guidelines for home oxygen\nuse in adults\nMaxine Hardinge,1\nJoe Annandale,2\nSimon Bourne,3\nBrendan Cooper,4\nAngela Evans,5\nDaryl Freeman,6\nAngela Green,7\nSabrine Hippolyte,8\nVikki Knowles,9\nWilliam MacNee,10\nLynn McDonnell,11\nKathy Pye,12\nJay Suntharalingam,13\nVandana Vora,14\nTom Wilkinson,15\nBritish Thoracic Society Home Oxygen Guideline Development Group, on behalf of the\nBritish Thoracic Society Standards of Care Committee\n\u25b8 Additional material is\npublished online only. To view\nplease visit the journal online\n(http:\/\/dx.doi.org\/10.1136\/\nthoraxjnl-2015-206865).\nFor numbered af\ufb01liations see\nend of article.\nCorrespondence to\nDr Maxine Hardinge, Oxford\nCentre of Respiratory Medicine,\nChurchill Hospital, Oxford\nUniversity Hospitals NHS Trust,\nHeadington, Oxford OX3 7LJ,\nUK; maxine.hardinge@ouh.\nnhs.uk\nReceived 28 January 2015\nAccepted 29 January 2015\nTo cite: Hardinge M,\nAnnandale J, Bourne S,\net al. Thorax 2015;70:\ni1\u2013i43.\nABSTRACT\nThe British Thoracic Society (BTS) Home Oxygen\nGuideline provides detailed evidence-based guidance for\nthe use of home oxygen for patients out of hospital.\nAlthough the majority of evidence comes from the use of\noxygen in patients with chronic obstructive pulmonary\ndisease, the scope of the guidance includes patients\nwith a variety of long-term respiratory illnesses and other\ngroups in whom oxygen is currently ordered, such as\nthose with cardiac failure, cancer and end-stage\ncardiorespiratory disease, terminal illness or cluster\nheadache. It explores the evidence base for the use of\ndifferent modalities of oxygen therapy and patient-\nrelated outcomes such as mortality, symptoms and\nquality of life. The guideline also makes\nrecommendations for assessment and follow-up\nprotocols, and risk assessments, particularly in the\nclinically challenging area of home oxygen users who\nsmoke. The guideline development group is aware of the\npotential for confusion sometimes caused by the current\nnomenclature for different types of home oxygen, and\nrather than renaming them, has adopted the approach\nof clarifying those de\ufb01nitions, and in particular\nemphasising what is meant by long-term oxygen therapy\nand palliative oxygen therapy. The home oxygen\nguideline provides expert consensus opinion in areas\nwhere clinical evidence is lacking, and seeks to deliver\nimproved prescribing practice, leading to improved\ncompliance and improved patient outcomes, with\nconsequent increased value to the health service.\nSUMMARY OF RECOMMENDATIONS AND\nGOOD PRACTICE POINTS\nEvidence for use of long-term oxygen therapy\nin patients with chronic obstructive pulmonary\ndisease\n\u25b8 Patients with stable chronic obstructive pulmon-\nary disease (COPD) and a resting PaO2 \u22647.3 kPa\nshould be assessed for long-term oxygen therapy\n(LTOT) which offers survival bene\ufb01t and\nimproves pulmonary haemodynamics. (Grade A)\n\u25b8 LTOT should be ordered for patients with stable\nCOPD with a resting PaO2 \u22648 kPa with evi-\ndence of peripheral oedema, polycythaemia\n(haematocrit \u226555%) or pulmonary hyperten-\nsion. (Grade A)\n\u25b8 LTOT should be ordered for patients with\nresting hypercapnia if they ful\ufb01l all other criteria\nfor LTOT. (Grade B)\nEvidence for use of LTOT in other respiratory or\ncardiac disease\n\u25b8 LTOT should be ordered for patients with inter-\nstitial lung disease (ILD) with a resting PaO2\n\u22647.3 kPa. (Grade D)\n\u25b8 LTOT should be ordered for patients with ILD\nwith a resting PaO2 \u22648 kPa in the presence of\nperipheral oedema, polycythaemia (haematocrit\n\u226555%) or evidence of pulmonary hypertension.\n(Grade D)\nGood practice point\n\u25b8 Patients with ILD who experience severe breath-\nlessness could be considered for palliative\noxygen therapy (POT). (\u221a)\nLTOT in patients with cystic \ufb01brosis\n\u25b8 LTOT should be ordered for patients with cystic\n\ufb01brosis (CF) with a resting PaO2 \u22647.3 kPa.\n(Grade D)\n\u25b8 LTOT should be ordered for patients with CF\nwith a resting PaO2 \u22648 kPa in the presence of\nperipheral oedema, polycythaemia (haematocrit\n\u226555%) or evidence of pulmonary hypertension.\n(Grade D)\nLTOT in patients with pulmonary hypertension\n\u25b8 LTOT should be ordered for patients with\npulmonary hypertension, including idiopathic\npulmonary hypertension, when the PaO2 is\n\u22648 kPa. (Grade D)\nLTOT in patients with neuromuscular or chest wall\ndisorders\n\u25b8 Non-invasive ventilation (NIV) should be the\ntreatment of choice for patients with chest wall\nor neuromuscular disease causing type 2 respira-\ntory failure. Additional LTOT may be required\nin case of hypoxaemia not corrected with NIV\n.\n(Grade D)\nLTOT in patients with advanced cardiac failure\n\u25b8 LTOT should be ordered for patients with\nadvanced cardiac failure with a resting PaO2\n\u22647.3 kPa. (Grade D)\n\u25b8 LTOT should be ordered for patients with\nadvanced cardiac failure with a resting PaO2\n\u22648 kPa in the presence of peripheral oedema,\npolycythaemia (haematocrit \u226555%) or evidence\nof pulmonary hypertension on ECG or echocar-\ndiograph. (Grade D)\nHardinge M, et al. Thorax 2015;70:i1\u2013i43. doi:10.1136\/thoraxjnl-2015-206865 i1\nBTS Guidelines\ngroup.bmj.com\non June 19, 2016 - Published by\nhttp:\/\/thorax.bmj.com\/\nDownloaded from\nOutcomes of LTOT in patients who continue to smoke\n\u25b8 If LTOT is ordered for patients who are continuing to\nsmoke, the potential for more limited clinical bene\ufb01t should\nbe discussed with the patient. (Grade D)\nReferral and assessment of patients for LTOT\n\u25b8 Written and verbal information should be given to patients\nreferred to home oxygen assessment services at the time of\nreferral. (Grade D)\n\u25b8 Patients with a resting stable oxygen saturation (SpO2) of\n\u226492% should be referred for a blood gas assessment in order\nto assess eligibility for LTOT. (Grade C)\nGood practice point\n\u25b8 In patients with clinical evidence of peripheral oedema, polycy-\nthaemia (haematocrit \u226555%) or pulmonary hypertension,\nreferral for LTOTassessment may be considered at SpO2 levels\n\u226494% to identify patients with a resting PaO2 \u22648 kPa. (\u221a)\nReferral for home oxygen at hospital discharge\n\u25b8 Patients should undergo formal assessment for LTOT after a\nperiod of stability of at least 8 weeks from their last exacerba-\ntion. (Grade B)\nGood practice points\n\u25b8 Patients who have borderline saturations (ie 93\u201394%) should\nhave their oxygen saturations monitored at their annual\nreview with their general practitioner (GP) or practice nurse,\nor sooner if they experience an exacerbation in the interim.\n(\u221a)\n\u25b8 Patients who exacerbate frequently and are unable to achieve\na period of stability lasting 8 weeks may need to be assessed\nat an earlier stage after exacerbation. If LTOT is ordered for\nsuch patients, they should be counselled that in the future\nLTOT may no longer be required once they achieve a more\nstable state. (\u221a)\n\u25b8 Patients should not normally have LTOT ordered at the time of\nan acute exacerbation of their underlying condition. However, if\nhome oxygen is ordered (eg, at hospital discharge), it should be\nlimited to patients with an SpO2 of \u226492%, who are breathless,\nand unable to manage off oxygen. These patients should\nundergo a blood gases assessment and be counselled that in the\nfuture LTOT may not be required after formal reassessment. (\u221a)\n\u25b8 The date of the patient\u2019s last exacerbation should be included\nin the referral request to the home oxygen assessment\nservice. (\u221a)\nUse of pulse oximetry, arterial and capillary blood gases in\nassessment for LTOT\n\u25b8 Patients potentially requiring LTOT should not be assessed\nusing pulse oximetry alone. (Grade D)\nAssessment using arterial blood gases and capillary blood gases\n\u25b8 Patients being assessed for LTOT should undergo initial\nassessment for suitability using arterial blood gases (ABG)\nsampling. (Grade A)\n\u25b8 Patients assessed for LTOT during a period of apparent clin-\nical stability should undergo two ABG measurements at least\n3 weeks apart, before the need for LTOT can be con\ufb01rmed.\n(Grade B)\n\u25b8 Patients undergoing LTOT assessment should be reassessed\nwith ABG after oxygen titration is complete to determine\nwhether adequate oxygenation has been achieved without\nprecipitating respiratory acidosis and\/or worsening hypercap-\nnia. (Grade D)\n\u25b8 For oxygen titration during LTOT assessment, capillary blood\ngases (CBG) sampling can be used in place of ABG sampling\nfor re-measuring PaCO2 and pH at different oxygen \ufb02ow\nrates. (Grade A)\n\u25b8 For oxygen titration during LTOT assessment, cutaneous cap-\nnography can be used in place of ABG sampling for\nre-measuring PaCO2 alone but not pH at different oxygen\n\ufb02ow rates. (Grade A)\nGood practice points\n\u25b8 Patients undergoing a radial ABG should be assessed with an\nAllen\u2019s test \ufb01rst, to ensure they have a dual blood supply to\nthe hand from both radial and ulnar arteries. (\u221a)\n\u25b8 Patients undergoing a radial ABG should be consented for\nthe procedure with a discussion of possible risks. (\u221a)\n\u25b8 In many community commissioned home oxygen service\u2013\nassessment and review (HOS-AR) services it is not practical\nfor patients to undergo ABG sampling during LTOT assess-\nment. Under such circumstances, a combination of CBGs and\noximetry (but not capnography) could be used as an alterna-\ntive tool for initial assessment for LTOT, and after oxygen\ntitration is complete. Some patients may receive LTOT\nunnecessarily using this approach, but it is unlikely that any\npatient would be inappropriately denied LTOT. (\u221a)\nManagement of hypercapnia during LTOT assessment\n\u25b8 Patients with baseline hypercapnia should be monitored for\nthe development of respiratory acidosis and worsening\nhypercapnia using ABGs after each titration of \ufb02ow rate, as\nwell as an ABG after oxygen titration is complete. (Grade D)\nGood practice points\n\u25b8 Patients who develop a respiratory acidosis and\/or a rise in\nPaCO2 of >1 kPa (7.5 mm Hg) during an LTOT assessment\nmay have clinically unstable disease. These patients should\nundergo further medical optimisation and be reassessed after\n4 weeks. (\u221a)\n\u25b8 Patients who develop a respiratory acidosis and\/or a rise in\nPaCO2 of >1 kPa (7.5 mm Hg) during an LTOT assessment\non two repeated occasions, while apparently clinically stable,\nshould only have domiciliary oxygen ordered in conjunction\nwith nocturnal ventilatory support. (\u221a)\nLTOT hours of use\n\u25b8 LTOT should be ordered for a minimum of 15 h per day, and\nup to 24 h per day may be of additional bene\ufb01t. (Grade C)\nLTOT \ufb02ow rates\n\u25b8 Patients eligible for LTOT should be initiated on a \ufb02ow rate\nof 1 L\/min and titrated up in 1 L\/min increments until SpO2\n>90%. An ABG should then be performed to con\ufb01rm that a\ntarget PaO2 \u22658 kPa (60 mm Hg) at rest has been achieved.\n(Grade B)\n\u25b8 Non-hypercapnic patients initiated on LTOT should increase\ntheir \ufb02ow rate by 1 L\/min during sleep in the absence of any\ncontraindications. (Grade B)\n\u25b8 Patients initiated on LTOT who are active outdoors should\nreceive an ambulatory oxygen assessment to assess whether\ntheir \ufb02ow rate needs increasing during exercise. (Grade B)\nGood practice points\n\u25b8 Ambulatory and nocturnal oximetry may be performed to\nallow more accurate \ufb02ow rates to be ordered for exercise and\nsleep, respectively. (\u221a)\ni2 Hardinge M, et al. Thorax 2015;70:i1\u2013i43. doi:10.1136\/thoraxjnl-2015-206865\nBTS Guidelines\ngroup.bmj.com\non June 19, 2016 - Published by\nhttp:\/\/thorax.bmj.com\/\nDownloaded from\n\u25b8 Patients initiated on LTOT who have cognitive, visual or\ncoordination impairments, may not be able to safely manipu-\nlate their own \ufb02ow rates and should be maintained on a\nsingle \ufb02ow rate. (\u221a)\n\u25b8 Flow rates may be increased at 20 min intervals during an\noxygen titration until a target PaO2 is achieved. (\u221a)\nPatient education at time of assessment\n\u25b8 Patients initiated on LTOT should be provided with formal\neducation by a specialist home oxygen assessment team to\nensure compliance with therapy. (Grade D)\n\u25b8 Patients being commenced on home oxygen on discharge\nfrom hospital should be advised that home oxygen may be\nremoved if reassessment shows clinical improvement.\n(Grade D)\nFollow-up of LTOT patients\n\u25b8 LTOT patients should receive follow-up at 3 months after\nLTOT has been ordered, which should include assessment of\nblood gases and \ufb02ow rate to ensure LTOT is still indicated\nand therapeutic. (Grade A)\n\u25b8 LTOT patients should receive follow-up visits at 6\u2013\n12 months after their initial 3-month follow-up, which can\nbe either home based or in combination with hospital visits.\n(Grade D)\n\u25b8 Follow-up visits should be conducted by a specialist home\noxygen assessment team with the necessary skills to deliver\npatient education and manage withdrawal of home oxygen.\n(Grade D)\nGood practice point\n\u25b8 All patients for whom LTOT has been ordered should be\nvisited at home within 4 weeks by a specialist nurse or\nhealthcare professional with experience of domiciliary\noxygen therapy. The visit provides an opportunity to high-\nlight potential risks and should be used to reinforce educa-\ntion and offer support to the patient and carer. Compliance\nmay be checked, along with smoking status, symptoms of\nhypercapnia and oxygen saturations on oxygen to check that\noxygen is therapeutic. (\u221a)\nNocturnal oxygen therapy\n\u25b8 Nocturnal oxygen therapy (NOT) is not recommended in\npatients with COPD who have nocturnal hypoxaemia but\nwho fail to meet the criteria for LTOT. (Grade A)\nGood practice point\n\u25b8 Other causes of nocturnal desaturation in COPD should be\nconsidered such as obesity hypoventilation, respiratory\nmuscle weakness or obstructive sleep apnoea (OSA). (\u221a)\nNOT in patients with cardiac disease and nocturnal desaturation\n\u25b8 NOT can be ordered for severe heart failure patients who do\nnot ful\ufb01l indications for LTOT and have evidence of sleep\ndisordered breathing (SDB) leading to daytime symptoms,\nafter other causes of nocturnal desaturation have been\nexcluded (eg, obesity hypoventilation or OSA) and heart\nfailure treatment has been optimised. Treatment with modal-\nities of ventilatory support should also be considered.\n(Grade B)\nGood practice point\n\u25b8 If NOT is ordered for patients with severe heart failure, it\nshould be ordered at a low \ufb02ow rate of 1\u20132 L\/min and response\nshould be assessed by a reduction in symptoms of daytime\nsleepiness, and SDB indices as measured by an overnight oxim-\netry study. A blood gas assessment should be undertaken to\nexclude worsening hypercapnia and respiratory acidosis.\nTreatment with modalities of ventilatory support should be\nconsidered for patients who are hypercapnic. (\u221a)\nNOT in patients with CF\n\u25b8 NOT should not be given to patients with CF with nocturnal\nhypoxaemia alone who do not ful\ufb01l LTOT criteria. It can be\nconsidered in patients with evidence of established ventilatory\nfailure, where it should be given with NIV support. (Grade B)\nNOT in patients with ILD\n\u25b8 NOT should not be given to patients with ILD with nocturnal\nhypoxaemia alone, who do not ful\ufb01l LTOTcriteria. (Grade B)\nNOT in patients with neuromuscular weakness\n\u25b8 Patients with neuromuscular weakness affecting respiratory\nmuscles should not have NOTalone ordered. It can be consid-\nered in patients with evidence of established ventilatory failure,\nwhere it should be given with NIV support. (Grade B)\nNOT in patients with OSA, obesity hypoventilation syndrome\nor overlap syndrome\n\u25b8 Patients with OSA, obesity hypoventilation syndrome (OHS) or\noverlap syndrome should not have NOT alone ordered. It can\nbe considered in patients with evidence of established ventila-\ntory failure, where it should be given with NIV support.\n(Grade D)\nAmbulatory oxygen therapy\n\u25b8 AOT should not be routinely offered to patients who are not\neligible for LTOT. (Grade B)\n\u25b8 AOT should not be routinely offered to patients already on\nLTOT. (Grade D)\n\u25b8 Ambulatory oxygen therapy (AOT) assessment should only\nbe offered to patients already on LTOT if they are mobile\noutdoors. (Grade A)\n\u25b8 AOT should be offered to patients for use during exercise in\na pulmonary rehabilitation programme or during an exercise\nprogramme following a formal assessment demonstrating\nimprovement in exercise endurance. (Grade B)\nGood practice points\n\u25b8 Patients started on AOT should be reviewed regularly. If AOT\nwas started during an exacerbation or when unwell, an\ninitial review at 4\u20136 weeks to check it is still indicated is\nessential. (\u221a)\n\u25b8 Home visits may be useful to identify problems with equip-\nment or set-up. Further reviews should be carried out every\n6 months when stable, or sooner if the patient\u2019s clinical\nstatus changes. (\u221a)\n\u25b8 AOT therapy may offer patients with active lifestyles or\nactive treatment regimens (eg, CF) additional bene\ufb01ts. All\npatients should be assessed for AOT in the context of their\ndaily activity and therapies. (\u221a)\n\u25b8 It is recognised that there may be some patients, for example\nwith ILD and disabling breathlessness, who do not qualify\nfor LTOT but who do desaturate on exercise who may\nbene\ufb01t from AOT. Once all other medical interventions have\nbeen optimised, these patients could be considered for AOT\nfollowing formal assessment and continued provision follow-\ning demonstration of bene\ufb01t and compliance. (\u221a)\n\u25b8 Patients with high respiratory rates (common in CF and ILD)\nshould receive AOT at a selected \ufb02ow rate via a Venturi\nHardinge M, et al. Thorax 2015;70:i1\u2013i43. doi:10.1136\/thoraxjnl-2015-206865 i3\nBTS Guidelines\ngroup.bmj.com\non June 19, 2016 - Published by\nhttp:\/\/thorax.bmj.com\/\nDownloaded from\nmask, which exceeds their peak tidal and exertional inspira-\ntory \ufb02ow, and be supplied with home oxygen equipment\nwhich is able to deliver the required high \ufb02ow rates. (\u221a)\n\u25b8 AOT may be offered to LTOT patients who could otherwise\nnot achieve 15 h per day oxygen usage, or who are severely\nhypoxaemic and are too symptomatic to leave their\nhouse without supplemental oxygen but may need to do so,\nfor example to attend their GP or hospital appointments.\nFormal assessment is not required in these circumstances.\n(\u221a)\nPalliative oxygen therapy\n\u25b8 Patients with cancer or end-stage cardiorespiratory disease\nwho are experiencing intractable breathlessness should not\nreceive treatment with POT if they are non-hypoxaemic or\nhave mild levels of hypoxaemia above current LTOT thresh-\nolds (SpO2 \u226592%). (Grade A)\n\u25b8 Patients with cancer or end-stage cardiorespiratory disease who\nare experiencing intractable breathlessness should receive\nassessment for a trial of treatment with opiates from an appro-\npriately trained healthcare professional. (Grade A)\n\u25b8 Patients with cancer or end-stage cardiorespiratory disease who\nare experiencing intractable breathlessness should receive\nassessment for a trial of treatment with non-pharmacological\ntreatments including fan therapy from an appropriately trained\nhealthcare professional. (Grade D)\nGood practice point\n\u25b8 POT may on occasion be considered by specialist teams for\npatients with intractable breathlessness unresponsive to all other\nmodalities of treatment. In those instances, individual formal\nassessment of the effect of palliative oxygen on reducing breath-\nlessness and improving quality of life should be made. (\u221a)\nShort burst oxygen therapy\n\u25b8 Short burst oxygen therapy (SBOT) should not be ordered\nfor use prior to or following exercise in hypoxaemic or nor-\nmoxic patients with COPD. (Grade A)\n\u25b8 SBOT should not be ordered on discharge from hospital for\nnon-hypoxaemic patients with severe COPD. (Grade A)\nUse of SBOT in cluster headache\n\u25b8 SBOT delivering high \ufb02ow oxygen therapy (12 L\/min via a\nnon-rebreather mask) should be offered to treat acute attacks\nof cluster headache (CH). (Grade A)\nGood practice point\n\u25b8 Appropriate equipment will need to be provided in order to\nensure delivery of high \ufb02ow rate oxygen at 12 L\/min for CH\nusing a non-rebreather mask. Patients will usually have\nwarning of a CH attack, and so provision should be made\nfor urgent 4 h installation of home oxygen, if available,\nrather than a permanent home supply being provided. (\u221a)\nEquipment for home oxygen therapy\n\u25b8 Oxygen concentrators should be used to deliver LTOT at\n\ufb02ow rates of 4 L\/min or less. (Grade B)\n\u25b8 Portable oxygen should be delivered by whatever mode is\nbest suited to the individual needs of the patient to increase\nthe daily amount of oxygen used and activity levels in mobile\npatients. (Grade C)\nGood practice point\n\u25b8 The type of portable device selected should balance patient\nfactors with cost effectiveness, resources and safety. (\u221a)\nOxygen delivery\n\u25b8 Nasal cannulae should be considered as the \ufb01rst choice of\ndelivery device for patients requiring home oxygen therapy.\nAs an alternative some patients may bene\ufb01t from or prefer a\nVenturi mask system. (Grade D)\n\u25b8 Oxygen-conserving devices can be used in home oxygen\npatients requiring high \ufb02ow rates to increase the time the\ncylinder will last. (Grade B)\nGood practice points\n\u25b8 Venturi masks should be considered in patients in whom\nthere are concerns about existing or developing hypercapnic\nrespiratory failure, those with a high resting respiratory rate\nor those with cognitive problems. (\u221a)\n\u25b8 Oxygen-conserving devices should be considered in patients\nwho are active outside the home, following an ambulatory\noxygen assessment. (\u221a)\nHumidi\ufb01cation\n\u25b8 Humidi\ufb01cation of home oxygen should not be ordered for\nnon-tracheostomy patients. (Grade D)\nGood practice point\n\u25b8 Patients receiving oxygen via a tracheostomy should receive\nhumidi\ufb01ed oxygen. (\u221a)\nCarrying home oxygen\n\u25b8 Less able patients should be offered wheeled devices or back-\npacks if assessment shows they improve ambulation and\nquality of life. (Grade B)\nGood practice point\n\u25b8 When being transported in cars, cylinders should be secured\neither with a seat belt, or in the foot-well or car boot, possibly\nusing a cylinder box. Liquid oxygen should always be trans-\nported in an upright position. A warning triangle may be dis-\nplayed and insurance companies should be informed. (\u221a)\nSafety and home oxygen therapy\n\u25b8 Smoking cessation should be discussed and written education\ngiven to all patients prior to ordering home oxygen and at\neach subsequent review if the patient continues to smoke.\n(Grade C)\n\u25b8 Patients should be made aware in writing of the dangers of\nusing home oxygen within the vicinity of any naked \ufb02ame\nsuch as pilot lights, cookers, gas \ufb01res and candles. (Grade D)\n\u25b8 Patients and family members who continue to smoke in the\npresence of home oxygen should be warned of the associated\ndangers of smoking in the presence of oxygen. (Grade D)\nGood practice points\n\u25b8 Safety should be a factor when making decisions regarding\nthe ordering of oxygen. Education and written information\nshould be provided to the patient and family or carers\nregarding the safe use of oxygen and its equipment. (\u221a)\n\u25b8 The risks of prescribing oxygen to active smokers should be\nconsidered on a case-by-case basis: this should include a home\nvisit to assess the patient\u2019s home situation, attitude toward risks\nand smoking behaviour. Home oxygen assessment services may\ndecide not to prescribe home oxygen to smokers if the risks are\nin their judgement too high. Particular consideration needs to\nbe given to risks to children and risks to neighbours in multiple\noccupancy dwellings. A risk assessment tool should be used,\nand the health professional who is undertaking the risk assess-\nment may need to visit the home in conjunction with the local\ni4 Hardinge M, et al. Thorax 2015;70:i1\u2013i43. doi:10.1136\/thoraxjnl-2015-206865\nBTS Guidelines\ngroup.bmj.com\non June 19, 2016 - Published by\nhttp:\/\/thorax.bmj.com\/\nDownloaded from\n\ufb01re service and\/or the oxygen contractor. Where there is rea-\nsonable doubt, the therapy should not be prescribed. (\u221a)\n\u25b8 Patients who continue to smoke or live with other household\nsmokers should be informed that the home oxygen order\nwill be reviewed and evidence of increased risk may lead to\nwithdrawal of home oxygen therapy. (\u221a)\n\u25b8 Carbon monoxide monitoring and measuring urine cotinine\nmay help identify those patients who continue to smoke. (\u221a)\n\u25b8 Patients should be made aware that they should not use\ne-cigarettes and chargers within the vicinity of their home\noxygen. (\u221a)\n\u25b8 Oil-based emollients and petroleum jelly can support com-\nbustion in the presence of oxygen. Patients should be made\naware that only water-based products should be used on the\nhands and face or inside the nose while using oxygen. (\u221a)\n\u25b8 The oxygen supplier should be informed if the patient con-\ntinues to smoke in order for the engineer to consider it in\nthe home oxygen supplier risk assessment. (\u221a)\n\u25b8 Patients and family or carers should be instructed not to\nremove the \ufb01re breaks or to change \ufb02ow rate on their\noxygen equipment. Only oxygen tubing and connections\nsupplied by the oxygen company should be used. (\u221a)\n\u25b8 The local \ufb01re service should be made aware of patients who are\nusing oxygen at home and especially those who continue to\nsmoke in order for a home safety assessment to be carried out.\n(\u221a)\n\u25b8 Patients and carers should be aware that tubing should be\nchecked on a regular basis and repositioned as necessary to\nensure safety by preventing trips and falls. (\u221a)\nINTRODUCTION\nThe British Thoracic Society (BTS) Home Oxygen Guideline\nprovides detailed evidence-based guidance for the use of home\noxygen for patients out of hospital. Although the majority of\nevidence comes from the use of oxygen in patients with chronic\nobstructive pulmonary disease (COPD), the scope of the\nguidance includes patients with a variety of long-term respira-\ntory illnesses and other groups in whom oxygen is currently\nordered, such as those with cardiac failure, cancer and end-stage\ncardiorespiratory disease, terminal illness and cluster headache\n(CH). It explores the evidence base for the use of different\nmodalities of oxygen therapy and patient-related outcomes such\nas mortality, symptoms and quality of life. The guideline also\nmakes recommendations for assessment and follow-up proto-\ncols, and risk assessments, particularly in the clinically challen-\nging area of home oxygen users who smoke. The guideline\ndevelopment group is aware of the potential for confusion\nsometimes caused by the current nomenclature for different\ntypes of home oxygen, and rather than renaming them has\nadopted the approach of clarifying those de\ufb01nitions, and in par-\nticular emphasising what is meant by long-term oxygen therapy\n(LTOT) and palliative oxygen therapy (POT). The home oxygen\nguideline provides expert consensus opinion in areas where clin-\nical evidence is lacking, and seeks to deliver improved prescrib-\ning practice, leading to improved compliance and improved\npatient outcomes, with consequent increased value to the health\nservice.\nTarget audience for the guideline\nThis guideline is aimed at all healthcare practitioners who are\ninvolved in the care of patients who use home oxygen therapy:\nthis will include primary care clinicians (general practitioners\n(GPs), and practice and district nurses), those working in\ncommunity nursing or palliative care teams, integrated respira-\ntory teams, home oxygen assessment services and hospital spe-\ncialist teams in respiratory medicine, cardiology, neurology,\noncology, geratology and palliative care.\nGroups covered\nThe home oxygen guideline addresses the use of home oxygen\nin adults with\n\u25b8 chronic respiratory disease including COPD, pulmonary hyper-\ntension, pulmonary vascular disease, cystic \ufb01brosis (CF), inter-\nstitial lung disease (ILD), chest wall disease, neuromuscular\ndisease, and pulmonary malignancy\n\u25b8 cardiac disease including congestive cardiac failure and adult\ncongenital heart disease\n\u25b8 CH.\nIt will also consider special situations including:\n\u25b8 palliative and end-of-life care\n\u25b8 patients discharged from hospital pending a formal assess-\nment when stable\n\u25b8 smokers.\nScope of the guideline\nThe guideline considers the evidence base and makes recom-\nmendations for the use or restricted use of the following types\nof home oxygen therapy:\n\u25b8 long-term oxygen therapy (LTOT)\n\u25b8 nocturnal oxygen therapy (NOT)\n\u25b8 ambulatory oxygen therapy (AOT)\n\u25b8 palliative oxygen therapy (POT)\n\u25b8 short burst oxygen therapy (SBOT).\nThe guideline considers the evidence base and makes recom-\nmendations for referral, assessment (including the roles of oxim-\netry, arterial blood gases (ABGs) and capillary blood gases\n(CBGs)), and follow-up of patients for home oxygen therapy.\nThe guideline reviews the different equipment used to deliver\nhome oxygen therapy.\nFinally, the guideline reviews safety issues around home oxygen\ntherapy, in particular risks of \ufb01re, burns and smoke inhalation\nfrom \ufb02ammable sources such as smoking. It outlines the risk\nassessment processes which were put in place by the National\nFramework Agreement for home oxygen therapy (2010) which\noutlined responsibilities for home oxygen providers.\nAreas not covered by the guideline\nThe guideline development group was aware of existing BTS\nguidelines in related areas and the following areas therefore fall\noutside the scope of this guideline:\n\u25b8 home oxygen in children (younger than 18)\u2014home oxygen\nin children remains as a separate guideline.1\n\u25b8 home oxygen use during acute exacerbations of respiratory\ndisease\u2014this is covered by the BTS Guideline for Emergency\nOxygen Use in Adult Patients.2\n\u25b8 home oxygen use during air travel\u2014see the 2011 BTS guide-\nline on recommendations for managing passengers with\nstable respiratory disease planning air travel.3\nThe guideline development group were unable to cover all\ndisease groups individually, for example bronchiectasis and\nasthma among others. In these areas no disease speci\ufb01c evidence\nfor oxygen use was found.\nMethodology\nThis guideline is based on the best available evidence. The\nmethodology used to write the guideline adheres strictly to the\nHardinge M, et al. Thorax 2015;70:i1\u2013i43. doi:10.1136\/thoraxjnl-2015-206865 i5\nBTS Guidelines\ngroup.bmj.com\non June 19, 2016 - Published by\nhttp:\/\/thorax.bmj.com\/\nDownloaded from\ncriteria as set by the AGREE collaboration, which is available\nonline (http:\/\/www.agreetrust.org\/resource-centre\/agree-ii\/). The\nBTS Standards of Care Committee (SOCC) guideline produc-\ntion manual is available at http:\/\/www.brit-thoracic.org.uk\/\nguidelines-and-quality-standards\/\nClinical questions and literature search\nClinical questions were structured in the PICO (Patient,\nIntervention, Control, Outcome) format (see online supple-\nmentary appendix 9) to de\ufb01ne the scope of the guideline and\ninform the literature search.\nSystematic electronic database searches were conducted in\norder to identify potentially relevant studies for inclusion in the\nguideline. For each topic area the following databases were\nsearched: Ovid MEDLINE (including MEDLINE In-Process),\nOvid EMBASE, and the Cochrane Library (including the\nCochrane Database of Systematic Reviews and the Database of\nAbstracts of Reviews of Effects) from 1980.\nThe searches were \ufb01rst run in July 2012 and updated in\nJanuary 2014 (see online supplementary appendix 10 for the\nsearch strategy). Searches included a combination of indexed\nterms and free text terms and were limited to English language\npublications only. The initial search identi\ufb01ed 1392 potential\nabstracts and the second search 326 abstracts.\nAppraisal of the literature\nAppraisal was performed to be compliant with the AGREE col-\nlaboration. Four individuals (MH, SH, TW\n, JS) read the title\nand abstract of each article retrieved by the literature searches\nand decided whether the paper was de\ufb01nitely relevant, possibly\nrelevant or not relevant to the project. Criteria formulated for\ncategorising the abstracts into these three groups were:\n\u25b8 whether the study addressed the clinical question;\n\u25b8 whether the appropriate study type was used to produce the\nbest evidence to answer the clinical question;\n\u25b8 review articles were excluded;\n\u25b8 the abstract was in English;\n\u25b8 abstracts were not rejected on the basis of the journal of pub-\nlication, country in which the research was performed or\npublished, or the date of publication.\nThe full paper was obtained for all relevant or possibly rele-\nvant abstracts and allocated to the relevant section(s) of the\nguideline.\nThe \ufb01rst screening process identi\ufb01ed 511 of the initial 1392\nreference abstracts to be de\ufb01nitely or possibly relevant to the\nguideline. Two guideline reviewers per section independently\nreviewed the abstracts to identify papers to be appraised for the\nguideline. The two reviewers for each section then independ-\nently appraised each paper assigned to them using the Scottish\nIntercollegiate Guidelines Network (SIGN) critical appraisal\nchecklists. The reliability of the evidence in each individual\nstudy was graded using the SIGN critical appraisal check lists\nand is shown in the evidence tables (++, + or \u2212) (see online\nsupplementary appendix 11). The body of evidence for each\nrecommendation was summarised into evidence statements and\ngraded using the SIGN grading system (see table 1).\nDisagreements were resolved by discussion with the section\npartner. The second literature search in January 2014 yielded\n326 abstracts. Of these, 56 were identi\ufb01ed as de\ufb01nitely or pos-\nsibly relevant to the guideline. However, all of the pertinent\nabstracts from this search had been identi\ufb01ed by the guideline\ndevelopment group (GDG) in the meantime and already\nincorporated.\nConsidered judgement and grading of evidence\nThe GDG used the evidence tables to judge the body of evi-\ndence and grade recommendations for this guideline. Evidence\ntables are available in the online supplementary appendix 11.\nWhere evidence was lacking to answer the formulated clinical\nquestions, expert opinions were obtained through consensus.\nThe following were considered in grading of the\nrecommendations:\n\u25b8 the available volume of the body of evidence;\n\u25b8 how applicable the obtained evidence was in making recom-\nmendations for the de\ufb01ned target audience of this guideline;\n\u25b8 whether the evidence was generalisable to the target popula-\ntion for the guideline;\n\u25b8 whether there was clear consistency in the evidence obtained\nto support recommendations;\n\u25b8 what the implications of recommendations would be on clin-\nical practice in terms of resources and skilled expertise;\n\u25b8 cost-effectiveness was not reviewed in detail as in-depth eco-\nnomic analysis of recommendations falls beyond the scope of\nthis guideline.\nRecommendations were graded from A to D as indicated by the\nstrength of the evidence as shown in table 2. In line with SIGN\nguidance, evidence rated \u2018minus\u2019 was considered by the GDG in\ncontext but in the absence of other supporting evidence with a\n\u201cplus\u201d rating, any recommendation made was Grade D. Important\npractical points lacking any research evidence and not likely to be\nresearch evidence in the future, were highlighted as \u2018good practice\npoints\u2019.\nDrafting the guideline\nThe GDG corresponded regularly by email and meetings of the\nfull group were held in November 2011, February and\nNovember 2012, and March, April and September 2013 in add-\nition to a number of teleconferences. The BTS SOCC reviewed\nthe draft guideline in March 2014. The draft guideline was\nmade available online in July\/August 2014 for public consult-\nation and circulated to all the relevant stakeholders. The BTS\nSOCC re-reviewed the revised draft guideline in December\n2014 and \ufb01nal SOCC approval was granted in January 2015.\nThis BTS guideline will be reviewed within the next 5 years.\nTable 1 Key to evidence statements\nGrade Evidence\n1++ High quality meta-analyses, systematic reviews of RCTs, or RCTs with a\nvery low risk of bias\n1+ Well conducted meta-analyses, systematic reviews of RCTs, or RCTs\nwith a low risk of bias\n1\u2212 Meta-analyses, systematic reviews of RCTs, or RCTs with a high risk of\nbias\n2++ High quality systematic reviews of case\u2013control or cohort studies or\nhigh quality case\u2013control or cohort studies with a very low risk of\nconfounding, bias or chance and a high probability that the relationship\nis causal\n2+ Well conducted case\u2013control or cohort studies with a low risk of\nconfounding, bias or chance and a moderate probability that the\nrelationship is causal\n2\u2212 Case\u2013control or cohort studies with a high risk of confounding, bias or\nchance and a significant risk that the relationship is not causal\n3 Non-analytic studies, for example case reports, case series\n4 Expert opinion\nRCT, randomised control trial.\ni6 Hardinge M, et al. Thorax 2015;70:i1\u2013i43. doi:10.1136\/thoraxjnl-2015-206865\nBTS Guidelines\ngroup.bmj.com\non June 19, 2016 - Published by\nhttp:\/\/thorax.bmj.com\/\nDownloaded from\nDeclarations of interest\nAll members of the GDG made declarations of interest in line\nwith BTS policy and further details can be obtained on request\nfrom BTS. GDG members are listed in appendix 8.\nAcknowledgements\nThe guideline development group members are grateful to:\n\u25b8 Wirral NHS home oxygen assessment service for the\nexample of a Home Oxygen Risk Assessment form (see\nappendix 4);\n\u25b8 Oxford Health Foundation Trust home oxygen assessment\nservice for an example of an Ambulatory Oxygen Assessment\non which appendix 1 is based;\n\u25b8 The British Lung Foundation for patient information lea\ufb02ets\nreferred to in appendix 6;\n\u25b8 Barema (the Association for Anaesthetic and Respiratory\nDevice Suppliers) and BOC Healthcare for the photographs\nof home oxygen equipment used to illustrate online supple-\nmentary appendix 12.\nAudit and research recommendations\n1. Research to investigate which patients with particular disease\nphenotypes bene\ufb01t from LTOT: for example smokers com-\npared with ex-smokers, those with pulmonary hypertension,\nthose with COPD-driven cachexia and frequent exacerbators.\n2. Research to investigate long-term outcomes (survival) in dis-\neases other than COPD such as CF, ILD and bronchiectasis.\n3. Research to investigate delivery of oxygen during pulmonary\nrehabilitation and maintenance classes, assessing impact on\noutcomes such as exacerbations, exercise tolerance and\nquality of life.\n4. Longitudinal studies to assess the impact of LTOT on pul-\nmonary haemodynamics in COPD patients with pulmonary\nhypertension using both direct (eg, cardiac catheterisation)\nand indirect (eg, NT-proBNP\n, echocardiography) parameters,\nalong with quality of life and exercise tolerance outcomes.\n5. A robust assessment of risk assessment measures with the\naim of developing an integrated pathway for home oxygen\nteams and oxygen provider services to manage patients who\nsmoke.\n6. Research to investigate the role of palliative oxygen in com-\nparison with or used together with other measures such as\nopiates, fan therapy and cognitive behavioural therapy.\n7. Research to investigate and compare the use of ABG and\nCBG in predicting need for LTOT and risk of hypercapnia.\n8. Audit of assessment, ordering for and follow-up of home\noxygen patients to improve and maintain standards of care\nfrom home oxygen assessment teams.\nTable 2 Grades of recommendations\nGrade Type of evidence\nA At least one meta-analysis, systematic review or RCT rated as 1++ and\ndirectly applicable to the target population or\nA systematic review of RCTs or a body of evidence consisting principally\nof studies rated as 1+ directly applicable to the target population and\ndemonstrating overall consistency of results\nB A body of evidence including studies rated as 2++ directly applicable to\nthe target population and demonstrating overall consistency of results\nor\nExtrapolated evidence from studies rated as 1++ or 1+\nC A body of evidence including studies rated as 2+ directly applicable to\nthe target population and demonstrating overall consistency of results\nor\nExtrapolated evidence from studies rated as 2++\nD Evidence level 3 or 4 or\nExtrapolated evidence from studies rated as 2+\n\u221a Important practical points for which there is no research evidence, nor\nis there likely to be any research evidence. The guideline committee\nwishes to emphasise these as Good Practice Points.\nRCT, randomised control trial.\nGlossary\/Abbreviations and symbols\nAbbreviations\nABG Arterial blood gas\nAHI Apnoea hypopnoea index\nAOT Ambulatory oxygen therapy\nASV Adaptive servo ventilation\nBIPAP Bi-level positive airway pressure\nBTS British Thoracic Society\nCBG Capillary blood gas\nCCF Congestive cardiac failure\nCCH Chronic cluster headache\nCF Cystic fibrosis\nCH Cluster headache\nCO Carbon monoxide\nCO2 Carbon dioxide\nCOPD Chronic obstructive pulmonary disease\nCPAP Continuous positive airway pressure\nCRQ Chronic respiratory disease questionnaire\nCSA Central sleep apnoea\nCSB Cheyne-stokes breathing\nECH Episodic cluster headache\nECOG PS Eastern Cooperative Oncology Group Performance Status\nEEG Electroencephalography\nELBG Earlobe blood gas\nESS Epworth sleepiness scale\nFiO2 Fraction of inspired oxygen\nGDG Guideline development group\nGP General practitioner\nH Hypoxaemia\nHAD Hospital anxiety and depression scale\nHb Haemoglobin\nHO Home oxygen\nHOOF Home oxygen order form\nHOS-AR Home oxygen service \u2013 assessment and review\nIPAH Idiopathic Pulmonary Arterial Hypertension\nIOT Intermittent oxygen therapy\nILD Interstitial lung disease\nkPa kilo Pascal (unit of measurement of pressure) 1kPa= 7.5mmHg\nL\/min Litres per minute (unit of measure of flow rate of oxygen)\nLTOT Long term oxygen therapy\nLVEF Left ventricular ejection fraction\nm Meter (unit of measurement of length)\nmmHg millimetres of mercury (unit of measurement of pressure)\nMMSE Mini mental state examination\nMQoLQ Migraine quality of life questionnaire\nMRC Medical Research Council\nNH Non hypoxaemic\nNHYA New York Heart Association\nNIV Non-invasive ventilation\nNIPPV Non-invasive positive pressure ventilation\nNOT Nocturnal oxygen therapy\nNRS Numeric rating scale\nHardinge M, et al. Thorax 2015;70:i1\u2013i43. doi:10.1136\/thoraxjnl-2015-206865 i7\nBTS Guidelines\ngroup.bmj.com\non June 19, 2016 - Published by\nhttp:\/\/thorax.bmj.com\/\nDownloaded from\nPartial pressure units of measurement and conversion\nbetween them\n\u25b8 Partial pressures of oxygen and carbon dioxide are measured\nusing kilopascals (kPa) and millimetres of mercury (mm Hg)\nwhere:\n\u25b8 1 kPa=7.5 mm Hg, and 1 mm Hg=0.133 kPa.\nLONG-TERM OXYGEN THERAPY\nLTOT can be de\ufb01ned as oxygen used for at least 15 h per day in\nchronically hypoxaemic patients. Chronic hypoxaemia is\nde\ufb01ned as a PaO2 \u22647.3 kPa or, in certain clinical situations,\nPaO2 \u22648.0 kPa. LTOT is delivered via an oxygen concentrator\nand should be differentiated from the use of oxygen as a pallia-\ntive measure for symptomatic relief in breathless patients, which\nwill be discussed in the palliative oxygen therapy section. LTOT\naddresses speci\ufb01c physiological inclusion criteria as outlined\nbelow.\nEvidence for use of LTOT in patients with COPD\nSurvival bene\ufb01t in COPD patients with LTOT\nTwo landmark randomised controlled trials (RCTs) showed sur-\nvival bene\ufb01t of LTOT in patients with COPD and severe chronic\nhypoxaemia when used for at least 15 h daily.\nThe Nocturnal Oxygen Therapy Trial (NOTT) was the \ufb01rst\nRCT of LTOT in patients with COPD.4\nIt included 203 patients\nwith COPD in six US centres with PaO2 \u22647.33 kPa (55 mm Hg),\nor PaO2 <7.87 kPa (59 mm Hg) with a raised haematocrit, signs\nof right heart failure or P pulmonale. It compared the effects of\n12 h nocturnal oxygen (n=102) therapy with continuous oxygen\n(24 h; n=101) therapy on mortality, pulmonary haemodynamics\nand exercise capacity at 12 months. The treatment groups were\nwell matched. There was 1.94 times the mortality in the NOT\ngroup compared to the continuous oxygen therapy group. This\nsurvival bene\ufb01t was present in relatively normocapnic patients,\nand in those without a raised pulmonary arterial pressure (PAP)\nbut was more pronounced in patients with hypercapnia, severe\nair\ufb02ow limitation, lower oxygen saturations and in those with\nneuropsychological impairment. There was also a correlation\nbetween the mean reduction in PAP in the \ufb01rst 6 months of LTOT\nand survival at 8-year follow-up.\nThe UK MRC (Medical Research Council) domiciliary oxygen\ntrial studied 87 patients with chronic bronchitis and emphysema\nwho were hypoxaemic (PaO2 5.3\u20138.0 kPa), who were mostly\nhypercapnic and who had a previous documented episode of\noedema indicating cor pulmonale. Patients were randomised to\nno oxygen therapy or 15 h\/day at an inspired oxygen concentra-\ntion to achieve a PaO2 >8 kPa.5\nOver a 5-year follow-up period\nin the MRC trial, 19\/42 died in the LTOT (treatment) group\ncompared with 30\/45 in the control (no oxygen) group.\nSubsequent studies have con\ufb01rmed a survival bene\ufb01t of LTOT\nwhen given for at least 15 h\/day in the presence of chronic hyp-\noxaemia, irrespective of chronic hypercapnia or previous epi-\nsodes of oedema or pulmonary hypertension.6\u20138\nThis survival\nbene\ufb01t was not seen in patients with moderate hypoxaemia. No\nsigni\ufb01cant differences were found in survival rates between\npatients treated with LTOT and controls in a population of 135\npatients with advanced air\ufb02ow limitation (mean (SD) FEV1 0.83\n(0.28) L) and moderate hypoxaemia (PaO2 7.4\u20138.7 kPa, 56\u201365\nmm Hg) followed up for at least 3 years or until death.9\nWomen\nhave a worse prognosis on LTOT than men.10\nMost patients\ntreated with LTOT die as a result of respiratory failure.11\nNutritional depletion is an independent risk factor for mortality\nand hospitalisation in patients with COPD receiving LTOT.12\nEvidence for blood gas criteria for selection of\nCOPD patients for LTOT\nCriteria for ordering LTOT and ABG parameters derive from\nthe two previously described landmark RCTs.4 5\nThe NOTT\ntrial included COPD patients with PaO2 \u22647.33 kPa\n(\u226455 mm Hg) or PaO2 \u22648 kPa (60 mm Hg) with a raised haem-\natocrit, signs of right heart failure or P pulmonale on electrocar-\ndiogram.4\nThe UK MRC domiciliary oxygen trial studied\noutcomes in patients with chronic bronchitis and emphysema\nwho were hypoxaemic (PaO2 5.3\u20138 kPa), mostly hypercapnic\nand who had a previous documented episode of oedema indi-\ncating cor pulmonale.5\nLTOT in hypercapnic COPD patients\nFew RCTs have directly studied the impact of providing oxygen\nby comparing a priori hypercapnic and normocapnic patients\nwith COPD. In the MRC trial, an analysis of predictors of mor-\ntality demonstrated that raised red cell mass and baseline PaCO2\nwere predictors of mortality in both the treatment and placebo\narms.5\nLongitudinal analysis demonstrated that a rising PaCO2\nand falling PaO2 were associated with poor outcomes in both\narms. The authors concluded that there was no evidence of\noxygen toxicity with this treatment regimen. In contrast, a study\nof 228 patients given an oxygen concentrator who were fol-\nlowed up for a maximum of 5 years, and analysed in three\nOHS Obesity Hypoventilation Syndrome\nOT Oxygen therapy\nOSA Obstructive sleep apnoea\nO2 Oxygen\nPAP Pulmonary artery pressure\nPCO2 Carbon dioxide tension (partial pressure) in blood or alveolus\nPaCO2 Arterial carbon dioxide tension (partial pressure)\nPaO2 Arterial oxygen tension (partial pressure)\nPO2 Oxygen tension (partial pressure) in blood or alveolus\nPCU Palliative care unit\nPICO Patient Intervention Control Outcome\nPOT Palliative oxygen therapy\nPPH Primary pulmonary hypertension\npH Unit of measurement of acidity of blood\nQoL Quality of life\nREM Rapid eye movement stage of sleep\nSBOT Short burst oxygen therapy\nSD Standard deviation\nSDB Sleep disorder breathing\nSF-A Validated sleep quality questionnaire\nSF 36 Short form (36) health questionnaire\nSIGN Scottish Intercollegiate Guideline Network\nSaO2 Arterial oxygen saturation measured by arterial blood gas\nco-oximetry\nSpO2 Arterial oxygen saturation measured by pulse oximetry\nSOCC British Thoracic Society Standards of Care Committee\nVAS Visual analogue scale\nVE Minute ventilation\n6MWT 6 minute walk test\nSymbols\n> Greater than or above\n\u2264 Less than or below\n> Greater than or equal to\n\u2264 Less than or equal to\n% Percent\ni8 Hardinge M, et al. Thorax 2015;70:i1\u2013i43. doi:10.1136\/thoraxjnl-2015-206865\nBTS Guidelines\ngroup.bmj.com\non June 19, 2016 - Published by\nhttp:\/\/thorax.bmj.com\/\nDownloaded from\ngroups (n=55, no use of oxygen; n=112, use for <15 h per\nday; and n=61, use for >15 h per day) showed that median sur-\nvival at 2 years was better in the groups receiving oxygen com-\npared to the no use group.8\nBaseline PaCO2 was not shown to\nbe a predictor of mortality and did not predict differences in\nmortality between the groups. However, the NOTT trial\nshowed the survival bene\ufb01t in the treatment groups was more\napparent in patients with hypercapnia.4\nThe effect of supplementary oxygen on the chemical control\nof ventilation has the potential to increase CO2 levels in patients\nreceiving 24 h\/day oxygen. Fleetham et al13\nstudied 30 hypox-\naemic COPD patients (mean PaO2 6.9 kPa) who were rando-\nmised to 12 or 24 h oxygen therapy for 12 months. Patients\ngiven 24 h oxygen had a blunted CO2 response. There was no\nchange in the hypoxaemic response in either group.\nEffects of LTOT on pulmonary haemodynamics in COPD patients\nThe effect of LTOT on PAP are small. In the NOTT trial, sur-\nvival after 8 years was related to the decrease in mean PAP\nduring the \ufb01rst 6 months of treatment.14\nThis subgroup analysis\nalso showed improvement in PAP and stroke volume in patients\nwith 24 h of oxygen therapy per day compared to those given\nonly 12 h of oxygen per day. In the MRC trial, LTOT prevented\na rise in PAP of 0.4 kPa (3 mm Hg), seen in the control group,\nalthough a fall in PAP was not found.5\nA small intervention\nstudy measured PAP and left ventricular ejection fraction (LVEF)\nbefore and after 6 months of LTOT and showed a signi\ufb01cant fall\nin mean PAP\n.15\nEffects of LTOT on sleep in COPD patients\nPatients with COPD can develop nocturnal hypoxaemia due to\nventilation\u2013perfusion mismatch, decreased functional capacity\nand nocturnal hypoventilation particularly pronounced during\nREM sleep. This in turn can lead to poor sleep quality with\nsleep fragmentation. Use of LTOT has been demonstrated to\ncorrect nocturnal SaO2, decrease sleep latency and improve\nsleep quality evaluated by EEG.16\nEffects of LTOT on quality of life and neuropsychological\nfunction in COPD patients\nHealth-related quality of life is impaired in patients with COPD.\nIn one study, the administration of LTOT showed no bene\ufb01cial\neffects on quality of life compared to patients not ful\ufb01lling cri-\nteria for LTOT.17\nIn the NOTT study, minor improvements in\nneuropsychological function were achieved after 12 months of\nLTOT compared to NOT.18\nThere was only modest improve-\nment in neuropsychological scores after 6 months of treatment.\nAn observational study has shown improvement in mood after\n1 year of treatment with LTOT.19\nHowever, psychological\nchanges due to LTOT are dif\ufb01cult to separate from the effects of\nother therapies.\nLTOT in COPD patients and impact upon hospital admissions\nLack of provision of LTOT to hypoxaemic COPD patients with\nPaO2 <7.3 kPa is an independent risk factor for hospital admis-\nsion with a COPD exacerbation.20\nConversely, use of LTOT in\nmoderately hypoxaemic patients (PaO2 7.3\u20139.5 kPa) does not\nsigni\ufb01cantly reduce hospital admission rates or bed days when\ncomparing a 10-month period before and after LTOT treat-\nment.21\nThe MRC trial did not \ufb01nd any impact on hospitalisa-\ntion from treatment with LTOT.5\nOther effects of LTOT in COPD patients\nA further bene\ufb01t of LTOT may be in the improvement of renal\nblood \ufb02ow, reducing activation of the renin angiotensin system\nand thus salt and water retention. However, one study of LTOT\nshowed no overall bene\ufb01t on renal function after 6 months of\ntreatment.22\nSupplemental oxygen therapy reduces secondary polycythae-\nmia, as seen by a fall in haematocrit and red cell mass.5\nA study\nin COPD patients showed that LTOT patients with a low haem-\natocrit have worse survival than patients with high haematocrits\n(>0.55).23\nEvidence statements\n\u25b8 Patients whose clinical condition is stable with a resting PaO2\n\u22647.3 kPa have improved life expectancy when treated with\nLTOT for at least 15 h\/day. Evidence level 1+\n\u25b8 Patients with stable COPD and a resting PaO2 \u22648.0 kPa with\nevidence of cor pulmonale, polycythaemia and\/or pulmonary\nhypertension have improved outcomes with LTOT. Evidence\nlevel 1+\n\u25b8 Use of continuous oxygen therapy (24 h) offers additional\nsurvival bene\ufb01t compared to shorter durations (12\u201315 h) but\ncan contribute to higher PaCO2 levels. Evidence level 1\u2212\n\u25b8 Use of LTOT in hypercapnic respiratory patients with COPD\ndoes not lead to increased morbidity, mortality or healthcare\nutilisation. Evidence level 1+\nRecommendations\n\u25b8 Patients with stable COPD and a resting PaO2 \u22647.3 kPa\nshould be assessed for LTOT, which offers survival bene\ufb01t\nand improves pulmonary haemodynamics. (Grade A)\n\u25b8 LTOT should be ordered for patients with stable COPD with\na resting PaO2 \u22648 kPa with evidence of peripheral oedema,\npolycythaemia (haematocrit \u226555%) or pulmonary hyperten-\nsion. (Grade A)\n\u25b8 LTOT should be ordered for patients with resting hypercap-\nnia if they ful\ufb01l all other criteria for LTOT. (Grade B)\nEvidence for use of LTOT in patients with other respiratory\nor cardiac disease\nLTOT in patient with ILD\nChronic hypoxaemia can occur in patients with severe ILD. As\nwith other progressive respiratory conditions, the development of\nprogressive hypoxaemia may lead to poor tissue oxygenation and\nthe development of complications such as pulmonary hyperten-\nsion. This in turn can worsen prognosis. However, there are no\nRCTs reporting the effects of use of LTOT in these disorders.\nTherefore, recommendations for use are extrapolated from evi-\ndence in COPD patients. In clinical practice, patients with severe\nbreathlessness due to ILD may hyperventilate to maintain oxygen\nsaturations, and often desaturate abruptly on minimal exertion.\nClinical management varies, with some centres measuring oxygen\nsaturation over a 24 h period to assess \u2018hypoxaemic burden\u2019 and\nprescribing home oxygen accordingly. There is at present no evi-\ndence to support home oxygen provision on this basis.\nEvidence statement\n\u25b8 The use of LTOT in patients with ILD may improve survival\nand tissue oxygenation, and prevent complications associated\nwith hypoxaemia such as worsening pulmonary hyperten-\nsion. Evidence level 4\nRecommendations\n\u25b8 LTOT should be ordered for patients with ILD with a resting\nPaO2 \u22647.3 kPa. (Grade D)\n\u25b8 LTOT should be ordered for patients with ILD with a resting\nPaO2 \u22648 kPa in the presence of peripheral oedema,\nHardinge M, et al. Thorax 2015;70:i1\u2013i43. doi:10.1136\/thoraxjnl-2015-206865 i9\nBTS Guidelines\ngroup.bmj.com\non June 19, 2016 - Published by\nhttp:\/\/thorax.bmj.com\/\nDownloaded from\npolycythaemia (haematocrit \u226555%) or evidence of pulmon-\nary hypertension. (Grade D)\nGood practice point\n\u25b8 Patients with ILD who experience severe breathlessness could\nbe considered for POT. (\u221a)\nLTOT in patients with CF\nPatients with CF may develop chronic hypoxaemia with increas-\ning severity of their disease. A Cochrane review examined 11\npublished studies of oxygen therapy in CF but no studies exam-\nined the use of LTOT.24\nRecommendations for use are extrapo-\nlated from evidence in COPD patients.\nEvidence statement\n\u25b8 The use of LTOT in patients with CF may improve survival\nand tissue oxygenation, and prevent complications associated\nwith hypoxaemia such as worsening pulmonary hyperten-\nsion. Evidence level 4\nRecommendations\n\u25b8 LTOT should be ordered for patients with CF with a resting\nPaO2 \u22647.3 kPa. (Grade D)\n\u25b8 LTOT should be ordered for patients with CF with a resting\nPaO2 \u22648 kPa in the presence of peripheral oedema, polycy-\nthaemia (haematocrit \u226555%) or evidence of pulmonary\nhypertension. (Grade D)\nLTOT in patients with pulmonary hypertension\nPulmonary hypertension may occur in a number of pulmonary\nvascular disorders such as idiopathic pulmonary arterial hyper-\ntension (IPAH), pulmonary arterial hypertension associated with\nportal hypertension, pulmonary arterial hypertension associated\nwith connective tissues disease, drug-induced thromboembolism,\npulmonary arterial hypertension and chronic thromboembolic\npulmonary hypertension (CTEPH), which can all predispose to\nhypoxaemia. There is no evidence of the effectiveness of LTOT\nin RCTs in patients with pulmonary hypertension, with the\nexception of those patients who develop pulmonary hyperten-\nsion as a complication of their COPD. Thus, use of LTOT in\nnon-COPD patients with pulmonary hypertension is to improve\ntissue oxygenation and to prevent complications associated with\nhypoxaemia, such as worsening pulmonary hypertension, rather\nthan to afford a speci\ufb01c survival bene\ufb01t.\nEvidence statement\n\u25b8 The use of LTOT in patients with pulmonary hypertension\nmay improve tissue oxygenation and prevent complications\nassociated with hypoxaemia rather than lead to a speci\ufb01c sur-\nvival bene\ufb01t. Evidence level 4\nRecommendation\n\u25b8 LTOT should be ordered for patients with pulmonary hyper-\ntension, including idiopathic pulmonary hypertension, when\nthe PaO2 is \u22648 kPa. (Grade D)\nLTOT in patients with neuromuscular or chest wall disorders\nPatients with chest wall disease (kyphoscoliosis, thoracoplasty)\nand neuromuscular disorders develop nocturnal hypoventila-\ntion, which causes nocturnal hypoxaemia and leads to chronic\nrespiratory failure. Non-invasive ventilation (NIV) is the\ntreatment of choice in these patients, although LTOT may be\nrequired additionally, particularly in patients with severe restrict-\nive disease or where there is co-existing airways disease or\nobesity causing hypoxaemia which NIV alone does not correct\n(although there are no studies of this approach).\nEvidence statement\n\u25b8 LTOT can be used in addition to NIV in patients with neuro-\nmuscular or chest wall disorders, particularly where there is\nco-existing airways disease or obesity causing hypoxaemia\nwhich NIV alone does not correct. Evidence level 4\nRecommendation\n\u25b8 NIV should be the treatment of choice for patients with\nchest wall or neuromuscular disease causing type 2 respira-\ntory failure. Additional LTOT may be required in case of\nhypoxaemia not corrected with NIV\n. (Grade D)\nLTOT in patients with advanced cardiac failure\nSome patients with advanced cardiac failure may have resting hyp-\noxaemia although hypoxaemia is most consistently demonstrated\nduring sleep in these patients. There are studies of NOT in patients\nwith heart failure (see the section on nocturnal oxygen therapy)\nbut no studies of the effects of LTOT in patients with chronic\nheart failure. The use of LTOT in patients with advanced cardiac\nfailure and resting hypoxaemia may lead to improved tissue oxy-\ngenation and prevent complications associated with hypoxaemia\nsuch as worsening pulmonary hypertension.\nEvidence statement\n\u25b8 The use of LTOT in patients with advanced cardiac failure\nand resting hypoxaemia may improve survival, tissue oxygen-\nation and prevent complications associated with hypoxaemia.\nEvidence level 4\nRecommendations\n\u25b8 LTOT should be ordered for patients with advanced cardiac\nfailure with a resting PaO2 \u22647.3 kPa. (Grade D)\n\u25b8 LTOT should be ordered for patients with advanced cardiac\nfailure with a resting PaO2 \u22648 kPa in the presence of periph-\neral oedema, polycythaemia (haematocrit \u226555%) or evidence\nof pulmonary hypertension on ECG or echocardiograph.\n(Grade D)\nOutcomes of LTOT in patients who continue to smoke\nAccurate reports of individual smoking status can be dif\ufb01cult to\nobtain reliably in clinical practice. All trial data around smoking\ncome from trials conducted with COPD patients.25\nUnfortunately, the small numbers of patients included in the\nmain RCTs is not optimal in discriminating between the impact\nof LTOT on smokers and non-smokers.4 5\nThere are no rando-\nmised or cohort studies investigating LTOT according to\nsmoking status.\nCigarette smoking predisposes to secondary polycythaemia,\naccelerated decline in lung function and increased mortality in\nCOPD. Thus, the bene\ufb01cial effect of LTOT may be offset by\nraised carboxyhaemoglobin levels from continued cigarette\nsmoking.26\nThe MRC study did not exclude smokers but did\n\u2018urge all patients to give up smoking\u2019.5\nIn the LTOT group,\n52% of the patients were smokers (reduced to 44% at the end\nof the study). There were no recorded adverse events attribut-\nable to smoking in the MRC trial. There was an overall survival\nbene\ufb01t in patients given oxygen (bene\ufb01ts in smoking and non-\nsmoking populations were not reported separately).\nThe signi\ufb01cant risk associated with combining cigarette\nsmoking and oxygen therapy is reviewed in a later safety section\nof the guideline.\nEvidence statement\n\u25b8 Evidence is insuf\ufb01cient to determine adverse clinical out-\ncomes related to the effect of continuing smoking in LTOT\npatients compared to non-smokers. Evidence level 2+\ni10 Hardinge M, et al. Thorax 2015;70:i1\u2013i43. doi:10.1136\/thoraxjnl-2015-206865\nBTS Guidelines\ngroup.bmj.com\non June 19, 2016 - Published by\nhttp:\/\/thorax.bmj.com\/\nDownloaded from\nRecommendation\n\u25b8 If LTOT is ordered for patients who are continuing to\nsmoke, the potential for more limited clinical bene\ufb01t should\nbe discussed with the patient. (Grade D)\nReferral and assessment of patients for LTOT\nReferral to home oxygen assessment services provides the\nappropriate means for patients to be assessed for home oxygen\ntherapy. Patients should have a de\ufb01nite diagnosis and be medic-\nally optimised prior to referral for assessment by an oxygen\nservice. These services should have the appropriate clinical\nexpertise, equipment and access to appropriate support services\nto enable the patient to have the best available care and out-\ncomes, with the best use of resources. Guidance for commis-\nsioners in England and Wales has been published.27\nPatient information on referral for home oxygen assessment\nIn order to support a patient in understanding the implications of\nattending an assessment for home oxygen therapy, information is\noften given (whether verbal or written) at the time of referral.\nFailing to attend for initial assessment or reassessment could result\nin suboptimal treatment, poor clinical outcomes and wasted\nresources. There is a lack of published trial data on the impact of\nproviding information on LTOT to patients in any format.\nEvidence statement\n\u25b8 Provision of written and verbal information to patients at the\npoint of referral to home oxygen assessment services can\nimprove attendance at \ufb01rst referral. Evidence level 4\nRecommendation\n\u25b8 Written and verbal information should be given to patients\nreferred to home oxygen assessment services at the time of\nreferral. (Grade D)\nUse of oximetry as a screening tool for patient selection for LTOT\nMeasurement of oxygen saturation using a pulse oximeter is\nwidely available and presents a possible tool to be used for screen-\ning patients who might be candidates for LTOT. Studies have\nexamined the use of an SpO2 value of \u226492% as a cut-off point at\nwhich patients will be deemed suitable for referral to an oxygen\nassessment service because of known evidence around ABG cri-\nteria for LTOT. Roberts et al28\nstudied use of SpO2 levels alone or\nin combination with FEV1 in 113 COPD patients referred for\nLTOT, and showed that using an SpO2 level of \u226492% resulted in\n100% sensitivity but a speci\ufb01city of only 69% in identifying\npatients with a PaO2 <7.3 kPa. There was a particularly poor cor-\nrelation between SpO2 values between 85% and 90% and ABGs.\nA study using pulse oximetry in screening patients in general prac-\ntice for LTOT assessed 13 of 114 patients with a resting SpO2 of\n\u226492% and found three patients had a resting PaO2 <7.3 kPa.29\nWhen Medicare guidelines for oxygen assessments were validated,\nan SpO2 level of 85% was found to still miss patients who would\nhave required an oxygen assessment, but did demonstrate that at\nthis level an oxygen assessment was not necessary for a large pro-\nportion of patients.30\nEvidence statement\n\u25b8 An oxygen saturation (SpO2) level of \u226492% can be used\nsafely to identify patients for referral for LTOT. Evidence\nlevel 2+\nRecommendation\n\u25b8 Patients with a resting stable oxygen saturation (SpO2) of\n\u2264 92% should be referred for a blood gas assessment in\norder to assess eligibility for LTOT. (Grade C)\nGood practice point\n\u25b8 In patients with clinical evidence of peripheral oedema, polycy-\nthaemia (haematocrit \u226555%) or pulmonary hypertension,\nreferral for LTOTassessment may be considered at SpO2 levels\n\u226494% to identify patients with a resting PaO2 \u22648 kPa. (\u221a)\nReferral for home oxygen at hospital discharge\nIt is recognised that an exacerbation of a cardiorespiratory con-\ndition may result in temporary worsening of hypoxaemia which\nmay improve over time with recovery. However, the time course\nof recovery may be variable and undertaking an assessment for\nhome oxygen prior to optimal treatment and recovery could\nresult in the overprescribing of home oxygen and unnecessary\nrepeated assessments for the patient. However, clinicians are fre-\nquently faced with the practical dif\ufb01culty of managing patients\nwho, having been treated with oxygen during the acute phase of\ntheir illness, feel they require oxygen in order to be discharged\nsafely home. These patients are either normoxaemic at rest or\nremain hypoxaemic at the point of hospital discharge.\nSeveral studies have looked at the timing of assessment for\nLTOT. In an RCT of 546 COPD patients allowing for a 2-month\nperiod of clinical stability rather than prescribing LTOT immedi-\nately after exacerbation, resulted in a 36% absolute difference in\nthose given LTOT at 2 months, with about a 15% difference at\n1 year.31\nThere was no signi\ufb01cant difference in quality of life,\nmortality or use of community health resources between the\ntwo groups at 1 year. A subgroup analysis of the NOTT trial\nshowed that 184\/409 (45%) patients in what was thought to be\na clinically stable group on trial entry, subsequently improved\ntheir PaO2 to levels which excluded them from the trial after at\nleast a 4-week follow-up period.32\nObservational studies of\nhome oxygen patients (the majority having COPD) who were\nsupplied with LTOT from hospital discharge or during a period\nof clinical instability found that 30\u201358% of patients reassessed\n1\u20133 months later no longer met the criteria for LTOT.33\u201335\nIn a\nstudy in which ABGs were measured monthly in 77 COPD\npatients following hospitalisation, improvements in levels of\nhypoxaemia were seen at each time point, with 30% of patients\nno longer meeting the criteria for LTOT at 4 months.36\nLater\nwithdrawal of LTOT if no longer required can lead to patient\ndistress, and be challenging for staff to manage.37\nNo studies have de\ufb01ned criteria for safe discharge home from\nhospital without home oxygen pending a formal LTOTassessment.\nEvidence statement\n\u25b8 Patients referred for LTOT assessment after an exacerbation\nof COPD can show improvement in hypoxaemia with recov-\nery above the threshold for LTOT after an 8-week period.\nEvidence level 1+\nRecommendation\n\u25b8 Patients should undergo formal assessment for LTOT after a\nperiod of stability of at least 8 weeks from their last exacerba-\ntion. (Grade B)\nGood practice points\n\u25b8 Patients who have borderline saturations (ie, 93\u201394%)\nshould have their oxygen saturations monitored at their\nannual review with their GP or practice nurse, or sooner if\nthey experience an exacerbation in the interim. (\u221a)\n\u25b8 Patients who exacerbate frequently and are unable to achieve\na period of stability lasting 8 weeks may need to be assessed\nat an earlier stage after exacerbation. If LTOT is ordered for\nsuch patients, they should be counselled that in the future\nLTOT may no longer be required once they achieve a more\nstable state. (\u221a)\nHardinge M, et al. Thorax 2015;70:i1\u2013i43. doi:10.1136\/thoraxjnl-2015-206865 i11\nBTS Guidelines\ngroup.bmj.com\non June 19, 2016 - Published by\nhttp:\/\/thorax.bmj.com\/\nDownloaded from\n\u25b8 Patients should not normally have LTOT ordered at the time\nof an acute exacerbation of their underlying condition.\nHowever, if home oxygen is ordered (eg, at hospital dis-\ncharge), it should be limited to patients with an SpO2 of\n\u226492%, who are breathless and unable to manage off oxygen.\nThese patients should undergo a blood gases assessment and\nbe counselled that in the future LTOT may not be required\nafter formal reassessment. (\u221a)\n\u25b8 The date of the patient\u2019s last exacerbation should be included in\nthe referral request to the home oxygen assessment service. (\u221a)\nUse of pulse oximetry, ABGs and CBGs in assessment for LTOT\nAssessment using pulse oximetry alone\nMeasurement of oxygen saturations (SaO2) provides informa-\ntion on the percentage of available haemoglobin that is com-\nbined with oxygen (ie, oxyhaemoglobin). The relationship\nbetween oxygen saturations and the PO2 in blood (PaO2) is\ndescribed by the oxyhaemoglobin dissociation curve. This curve\nis very steep once PaO2 falls below 8 kPa (60 mm Hg) and thus\nsmall changes in PaO2 can greatly change oxygen saturations\u2014\nthis characteristic allows the use of SaO2 to give estimates of\nPaO2 in hypoxaemic patients.\nWhereas SaO2 is measured directly from blood using\nCO-oximetry, pulse oximetry (SpO2) measures oxygen saturations\nindirectly by comparing the absorbance of transmitted light before\nand during arterial pulsation at external sites such as earlobes or\n\ufb01ngertips. This non-invasive tool carries a number of advantages\nas SpO2 can be measured rapidly with portable equipment by staff\nwho are not necessarily skilled in arterial puncture. Conversely,\nthe ability of SaO2 and SpO2 to estimate PaO2 is in\ufb02uenced by\nchanges in the oxygen dissociation curve (eg, due to the presence\nof acidosis or changes in temperature), while oximetry alone\ncannot detect hypercapnia or acidosis.\nSeveral studies have examined the use of pulse oximetry alone\nto determine LTOT requirement. In the largest study, 846 stable\npatients with chronic lung disease (74.2% COPD) underwent\nLTOTassessment using both SaO2 (measured following ABG sam-\npling) and SpO2 measurements.38\nSpO2 overestimated SaO2 in the\npresence of hypercapnia (PaCO2 >6.4 kPa, 48 mm Hg), while\nagreement between SpO2 and SaO2 was also poor under hypoxae-\nmic conditions (PaO2 <7.2 kPa, 54 mm Hg). A smaller study of\n55 stable patients with chronic lung disease and a resting PaO2\n<8.65 kPa measured both PaO2 and SpO2 simultaneously on air\nat rest.30\nUsing SpO2 <88% as a threshold for prescribing LTOT\nwould have led to 24\u201357% being denied LTOT and 7\u201321% being\ntreated inappropriately, depending upon which brand of oximeter\nwas used. Similar \ufb01ndings were reported from a study of 100\npatients undergoing LTOT assessment, where using SpO2 alone\nwith a <88% threshold would have led to 56% of patients being\ninappropriately denied LTOT.35\nNo patient would have had LTOT\nordered unnecessarily.\nEvidence statement\n\u25b8 Pulse oximetry (SpO2) agrees poorly with ABG CO-oximetry\n(SaO2) and arterial oxygen tension (PaO2) and cannot be\nused alone to assess the need for LTOT. Evidence level 3\nRecommendation\n\u25b8 Patients potentially requiring LTOT should not be assessed\nusing pulse oximetry alone. (Grade D)\nABG and CBG\nABG sampling, performed via radial artery puncture, allows\nPaO2, PaCO2 and pH to be measured directly from arterial\nblood. Evidence for using ABGs to select patients for LTOT\ncomes from previously reviewed trials.4 5 36\nIn the NOTT trial,\nsubjects underwent ABG sampling on two occasions more than\n1 week apart during a 3-week observation period and were only\nrecruited if they ful\ufb01lled the criteria of resting PaO2 \u22647.33 kPa\n(55 mm Hg) or PaO2 \u22647.86 kPa (59 mm Hg) in the presence of\none of oedema, haematocrit \u226555% or P pulmonale on ECG on\nboth occasions.4\nIn the MRC trial, ABG measurements were\nrepeated more than 3 weeks apart in stable patients who were\nincluded if their resting PaO2 was between 5.3 kPa (40 mm Hg)\nand 8 kPa (60 mm Hg).5\nAlthough ABG sampling allows direct measurement of PaO2,\nit involves puncture of the radial artery and thus can be painful\nand can only be performed by trained healthcare professionals.\nThere may be other considerations to take into account, such as\na patient\u2019s past experience of ABG sampling and whether they\nare on anticoagulants. CBG sampling conversely only requires a\nsmall sample of blood (125 mL) from a relatively super\ufb01cial site\n(typically at the \ufb01ngertip or earlobe). It is therefore less invasive,\noften better tolerated and can be performed by a wider range of\nhealthcare professionals, although training and technique are\nstill important to obtain adequately \u2018arterialised\u2019 samples. The\ndifference in PO2 levels at an arterial level versus venous level\ncan be signi\ufb01cant, typically 8 kPa (60 mm Hg) at rest and up to\n10 kPa (75 mm Hg) during exercise.39\nTo help raise capillary\nPO2 to a level closer to arterial PO2, a number of manoeuvres\ncan be used prior to sampling, including the use of topical vaso-\ndilators and heat.\nA meta-analysis included 886 subjects from 29 studies.40\nThe\nstudies included both healthy subjects and patients with chronic\nlung disease under a number of situations, including high altitude.\nBoth earlobe CBGs and \ufb01ngertip CBGs were compared against\nABGs, and both gave accurate estimates of pH and PaCO2,\nalthough earlobe sampling gave a more accurate estimate for\nPaCO2. Earlobe CBGs were superior to \ufb01ngertip CBGs in estimat-\ning PaO2 but continued to underestimate PaO2 by a mean of\n0.32 kPa (2.4 mm Hg) difference (1.9\u20132.8), residual SE 0.8 kPa\n(6 mm Hg). The authors concluded that earlobe sampling gave a\nreasonable estimate of PaO2 unless precision was required.\nIn a comparison of simultaneous earlobe CBGs and radial ABGs\nfrom 40 patients with chronic lung disease, including 29 patients\nwith COPD,41\nthere was a good correlation between CBGs and\nABGs for estimating PaO2, with CBGs underestimating PaO2 by a\nmean of just 0.17 kPa, albeit with a relatively wide 95% CI\n(\u22121.09 kPa to +0.75 kPa). A subgroup analysis suggested that\nCBGs were more accurate in hypoxaemic patients, with CBGs\nunderestimating by <0.5 kPa in \u2018nearly all\u2019 patients with PaO2\n<8 kPa. In another study carrying out a comparison of simultan-\neous PaO2 and earlobe CBG measurements in 100 patients under-\ngoing LTOT assessment, CBGs alone would have resulted in 9\/55\n(ie, 16%) receiving LTOT inappropriately. No patients would have\nbeen denied LTOT.35\nConversely, patients found ABGs more\nuncomfortable than CBGs (p<0.0001).\nA repeat ABG after oxygen titration is completed allows\naccurate reassessment of PaO2, PaCO2 and pH, but can be\nuncomfortable for patients. Cutaneous capnography was used\nto reassess PaCO2 in comparison with ABGs in 20 subjects with\nchronic lung disease who received oxygen at gradually increas-\ning rates until SaO2 was >90%.42\nCapnography accurately esti-\nmated PaCO2 with minimal bias. Earlobe CBGs have also been\nshown to give accurate estimates of pH and PaCO2 that are\ncomparable to those achieved from ABGs.40\nNo studies were identi\ufb01ed which showed that ABGs provided\ninaccurate results due to patient hyperventilation secondary to\ni12 Hardinge M, et al. Thorax 2015;70:i1\u2013i43. doi:10.1136\/thoraxjnl-2015-206865\nBTS Guidelines\ngroup.bmj.com\non June 19, 2016 - Published by\nhttp:\/\/thorax.bmj.com\/\nDownloaded from\npain induced by the procedure. In clinical practice, many ser-\nvices routinely use local anaesthetic when performing radial\nABGs. There are also no outcome data comparing complication\nrates between radial ABGs and earlobe CBGs.\nEvidence statements\n\u25b8 ABG sampling, performed twice at least 3 weeks apart,\nduring a stable phase of their condition, identi\ufb01es patients\nwho may bene\ufb01t from LTOT. Evidence level 1++\n\u25b8 Both earlobe and \ufb01ngertip CBGs provide accurate estimates\nof arterial carbon dioxide tension and arterial pH during\nLTOT assessment and oxygen titration. Evidence level 1+\n\u25b8 Earlobe CBGs provide a more accurate estimate of arterial\noxygen tension than \ufb01ngertip CBGs. Evidence level 1+\n\u25b8 Use of earlobe CBGs alone for LTOT assessment leads to\nsome patients inappropriately receiving LTOT. Evidence\nlevel 3\n\u25b8 Patients tolerate earlobe CBG testing better than ABG sam-\npling. Evidence level 3\n\u25b8 During an LTOT assessment, cutaneous capnography can be\nused in place of ABG sampling for reassessing PaCO2 but not\npH after oxygen titration. Evidence level 3\nRecommendations\n\u25b8 Patients being assessed for LTOT should undergo initial\nassessment for suitability using ABG sampling. (Grade A)\n\u25b8 Patients assessed for LTOT during a period of apparent clin-\nical stability should undergo two ABG measurements at least\n3 weeks apart, before the need for LTOT can be con\ufb01rmed.\n(Grade B)\n\u25b8 Patients undergoing LTOT assessment should be reassessed\nwith ABG after oxygen titration is complete to determine\nwhether adequate oxygenation has been achieved without\nprecipitating respiratory acidosis and\/or worsening hypercap-\nnia. (Grade D)\n\u25b8 For oxygen titration during LTOT assessment, CBG sampling\ncan be used in place of ABG sampling for re-measuring\nPaCO2 and pH at different oxygen \ufb02ow rates. (Grade A)\n\u25b8 For oxygen titration during LTOT assessment, cutaneous cap-\nnography can be used in place of ABG sampling for\nre-measuring PaCO2 alone but not pH at different oxygen\n\ufb02ow rates. (Grade A)\nGood practice points\n\u25b8 Patients undergoing a radial ABG should be assessed with an\nAllen\u2019s test \ufb01rst, to ensure they have a dual blood supply to\nthe hand from both radial and ulnar arteries. (\u221a)\n\u25b8 Patients undergoing a radial ABG should be consented for\nthe procedure with a discussion of possible risks. (\u221a)\n\u25b8 In many community commissioned home oxygen service\u2014\nassessment and review (HOS-AR) services, it is not practical\nfor patients to undergo ABG sampling during LTOT assess-\nment. Under such circumstances, a combination of CBGs and\noximetry (but not capnography) could be used as an alterna-\ntive tool for initial assessment for LTOT, and after oxygen\ntitration is complete. Some patients may receive LTOT\nunnecessarily using this approach, but it is unlikely that any\npatient would be inappropriately denied LTOT. (\u221a)\nManagement of hypercapnia during LTOT assessment\nPatients with chronic lung disease may develop resting hyper-\ncapnia as the severity of their disease progresses. In such cases,\noxygen supplementation can cause suppression of existing\nhypoxaemic respiratory drive with consequent diminution of\nminute ventilation and worsening hypercapnia and V\/Q\nmismatch. This has the potential to lead to the development of\nrespiratory acidosis and progressive ventilatory failure.\nFew studies exist to support best practice where patients became\nacidotic or excessively hypercapnoeic during an LTOTassessment.\nNeither the MRC5\nnor the NOTT4\nstudies excluded patients with\nhypercapnia. In the MRC study, average PaCO2 ranged between\n7.1 and 7.3 kPa (53.2\u201354.9 mm Hg) for both control and treated\ngroups. Subjects received oxygen at 2 L\/min or higher if necessary\nto achieve PaO2 >8 kPa (60 mm Hg), and no hypercapnia-related\nissues during the assessment process were reported. Although the\nNOTT study did not explicitly exclude patients with hypercapnia,\npatients in both groups were mostly normocapnoeic (mean PaCO2\n5.7 kPa, 43 mm Hg).4\nAgain no hypercapnia-related issues during\nthe assessment process were reported. Chiang et al43\nstudied venti-\nlatory responses to CO2 stimulation in 26 COPD patients, 12 with\nresting hypercapnia, following oxygen supplementation with\n2 L\/min oxygen. Hypercapnic patients showed a rise in mean\nPCO2 from 7.1\u00b10.2 kPa to 7.8\u00b10.3 kPa without developing acid-\nosis and also a blunted response to CO2 stimulation. However,\nthere were no reported adverse clinical events during this short-\nterm study.\nEvidence statement\n\u25b8 Patients with baseline hypercapnia can undergo LTOT assess-\nment without adverse outcome but require monitoring of\npH and PCO2 levels during and at the end of assessment.\nEvidence level 4\nRecommendation\n\u25b8 Patients with baseline hypercapnia should be monitored for the\ndevelopment of respiratory acidosis and worsening hypercap-\nnia using ABGs after each titration of \ufb02ow rate, as well as ABG\nsampling after oxygen titration is complete. (Grade D)\nGood practice points\n\u25b8 Patients who develop a respiratory acidosis and\/or a rise in\nPaCO2 of >1 kPa (7.5 mm Hg) during an LTOT assessment\nmay have clinically unstable disease. These patients should\nundergo further medical optimisation and be reassessed after\n4 weeks. (\u221a)\n\u25b8 Patients who develop a respiratory acidosis and\/or a rise in\nPaCO2 of >1 kPa (7.5 mm Hg) during an LTOT assessment\non two repeated occasions, while apparently clinically stable,\nshould only have domiciliary oxygen ordered in conjunction\nwith nocturnal ventilatory support. (\u221a)\nUse of LTOT: hours of use and \ufb02ow rates\nLTOT hours of use\nThe bene\ufb01ts of LTOT are derived from normalisation of abnor-\nmal physiology driven by chronic hypoxaemia and have been\nachieved with use of LTOT for 15 h\/day.5\nTherefore, there is a\nhypothetical advantage of longer durations of oxygen therapy in\ncorrecting these abnormalities for greater periods of each day\nand particularly at night, when hypoxaemia may be more pro-\nfound during sleep. Comparison of the effects of 12 h NOT\nwith continuous oxygen (24 h) therapy in the NOTT study\ndemonstrated a 1.94 times higher mortality in the NOT group:\nthis survival bene\ufb01t may be offset by the practicalities of\nincreased oxygen use and the impact upon mobility.4\nIn a pragmatic 5-year follow-up study of 228 patients for\nwhom an oxygen concentrator was ordered, comparisons were\nmade between no oxygen use (n=55), oxygen use for <15 h\nper day (n=112) and oxygen use for >15 h per day (n=61).\nOverall survival at 2 years was better in the groups receiving\noxygen compared to the no oxygen group, but there was no dif-\nference between the oxygen groups.8\nHardinge M, et al. Thorax 2015;70:i1\u2013i43. doi:10.1136\/thoraxjnl-2015-206865 i13\nBTS Guidelines\ngroup.bmj.com\non June 19, 2016 - Published by\nhttp:\/\/thorax.bmj.com\/\nDownloaded from\nThere is no evidence base for duration of LTOT use in\nnon-COPD respiratory disease or cardiac disease.\nEvidence statements\n\u25b8 LTOT ordered for COPD patients for at least 15 h and up to\n24 h per day confers a mortality bene\ufb01t and improvement in\nphysiological indices. Evidence level 1+\n\u25b8 Use of LTOT for 24 h versus 12 h offers additional bene\ufb01ts\nespecially for COPD patients with more severe disease (higher\nPaCO2, higher haematocrit, higher pulmonary artery pressure\nand more neuropsychological impairment). Evidence level 2+\nRecommendation\n\u25b8 LTOT should be ordered for a minimum of 15 h per day, and\nup to 24 h per day may be of additional bene\ufb01t. (Grade C)\nLTOT \ufb02ow rates\nDaytime activity and LTOT \ufb02ow rates\nA \ufb02ow rate based on a single measure of oxygenation at rest may\nnot necessarily guarantee adequate oxygenation during\nday-to-day activities where oxygen requirements may \ufb02uctuate.\nAlthough transient hypoxaemia could temporarily increase both\npulmonary artery pressures and the risk of arrhythmias, it is\nunclear to what degree such \ufb02uctuations in oxygenation during\ndaily life can offset the potentially bene\ufb01cial effects of LTOT.\nPatients in the MRC study were started on a \ufb02ow rate of 2 L\/min,\nwhich was increased incrementally until a PaO2 >8 kPa\n(60 mm Hg) was achieved,5\nand patients in the NOTT trial\nstarted on a \ufb02ow rate of 1 L\/min, which was increased in 1 L\/min\nincrements up to a maximum of 4 L\/min until PaO2 >8 kPa\n(60 mm Hg) was achieved.4\nFlow rates were not altered to re\ufb02ect\nexercise. However, a number of studies suggest that determining\n\ufb02ow rates using a single measure of PaO2 at rest may not guaran-\ntee adequate oxygenation during exercise:44\u201347\nstable COPD\npatients receiving LTOT at a single \ufb02ow rate spent between 70%\nand 87% of the daytime with SpO2 >90% when performing\nday-to-day activities. Individual tailoring of \ufb02ow rates to suit\npatients\u2019 requirements during exercise, rest and sleep can reduce\nmedian oxygen \ufb02ow rate from 2.5 to 1.2 L\/min, while the per-\ncentage of time SpO2 was within the target range increased from\n24.8% to 52.8% (p=0.001).48\nNocturnal oxygen requirements and LTOT\nPatients can desaturate during sleep as a result of reduced minute\nventilation and impaired ventilatory responses and so oxygen\nrequirements overnight may also differ from those at rest when\nawake. Several studies have suggested that a \ufb02ow rate established\nfrom resting ABGs while awake may not allow adequate oxygen-\nation overnight with patients spending only between 72% and\n77% of the time with SpO2 >90% overnight.46 49 50\nPatients\nwith more severe COPD and worse daytime ABGs spent a signi\ufb01-\ncantly greater proportion of the night with hypoxaemia.51\nIn the\nNOTT study, oxygen was automatically increased by 1 L\/min\nduring sleep without reported adverse events.4\nNo data were\nfound with respect to other diagnostic patient groups.\nEvidence statements\n\u25b8 Patients for whom LTOT is ordered at a single \ufb02ow rate suf\ufb01-\ncient to achieve PaO2 >8 kPa (60 mm Hg) at rest demon-\nstrate a survival bene\ufb01t from LTOT. Evidence level 1+\n\u25b8 LTOT ordered at a single \ufb02ow rate to provide adequate oxy-\ngenation at rest may offer inadequate oxygenation during\nexercise and\/or sleep. Evidence level 3\n\u25b8 LTOT ordered for patients at different \ufb02ow rates for use\nduring sleep and exercise demonstrates a survival bene\ufb01t\nfrom LTOT. Evidence level 1+\nRecommendations\n\u25b8 Patients eligible for LTOT should be initiated on a \ufb02ow rate\nof 1 L\/min and titrated up in 1 L\/min increments until SpO2\n>90%. An ABG should then be performed to con\ufb01rm that a\ntarget PaO2 \u22658 kPa (60 mm Hg) at rest has been achieved.\n(Grade B)\n\u25b8 Non-hypercapnic patients initiated on LTOT should increase\ntheir \ufb02ow rate by 1 L\/min during sleep in the absence of any\ncontraindications. (Grade B)\n\u25b8 Patients initiated on LTOT who are active outdoors should\nreceive an ambulatory oxygen assessment to assess whether\ntheir \ufb02ow rate needs to increase during exercise. (Grade B)\nGood practice points\n\u25b8 Ambulatory and nocturnal oximetry may be performed to\nallow more accurate \ufb02ow rates to be ordered for use during\nexercise and sleep, respectively. (\u221a)\n\u25b8 Patients initiated on LTOT who have cognitive, visual or\ncoordination impairments, may not be able to safely manipu-\nlate their own \ufb02ow rates and should be maintained on a\nsingle \ufb02ow rate. (\u221a)\n\u25b8 Flow rates may be increased at 20 min intervals during an\noxygen titration until a target PaO2 is achieved. (\u221a)\nPatient education at time of assessment\nA few studies have evaluated the provision of patient education,\nusually in the form of verbal or written information, at the time\nof oxygen assessment. A comparison of patients who had\nreceived formal assessment with ABGs on two separate occa-\nsions together with education by a specialist respiratory team\nwith patients commencing LTOT in primary care, mostly on the\nbasis of oximetry alone, demonstrated a signi\ufb01cantly higher\ncompliance (82% vs 44%; p=0.002) and understanding of the\nrationale for treatment (93% vs 41%; p<0.00001).52\nThese\n\ufb01ndings were supported by a large case series of 930 patients in\nwhom education consisting of a home visit by a nurse or physio-\ntherapist was an important factor in those patients\u2019 compliance\nwith \u226515 h\/day of oxygen use.53\nOrdering LTOT on hospital\ndischarge does not prepare patients for a follow-up assessment\nor the implications of oxygen removal if they no longer meet\nthe criteria for LTOT:54\npsychological dependence on oxygen\ntherapy was reported as a major issue in these patients, causing\ndistress for patients and staff as well as requiring signi\ufb01cant\nresources and expertise to address.\nEvidence statements\n\u25b8 Patients initiated on LTOT without formal education exhibit\npoor compliance with therapy. Evidence level 2+\n\u25b8 Providing written information to patients commenced on\nhome oxygen in hospital does not prepare them for\nfollow-up or the implication of not meeting the criteria for\nLTOT. Evidence level 3\nRecommendations\n\u25b8 Patients initiated on LTOT should be provided with formal\neducation by a specialist home oxygen assessment team to\nensure compliance with therapy. (Grade D)\n\u25b8 Patients being commenced on home oxygen on discharge from\nhospital should be advised that home oxygen may be removed\nif reassessment shows clinical improvement. (Grade D)\nFollow-up of LTOT patients\nFollow-up of LTOT patients is necessary for a variety of\nreasons: to ensure that LTOT treatment is still required, that the\noxygen order is still adequate (and therefore that the potential\ni14 Hardinge M, et al. Thorax 2015;70:i1\u2013i43. doi:10.1136\/thoraxjnl-2015-206865\nBTS Guidelines\ngroup.bmj.com\non June 19, 2016 - Published by\nhttp:\/\/thorax.bmj.com\/\nDownloaded from\nfor healthcare gains such as survival are realised), that patients\nare compliant with treatment, and that any concerns or pro-\nblems are addressed. Although home oxygen patients may be a\nrelatively small group of lung disease patients in general, they\nare a very resource intensive group. Targeted follow-up of this\ngroup could provide signi\ufb01cant bene\ufb01ts in terms of cost effect-\nive healthcare utilisation.\nThe original MRC and NOTT LTOT studies both provided\ntitration of \ufb02ow rate at a 3-month follow-up appointment as\npart of their protocol.4 5\nCottrell et al55\nrandomised 50 LTOT\npatients to follow-up at 2, 6 or 12 months. They costed hospital\ninterventions given\/required over a 1-year period, and found\nthat the 2-monthly follow-up group had signi\ufb01cantly higher\nevaluation costs with no bene\ufb01t in terms of emergency depart-\nment or hospital visits, length of stay in hospital or mortality:\nthe only clinical bene\ufb01t shown was an improvement in the psy-\nchological component of the sickness impact pro\ufb01le.\nOther studies have focused on the setting for reassessment\nusing different models, some of which might now be called\n\u2018integrated respiratory services\u2019. Cross-sectional studies have\nreported \u2018added value\u2019 from reviewing patients in their homes,\nwhich included identifying and correcting problems with the\nconcentrator, humidi\ufb01er, the length of the patient\u2019s tubing and\nfactors impacting on the patient\u2019s usage.56 57\nIn a prospective\n10-year case\u2013control study in which 217 LTOT patients were\nrandomised to \u2018home care\u2019 (de\ufb01ned as 6-monthly hospital\nappointments and 2\u20133-monthly home visits) or standard care\n(management by hospital physician only), home care decreased\nexacerbation rates.58\nRandomisation of 122 LTOT patients to\nfollow-up with a hospital-based homecare programme (monthly\nphone call, home visits every 3 months, and home or hospital\nvisits on a demand basis) or conventional medical care, demon-\nstrated signi\ufb01cantly decreased costs in the homecare follow-up\ngroup, which was mainly due to a reduction in use of hospital\nresources, despite the cost of running the service itself.59\nReports from focus groups60\nand case series53\nhighlight the\nimportance of education from specialist nurses or physiothera-\npists in increasing compliance and addressing patient concerns.\nWithdrawal of home oxygen\nCase series in which LTOT patients have been followed up have\nshown that a signi\ufb01cant proportion of patients no longer required\noxygen as originally ordered.33 61\nIn addition, it has been well\nrecognised that compliance with LTOT can be poor and that with-\ndrawal of home oxygen through non-use is sometimes indicated.\nWithdrawal of LTOTcan be distressing to patients, challenging for\nstaff and entail a signi\ufb01cant use of resources.37\nSee appendix 7 for\na suggested protocol for withdrawal of home oxygen therapy.\nEvidence statements\n\u25b8 Follow-up of LTOT patients 3 months after starting LTOT,\ncan ensure that LTOT is still required and that the \ufb02ow rate\nis appropriate. Evidence level 1+\n\u25b8 Six-monthly follow-up has a similar effect to 2-monthly\nfollow-up in terms of healthcare utilisation but at decreased\ncost. Evidence level 3\n\u25b8 Home follow-up alone or in combination with hospital\nfollow-up is more effective than hospital follow-up. Evidence\nlevel 2+\n\u25b8 Follow-up with a specialist home oxygen assessment team\nincluding education improves compliance with LTOT.\nEvidence level 3\nRecommendations\n\u25b8 LTOT patients should receive follow-up at 3 months after\nLTOT is ordered, which should include assessment of blood\ngases and \ufb02ow rate to ensure LTOT is still indicated and\ntherapeutic. (Grade A)\n\u25b8 LTOT patients should receive follow-up visits at 6\u2013\n12 months after their initial 3-month follow-up, which can\nbe either home based or in combination with hospital or\nclinic visits. (Grade D)\n\u25b8 Follow-up visits should be conducted by a specialist home\noxygen assessment team with the necessary skills to deliver\npatient education and manage withdrawal of home oxygen.\n(Grade D)\nGood practice point\n\u25b8 All patients for whom LTOT has been ordered should be\nvisited at home within 4 weeks by a specialist nurse or\nhealthcare professional with experience of domiciliary\noxygen therapy. The visit provides an opportunity to high-\nlight potential risks and should be used to reinforce educa-\ntion and offer support to the patient and carer. Compliance\nmay be checked, along with smoking status, symptoms of\nhypercapnia and oxygen saturations on oxygen to check that\noxygen is therapeutic. (\u221a)\nNOCTURNAL OXYGEN THERAPY\nNOT is oxygen administered overnight alone without additional\noxygen therapy during awake or daytime hours. Before daytime\nresting hypoxaemia develops, many patients develop nocturnal\nor sleep time oxygen desaturation due to a combination of wor-\nsening V\/Q mismatch in a supine posture and lack of drive to\nventilatory muscles during sleep. This section refers to patients\nwho are either normoxic during the day, or have mild daytime\nhypoxaemia but do not ful\ufb01l LTOT criteria.\nNOT in COPD patients with nocturnal desaturation\nThe worsening of hypoxaemia during sleep in patients with\nadvanced COPD has been well established in many studies.\nThere is retrospective evidence that nocturnal desaturation is\nassociated with worse survival. The evidence as to whether\npatients who fail to meet the criteria for LTOT but are hypoxae-\nmic during sleep bene\ufb01t from NOT is assessed here.\nThere are only a small numbers of studies addressing this\npopulation of patients. Of these, three studies examined out-\ncomes over 2\u20133 years, and three studies looked at mortality.\nPatients were recruited from out-patients settings, largely in\nteaching hospitals. In a multicentre study, 76 patients with\nCOPD (obstructive sleep apnoea (OSA) excluded) were identi-\n\ufb01ed as having nocturnal desaturation but did not qualify for\nLTOT.62\nA total of 41 patients were randomised to receive NOT\nwhich was titrated to achieve saturations >90% throughout the\nnight. In the follow-up period, 22 patients went on to develop\nhypoxaemia requiring LTOT, 16 patients died (nine in the\nLTOT group), and there was no difference in the PAP (measured\nby cardiac catheter) between the two groups. A double-blind\ncrossover study63\nrandomised 23 patients with COPD and noc-\nturnal hypoxaemia to receive air or NOT over a 1-night period.\nNo difference was seen in the quality of sleep (assessed by ques-\ntionnaire and EEG) between the two groups. In six centres, 203\npatients diagnosed with COPD and signi\ufb01cant hypoxaemia\n(PaO2 <7.8 kPa, 59 mm Hg) were randomised to continuous\noxygen therapy (24 h) or NOT (12 h).4\nThe primary end point\nwas all cause mortality. There was a 1.94 times increase in \u2018all\ncause\u2019 mortality in the NOT group compared to the continuous\noxygen therapy group. A multicentre retrospective study investi-\ngated the data of patients from \ufb01ve centres who had polysomno-\ngraphy performed.64\nPatients had mild to moderate daytime\nHardinge M, et al. Thorax 2015;70:i1\u2013i43. doi:10.1136\/thoraxjnl-2015-206865 i15\nBTS Guidelines\ngroup.bmj.com\non June 19, 2016 - Published by\nhttp:\/\/thorax.bmj.com\/\nDownloaded from\nhypoxaemia with a PaO2 >60 mmg Hg (8 kPa) and evidence of\ndesaturation during sleep without signs of sleep apnoea. A total\nof 169 subjects with COPD (77 desaturators and 92 non-\ndesaturators) were analysed. The mean survival was signi\ufb01cantly\nless in the desaturator group (2.89\u00b11.7 years vs 3.7\u00b11.7 years;\np<0.003). Thirty-\ufb01ve of the desaturator group were reported to\nhave received some form of oxygen supplementation, however\nit was not clear how many hours this was for or if it was used\nnocturnally; on analysis it did not alter survival. In a double-\nblind study of 51 patients with moderate COPD and daytime\nPaO2 >60 mm Hg including 38 with desaturation, patients were\nallocated to receive NOT at 3 L\/min or room air.65\nAfter\n3 years, the NOT-treated group PAP had reduced by 0.49 kPa\n(3.7 mm Hg) and had increased in the air-treated group by\n0.52 kPa (3.9 mm Hg; p<0.02). There was no difference in\nmortality; however, only nine in the sham group and seven in\nthe oxygen group completed the study.\nEvidence statements\n\u25b8 Patients with mild daytime hypoxaemia and nocturnal hyp-\noxaemia have a worse survival compared to patients with no\nnocturnal desaturation. Evidence level 1+\n\u25b8 When administered to patients who are either normoxaemic\nor have baseline ABG levels above the threshold for LTOT,\nNOT alone does not show consistent improvements in\npulmonary haemodynamics leading to a survival advantage.\nEvidence level 1+\n\u25b8 No additional signi\ufb01cant bene\ufb01t in sleep quality is derived\nfrom nocturnal supplemental oxygen in patients with noctur-\nnal hypoxaemia. Evidence level 1\u2212\nRecommendation\n\u25b8 NOT is not recommended in patients with COPD who have\nnocturnal hypoxaemia but who fail to meet the criteria for\nLTOT. (Grade A)\nGood practice point\n\u25b8 Other causes of nocturnal desaturation in COPD should be\nconsidered such as obesity hypoventilation, respiratory\nmuscle weakness or OSA. (\u221a)\nNOT in patients with cardiac disease and\nnocturnal desaturation\nA variety of factors can contribute to the development of noc-\nturnal hypoxaemia in patients with heart failure: hypoventila-\ntion during sleep, reduced oxygen stores due to restricted lung\nvolumes, sleep disordered breathing (SDB) and impaired gas\nexchange due to ventilation\u2013perfusion mismatch. As previously,\nthis section refers to patients who are either normoxic during\nthe day, or have mild daytime hypoxaemia but do not ful\ufb01l\nLTOT criteria.\nSDB in heart failure is due to central sleep apnoea (CSA)\nassociated with Cheyne-Stokes respiration (CSR), often in com-\nbination with OSA. These frequently co-exist, and can be clinic-\nally dif\ufb01cult to differentiate. The presence of SDB is associated\nwith atrial \ufb01brillation and a worse New York Heart Association\n(NYHA) functional class. It is commoner in male patients, those\nover 60 years of age, and those with daytime hypocapnia\n(PaCO2 <5.06 kPa, 38 mm Hg). SDB in heart failure can have\nfew symptoms and come to light following reports by carers, or\npresents with symptoms of disrupted sleep such as increased\ndaytime sleepiness, poor subjective sleep quality, insomnia,\ninattention and poor concentration. Recurrent nocturnal desa-\nturations can lead to paroxysmal nocturnal dyspnoea, morning\nheadaches, nocturnal angina and arrhythmias. SDB is important\nin the context of heart failure as it can predict mortality and\nalso contribute to disease progression (through intermittent hyp-\noxaemia and arousals inducing adrenergic surges and negative\nintra-pleural pressure swings which increase left ventricular\ntransmural pressure leading to an increase in afterload). Some\ninternational guidelines on heart failure management advocate\nscreening for SDB in selected patients. Treatment approaches\nhave been to maximise treatment for the underlying cardiac\ndisorder, and to consider additional therapies which include\nNOT or ventilatory support such as continuous positive airways\npressure (CPAP), adaptive servo-ventilation (ASV) or NIV\n.\nThere are signi\ufb01cant limitations in the evidence of the impact\nof treatment of SDB on heart-related outcomes: most studies\nevaluate surrogate outcomes (blood pressure, cardiac function,\ncatecholamines) rather than clinically important outcomes\n(health-related quality of life, hospitalisation and mortality). In\naddition, the literature evaluating NOT against modalities of\nventilation is limited.\nEffect of NOT on SDB in severe cardiac disease\nSeveral studies examined the effects of low \ufb02ow oxygen (2\u2013\n4 L\/min delivered by nasal cannulae) on SDB in patients with\nmoderate to severe heart failure. In two non-randomised studies,\nSDB was assessed using the Apnoea Hyponoea Index (AHI) and\ntotal sleep time as outcome measures, thus including both central\nand obstructive apnoeas. One of these trials reported \ufb01ndings on\nin-patients with severe heart failure and CSR on a transplant\nwaiting list and showed that NOT led to a signi\ufb01cant improve-\nment in sleep quality after 1 night, which effect was sustained by\nuse over 1 month (AHI reduced from 57\u00b161 events\/h to 12\u00b117\nevents\/h).66\nIn the other non-RCT of patients with moderate to\nsevere heart failure (LVEF <45%), NOT signi\ufb01cantly reduced\ntotal AHI in 41% of patients (mainly reducing the CSA index)\nbut did not affect total sleep time.67\nTwo RCTs of moderate to\nsevere heart failure patients with CSR showed a reduction in\nCSR after 1 night of treatment with oxygen from 50.7\u00b112% to\n24.2\u00b15.4% of total sleep time and after 4 weeks from 33.6\n\u00b17.4% to 10.7\u00b13.9% of total sleep time, respectively.68 69\nIn\naddition, Staniforth et al69\nreported a reduction in CSAs from\n18.4\u00b14.1\/h to 3.8\u00b12.1\/h. Despite these improvements in sleep\nstudy parameters, no improvement in patient-reported symptom\nscores of sleep fragmentation were seen including the Epworth\nsleepiness scale and visual analogue scale (VAS),69\nor the SF-A\nsleep questionnaire.70\nEffect of NOT on cardiac function in severe cardiac disease\nStudies examined cardiac function using transthoracic echocar-\ndiograms, assessment of NYHA functional class and plasma or\nurinary neuropeptide levels. No studies assessed the effects on\nnocturnal angina. No change in left ventricular function was\nseen following NOT.66 67 71 72\nDespite no demonstrable\nimprovement in echocardiogram parameters, one study reported\na statistically signi\ufb01cant improvement in NYHA functional class\ncompared with an untreated control group after 52 weeks of\nNOT use.71\nNo studies demonstrated any effect on plasma or\nurinary neuropeptide levels. Two studies did not demonstrate\nany reduction in the frequency of ventricular arrhythmias\nduring sleep.67 73\nEffect of NOT on quality of life, activity and cognition in severe\ncardiac disease\nQuality of life assessed using a disease-speci\ufb01c questionnaire in a\n4-week crossover study showed no improvement,69\nwhereas a\ncase series also reporting after 4 weeks and using the Minnesota\nLiving with Heart Failure (MLHF) Questionnaire did show\ni16 Hardinge M, et al. Thorax 2015;70:i1\u2013i43. doi:10.1136\/thoraxjnl-2015-206865\nBTS Guidelines\ngroup.bmj.com\non June 19, 2016 - Published by\nhttp:\/\/thorax.bmj.com\/\nDownloaded from\nimprovement.74\nAnother study used the Dartmouth CO-OP\nFunctional Health Assessment Charts which showed no\nimprovement in daytime symptoms after 1 week.70\nExercise capacity was assessed in two case series of patients\nusing NOT for 4 weeks74\nand 3 months:72\nboth reported an\nimprovement in the 6-minute walk test (6MWT). Activity assessed\nby the Speci\ufb01c Activity Scale showed signi\ufb01cant improvement in a\n52-week RCT.71\nOne study examined effects on cognitive function in detail in\npatients receiving NOT using a variety of measures.69\nNo\nimprovements were seen after 4 weeks in this double-blind\ncross-over study. In contrast, Andreas et al used some similar\nmeasures which did demonstrate improvement after NOT.70\nEffect of NOT on healthcare utilisation or mortality\nNo studies evaluated the effects of NOT use on healthcare util-\nisation or mortality: most studies evaluate surrogate outcomes.\nEvidence statements\n\u25b8 Treatment of heart failure patients who are symptomatic\nfrom SDB with NOT leads to a reduction in SDB. Evidence\nlevel 1\u2212\n\u25b8 Treatment of symptomatic severe heart failure patients with\nNOT leads to modest improvement in exercise capacity.\nEvidence level 3\n\u25b8 Treatment of heart failure patients with NOT does not lead\nto improvement in quality of life, cognitive function, or\ncardiac function including ventricular arrhythmias. Evidence\nlevel 1+\nRecommendation\n\u25b8 NOT can be ordered for severe heart failure patients who do\nnot ful\ufb01l indications for LTOT, and have evidence of SDB\nleading to daytime symptoms, after other causes of nocturnal\ndesaturation have been excluded (eg, obesity hypoventilation\nor OSA) and heart failure treatment has been optimised.\nTreatment with modalities of ventilatory support should also\nbe considered. (Grade B)\nGood practice point\n\u25b8 If NOT is ordered for patients with severe heart failure, it\nshould be ordered at a low \ufb02ow rate of 1\u20132 L\/min and response\nshould be assessed by a reduction in symptoms of daytime\nsleepiness, and SDB indices as measured by an overnight oxim-\netry study. A blood gas assessment should be undertaken to\nexclude worsening hypercapnia and respiratory acidosis.\nTreatment with modalities of ventilatory support should be\nconsidered for patients who are hypercapnic. (\u221a)\nNOT in patients with other respiratory diseases and\nnocturnal desaturation\nUse of NOT in patients with CF\nPatients with CF develop progressive air\ufb02ow obstruction, venti-\nlatory failure and nocturnal desaturations with sleep fragmenta-\ntion (which may in addition result from cough). Development\nof nocturnal hypoxaemia and hypercapnia are known to be\npoor prognostic signs in patients with CF and use of NOT has\nbeen examined to see whether it will improve blood gas para-\nmeters and so improve prognosis. Four studies have examined\nthe use of NOT in adult patients with CF, of which two studies\nwere designed to evaluate the role of bi-level positive airway\npressure (BiPAP) and used NOT, with and without air, in their\ncontrol arm. All studies were single night studies of the varying\nmodalities of NOT and between them examined effects on sleep\nquality, blood gas parameters and ventilation. No studies\nexamined effects on pulmonary hypertension, quality of life,\nactivity and cognition, or healthcare utilisation.\nTwenty-eight patients with CF who received NOT were fol-\nlowed over 2 years.75\nNo statistically signi\ufb01cant improvement in\nsurvival, lung or cardiac outcomes was seen, although school and\nwork attendance had improved. However, actual hours of oxygen\nuse were low. In a small RCT of 10 patients with mean FEV1\n<25% predicted (four with daytime hypercapnia), patients who\nwere randomised to receive NOT over 2 nights rather than room\nair improved overnight oxygen saturation levels, but did not\nimprove sleep parameters.76\nTranscutaneous PCO2 rose in all\nstages of sleep, predominantly in REM sleep, but not to a level\nwhich was felt to be clinically signi\ufb01cant. A small study of six sub-\njects with mean FEV1 <29% predicted (two with daytime hyper-\ncapnia) reported results receiving room air, BiPAP or NOT over\n3 nights in random order.77\nNOT led to improved overnight oxy-\ngenation but no change in sleep quality. However, two patients\ndeveloped symptomatic hypercapnia which was not seen with\nBiPAP and NOT given together, where there was substantial\nimprovement in levels of hypercapnia. Another similar small study\nof 13 patients with mean FEV1 <32% predicted (six with daytime\nhypercapnia) showed a non-signi\ufb01cant rise in transcutaneous CO2\nwith NOTwhich improved with BiPAP\n.78\nEvidence statements\n\u25b8 Treatment of CF patients with NOT improves nocturnal oxy-\ngenation but there is no evidence of long-term bene\ufb01t on\nsurvival. Evidence level 1+\n\u25b8 Treatment of CF patients with NOT does not improve sleep\nquality. Evidence level 1+\n\u25b8 Treatment of CF patients with NOT can cause hypercapnia,\nwhich can be improved with provision of NIV along with\nNOT. Evidence level 1+\nRecommendation\n\u25b8 NOT should not be given to CF patients with nocturnal\nhypoxaemia alone who do not ful\ufb01l LTOT criteria. It can be\nconsidered in patients with evidence of established ventila-\ntory failure, where it should be given with NIV support.\n(Grade B)\nUse of NOT in patients with ILD\nPatients with ILD have been found to develop progressive day\nand night-time hypoxaemia, sleep disruption and poor sleep\nquality. Evidence is limited in this area and no studies have\nexamined the long-term use of nocturnal oxygen or its effects\non mortality, pulmonary haemodynamics or healthcare utilisa-\ntion in ILD. Only one study has prospectively examined the\neffect of NOT in patients with ILD compared with air.79\nThis\nwas a 2-night study comparing room air with NOT titrated at\n1\u20133 L\/min via nasal prongs to give an oxygen saturation reading\nof >90%. However, the study took place among long-term resi-\ndents of Mexico city who were therefore acclimatised to living\nat altitude (\u2018normal\u2019 control subjects had a mean PaO2 of\n6.7 kPa). They found that NOT corrected nocturnal hypox-\naemia, improved tachycardia and tachypnoea but that there was\nno change in sleep ef\ufb01ciency.\nEvidence statements\n\u25b8 Treatment of ILD patients with nocturnal episodic\nhypoxaemia, but without established daytime blood gas\nabnormalities, with NOT improves nocturnal oxygenation,\nbut there is no evidence of long-term bene\ufb01t on survival.\nEvidence level 1+\n\u25b8 Treatment of ILD patients with NOT does not improve sleep\nquality. Evidence level 1+\nHardinge M, et al. Thorax 2015;70:i1\u2013i43. doi:10.1136\/thoraxjnl-2015-206865 i17\nBTS Guidelines\ngroup.bmj.com\non June 19, 2016 - Published by\nhttp:\/\/thorax.bmj.com\/\nDownloaded from\nRecommendation\n\u25b8 NOT should not be given to patients with ILD with noctur-\nnal hypoxaemia alone, who do not ful\ufb01l LTOT criteria.\n(Grade B)\nUse of NOT in patients with neuromuscular weakness\nPatients with neuromuscular weakness can develop progressive\nweakness of all muscle groups including respiratory muscle weak-\nness. If this occurs, they may develop nocturnal desaturation, par-\nticularly during REM sleep, prior to developing daytime type 2\nrespiratory failure. No studies have examined the long-term use of\nnocturnal oxygen or its effects on mortality, pulmonary haemo-\ndynamics or healthcare utilisation in neuromuscular weakness.\nEvidence comes from one study which examined the use of NOT\nin patients with Duchenne muscular dystrophy, who had normal\ndaytime blood gases but evidence of episodic nocturnal hypox-\naemia.80\nNo bene\ufb01cial effect was found on sleep quality, but there\nwas a signi\ufb01cant worsening of the duration of hypopnoeas and\ncentral apnoeas. In addition, levels of hypercapnia were not moni-\ntored and the concern that NOT in the absence of NIV support\nmay worsen ventilatory failure remains.\nEvidence statement\n\u25b8 Treatment of patients with neuromuscular weakness and noc-\nturnal episodic hypoxaemia with NOT, without established\ndaytime blood gas abnormalities, does not improve sleep\nquality and worsens CSA. Evidence level 1+\nRecommendation\n\u25b8 Patients with neuromuscular weakness affecting respiratory\nmuscles should not have NOT alone ordered. It can be\nconsidered in patients with evidence of established ventila-\ntory failure, where it should be given with NIV support.\n(Grade B)\nUse of NOT in patients with Cheyne-Stokes respiration, obesity\nhypoventilation syndrome and overlap syndrome\nPatients with OSA experience recurrent episodic desaturation\nthroughout the night, which leads to sleep fragmentation, which\nusually manifests as daytime sleepiness. Treatment for moderate\nto severe OSA is with a combination of weight loss and CPAP\ntreatment. Some obese patients may develop obesity hypoventi-\nlation syndrome (OHS) de\ufb01ned as obesity with body mass index\n(BMI) >30 kg\/m2\nand awake hypercapnia in the absence of\nother causes of hypoventilation. In these patients there can be\nsustained nocturnal hypoxaemia. Some patients can develop an\n\u2018overlap syndrome\u2019 in which there is a combination of OHS and\nOSA (often with underlying lung disease such as COPD) with\nworsening daytime ventilatory failure.\nThere are no trials of home oxygen therapy in the treatment\nof OHS or overlap syndrome. Oxygen has been used as an\nadd-on therapy to NIV\n.\nRecommendation\n\u25b8 Patients with OSA, OHS or overlap syndrome should not\nhave NOT alone ordered. It can be considered in patients\nwith evidence of established ventilatory failure, where it\nshould be given with NIV support. (Grade D)\nAMBULATORY OXYGEN THERAPY\nAOT is de\ufb01ned as the use of supplemental oxygen during exer-\ncise and activities of daily living.81\nIn mobile patients who are\nnot suf\ufb01ciently hypoxaemic to qualify for LTOT but who\ndesaturate on exercise, AOT has historically been used to opti-\nmise saturations and short-term exercise capacity. AOT is also\noften supplied to LTOT users, either to allow those who are\nmobile outdoors to optimise their exercise capacity and achieve\ntheir recommended hours per day usage, or to enable more\nimmobile patients to leave the house in a wheelchair\/scooter on\noccasion, for example for hospital appointments. In some\npatient groups such as those with CF, AOT may be used to\nmaintain an exercise regime or to enable effective airways\nclearance.\nAOT in patients not eligible for LTOT\nThere are a number of hypothetical bene\ufb01ts from the use of\nAOT in patients who are not hypoxaemic at rest but who desat-\nurate on exercise, including increased oxygen transport, allow-\ning greater utilisation of oxygen by exercising muscles, delayed\nonset of inspiratory muscle fatigue, reduction in symptoms of\ndyspnoea and improved right ventricular function.\nStudies that have examined the use of AOT in non-LTOT\nusers can be divided into those which have assessed the acute\nimpact of AOT on exercise capacity during a single assessment,\nthose studying the potential bene\ufb01ts of AOT during an exercise\ntraining programme, and those that have examined the potential\nlonger term bene\ufb01ts of AOT on activity levels and quality of life.\nUse of AOT during exercise\nA Cochrane review of single assessment cross-over studies on\nthe short-term impact of AOT versus placebo air on exercise\ncapacity in moderate to severe COPD patients, reported that\nAOT signi\ufb01cantly improved all outcomes of endurance exercise\ncapacity (distance, time, number of steps) and that maximal\nexercise work rate also increased.82\nBene\ufb01ts in terms of reduced\nbreathlessness, levels of oxygenation and minute ventilation at\nthe time that the placebo test ended were also reported.\nHowever, the clinical signi\ufb01cance of the size of improvement\nseen in these single assessment studies is unclear.83\nThe addition of supplemental oxygen during exercise training\nmay allow patients who normally desaturate on exercise to toler-\nate higher levels of activity and therefore gain more from train-\ning. A meta- analysis included three RCTs examining the use of\nAOT during exercise training in COPD patients using compar-\nable outcome measures.84\nAlthough there were signi\ufb01cant\nimprovements in two parameters (constant power exercise time\nand constant power exercise end-of-test Borg score), there was\nno bene\ufb01cial effect from oxygen-supplemented training in a\nnumber of other parameters including maximal exercise out-\ncomes, functional exercise outcomes (6MWT), shuttle walk\ndistance, health-related quality of life and oxygenation status.\nA recent single-blinded RCTexamined use of AOT in a pulmon-\nary rehabilitation programme in 51 \u2018oxygen responders\u2019 who\nwere selected based on whether they had >10% improvement in\nexercise capacity when using AOT at baseline.85\nSigni\ufb01cant\nimprovements in walking distance as measured by an endurance\nshuttle walking test pre- and post-course (490 m, 95% CI 228 to\n750; p\u22640.001) were shown for those who had used AOT during\npulmonary rehabilitation. This area has also been reviewed in the\nBTS Guideline on Pulmonary Rehabilitation in Adults 2013.86\nIn a study of CF patients with advanced lung disease and\nnormal resting oxygen saturations, patients could exercise for\nlonger periods using supplemental oxygen during graded exer-\ncise tests.87\nIn a Cochrane review of AOT in CF, six studies eval-\nuated oxygen supplementation during exercise. Oxygenation\nimproved, but mild hypercapnia resulted and participants receiv-\ning oxygen therapy were able to exercise for a signi\ufb01cantly\ni18 Hardinge M, et al. Thorax 2015;70:i1\u2013i43. doi:10.1136\/thoraxjnl-2015-206865\nBTS Guidelines\ngroup.bmj.com\non June 19, 2016 - Published by\nhttp:\/\/thorax.bmj.com\/\nDownloaded from\nlonger duration.24\nEvidence for an effect of AOT on daily activ-\nity is lacking, but in clinical practice use of AOT to support\nexercise, physiotherapy and activities of daily living in patients\nwith CF is commonplace.\nLong-term impact of AOT\nThere are limited data on whether the symptomatic bene\ufb01ts out-\nweigh the practical dif\ufb01culties associated with using AOT in\neveryday life.\nA large parallel double-blinded 12-week RCT randomised\n143 COPD patients to use of AOT versus a control group using\ncompressed air.88\nThere were no signi\ufb01cant improvements in\nthe AOT group in terms of dyspnoea, quality of life or func-\ntional capacity, although only 50 patients were shown to desat-\nurate (de\ufb01ned in this case as SpO2 <88%). Average cylinder\nusage in both groups was low at just 40 min\/day, and 46% of\nthe AOT group reported they would prefer to cease using\noxygen therapy altogether at the end of the study. A number of\nsmaller studies (ie, n=20\u201345 patients) have examined the short-\nterm bene\ufb01ts of AOT in either crossover or parallel blinded\nstudies, lasting between 6 and 10 weeks.89\u201393\nModest statistic-\nally signi\ufb01cant improvements were seen in exercise capacity93\nand in health-related quality of life.89\nHowever, the majority\nfailed to show any sustained bene\ufb01t from AOT in a number of\nvariables, including dyspnoea, exercise capacity, St. George\u2019s\nRespiratory Questionnaire (SGRQ), health-related quality of\nlife, activity levels, distance walked or time away from home.\nAOT in patients eligible for LTOT\nAOT is often ordered for LTOT patients, or those who require\noxygen 24 h per day, to allow those who regularly mobilise out-\ndoors to leave the house and maintain their oxygen saturations\nwithin desired levels. Conversely for patients who require LTOT\nor are dependent on oxygen 24 h per day, but are not able to\nmobilise outdoors, AOT may assist them to leave the house on\nan occasional basis, for example for hospital appointments.\nRe-analysis of data from the NOTT study4 94\nshowed that in\nLTOT patients, AOT increased the chances of patients achieving\nthe 15 oxygen hours per day threshold, which has been shown\nto confer survival bene\ufb01ts, a \ufb01nding supported by other\nstudies.95\nHowever, AOT may prove burdensome for LTOT\npatients and not improve quality of life or exercise capacity. A\n1-year double-blinded crossover trial in 24 LTOT patients allo-\ncated them to one of: standard therapy of LTOT via an oxygen\nconcentrator only, standard therapy plus AOT, or standard\ntherapy plus ambulatory compressed air. Use of AOT did not\nimprove any of the primary outcome measures, including\nquality of life, exercise tolerance or daily duration of oxygen\nuse, and the trial was stopped prematurely after an interim ana-\nlysis.96\nHowever, patients were expected to collect their oxygen\ncylinders from the hospital themselves, which is likely to have\nhad an impact on usage.\nSome patients \ufb01nd the weight of standard cylinders prohibits\nuse, and so lightweight cylinders may be considered. Use of\nlightweight cylinders for AOT in comparison with \u2018normal\u2019\nweight cylinders had no impact on the hours of use or on activ-\nity levels, both of which were low at randomisation and\nthroughout the study in a 6-month unblinded RCT of 17 LTOT\npatients.97\nPoor compliance with AOT may result from lack of\ninformation provision, perceived unreliability of the delivery\nsystem, system weight, self-consciousness in public, and carer\nissues surrounding managing and using AOTequipment.98\nAssessment for AOT\nOxygen saturation (SpO2) measured from a \ufb01nger probe or the\nearlobe, is frequently used in clinical practice during exercise to\nassess patients and their response to AOT. When oximetry in 20\nCOPD patients performing 6MWTs with AOT both non-\ninvasively using ear-oximetry (SpO2) and invasively using\nCO-oximetry (SaO2) was compared,97\n\ufb02ow rates were incremen-\ntally increased until both SaO2 and SpO2 were >90%. Signi\ufb01cant\ndifferences were noted between SpO2 and SaO2 readings, which\nwould potentially have led to different \ufb02ow rates being ordered\nin 50% of subjects. For patients with a high respiratory rate, for\nexample those with CF or ILD, assessment using Venturi oxygen\nat a \ufb02ow rate suf\ufb01cient to exceed the patient\u2019s peak tidal (and\nexertional) inspiratory \ufb02ow can offer advantages over oxygen\ntherapy delivered by nasal cannulae. If total gas \ufb02ow exceeds the\npatient\u2019s inspiratory \ufb02ow rate, a Venturi mask will deliver an\naccurate oxygen concentration which may decrease the work of\nbreathing and facilitate CO2 control.99\nSee the section on equip-\nment for information on oxygen conservers.\nEvidence statements\n\u25b8 AOT has been shown to improve survival in patients on\nLTOT by helping them to achieve 15 h per day usage.\nEvidence level 1++\n\u25b8 AOT acutely increases exercise capacity in laboratory-based\nexercise tests in patients who are not eligible for LTOT but\nwho desaturate during exercise. Evidence level 1+\n\u25b8 Long-term use of AOT has not been shown to confer any\nsustained bene\ufb01ts in dyspnoea, exercise capacity, functional\ncapacity, time away from home or quality of life in patients\nwho are not eligible for LTOT. Evidence level 1+\n\u25b8 AOT has not been shown to improve quality of life, exercise\ntolerance or oxygen usage in patients on LTOT. Evidence\nlevel 1\u2212\n\u25b8 AOT leads to improvement in walking distance when given in a\npulmonary rehabilitation programme setting to patients who\nhave demonstrated a >10% improvement in exercise capacity\nwhen using AOTat baseline assessment. Evidence level 1\u2212\nRecommendations\n\u25b8 AOT should not be routinely offered to patients who are not\neligible for LTOT. (Grade B)\n\u25b8 AOT should not be routinely offered to patients already on\nLTOT. (Grade D)\n\u25b8 AOT assessment should only be offered to patients already\non LTOT if they are mobile outdoors. (Grade A)\n\u25b8 AOT should be offered to patients for use during exercise in\na pulmonary rehabilitation programme or during an exercise\nprogramme following a formal assessment demonstrating\nimprovement in exercise endurance. (Grade B)\nGood practice points\n\u25b8 Patients started on AOT should be reviewed regularly. If AOT\nwas started during an exacerbation or when unwell, an initial\nreview at 4\u20136 weeks to check it is still indicated is essential.\n(\u221a)\n\u25b8 Home visits may be useful to identify problems with equip-\nment or set-up. Further reviews should be carried out every\n6 months when stable, or sooner if the patient\u2019s clinical\nstatus changes. (\u221a)\n\u25b8 AOT therapy may offer patients with active lifestyles or\nactive treatment regimens (eg, CF) additional bene\ufb01ts. All\npatients should be assessed for AOT in the context of their\ndaily activity and therapies. (\u221a)\n\u25b8 It is recognised that there may be some patients, for example\nwith ILD and disabling breathlessness, who do not qualify\nHardinge M, et al. Thorax 2015;70:i1\u2013i43. doi:10.1136\/thoraxjnl-2015-206865 i19\nBTS Guidelines\ngroup.bmj.com\non June 19, 2016 - Published by\nhttp:\/\/thorax.bmj.com\/\nDownloaded from\nfor LTOT but who do desaturate on exercise, who may\nbene\ufb01t from AOT. Once all other medical interventions\nhave been optimised, these patients could be considered for\nAOT following formal assessment and AOT use could con-\ntinue following demonstration of bene\ufb01t and compliance.\n(\u221a)\n\u25b8 Patients with high respiratory rates (common in CF and ILD)\nshould receive AOT at a \ufb02ow rate via a Venturi mask, which\nexceeds their peak tidal and exertional inspiratory \ufb02ow, and\nbe supplied with home oxygen equipment which is able to\ndeliver the required high \ufb02ow rates. (\u221a)\n\u25b8 AOT may be offered to LTOT patients who could otherwise\nnot achieve 15 h per day oxygen usage, or who are severely\nhypoxaemic and are too symptomatic to leave their house\nwithout supplemental oxygen but may need to do so, for\nexample to attend GP or hospital appointments. Formal\nassessment is not required in these circumstances. (\u221a)\nFor suggested patient selection criteria and an AOT assessment\nprocedure for AOT during pulmonary rehabilitation, see appen-\ndix 1.\nPALLIATIVE OXYGEN THERAPY\nThe term \u2018palliative oxygen therapy\u2019 (POT) refers to the use of\noxygen to relieve the sensation of refractory persistent breath-\nlessness in advanced disease or life-limiting illness irrespective of\nunderlying pathology where all reversible causes have been or\nare being treated optimally.\nDyspnoea is common in patients with advanced life-limiting\nillness of all types. Breathlessness is a subjective sensation which\narises from a complex interaction of physiological and psycho-\nlogical stimuli and processing.100\nA number of small studies\nhave demonstrated the bene\ufb01t of non-pharmacological techni-\nques such as breathing control\/pacing, acupuncture101 102\nor a\nhand-held fan,103\nwhile the evidence supporting pharmaco-\nlogical management, principally opioids, is well established.104\nThis section discusses the role of home oxygen in the manage-\nment of intractable breathlessness in patients with advanced\ncancer or end-stage cardiorespiratory disease. The evidence\nreviewed dates from subsequent studies since the publication of a\nreport of the Expert Working Group of the Scienti\ufb01c Committee\nof the Association of Palliative Medicine on the use of oxygen in\nthe palliation of breathlessness in 2004.105\nHowever, as most par-\nticipants in studies had an Eastern Cooperative Oncology Group\n(ECOG) performance status of 2 or 3, this population might not\nbe representative of the sickest patients in palliative care.\nEffects of POT in comparison with air\nThe studies reviewed excluded patients with cognitive impair-\nment106 107\nand those with a prognosis of <1 month.107\nOxygen\nwas delivered by nasal cannula or mask, and \ufb02ow rate varied\nfrom 2 to 5 L\/min. Studies also varied regarding duration of\noxygen therapy, ranging from 15 min106\nand 60 min108\nto\n15 h.107\nOxygen was delivered at rest in two studies,106 109\non\nexertion in one108\nand continuously for 15 h in another study.107\nNo studies looked at life expectancy, but one study reported\nquality of life.107\nA double-blind crossover study randomised 51 patients with\nadvanced cancer, 17 of whom were hypoxaemic (SpO2 <90%)\nto 15 min of either air or palliative oxygen.106\nPatients (whether\nhypoxaemic at baseline or not) improved symptomatically with\nboth air and oxygen, but there were no signi\ufb01cant differences\nbetween the treatments. A systematic review and meta-analysis\nof the ef\ufb01cacy of palliative oxygen for relief of dyspnoea in\nhypoxaemic (mean SpO2 88%) or non-hypoxaemic cancer\npatients included 134 patients.108\nAlthough palliative oxygen\nwas administered in a variety of ways (nasal cannula or mask;\nrest or 6MWT; \ufb02ow rate 3\u20135 L\/min), there was no improvement\nin dyspnoea. A double-blind RCT compared air with palliative\noxygen (2 L\/min for 15 h per day for 7 days from a concentra-\ntor) in 239 patients with cancer or end-stage cardiorespiratory\ndisease.107\nThere was no statistically signi\ufb01cant difference\nbetween the two groups in breathlessness (measured twice\ndaily), frequency of side effects, or change in quality of life\nbetween groups. Finally, a cohort study failed to demonstrate\nany symptomatic bene\ufb01t over 2 weeks of the provision of home\npalliative oxygen as measured by routine recording of breath-\nlessness with each clinical encounter with a specialist commu-\nnity palliative care team.110\nEffects of POT in comparison with other therapies such as\nopiates, fan therapy and cognitive behaviour therapy\nThere are no reported studies comparing POT with fan therapy,\ncognitive behavioural therapy or other techniques for symptom-\natic relief of breathlessness.\nOne study assessed the effects of oxygen and opioid treatment\non ventilation and palliation of dyspnoea in hypoxaemic (SpO2\n<90%) and non-hypoxaemic (SpO2 \u226590%) palliative care\npatients (either opioid-naive or pre-treated with strong opioids)\nin a prospective non-randomised study.109\nWhereas opioid\nadministration resulted in a signi\ufb01cant decrease in the intensity\nof dyspnoea in hypoxaemic or in non-hypoxaemic patients,\nnasal oxygen therapy did not. There was no signi\ufb01cant correl-\nation between intensity of dyspnoea and SpO2, and no signi\ufb01-\ncant difference between hypoxaemic or non-hypoxaemic\npatients with regard to transcutaneous CO2 increase or SpO2\ndecrease after administration of opioids.\nEvidence statements\n\u25b8 Measurements of oxygenation do not correlate well with the\nsubjective experience of dyspnoea in patients with cancer or\nend-stage cardiorespiratory disease. Evidence level 2+\n\u25b8 Hypoxaemic patients do not experience a signi\ufb01cant differ-\nence in symptoms between air and POT despite having\nimproved oxygen saturations when administered oxygen.\nEvidence level 2+\n\u25b8 Non-hypoxaemic patients or those with mild levels of hypox-\naemia who would not normally qualify for LTOT do not\nexperience symptomatic bene\ufb01t with POT compared with air.\nEvidence level 1++\n\u25b8 Opioids are signi\ufb01cantly better than POT in reducing the\nintensity of dyspnoea in non-hypoxaemic or hypoxaemic\npatients. Evidence level 1+\nRecommendations\n\u25b8 Patients with cancer or end-stage cardiorespiratory disease\nwho are experiencing intractable breathlessness should not\nreceive treatment with POT if they are non-hypoxaemic or\nhave mild levels of hypoxaemia above current LTOT thresh-\nolds (SpO2 \u226592%). (Grade A)\n\u25b8 Patients with cancer or end-stage cardiorespiratory\ndisease who are experiencing intractable breathlessness\nshould receive assessment for a trial of treatment with\nopiates from an appropriately trained healthcare profes-\nsional. (Grade A)\n\u25b8 Patients with cancer or end-stage cardiorespiratory disease\nwho are experiencing intractable breathlessness should\nreceive assessment for a trial of treatment with non-\npharmacological treatments including fan therapy, from an\nappropriately trained healthcare professional. (Grade D)\ni20 Hardinge M, et al. Thorax 2015;70:i1\u2013i43. doi:10.1136\/thoraxjnl-2015-206865\nBTS Guidelines\ngroup.bmj.com\non June 19, 2016 - Published by\nhttp:\/\/thorax.bmj.com\/\nDownloaded from\nGood practice point\n\u25b8 POT may on occasion be considered by specialist teams for\npatients with intractable breathlessness unresponsive to all\nother modalities of treatment. In those instances, individual\nformal assessment of the effect of palliative oxygen on redu-\ncing breathlessness and improving quality of life should be\nmade. (\u221a)\nFor suggested patient selection criteria and a protocol for POT\nassessment, see appendix 3.\nSHORT BURST OXYGEN THERAPY\nSBOT is typically given to patients for the relief of breathless-\nness not relieved by any other treatments. It is used intermit-\ntently at home for short periods, for example 10\u201320 min at a\ntime. Oxygen used in this way has traditionally been ordered\nfor non-hypoxaemic patients and used for subjective relief of\ndyspnoea prior to exercise for oxygenation or after exercise for\nrelief of dyspnoea and recovery from exertion.\nUse of SBOT in respiratory disease\nThe studies reviewed were limited to patients with COPD and\nincluded normoxic and hypoxaemic patients with moderate to\nsevere disease. Two studies examined oxygen delivery before\nand after exercise, while four studies administered oxygen after\nexercise. One study that examined the bene\ufb01t of oxygen after\nexercise included patients given LTOT,111\nhowever hypoxaemic\nand non-hypoxaemic patients were not analysed separately.\nThere were no studies that speci\ufb01cally examined the bene\ufb01ts of\nSBOT ordered for hypoxaemic patients alone.\nIn order to examine the effect of supplemental oxygen before\nand after exercise in stable COPD patients with moderate to severe\ndisease who demonstrated exercise desaturation, Nandi et al112\nundertook two double-blind randomised studies. In the \ufb01rst study,\n34 subjects received either cylinder air or oxygen 28% at a \ufb02ow\nrate of 4 L\/min for 10 min before a 6MWT. In the second study,\n18 subjects received either cylinder air or cylinder oxygen for\n5 min immediately after a 6MWT. Those that took part in both\nstudies did so on different days. Distance walked, oxygen satura-\ntions and breathlessness as measured by a VAS were recorded as\nwas time to recovery. No difference was found in distance walked,\nsubjective breathlessness or recovery time when oxygen was admi-\nnistered prior to exercise. Nor was there any signi\ufb01cant difference\nin distance walked, recovery time or breathlessness when oxygen\nwas administered following exercise. The authors concluded that\nno recommendation could be made to support a useful therapeutic\nrole for SBOT.\nSimilarly, SBOTwas not found to have any effect on perform-\nance when administered before and after exercise in 22 non-\nhypoxaemic COPD patients with moderate to severe disease.113\nSubjects undertook four 6MWTs at each of two sessions.\nCylinder air or oxygen was randomly administered prior to the\n\ufb01rst two walk tests and during recovery following the \ufb01nal two\ntests. The group found no signi\ufb01cant difference in distance\nwalked or breathlessness as measured by the Borg score for air\nand oxygen given prior to exercise and no signi\ufb01cant difference\nin mean time to resting Borg score when oxygen was given after\nexercise.\nAnother study compared oxygen, air, fan and no treatment in\n34 stable patients with moderate to severe COPD who were\nshort of breath on minimal exertion and who were not hypox-\naemic (SaO2 \u226493% at rest).114\nPatients undertook an exercise\nstep test on four occasions and after each test were given either\noxygen 4 L\/min from a face mask, air from a face mask, air\nfrom a fan, or no intervention. Fourteen patients desaturated on\nexercise below 90%. Oxygen therapy had no signi\ufb01cant effect\non Borg scores even for those patients who desaturated. Oxygen\nsaturation rose more quickly and to a higher level when the\noxygen mask was used compared with other treatments\n(p<0.009), but this increase of 2% had no effect on subjective\nbreathlessness as measured by the Borg score.\nPatients were asked to choose whether they received treatment\nbefore or after exercise in a study that examined 22 stable COPD\npatients with moderate to severe disease.111\nSubjects were studied\nat home undertaking an activity of choice (mean resting SaO2\n93.1% (range 82\u201398%)). All had domiciliary oxygen ordered for\nthem and 50% were on LTOT. In this double-blind study, cylinder\nair or oxygen was randomly administered after exercise.\nInterestingly, all subjects chose after exercise. The exercise was\nrepeated after a rest period and the alternative treatment adminis-\ntered. There was no difference in recovery times with oxygen com-\npared with air. Five patients were able to correctly identify oxygen\nfrom air on both occasions. This group had shorter subjective and\nobjective recovery times when compared with the rest of the\ngroup, although this did not reach statistical signi\ufb01cance.\nA reduced recovery time as measured by a VAS was associated\nwith oxygen use compared with compressed air or placebo in a\nstudy of 19 subjects with stable severe COPD (mean (SD) PaO2\n8.05 (1.52) kPa).115\nSubjects undertook three step tests to\nmaximal dyspnoea and then were administered either cylinder\noxygen 67% via a mask, cylinder air at the same \ufb02ow for\n20 min, or no mask in random order. The results were not\nfound to be reproducible when the seven responders were\nre-tested after a time lapse of between 1 week and 1 month.\nIn a study undertaken by Stevenson and Calverley, 18 stable\nCOPD patients were included, none of whom were hypoxaemic at\nrest, although six patients did desaturated on exercise (range\n88\u201396%).116\nPatients attended on two occasions at least 1 week\napart. At each visit, patients performed a maximal cardiorespira-\ntory exercise test following which they randomly received either\nair or oxygen (FiO2 0.4) in a single-blind crossover fashion. At one\nvisit the subject remained instrumented during recovery, while at\nthe other visit the mouthpiece and nose clips were replaced with a\nVenturi mask at a \ufb02ow rate of 10 L\/min. The results revealed that\nfollowing exercise, administration of oxygen when compared with\ncompressed air was associated with a reduced ventilatory effort\nand dynamic hyperin\ufb02ation resolution was shorter; however, there\nwas no reduction of breathlessness as measured by the Borg score\nat any time during recovery between oxygen and air inhalation,\nnor did oxygen in\ufb02uence the rate at which symptoms were\nresolved. The authors concluded that the routine use of oxygen to\naid recovery of symptoms after exercise does not appear to be\njusti\ufb01ed.\nHealthcare utilisation and quality of life were measured in a ran-\ndomised double-blind placebo-controlled trial in patients with\nmoderate to severe disease following an admission to hospital with\nan exacerbation of COPD.117\nA total of 78 non-hypoxaemic\npatients were recruited and were randomised to cylinder air, cylin-\nder oxygen or usual care for 6 months following discharge from\nhospital. The subjects who were randomised to cylinder air or\ncylinder oxygen were instructed to use it at 2 L\/min via nasal can-\nnulae as needed for relief of distressing or limiting breathlessness.\nCylinder use was self-recorded in patient diaries. Healthcare util-\nisation was assessed by number of COPD-related readmissions and\nunscheduled emergency department or primary care visits.\nQuality of life was measured using the Chronic Respiratory\nDisease Questionnaire (CRQ), the Hospital Anxiety and\nDepression Scale (HAD) and the Medical Outcomes Study Short\nHardinge M, et al. Thorax 2015;70:i1\u2013i43. doi:10.1136\/thoraxjnl-2015-206865 i21\nBTS Guidelines\ngroup.bmj.com\non June 19, 2016 - Published by\nhttp:\/\/thorax.bmj.com\/\nDownloaded from\nForm (SF-36). There was no signi\ufb01cant difference between patient\ngroups in any of the health-related quality of life measures apart\nfrom the emotions domain of the CRQ for the usual care group.\nHospital readmission and healthcare utilisation were high.\nHowever, there was no signi\ufb01cant difference between groups.\nCylinder use was initially high but fell rapidly within weeks in\nboth the cylinder air and oxygen groups. The authors conclude\nthat these results do not offer any support for the use of SBOTon\ndischarge from hospital following an acute exacerbation of COPD.\nEvidence statements\n\u25b8 SBOT does not improve exercise tolerance or reduce breath-\nlessness when administered either before or following exer-\ncise to hypoxaemic or non-hypoxaemic patients with\nmoderate to severe COPD. Evidence level 1++\n\u25b8 SBOT does not improve health-related quality of life or\nreduce healthcare utilisation when ordered for patients fol-\nlowing an acute exacerbation of COPD. Evidence level 1++\nRecommendations\n\u25b8 SBOT should not be ordered for use prior to or following\nexercise in hypoxaemic or normoxic patients with COPD.\n(Grade A)\n\u25b8 SBOT should not be ordered on discharge from hospital for\nnon-hypoxaemic patients with severe COPD. (Grade A)\nUse of SBOT in CH\nCH pain is the most severe of the primary headache syndromes.\nIt is characterised by periodic attacks of strictly unilateral pain\nassociated with ipsilateral cranial autonomic symptoms. The\nmajority of patients have episodic cluster headache (ECH), with\ncluster periods that typically occur in a circannual rhythm, while\n10% have the chronic form (CCH), with no signi\ufb01cant remis-\nsions between cluster periods. High \ufb02ow oxygen therapy is used\nto relieve pain and is delivered usually from static oxygen cylin-\nders in the patient\u2019s home.\nIn a double-blind randomised, placebo-controlled cross-over\ntrial, 109 adults were treated for CH attacks with either 100%\noxygen (12 L\/min) or inhaled air, given via a facial mask for\n15 min at the start of an attack. Fifty-seven patients with ECH\nand 19 with CCH were available for the analysis.118\nOxygen was\nsigni\ufb01cantly superior to placebo in elimination of pain or provi-\nsion of \u2018adequate pain relief\u2019 at 15 min in 78% of patients (vs\n20% with air). In a case series of 52 randomly selected out-\npatients with either active ECH or CCH, 100% oxygen was\nadministered through a facial mask at a rate of 7 L\/min for\n15 min at the onset of each of 10 cluster attacks.119\nOverall, 75%\nof patients obtained signi\ufb01cant relief (de\ufb01ned as complete or\nalmost complete reduction of pain in seven of 10 attacks within\n15 min) from cluster pain. These \ufb01ndings were supported by a\ndouble-blind crossover study of 19 patients where use of SBOT\n(6 L\/min via non-rebreather face masks for 15 min) produced sig-\nni\ufb01cantly higher average relief scores for all oxygen-treated\npatients.120\nA case report of three patients unresponsive to\noxygen given at 7\u201310 L\/min reported complete or near complete\nalleviation of headache after 100% oxygen at a rate of 14\u201315\nL\/min.121\nNon-responders to SBOT have more often smoked in\nthe past (p=0.014), had longer CH attacks (p=0.049), and\nreported more inter-ictal headache (p=0.02) than responders.122\nA single-blind crossover trial of 50 patients has compared sub-\nlingual ergotamine tartrate to SBOT (100% oxygen via a face\nmask, at a rate of 7 L\/min for 15 min) for symptomatic relief of\ncluster attacks showed no statistical difference between treat-\nment groups.119\nNICE (National Institute of Health and Care Excellence) guide-\nlines on the diagnosis and management of headaches in young\npeople and adults, published in September 2012, recommend\noxygen and\/or a subcutaneous or nasal triptan for the acute treat-\nment of CH.123\nIt is recommended that oxygen should be given at\na \ufb02ow rate of at least 12 L\/min with a non-rebreather mask and a\nreservoir bag arranged as home oxygen. (NICE refers to ambula-\ntory oxygen in this context which differs from the de\ufb01nition of\nambulatory oxygen used in this guideline).\nEvidence statement\n\u25b8 SBOT delivering high \ufb02ow oxygen (12 L\/min via a non-\nrebreather mask) is an effective symptomatic treatment for\nacute CH attacks. Evidence level 1+\nRecommendation\n\u25b8 SBOT delivering high \ufb02ow oxygen therapy (12 L\/min via a\nnon-rebreather mask) should be offered to treat acute attacks\nof CH. (Grade A)\nGood practice point\n\u25b8 Appropriate equipment will need to be provided in order to\nensure delivery of high \ufb02ow rate oxygen at 12 L\/min for CH\nusing a non-rebreather mask. Patients will usually have\nwarning of a CH attack, and so provision should be made\nfor urgent 4 h installation of home oxygen, if available,\nrather than a permanent home supply being provided. (\u221a)\nEQUIPMENT FOR HOME OXYGEN THERAPY\nThe equipment for home oxygen therapy can be divided into\nthree categories: oxygen source (concentrators, cylinders and\nliquid oxygen), oxygen delivery (cannulae, masks, conservers\nand tracheal devices) and supplementary equipment (humidi\ufb01ers\nand equipment to carry oxygen). Please see online supplemen-\ntary appendix 12 for illustrations and further details of equip-\nment types.\nOxygen source: concentrators, cylinders and liquid oxygen \u2013\ndescription and indications for use\nHome oxygen can be delivered from cylinders, concentrators or\nas liquid oxygen. Each of these oxygen sources can be static or\nportable, and the source selected is dependent upon the mobil-\nity and clinical circumstances of the patient, along with the costs\nof installation and supply as determined by the oxygen provider.\nThere are few published studies comparing the different modes\nof oxygen source in different clinical situations. Some studies\nhave compared similar devices, but many of these are now out-\ndated and technology has superseded them.\nConcentrators\nThe most common device for LTOT delivery is an oxygen con-\ncentrator which can either be \ufb01xed in a room in the house or is\nportable to go with the patient around the home, outside the\nhome and in the workplace. An oxygen concentrator is an elec-\ntrically driven device which takes room air and passes it through\na \ufb01ltering system, removing nitrogen, to supply an oxygen-\nenriched gas mixture (usually 85\u201395% oxygen).\nPerformance of oxygen concentrators can vary depending on\nthe technology used.124\u2013130\nThe maximum oxygen concentra-\ntion delivered by an oxygen concentrator is 96%,124\nbut there\ncan be a difference in performance between devices depending\nupon \ufb02ow rate. In a study that assessed a number of oxygen\nconcentrators, all concentrators were found to deliver suf\ufb01cient\noxygen to achieve target oxygen saturation levels above 92% at\n\ufb02ow rates of 2 L\/min, of 85\u201394% at 3 L\/min and of 69\u201385% at\n4 L\/min depending upon the device.126\nThis can result in\ni22 Hardinge M, et al. Thorax 2015;70:i1\u2013i43. doi:10.1136\/thoraxjnl-2015-206865\nBTS Guidelines\ngroup.bmj.com\non June 19, 2016 - Published by\nhttp:\/\/thorax.bmj.com\/\nDownloaded from\npatients not receiving their oxygen as ordered.131\nIn another\nseries of 2400 oxygen concentrator users, where the \ufb02ow rate\nwas 2 L\/min or less in 79% of users, the mean\u00b1SD oxygen sat-\nuration achieved was 92\u00b16%.127\nIt is current clinical practice to\nuse a combination of two oxygen concentrators joined via a\nT-piece to deliver high \ufb02ow rates, for example 12 L\/min when\nrequired, although there is no clinical trial evidence to support\nthis practice and it is unknown whether the equipment used per-\nforms adequately in this way.\nHome concentrators\nHome concentrators will be installed and regularly maintained\nby oxygen provider companies. In order to reduce risk of falls\nfrom tripping over long lengths of tubing, they may be \u2018piped\nin\u2019 to the home with appropriate tubing to areas where the\npatient will use the oxygen (bedroom, living room). All concen-\ntrators should have \ufb01re breaks inserted into the tubing\u2014one at\nthe patient end and one at the machine end\u2014to reduce the risk\nof potentially catastrophic \ufb01res (see the section on safety and\nhome oxygen). Oxygen concentrators can deliver \ufb02ow rates of\nup to 4 L\/min, adjustable in 0.5 L\/min increments. Where low\n\ufb02ow is needed, for example in paediatric, NIV use and oxygen-\nsensitive patients, \ufb02ow metres that reduce \ufb02ow can be added to\nthe standard concentrator. High \ufb02ow oxygen concentrators can\ndeliver \ufb02ow rates of 8 L\/min. For very high \ufb02ows, concentrators\ncan be joined via a T-piece and each concentrator must be set to\nthe same \ufb02ow, for example 12 L\/min required would need two\nhigh \ufb02ow concentrators both set at 6 L\/min, although there is\nno research evidence to support their use in this way. This\noption may not be available and it is suggested that home\noxygen teams check with their oxygen supplier. Concentrators\nare recommended for patients using oxygen for more than 1.4 h\na day.132\nPractical considerations for patients are the need to\nchange \ufb01lters weekly, regular servicing of the machine, the\nwarm-up period of the machine and the noise of the device. A\nnew development is a concentrator which can be used to re\ufb01ll\nsmall portable cylinders at home, known as a \u2018home \ufb01ll\u2019 oxygen\nsystem.\nTransportable and portable concentrators\nTransportable concentrators are similar to home concentrators\nbut smaller in size and more portable with a typical weight\nbeing 4.5\u20138.6 kg. They come with batteries as well as a mains\nattachment, allowing use outside as well as inside the home.\n(Inside the home, a transportable concentrator can be used as a\nstandard concentrator as well as ful\ufb01lling the patient\u2019s ambula-\ntory needs.) The battery for use outside the home does limit the\ntime they can be used without recharging and will depend on\nthe \ufb02ow rate and whether the pulsed mode is used. They can be\nused and charged in cars. Most are now approved for use on\ncommercial aircraft, although patients are currently advised not\nto take their supplied equipment out of the country as it will\nnot be supported by the oxygen supplier in the event of a mal-\nfunction when abroad. Current models are available that deliver\nup to 3 L\/min continuous oxygen and 6 L\/min pulsed oxygen,\nand come with a power adapter to plug into an electrical\nsource, or a battery back-up.\nPortable concentrators are somewhat lighter than transport-\nable concentrators, with a typical weight being 3.3\u20134.5 kg. The\nmajority of portable oxygen concentrators provide pulsed\noxygen only. Therefore, they are not suitable for use when\nsleeping. It should be noted that some portable concentrators\nhave numerical settings, for example number 2 does not equate\nto 2 L\/min, and some do not alarm when they malfunction.\nCylinder oxygen\nA cylinder is a strengthened metal container containing com-\npressed gas held under high pressure safely for use via its regula-\ntor (tap). Oxygen cylinders come in a range of sizes and hence\ncapacity, ranging from small portable cylinders to large static\ncylinders (see online supplementary appendix 12), and are\ncolour coded to distinguish them from other medical gases.\nCurrently, oxygen cylinders are white with writing denoting the\ncontent down the side, and black with white shoulder: all\nmedical oxygen cylinders will be white bodied by 2025. The\n\ufb02ow rate can be \ufb01xed or variable depending on patient require-\nments. All systems containing compressed gases in the UK are\nsubject to the Pressure Systems Safety Regulations 2000 (SI\n2000 No 128), which are intended to prevent the risk of injury\nfrom pressurised systems.\nHistorically, static cylinders have usually been used to deliver\nshort burst or palliative oxygen in the home but now \ufb01nd their\nmain use as back-up cylinders if there is a power cut or concen-\ntrator failure or in the treatment of CH patients. Lightweight\ncylinders (example weight 8 kg\/3.6 lb) and standard ambulatory\ncylinders (example weight 3.2 kg\/7 lb) are available for ambula-\ntory use.\nLiquid oxygen\nLiquid oxygen is oxygen that is cooled so that it condenses from\na gas to a liquid which can be stored in insulated containers.\nLiquid oxygen is generally stored in large Dewar \ufb02asks with a\ndecanting system to deliver it to smaller portable Dewar \ufb02asks.\nThe length of time these can last will depend on the \ufb02ow pro-\nvided and the size of the Dewar \ufb02ask. Users need to be trained\nto connect the two containers to reduce problems of gas\nleakage and also to prevent users received cold burns through\ninappropriate handing of the device. Choices between these\ndevices should take account of individual patient\u2019s dexterity,\nvisual acuity and strength. Liquid oxygen Dewar \ufb02asks can only\nbe installed on a ground \ufb02oor due to venting and safety\nconsiderations.\nComparison of different oxygen sources in clinical trials\nThe majority of clinical trials in this area focus on delivery of\nportable oxygen either to facilitate use of ambulatory oxygen or\nto use as a method of delivery of LTOT with home oxygen con-\ncentrators. There are six methods of delivering portable oxygen:\nliquid, home \ufb01ll cylinder, portable cylinder, lightweight cylinder,\nportable and transportable oxygen concentrator.\nUse of portable oxygen to deliver ambulatory oxygen\nSeveral small RCTs have compared different modalities of port-\nable oxygen97 133 134\nin short-term or exercise test-based\nstudies. Comparison of standard portable cylinders with light-\nweight cylinders97\nand safe-\ufb01ll portable cylinders133\nshowed no\ndifference in activity levels (which were low), oxygen saturation,\nBorg score or 6MWT between the different modalities. In a\ncomparison of four different methods of supplying portable\noxygen (liquid, home \ufb01ll cylinder, portable concentrator and\nlightweight cylinder) in 44 patients with stable severe COPD,\nthere were no differences between oxygen saturation, distance\nwalked or time used.134\nCylinder oxygen was least favoured by\npatients and liquid oxygen was most favoured with the lowest\nlong-term costs. Despite a lack of improvement in quality of life\nin this study, the patients using liquid oxygen in comparison\nwith portable cylinders spent signi\ufb01cantly longer outside the\nhouse and used their oxygen more.135\nIn another study of\nHardinge M, et al. Thorax 2015;70:i1\u2013i43. doi:10.1136\/thoraxjnl-2015-206865 i23\nBTS Guidelines\ngroup.bmj.com\non June 19, 2016 - Published by\nhttp:\/\/thorax.bmj.com\/\nDownloaded from\npatients with severe COPD comparing continuous \ufb02ow liquid\noxygen with a portable concentrator, there was no signi\ufb01cant\ndifference in use or level of oxygenation. The \ufb02ow rate of\noxygen needed on ambulation was an average of three times\nhigher than at rest.136\nUse of portable oxygen to deliver LTOT\nSmall RCTs and an observational study have examined the use\nof portable oxygen in contributing to the delivery of LTOT.\nPortable devices compared with home-based LTOT alone\nimproved oxygen usage.95\nUse of liquid oxygen with or instead\nof a concentrator can increase daily use of oxygen137\u2013139\nand\nimprove quality of life,137\nbut overall costs can be higher.137 138\nStatic cylinder use\nA survey of patients using static oxygen cylinders at home found\nthat most had a diagnosis of COPD and used oxygen regularly\nfor short-term relief of breathlessness, with 58% using their\noxygen at least once a day. On average these patients used three\ncylinders each per month.140\nEvidence statements\n\u25b8 Portable oxygen provides greater oxygen daily usage and\nimproved quality of life than static concentrators alone.\nEvidence level 1\u2212\n\u25b8 There is no conclusive difference in activity levels or utilisa-\ntion between different methods of portable oxygen, but\npatient preference is generally for liquid oxygen. Evidence\nlevel 1\u2212\n\u25b8 Lightweight cylinders do not improve walking distance or\noxygen utilisation and may lead to increased costs. Evidence\nlevel 1\u2212\n\u25b8 Oxygen concentrators are the most cost-effective way to\ndeliver LTOT, but can have variable ef\ufb01ciency depending on\n\ufb02ow rates, particularly above 4 L\/min. Evidence level 2++\nRecommendations\n\u25b8 Oxygen concentrators should be used to deliver LTOT at\n\ufb02ow rates of 4 L\/min or less. (Grade B)\n\u25b8 Portable oxygen should be delivered by whatever mode is\nbest suited to the individual needs of the patient to increase\nthe daily amount of oxygen used and activity levels in mobile\npatients. (Grade C)\nGood practice point\n\u25b8 The type of portable device selected should balance patient\nfactors with cost effectiveness, resources and safety. (\u221a)\nOxygen delivery: nasal cannulae and masks,\noxygen-conserving devices and trans-tracheal devices\u2013\ndescription and indications for use\nMethods of home oxygen delivery depend upon the patient\u2019s\nrequirements and the setting for delivery of care. Interfaces used\nfor home oxygen fall into two main categories: nasal cannulae\nand face masks using the Venturi system. Trans-tracheal delivery\nis rarely used but will be brie\ufb02y described. In addition, oxygen-\nconserving devices may be used to facilitate oxygen delivery.\nMost home oxygen tubing has a \u2018\ufb01re break\u2019 inserted at the\npatient end of the tubing just before the nasal cannula or mask:\nthis is a thermal fuse which when triggered will stop the oxygen\nsupply in the event of \ufb01re.\nNasal cannulae and masks\nNasal cannulae are the most common interface for oxygen\ndelivery. This is largely the result of a compromise between\npatient comfort and tolerance when using oxygen for 15 h\/day\nand the need for controlled oxygen concentration delivery.\nNasal cannulae are usually lightweight, soft plastic\/silicone\ntipped tubing that are dual-pronged and sit in the nostrils, held\nin position by looping the tubing over the pinna of the ears, and\nallow oxygen delivery continuously into the nose. The nasal\ncannula delivers a low \ufb02ow of oxygen entrained in a larger\nvolume of atmospheric air so that each litre per minute of\noxygen \ufb02ow adds about 3\u20134% to the inspired oxygen concentra-\ntion. The respiratory rate as well as underlying disease process\nwill determine the actual oxygen delivery. However, a small\nnon-randomised trial showed that oxygen delivery with nasal\ncannulae can be very variable, with individual inspired oxygen\nconcentrations varying between 24% and 35% with the same\n\ufb02ow rate of 2 L\/min.141\nHigh \ufb02ow nasal cannulae are used in\ncritically unwell patients and not appropriate to the home\noxygen population.\nOxygen masks are minimal volume, made of clear, soft plastic\nand held over the nose and mouth with elasticated straps for\ncomfort. Venturi masks are designed to deliver accurate concen-\ntrations of oxygen when used with certain \ufb02ow rates. They are\nfavoured for delivery of controlled oxygen concentrations\nwhere this is clinically important, such as in patients with hyper-\ncapnic respiratory failure requiring LTOT. Other patient factors\nmay be relevant such as confused or demented patients where\n\ufb02ows might be altered in error.\nOther interfaces such as the OxyArm have been developed\nallowing minimal head contact but no facial contact, and the\npotential for use in both nose and mouth breathers, and in\npatients with high respiratory rates. When used in stable COPD\npatients requiring LTOT over a 4-week period, nasal cannulae\nand OxyArm gave similar oxygen delivery, but fewer patients\npreferred the OxyArm due to dislodgement and reduced\nmobility.142\nOxygen-conserving devices\nOxygen-conserving devices deliver oxygen during inspiration\nonly and, by reducing oxygen wasted during expiration, enable\ncylinders to last longer compared to constant \ufb02ow. This can\nreduce costs by reducing the number of home deliveries. Most\noxygen delivery systems now have conservers \ufb01tted as standard.\nEach model of conserver will have very different speci\ufb01cations\nchosen by the manufacturers to suit the device and are not able\nto be changed by the users. This high degree of variability\nmeans that they are not truly comparable from one make or\nmodel to another. Reservoir cannulae are a form of oxygen-\nconserving device but are rarely used in home oxygen services;\ninformation about them can be found in the BTS Emergency\nOxygen guidelines. Historical studies performed prior to con-\nservers becoming standard equipment have not been reviewed.\nMost studies have agreed that conservers can reduce oxygen\nusage by as much as 50%.126 143 144\nThe demand oxygen deliv-\nery system produced only a small increase in walk distance\nwithout elevation of oxygen saturation, but was inferior to con-\ntinuous \ufb02ow oxygen in most of the measured variables when\ncompared directly.145\nHowever, it has been suggested that\noxygen-conserving devices vary in their ability to maintain SaO2\nlevels during exercise146 147\nand that some patients (particularly\nthose who mouth breathe) may struggle to trigger them, and\ntherefore patients should have ambulatory assessments before\nbeing issued with them. The evidence for the use of nocturnal\noxygenation using a pulsed-dose oxygen-conserving device com-\npared to continuous \ufb02ow is limited.148\nContinuous oxygen was\ncompared with pulsed oxygen delivery at two different settings\nand showed no clinical difference. The evidence for the use of\ni24 Hardinge M, et al. Thorax 2015;70:i1\u2013i43. doi:10.1136\/thoraxjnl-2015-206865\nBTS Guidelines\ngroup.bmj.com\non June 19, 2016 - Published by\nhttp:\/\/thorax.bmj.com\/\nDownloaded from\npulse dose conservers at night is at best very poor and requires\nmore research.\nTrans-tracheal oxygen\nThis form of oxygen can be used but rarely in the home setting\nand requires dedicated support from a trained team. Oxygen is\ndelivered via a catheter inserted percutaneously between the\nsecond and third tracheal rings. By reducing anatomical dead\nspace, it allows lower levels of oxygen to be required than nasal\ncannulae, and reduces the work of breathing. Serious complica-\ntions can include catheter displacement, obstruction of the cath-\neter by mucous, and infection.\nEvidence statements\n\u25b8 Nasal cannulae can be used to deliver home oxygen at low\n\ufb02ow rates and are acceptable to patients. Evidence level 4\n\u25b8 Nasal cannulae provide variable inspired concentrations of\noxygen when used at the same \ufb02ow rate in different patients.\nEvidence level 4\n\u25b8 Oxygen-conserving devices reduce total oxygen usage.\nEvidence level 1+\n\u25b8 Oxygen-conserving devices vary in their ability to maintain\nSaO2 levels during exercise, and some patients struggle to\ntrigger them. Evidence level 1+\nRecommendations\n\u25b8 Nasal cannulae should be considered as the \ufb01rst choice of\ndelivery device for patients requiring home oxygen therapy.\nAs an alternative, some patients may bene\ufb01t from or prefer a\nVenturi mask system. (Grade D)\n\u25b8 Oxygen-conserving devices can be used in home oxygen\npatients requiring high \ufb02ow rates to increase the time the\ncylinder will last. (Grade B)\nGood practice points\n\u25b8 Venturi masks should be considered in patients in whom\nthere are concerns about existing or developing hypercapnic\nrespiratory failure, those with a high resting respiratory rate\nor those with cognitive problems. (\u221a)\n\u25b8 Oxygen-conserving devices should be considered in patients\nwho are active outside the home, following an ambulatory\noxygen assessment. (\u221a)\nOther equipment: trolleys and backpacks, humidi\ufb01ers\u2013\ndescription and indications for use\nPatient compliance with treatment is greatly improved with sup-\nplementary equipment which may help address practical issues\naround home oxygen provision.\nHumidi\ufb01cation\nOxygen is sometimes humidi\ufb01ed in an attempt to prevent a\ndrying effect of oxygen if delivered at high \ufb02ow rates or in\npatients with excessive chest secretions such as those with CF or\nbronchiectasis. Systems are available for the humidi\ufb01cation of\nsupplemental oxygen by bubbling oxygen through sterile water.\nWhereas nebulised saline given in single doses can help airways\nclearance in the presence of thick secretions, there is no\nevidence to support the use of continuous humidi\ufb01cation and\nthe effect on patient comfort is negligible.147 148\nSome studies\nconclude the risks of infection contraindicate its use.149 150\nFor\npatients with a tracheostomy tube, natural mechanisms to warm\nand moisturise inspired gases have been bypassed. It is therefore\nessential to humidify any supplemental oxygen being delivered\nto the tracheostomised patient to help maintain a patent trache-\nostomy tube, reduce the build-up of secretions within the inner\ntube or the tracheostomy itself, and minimise any subjective dis-\ncomfort that the patient may experience. However, there are no\ntrial data to evaluate this approach. More detail about the use of\noxygen in tracheostomy patients is given in the BTS emergency\noxygen guideline.2\nEvidence statement\n\u25b8 There is no evidence of patient bene\ufb01t from use of humidi-\n\ufb01ed oxygen. Evidence level 3\nRecommendation\n\u25b8 Humidi\ufb01cation of home oxygen should not be ordered for\nnon-tracheostomy patients. (Grade D)\nGood practice point\n\u25b8 Patients receiving oxygen via a tracheostomy should receive\nhumidi\ufb01ed oxygen. (\u221a)\nCarrying home oxygen: trolleys and backpacks\nPatients can bene\ufb01t from the provision of trolleys, wheeled carts\nor backpacks to enable them to carry home oxygen equipment.\nThis may be necessary because of the weight of the equipment\nwhen carried or to provide greater convenience. Less able\npatients \ufb01nd trolleys and wheeled carts easier to use than back-\npacks.149 150\nStudies have shown that their use can improve\npatient quality of life, distance walked and symptoms during\nexercise in patients who are habitually mobile.\nEvidence statement\n\u25b8 Trolleys or wheeled devices to enable patients to carry home\noxygen can improve patient quality of life, distance walked\nand symptoms during exercise in patients who can walk\nmore than 300 m. Evidence level 1+\nRecommendation\n\u25b8 Less able patients should be offered wheeled devices or back-\npacks if assessment shows they improve ambulation and\nquality of life. (Grade B)\nGood practice point\n\u25b8 When being transported in cars, cylinders should be secured\neither with a seat belt, or in the foot-well or car boot, possibly\nusing a cylinder box. Liquid oxygen should always be trans-\nported in an upright position. A warning triangle may be dis-\nplayed and insurance companies should be informed. (\u221a)\nSAFETY AND HOME OXYGEN THERAPY\nSmoking and home oxygen therapy\nThere is increasing recognition of the signi\ufb01cant risks of \ufb01re and\npersonal injury associated with smoking and the use of home\noxygen therapy. LTOT patients can be enabled to achieve smoking\ncessation,52\nbut despite these necessary interventions, many\npatients with respiratory disease, and especially COPD, continue\nto smoke. In addition, the clinician\u2019s assessment of smoking status\nrelies mainly on patients\u2019 testimony and evidence has shown that\nthis can be inaccurate.61\nThere have been no high quality trials to\nenable an objective assessment of the risks and bene\ufb01ts of the use\nof home oxygen in those who continue to smoke. However, there\nis emerging evidence from case reports of the risks of continued\nsmoking and oxygen use. A study in four American states from\n2000 to 2007 documented 38 fatalities associated with smoking\nand oxygen therapy, and 16 non-fatal injuries reported which\nincluded harm to two \ufb01re-\ufb01ghters and one policeman.151\nOf the\nfatalities, 34 (89%) were using LTOTand smoking at the time the\n\ufb01re began, three were household members of smokers receiving\nLTOT, and one was a non-smoker with LTOT who was uninten-\ntionally ignited by a family member who was smoking. Two retro-\nspective case series of patients admitted to burns units reported\nHardinge M, et al. Thorax 2015;70:i1\u2013i43. doi:10.1136\/thoraxjnl-2015-206865 i25\nBTS Guidelines\ngroup.bmj.com\non June 19, 2016 - Published by\nhttp:\/\/thorax.bmj.com\/\nDownloaded from\nharm caused by smoking while using home oxygen.152 153\nOf 27\npatients over a 7-year period who were identi\ufb01ed with burns dir-\nectly attributed to home oxygen use, 24 were smoking while using\noxygen, two were lighting pilot lights, and one was lighting his\nwife\u2019s cigarette.152\nOf 21 patients in a 12-year period who experi-\nenced partial thickness burn injuries, 57% sustained inhalation\ninjury, \ufb01ve (22%) required intubation and mechanical ventilation,\nand two died during hospitalisation.153\nIn addition, 86 home\noxygen-related burn injuries were documented in a retrospective\nstudy designed to compare the outcome characteristics of patients\nadmitted to a burns unit who had been intubated compared with\nthose who had not been intubated.154\nLighting a cigarette was the\ncause of the majority of injuries (87%), while exposure to other\nnaked \ufb02ame sources accounted for others (lighting a cooker 5%,\nelectrical spark 5%, candles 2%, and other open \ufb02ames 1%).\nThere are an increasing number of anecdotal reports of e-cigarettes\nand chargers causing \ufb01re-related incidents if used in the vicinity of\nhome oxygen.\nNo studies were identi\ufb01ed that examined improvements in\nsafety if smoking status in home oxygen patients was monitored\neither by urinary cotinine measurements or CO (carbon monox-\nide) monitoring compared to no monitoring.\nRole of risk assessments\nRecognition of the danger of \ufb01re and personal injury caused by\nsmoking and home oxygen use has led to pragmatic approaches\nto individual assessment of risks on a case-by-case basis. A risk\nassessment may be conducted by the home oxygen assessment\nservice and the \ufb01re and rescue service according to local proto-\ncols. Home oxygen suppliers carry out a formal risk assessment\ntwice under the current UK National Framework Agreement:\nonce at the time of taking the order and a \ufb01eld-based assessment\nat the patient\u2019s location when the order is delivered. Further\nrisk assessment should then take place every 6 months there-\nafter. See appendix 4 for examples of risk assessment tools.\nSome home oxygen services have adopted the practice of\nasking patients to sign a disclaimer acknowledging the risks of\nbehaviours such as smoking near home oxygen.\nResponsibilities of the oxygen supplier\nCertain responsibilities around risk assessment are outlined in\nthe National Framework Agreement for home oxygen services\n(December 2000, transitioned to NHS England 2013), which\noutlines the contractual obligations of home oxygen supply\ncompanies in England and Wales. In Scotland, a national home\noxygen service was established by Health Facilities Scotland in\n2012, and the single contracted supplier is also obliged to carry\nout a similar risk assessment prior to oxygen installation.\nThese risk assessment obligations for home oxygen suppliers\nin England are:\n\u25b8 A desk risk assessment should be conducted upon receipt of\na home oxygen order to ensure that the oxygen equipment\nordered matches the requirements and the equipment can be\ndelivered safely.\n\u25b8 The supplier shall ensure that a \ufb01eld-based risk assessment is\ncarried out at the time of installation to verify whether the\nrequirement of the home oxygen order form (HOOF) can be\nsupplied safely and in accordance with the requirements. See\nappendix 5 for details of HOOF forms.\n\u25b8 A \ufb01eld-based risk assessment must be conducted in each\npatient\u2019s primary and\/or secondary location every 6 months\nafter the initial \ufb01eld-based risk assessment to ensure that risk\nis monitored on an ongoing basis. The supplier shall \ufb01le a\ncopy of such \ufb01eld-based risk assessment and provide it to the\nclinical commissioning group home oxygen service lead\nwhere risk has been identi\ufb01ed\n\u25b8 The \ufb01eld-based risk assessment will identify potential \ufb01re-\nrelated risk in the patient\u2019s home. During this assessment,\nthe supplier shall check for the presence of an operational\nsmoke detector or alarm. In the event that a smoke detector\nor \ufb01re alarm is not present, the supplier shall inform the\nlocal \ufb01re authorities of this fact, together with any speci\ufb01c\n\ufb01re risks that have been identi\ufb01ed.\n\u25b8 The concentrator and any cylinders are positioned with suf\ufb01-\ncient ventilation and at a safe distance from any naked \ufb02ame,\ncooking or heating appliance.\n\u25b8 Oxygen equipment should be placed in a position where it\nwill not cause an obstruction to patients or family members,\nespecially those who may have mobility or sight impairment.\n\u25b8 A \ufb01xed installation should be considered to \ufb01x tubing and\nreduce trip hazard.\n\u25b8 A second concentrator may be necessary in larger properties\nor if patients have dif\ufb01culty using the stairs.\n\u25b8 Verbal and written information should be given to the patient\nor carer regarding the use of the equipment provided.\n\u25b8 The engineer should be satis\ufb01ed that the patient can use the\nprovided oxygen equipment safely.\n\u25b8 The oxygen concentrator must be checked regularly to ensure\nthe \ufb01lters are cleaned, the \ufb02ow metres are accurate, and the\nconcentrator delivers oxygen at the correct concentration.\n\u25b8 The oxygen contractor should inform the assessment service\nof any safety issues concerning the patient and the oxygen\nequipment and its use.\n\u25b8 The data collected by the oxygen contractor related to safety\nsuch as \ufb01re and accidents as a result of oxygen equipment\nand its use in the home, should be made available to oxygen\nassessment services.\nRole of the \ufb01re and rescue service\nAlthough this is not mandatory for the \ufb01re and rescue service, a\ncommunity \ufb01re safety of\ufb01cer may visit to discuss \ufb01re safety,\nsmoke alarms and safe exit routes in the event of a \ufb01re.\nTrips and falls\nPatients with home oxygen often have mobility or sight impair-\nment, and equipment and tubing can jeopardise safety. No\nstudies were found that examined the number of accidents that\noccurred as the result of home oxygen equipment or tubing.\nEvidence statements\n\u25b8 Serious burns, inhalation injury or death can be caused by\nusing oxygen while smoking or using oxygen near a naked\n\ufb02ame. Evidence level 3\n\u25b8 Patients who are educated regarding the dangers of smoking\nand using oxygen are more likely to quit smoking. Evidence\nlevel 2+\nRecommendations\n\u25b8 Smoking cessation should be discussed and written education\ngiven to all patients prior to ordering home oxygen and at\neach subsequent review if the patient continues to smoke.\n(Grade C)\n\u25b8 Patients should be made aware in writing of the dangers of\nusing home oxygen within the vicinity of any naked\n\ufb02ame such as pilot lights, cookers, gas \ufb01res and candles.\n(Grade D)\n\u25b8 Patients and family members who continue to smoke in the\npresence of home oxygen should be warned of the associated\ndangers of smoking in the presence of oxygen. (Grade D)\ni26 Hardinge M, et al. Thorax 2015;70:i1\u2013i43. doi:10.1136\/thoraxjnl-2015-206865\nBTS Guidelines\ngroup.bmj.com\non June 19, 2016 - Published by\nhttp:\/\/thorax.bmj.com\/\nDownloaded from\nGood practice points\n\u25b8 Safety should be a factor when making decisions regarding\nordering home oxygen. Education and written information\nshould be provided to the patient and their family or carers\nregarding the safe use of oxygen and its equipment. (\u221a)\n\u25b8 The risks of prescribing oxygen to active smokers should be\nconsidered on a case-by-case basis: this should include a\nhome visit to assess the patient\u2019s home situation, attitude\ntoward risks and smoking behaviour. Home oxygen assess-\nment services may decide not to prescribe home oxygen to\nsmokers if the risks are in their judgement too high.\nParticular consideration needs to be given to risks to children\nand risks to neighbours in multiple occupancy dwellings.\nA risk assessment tool should be used, and the health profes-\nsional who is undertaking the risk assessment may need to\nvisit the home in conjunction with the local \ufb01re service\nand\/or the oxygen contractor. Where there is reasonable\ndoubt, the therapy should not be prescribed. (\u221a)\n\u25b8 Patients who continue to smoke or live with other household\nsmokers should be informed that the order for home oxygen\nwill be reviewed and evidence of increased risk may lead to\nwithdrawal of home oxygen therapy. (\u221a)\n\u25b8 Carbon monoxide monitoring and measuring urine cotinine\nmay help identify those patients who continue to smoke. (\u221a)\n\u25b8 Patients should be made aware that they should not use\ne-cigarettes and chargers within the vicinity of their home\noxygen. (\u221a)\n\u25b8 Oil-based emollients and petroleum jelly can support com-\nbustion in the presence of oxygen. Patients should be made\naware that only water-based products should be used on the\nhands and face or inside the nose while using oxygen. (\u221a)\n\u25b8 The oxygen supplier should be informed if the patient con-\ntinues to smoke in order for the engineer to consider it in\nthe home oxygen supplier risk assessment. (\u221a)\n\u25b8 Patients and family or carers should be instructed not to\nremove the \ufb01re breaks or to change the \ufb02ow rate on their\noxygen equipment. Only oxygen tubing and connections\nsupplied by the oxygen company should be used. (\u221a)\n\u25b8 The local \ufb01re service should be made aware of patients who\nare using oxygen at home and especially those who continue\nto smoke in order for a home safety assessment to be carried\nout. (\u221a)\n\u25b8 Patients and carers should be aware that tubing should be\nchecked on a regular basis and repositioned as necessary to\nensure safety by preventing trips and falls. (\u221a)\nCONCLUSION\nThis guideline has reviewed the indications for the ordering\nand provision of home oxygen. It has con\ufb01rmed which patients\nwill bene\ufb01t from LTOT, how they should be assessed and mon-\nitored, focusing on dif\ufb01cult clinical situations such as hospital\ndischarge and management of hypercapnia. It has outlined\nrecommended \ufb02ow rates and duration of use, along with a\nreview of all modalities of equipment used to deliver home\noxygen. It has given recommendations for use of NOT in\npatients with advanced cardiac disease who are symptomatic\nfrom SDB and for use of SBOT in acute CH alone. It has\nrecommended use of AOT is limited to patients with evidence\nof improvement of exercise tolerance when using AOT as part\nof a pulmonary rehabilitation programme. Finally, it has con-\nsidered in detail the safety aspects of home oxygen delivery,\nparticularly in the challenging area of risk assessment in con-\ntinuing smokers.\nAuthor af\ufb01liations\n1\nOxford Centre of Respiratory Medicine, Oxford University Hospitals NHS Trust,\nOxford, UK\n2\nHywel Dda University Health Board, Prince Philip Hospital, Llanelli, UK\n3\nPortsmouth NHS Trust, Portsmouth, UK\n4\nLung Function and Sleep, Queen Elizabeth Hospital Birmingham, Birmingham, UK\n5\nStaffordshire and Stoke-on-Trent Partnership Trust, Staffordshire, UK\n6\nMundesley Medical Centre, Mundesley, UK\n7\nImprovement Academy (Y&H AHSN) Bradford Teaching Hospitals NHS FT,\nWake\ufb01eld, UK\n8\nRoyal Brompton Hospital, London, UK\n9\nRespiratory Care Team, Virgin Care, Surrey, UK\n10\nUniversity of Edinburgh, Edinburgh, UK\n11\nDepartment of Physiotherapy, Guy\u2019s and St Thomas\u2019 NHS Foundation Trust, St\nThomas\u2019 Hospital, London, UK\n12\nAintree University Hospital, Liverpool, UK\n13\nRespiratory Department, Royal United Hospital, Bath, UK\n14\nNorthern General Hospital, Shef\ufb01eld, UK\n15\nClinical and Experimental Medicine, Faculty of Medicine, University of\nSouthampton, Southampton, UK\nContributors MH, as chair of the guideline development group oversaw the\ndevelopment of the guideline, adhering to British Thoracic Society guideline\nmethodology, and is responsible for the \ufb01nal guideline document. JA, SB, BC, AE,\nDF, AG, SH, VK, WM, LM, KP, JS, VV, TW, all members of the British Thoracic\nSociety Home Oxygen Guideline Development Group, were responsible for\ndevelopment of the scope of the guideline, review of evidence, drafting text and\nrecommendations.\nCompeting interests All guideline group members completed the BTS declaration\nof interest form in line with BTS policy, and copies of all declarations are available\non the BTS website or on request from BTS Head Of\ufb01ce.\nProvenance and peer review Not commissioned; internally peer reviewed.\nREFERENCES\n1 Balfour-Lynn IM, Field DJ, Gringras P, et al. BTS guidelines for home oxygen in\nchildren. Thorax 2009;64(Suppl 2):ii1\u201326.\n2 O\u2019Driscoll BR, Howard LS, Davison AG, et al. BTS guideline for emergency oxygen\nuse in adult patients. Thorax 2008;63(Suppl 6):vi1\u201368.\n3 Ahmedzai S, Balfour-Lynn IM, Bewick T, et al. 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Am J Respir Crit Care\nMed 2001;163:129\u201334.\n79 Vazquez JC, Perez-Padilla R. Effect of oxygen on sleep and breathing in patients\nwith interstitial lung disease at moderate altitude. Respiration 2001;68:584\u20139.\n80 Smith PE, Edwards RH, Calverley PM. Oxygen treatment of sleep hypoxaemia in\nDuchenne muscular dystrophy. Thorax 1989;44:997\u20131001.\n81 Wedzicha JA. Domiciliary oxygen therapy services: clinical guidelines and advice for\nprescribers. Summary of a report of the Royal College of Physicians. J R Coll\nPhysicians Lond 1999;33:445\u20137.\n82 Bradley JM, O\u2019Neill BM. Short-term ambulatory oxygen for chronic obstructive\npulmonary disease. Cochrane Database Syst Rev 2005;(4):CD004356.\n83 Bradley JM, Lasserson T, Elborn S, et al. A systematic review of randomized\ncontrolled trials examining the short-term bene\ufb01t of ambulatory oxygen in COPD\n(Brief record). Chest 2007;131:278\u201385.\n84 Nonoyama M, Brooks D, Lacasse Y, et al. Oxygen therapy during exercise training\nin chronic obstructive pulmonary disease. Cochrane Database Syst Rev 2007;(2):\nCD005372.\n85 Dyer F, Callaghan J, Cheema K, et al. Ambulatory oxygen improves the\neffectiveness of pulmonary rehabilitation in selected patients with chronic\nobstructive pulmonary disease. Chron Respir Dis 2012;9:83\u201391.\n86 Bolton CE, Bevan-Smith EF, Blakey JD, et al. British Thoracic Society guideline on\npulmonary rehabilitation in adults. Thorax 2013;68(Suppl 2):ii1\u201330.\n87 Marcus CL, Bader D, Stabile MW, et al. Supplemental oxygen and exercise\nperformance in patients with cystic \ufb01brosis with severe pulmonary disease. Chest\n1992;101:52\u20137.\n88 Moore RP, Berlowitz DJ, Denehy L, et al. A randomised trial of domiciliary,\nambulatory oxygen in patients with COPD and dyspnoea but without resting\nhypoxaemia. Thorax 2011;66:32\u20137.\n89 Eaton T, Garrett JE, Young P, et al. Ambulatory oxygen improves quality of\nlife of COPD patients: a randomised controlled study. Eur Respir J\n2002;20:306\u201312.\n90 Nonoyama ML, Brooks D, Guyatt GH, et al. Effect of oxygen on health quality of\nlife in patients with chronic obstructive pulmonary disease with transient exertional\nhypoxemia. Am J Respir Crit Care Med 2007;176:343\u20139.\n91 Sandland CJ, Morgan MD, Singh SJ. Patterns of domestic activity and ambulatory\noxygen usage in COPD. Chest 2008;134:753\u201360.\n92 Ringbaek T, Martinez G, Lange P. The long-term effect of ambulatory oxygen in\nnormoxaemic COPD patients: a randomised study. Chron Respir Dis\n2013;10:77\u201384. http:\/\/onlinelibrary.wiley.com\/o\/cochrane\/clcentral\/articles\/157\/\nCN-00861157\/frame.html\n93 McDonald CF, Blyth CM, Lazarus MD, et al. Exertional oxygen of limited bene\ufb01t in\npatients with chronic obstructive pulmonary disease and mild hypoxemia. Am J\nRespir Crit Care Med 1995;152(5 Pt 1):1616\u201319.\n94 Petty TL, Bliss PL. Ambulatory oxygen therapy, exercise, and survival with\nadvanced chronic obstructive pulmonary disease (the Nocturnal Oxygen Therapy\nTrial revisited). Respir Care 2000;45:204\u201311; discussion 11\u20133.\n95 Vergeret J, Brambilla C, Mounier L. Portable oxygen therapy: use and bene\ufb01t in\nhypoxaemic COPD patients on long-term oxygen therapy. Eur Respir J\n1989;2:20\u20135.\n96 Lacasse Y, Lecours R, Pelletier C, et al. Randomised trial of ambulatory oxygen in\noxygen-dependent COPD. Eur Respir J 2005;25:1032\u20138.\n97 Casaburi R, Porszasz J, Hecht A, et al. In\ufb02uence of lightweight ambulatory oxygen\non oxygen use and activity patterns of COPD patients receiving long-term oxygen\ntherapy. COPD 2012;9:3\u201311.\n98 Arnold E, Bruton A, Donovan-Hall M, et al. Ambulatory oxygen: why do COPD\npatients not use their portable systems as prescribed? A qualitative study. BMC\nPulm Med 2011;11:9.\n99 Hill SL, Barnes PK, Hollway T, et al. Fixed performance oxygen masks: an\nevaluation. Br Med J (Clin Res Ed) 1984;288:1261\u20133.\n100 Ripamonti C, Bruera E. Dyspnea: pathophysiology and assessment. J Pain\nSymptom Manage 1997;13:220\u201332.\n101 Corner J, Plant H, A\u2019Hern R, et al. Non-pharmacological intervention for\nbreathlessness in lung cancer. Palliat Med 1996;10:299\u2013305.\n102 Filshie J, Penn K, Ashley S, et al. Acupuncture for the relief of cancer-related\nbreathlessness. Palliat Med 1996;10:145\u201350.\n103 Galbraith S, Fagan P, Perkins P, et al. Does the use of a handheld fan improve\nchronic dyspnea? A randomized, controlled, crossover trial. J Pain Symptom\nManage 2010;39:831\u20138.\n104 Jennings AL, Davies AN, Higgins JP, et al. Opioids for the palliation of breathlessness\nin terminal illness. Cochrane Database Syst Rev 2001;(4):CD002066.\n105 Booth S, Anderson H, Swannick M, et al. The use of oxygen in the palliation of\nbreathlessness. A report of the expert working group of the Scienti\ufb01c Committee\nof the Association of Palliative Medicine. Respir Med 2004;98:66\u201377.\n106 Philip J, Gold M, Milner A, et al. A randomized, double-blind, crossover trial of the\neffect of oxygen on dyspnea in patients with advanced cancer. J Pain Symptom\nManage 2006;32:541\u201350.\n107 Abernethy AP, McDonald CF, Frith PA, et al. Effect of palliative oxygen versus\nroom air in relief of breathlessness in patients with refractory dyspnoea: a\ndouble-blind, randomised controlled trial. Lancet 2010;376:784\u201393.\n108 Uronis HE, Currow DC, McCrory DC, et al. Oxygen for relief of dyspnoea in mildly-\nor non-hypoxaemic patients with cancer: a systematic review and meta-analysis.\nBr J Cancer 2008;98:294\u20139.\n109 Clemens KE, Quednau I, Klaschik E. Use of oxygen and opioids in the palliation of\ndyspnoea in hypoxic and non-hypoxic palliative care patients: a prospective study.\nSupport Care Cancer 2009;17:367\u201377.\n110 Currow DC, Agar M, Smith J, et al. Does palliative home oxygen improve\ndyspnoea? A consecutive cohort study. Palliat Med 2009;23:309\u201316.\n111 Quantrill SJ, White R, Crawford A, et al. Short burst oxygen therapy after activities\nof daily living in the home in chronic obstructive pulmonary disease. Thorax\n2007;62:702\u20135.\n112 Nandi K, Smith AA, Crawford A, et al. Oxygen supplementation before or after\nsubmaximal exercise in patients with chronic obstructive pulmonary disease.\nThorax 2003;58:670\u20133.\n113 Lewis CA, Eaton TE, Young P, et al. Short-burst oxygen immediately before and\nafter exercise is ineffective in nonhypoxic COPD patients. Eur Respir J\n2003;22:584\u20138.\n114 O\u2019Driscoll BR, Neill J, Pulakal S, et al. A crossover study of short burst oxygen\ntherapy (SBOT) for the relief of exercise-induced breathlessness in severe COPD.\nBMC Pulm Med 2011;11:23.\n115 Evans TW, Waterhouse JC, Carter A, et al. Short burst oxygen treatment for\nbreathlessness in chronic obstructive airways disease. Thorax 1986;41:611\u201315.\n116 Stevenson NJ, Calverley PM. Effect of oxygen on recovery from maximal\nexercise in patients with chronic obstructive pulmonary disease. Thorax\n2004;59:668\u201372.\n117 Eaton T, Fergusson W, Kolbe J, et al. Short-burst oxygen therapy for COPD\npatients: a 6-month randomised, controlled study. Eur Respir J 2006;27:697\u2013704.\n118 Cohen AS, Burns B, Goadsby PJ. High-\ufb02ow oxygen for treatment of cluster\nheadache: a randomized trial. JAMA 2009;302:2451\u20137.\n119 Kudrow L. Response of cluster headache attacks to oxygen inhalation. Headache\n1981;21:1\u20134.\n120 Fogan L. Treatment of cluster headache. A double-blind comparison of oxygen v\nair inhalation. Arch Neurol 1985;42:362\u20133.\n121 Rozen TD. High oxygen \ufb02ow rates for cluster headache. Neurology 2004;63:593.\n122 Backx APM, Haane DYP, De Ceuster L, et al. Cluster headache and oxygen: is it\npossible to predict which patients will be relieved? A retrospective cross-sectional\ncorrelation study. J Neurol 2010;257:1533\u201342.\n123 NICE. NICE Guideline for the diagnosis and management of headaches in young\npeople and adults. NICE, 2012.\n124 Johns DP, Rochford PD, Streeton JA. Evaluation of six oxygen concentrators.\nThorax 1985;40:806\u201310.\n125 Hall LW, Kellagher RE, Fleet KJ. A portable oxygen generator. Anaesthesia\n1986;41:516\u201318.\n126 Gould GA, Scott W, Hayhurst MD, et al. Technical and clinical assessment of\noxygen concentrators. Thorax 1985;40:811\u201316.\n127 [No authors listed]. Home controls of a sample of 2,414 oxygen concentrators.\nSous-Commission Technique ANTADIR. Eur Respir J 1991;4:227\u201331.\n128 Burioka N, Takano K, Hoshino E, et al. Clinical utility of a newly developed\npressure swing adsorption-type oxygen concentrator with a membrane humidi\ufb01er.\nRespiration 1997;64:268\u201372.\n129 Burioka N, Takano K, Suyama H, et al. Ef\ufb01cacy of newly developed pressure swing\nadsorption type oxygen concentrator with membrane humidi\ufb01er: comparison with\nconventional oxygen concentrator with bubble water humidi\ufb01er. Intern Med\n1997;36:861\u20134.\n130 Pesce LI, Bassi GN, Santovito A. Clinical usefulness of a new portable oxygen\nconcentrator. Monaldi Arch Chest Dis 1994;49:444\u20136.\n131 Shiner RJ, Zaretsky U, Mirali M, et al. Evaluation of domiciliary long-term oxygen\ntherapy with oxygen concentrators. Isr J Med Sci 1997;33:23\u20139.\n132 Jackson M, Shneerson J. An evaluation of the use of concentrators for domiciliary\noxygen supply for less than 8 h day-1. Respir Med 1998;92:250\u20135.\n133 Cuvelier A, Nuir JF, Chakroun N, et al. Re\ufb01llable oxygen cylinders may be an\nalternative for ambulatory oxygen therapy in COPD. Chest 2002;122:451\u20136.\n134 Strickland SL, Hogan TM, Hogan RG, et al. A randomized multi-arm\nrepeated-measures prospective study of several modalities of portable oxygen\nHardinge M, et al. Thorax 2015;70:i1\u2013i43. doi:10.1136\/thoraxjnl-2015-206865 i29\nBTS Guidelines\ngroup.bmj.com\non June 19, 2016 - Published by\nhttp:\/\/thorax.bmj.com\/\nDownloaded from\ndelivery during assessment of functional exercise capacity. Respir Care\n2009;54:344\u20139.\n135 Lock SH, Blower G, Prynne M, et al. Comparison of liquid and gaseous oxygen for\ndomiciliary portable use. Thorax 1992;47:98\u2013100.\n136 Nasilowski J, Przybylowski T, Zielinski J, et al. Comparing supplementary oxygen\nbene\ufb01ts from a portable oxygen concentrator and a liquid oxygen portable device\nduring a walk test in COPD patients on long-term oxygen therapy. Respir Med\n2008;102:1021\u20135.\n137 Andersson A, Str\u00f6m K, Brodin H, et al. Domiciliary liquid oxygen versus\nconcentrator treatment in chronic hypoxaemia: a cost-utility analysis. Eur Respir J\n1998;12:1284\u20139.\n138 Katsenos S, Charisis A, Daskalopoulos G, et al. Long-term oxygen therapy in\nchronic obstructive pulmonary disease: the use of concentrators and liquid oxygen\nsystems in north-western Greece. Respiration 2006;73:777\u201382.\n139 Czajkowska-Malinowska M, Poltyn B, Ciesielska A, et al. Comparison of the\nresults of long term oxygen therapy in patients treated sequentially using\nstationary or a portable source of oxygen. Pneumonol Alergol Pol\n2012;80:308\u201316.\n140 Okubadejo AA, Paul EA, Wedzicha JA. Domiciliary oxygen cylinders: indications,\nprescription and usage. Respir Med 1994;88:777\u201385.\n141 Bazuaye EA, Stone TN, Corris PA, et al. Variability of inspired oxygen\nconcentration with nasal cannulas. Thorax 1992;47:609\u201311.\n142 Paul J, Otvos T. Comparison of nasal cannulas and the OxyArm in patients\nrequiring chronic domiciliary oxygen therapy. Can Respir J 2006;13:421\u20136.\n143 Domingo C, Roig J, Coll R, et al. Evaluation of the use of three different devices\nfor nocturnal oxygen therapy in COPD patients. Respiration 1996;63:230\u20135.\n144 Moore-Gillon JC, George RJ, Geddes DM. An oxygen conserving nasal cannula.\nThorax 1985;40:817\u201319.\n145 Roberts CM, Bell J, Wedzicha JA. Comparison of the ef\ufb01cacy of a demand oxygen\ndelivery system with continuous low \ufb02ow oxygen in subjects with stable COPD and\nsevere oxygen desaturation on walking. Thorax 1996;51:831\u20134.\n146 Braun SR, Spratt G, Scott GC, et al. Comparison of six oxygen delivery systems for\nCOPD patients at rest and during exercise. Chest 1992;102:694\u20138.\n147 Marti S, Pajares V, Morante F, et al. Are oxygen-conserving devices effective for\ncorrecting exercise hypoxemia? Respir Care 2013;58:1606\u201313.\n148 Chatburn RL, Lewarski JS, McCoy RW. Nocturnal oxygenation using a pulsed-dose\noxygen-conserving device compared to continuous \ufb02ow. Respir Care\n2006;51:252\u20136.\n149 Leggett RJ, Flenley DC. Portable oxygen and exercise tolerance in patients with\nchronic hypoxic cor pulmonale. BMJ 1977;2:84\u20136.\n150 Crisafulli E, Costi S, De BF, et al. Effects of a walking aid in COPD patients\nreceiving oxygen therapy. Chest 2007;131:1068\u201374.\n151 Centers for Disease Control and Prevention. Fatal \ufb01res associated with smoking\nduring long-term oxygen therapy\u2014Maine, Massachusetts, New Hampshire, and\nOklahoma, 2000\u20132007. MMWR Morb Mortal Wkly Rep 2008;57:852\u20134.\n152 Robb BW, Hungness ES, Hershko DD, et al. Home oxygen therapy: adjunct or risk\nfactor? Burn Care Rehabil 2003;24:403\u20136; discussion 02.\n153 Chang TT, Lipinski CA, Sherman HF. A hazard of home oxygen therapy. Burn Care\nRehabil 2001;22:71\u20134; discussion 70\u20131.\n154 Amani H, Lozano DD, Blome-Eberwein S. Brother, have you got a light? Assessing\nthe need for intubation in patients sustaining burn injury secondary to home\noxygen therapy. J Burn Care Res 2012;33:e280\u20135.\ni30 Hardinge M, et al. Thorax 2015;70:i1\u2013i43. doi:10.1136\/thoraxjnl-2015-206865\nBTS Guidelines\ngroup.bmj.com\non June 19, 2016 - Published by\nhttp:\/\/thorax.bmj.com\/\nDownloaded from\nAPPENDIX 1: PROTOCOL FOR AMBULATORY OXYGEN THERAPY ASSESSMENT\nAIMS OF ASSESSMENT FOR EACH PATIENT\n(1) To determine if there is desaturation on exercise, de\ufb01ned as a drop in SpO2 of \u22654% to<90%\n(2) To determine the most appropriate device and setting to correct exercise desaturation\nCONSIDERATIONS\n\u2022 This protocol is designed to be generic and can be adapted for any valid and repeatable walking test.\n\u2022 A 6 Minute Walking Test (6MWT) should be performed over a 30m course (cones 29m apart), but it is recognised that due to a\nlack of space a modi\ufb01ed 10m-6MWT (cones 9m apart) may be used as an alternative (1, 2). Incremental and Endurance Shuttle\nWalking Tests (ESWT) are performed over a 10m course (cones 9m apart). There is some evidence to show that endurance tests,\nsuch as the ESWT, may be more sensitive than standard tests (3, 4).\n\u2022 Desaturation during baseline endurance shuttle walking test (ESWT) has been found to predict required \ufb02ow rate (see annex 1).\nThis is unlikely to predict as robustly when desaturations produced during other walking tests are used but may give some\nguidance.\n\u2022 A practice walk test should be performed and without one the improvement in walking distance from air to oxygen is likely to be\noverestimated.\n\u2022 Local policy and individual patient capabilities will affect the maximum number of tests performed in one appointment. Two\nappointments may be required to titrate oxygen fully.\n\u2022 It is not possible to correct SpO2 in every patient to >90% using 6 litres per minute (lpm) oxygen or the maximum settings on\nother devices. In this situation discussion with patient and their consultant may help determine if a higher \ufb02ow rate may be suit-\nable. Portability and \/ or duration of use declines considerably above 6 lpm.\n\u2022 Authors have described a dose response to oxygen i.e. for each increase in \ufb02ow rate there is an increase in exercise performance\n(3). Those whose performance has not improved on oxygen should therefore be trialled on a higher \ufb02owrate \/ setting.\n\u2022 Carrying the cylinder \/ device negates the effect of the oxygen but wheeling it does not (5). Therefore patients must have AOT\n\ufb02ow rate \/ setting titrated while carrying \/ wheeling the oxygen device as they plan to use it in everyday life.\n\u2022 Different oxygen devices weigh different amounts and oxygen conservers vary in sensitivity and functionality which result in\ndevices responding differently to different patients (6). Patients must have the \ufb02ow \/ setting titrated on the device that they are to\nbe prescribed.\nEQUIPMENT REQUIRED\n\u2022 Long, \ufb02at, corridor at least 32m long (12m for modi\ufb01ed\n6MWT)\n\u2022 2 cones\n\u2022 2 chairs (placed beyond each cone)\n\u2022 Stopwatch\/CD & CD player\n\u2022 Ambulatory oxygen equipment (hired\/supplied\nby oxygen provider)\n\u2022 Nasal cannulae\n\u2022 Pulse oximeter\n\u2022 Modi\ufb01ed BORG breathlessness scale\n\u2022 Oxygen risk assessment\n\u2022 Patient information lea\ufb02ets\nPREPARATION\n\u2022 Explain the purpose of AO\n\u2022 Outline the AO assessment process\n\u2022 Gain informed consent for assessment\n\u2022 Con\ufb01rm indication for AO (including outdoor mobility)\n\u2022 Complete risk assessment\n\u2022 Ensure 20 mins rest before walking test (included in dis-\ncussion time)\n\u2022 Set up walking test circuit\n\u2022 Read \/ play test instructions\n\u2022 Ask if the patient has any questions\n\u2022 Perform practice test\n\u2022 Ensure further 20 mins rest before retest\nDEMONSTRATING A POSITIVE IMPROVEMENT WITH AO\n2 out of 3 of the markers below are required to show that the patient bene\ufb01ts from AO.\n\u2022 SpO2s \u226590% throughout\n\u2022 \u2265 10% increase in walking distance from baseline (7)\n\u2022 Improvement in BORG of at least 1 point from baseline (8)\nFOLLOW-UP\n8 week review:\nCheck patient\u2019s concordance with the oxygen order (call the oxygen delivery company to determine their usage) and compare this\nwith the patient\u2019s diary card when they attend. Discuss any discrepancies or issues highlighted.\nTroubleshoot any device issues. Review device and oxygen order as required.\nAnnual review:\nReassess using current prescription and adjust \ufb02ow rate and device as required.\nHardinge M, et al. Thorax 2015;70:i1\u2013i43. doi:10.1136\/thoraxjnl-2015-206865 i31\nBTS Guidelines\ngroup.bmj.com\non June 19, 2016 - Published by\nhttp:\/\/thorax.bmj.com\/\nDownloaded from\ni32 Hardinge M, et al. Thorax 2015;70:i1\u2013i43. doi:10.1136\/thoraxjnl-2015-206865\nBTS Guidelines\ngroup.bmj.com\non June 19, 2016 - Published by\nhttp:\/\/thorax.bmj.com\/\nDownloaded from\nANNEX 1\nSuggested AO \ufb02ow rates according to baseline ESWT desaturations (9):\nOxygen saturation range (%) Suggested AO flow rate (l\/min)\n86-89 3\n80-85 4\n74-79 5\n73 or below 6\nReferences\n(1) Beekman E, Mesters I, Gosselink R, Klaassen MPM, Hendriks EJM, Van Schayck OCP\n, De Bie RA. The \ufb01rst reference equations\nfor the 6-minute walking distance over a 10 metre course. Thorax 2014. http:\/\/thorax.bmj.com\/content\/early\/2014\/04\/23\/\nthoraxjnl-2014-205228\n(2) Crapo RO, Casaburi R, Coates AL, et al (2002) American Thoracic Society Statement \u2013 Guidelines for the six-minute walk test.\nAmerican Journal of Respiratory and Critical Care Medicine. 166 p 111\u2013117. http:\/ajrccm.atsjournals.org\/cgi\/content\/full\/166\/1\/\n111 [accessed 02\/07\/2007]\n(3) Davidson AC, Leach R, George RJD, Geddes DM. 1988. Supplemental oxygen and exercise ability in chronic obstructive airways\ndisease. Thorax, 43: 965\u2013971.\n(4) Ambulatory oxygen therapy assessment: a comparative study of incremental shuttle and 6-minute walking tests A. Lewko,\nJ. Marshall, R. Garrod Physiotherapy \u2013 December 2007 (Vol. 93, Issue 4, Pages 261-266, DOI: 10.1016\/j.\nphysio.2007.03.002).\n(5) Leggett RJE, Flenley DC. 1977. Portable oxygen and exercise tolerance in patients with chronic hypoxic cor pulmonale. British\nMedical Journal, ii: 84\u201386.\n(6) Bliss PL, McCoy RW\n, Adams AB. 1999. A bench Study Comparison of Demand Oxygen Delivery Systems and Continuous Flow\nOxygen. Respiratory Care, 44 (8): 925\u2013931.\n(7) Dyer F, Callaghan J, Cheema K, Bott J. Ambulatory oxygen improves the effectiveness of pulmonary rehabilitation in selected\npatients with chronic obstructive pulmonary disease. Chronic Respiratory Disease 2012;9:83\u201391\n(8) Ries AL. Minimally Clinically Important Difference for the UCSD Shortness of Breath Questionnaire, Borg Scale, and Visual\nAnalog Scale. Journal of Chronic Obstructive Pulmonary Disease 2005; 2 (1) 105\u2013110.\n(9) Cornish L, Dyer F, Cheema K, Bott J. Is it possible to predict ambulatory oxygen (AO) requirements? Thorax 2013;68:Suppl 3\nA92 doi:10.1136\/thoraxjnl-2013-204457.188\nHardinge M, et al. Thorax 2015;70:i1\u2013i43. doi:10.1136\/thoraxjnl-2015-206865 i33\nBTS Guidelines\ngroup.bmj.com\non June 19, 2016 - Published by\nhttp:\/\/thorax.bmj.com\/\nDownloaded from\nAPPENDIX 2: ASSESSMENT REFERRAL FORM\ni34 Hardinge M, et al. Thorax 2015;70:i1\u2013i43. doi:10.1136\/thoraxjnl-2015-206865\nBTS Guidelines\ngroup.bmj.com\non June 19, 2016 - Published by\nhttp:\/\/thorax.bmj.com\/\nDownloaded from\nAPPENDIX 3: ASSESSMENT PROTOCOL FOR PALLIATIVE OXYGEN\nThere is no consensus for the correct clinical assessment strategy for the use of oxygen in palliative care, although multiple\ntools exist for assessing dyspnoea. This assessment protocol is suggested best practice by the guideline group and applies to\npatients with cancer or end stage cardio-respiratory disease who are experiencing intractable breathlessness, who are hypoxae-\nmic with resting SpO2<92% or who are normoxaemic but in whom all other approaches have been exhausted. The Numerical\nRating Scale score is recommended as this approach was used in evidence sited. First ensure patient is on maximum treatment\nfor underlying diseases where possible and reversible causes for breathlessness have been or are being treated optimally.\n\u2022 As distress from breathlessness can be multi-dimensional, ensure psycho-social factors have been assessed and addressed.\n\u2022 Trial of non-pharmacological measures including teaching of breathing relaxation and life modifying strategies by involving physio\nand occupational therapists.\n\u2022 Trial of hand held fan before consideration of oxygen therapy.\n\u2022 Assess response to opioids if they have been tried.\n\u2022 Check SpO2 using pulse oximetry at rest and\/ or after exertion.\nThe subjective severity and intensity of breathlessness should therefore be recorded regularly to evaluate the degree of suffering\ncaused and the effect of treatment. A numerical rating scale (NRS) from 0 to 10 has been found useful for this purpose (0=no short-\nness of breath, 10=worst shortness of breath imaginable). Treatment should focus on patients with dyspnoea scores (NRS) of \u22654,\nand especially those with scores \u22657. Recurrent assessment with standardized scales is prudent, especially when using an N-of-1\napproach, as it is dif\ufb01cult to predict which patients will bene\ufb01t (1).\nPRESCRIPTION\nAs distress from breathlessness is not correlated to degree of hypoxemia, the \ufb02ow rates for symptom relief in the studies identi\ufb01ed\nrange from 2\u20135 litres\/min. It is suggested therefore that oxygen \ufb02ow rates be determined by symptom score on an individual basis\nrather than SpO2 reading. Additional consideration needs to be given to potential risks of hypercapnia if oxygen is given at higher\n\ufb02ow rates.\nEQUIPMENT\nConcentrator or cylinder as determined by patient\u2019s needs.\nFOLLOW UP\nOxygen therapy like any pharmacological intervention should be best considered on trial basis and be reviewed regularly while balan-\ncing between bene\ufb01ts and risks.\nMost bene\ufb01t is likely to occur in the \ufb01rst 24 hours, and nearly all symptomatic and functional improvements within the \ufb01rst 3 days\nof use (1). Follow-up and assessment of response should \ufb01t with these timescales.\n1. Nonoyama ML, Brooks D, Guyatt GH, et al. Effect of oxygen on health quality of life in patients with chronic obstructive\npulmonary disease with transient exertional hypoxemia. Am J Respir Crit Care Med 2007;176(4):343\u20139\nHardinge M, et al. Thorax 2015;70:i1\u2013i43. doi:10.1136\/thoraxjnl-2015-206865 i35\nBTS Guidelines\ngroup.bmj.com\non June 19, 2016 - Published by\nhttp:\/\/thorax.bmj.com\/\nDownloaded from\nAPPENDIX 4: RISK ASSESSMENT TOOLS*\n*The risk assessment templates provided have not been validated.\nFIELD BASED RISK ASSESSMENT REPORT TEMPLATE AS USED BY HOME OXYEN PROVIDER COMPANY\nWritten con\ufb01rmation that the risk assessment has been conducted at the Patient\u2019s home at the due date and report of the \ufb01ndings\nof the assessment shall include, but not necessarily be limited to, the following information:-\nPatient Name Patient Number\nPatient Address Job Type\nPotential Risks YES NO Comments \/ Observations\nInitial Desk Based Assessment Completed\nProperty Access\nSuitable parking, good surface condition and safe access to property\nSuitable access using path\/stairs (not too steep or narrow)\nIs a Lift\/Escalator available?\nPatient \/ Carer\nAre there any language barriers, does the Patient\/carer understand the safety demonstration?\nDoes the Patient\/carer understand and are they able to operate the Equipment provided?\nDoes Patient \/ Carer smoke or is there evidence of smoking in the Patient\u2019s residence?\nIs any other Equipment used in combination with the oxygen therapy Equipment?\nIs the Patient able to replace the filter autonomously?\nOxygen Equipment usage and storage\nIs Equipment used \/ stored in Workshop, Garage or Kitchen?\nIs Equipment used \/ stored within 3m of open flame 1.5m of electrical appliance, flammable material,\nPaint, oils or grease?\nIs usage \/ storage area safe, suitable, clean and adequately ventilated in relation to the Patients safety\nand the safety of other people that have authorised access to the location?\nIs usage\/storage etc adequate where there is more than one Patient using Oxygen e.g. care homes\nCan Equipment be located to allow a maximum of 15m free line without causing obstructions\/hazards\nwhen in use?\nIf delivery is made in the absence of Patient\/carer, has suitable, safe, secure storage been agreed?\nConcentrator installations \u2013 Has mains outlet socket passed safety test?\nDoes the Patient need to use stairs in the property\nCan the Patient safely climb stairs whilst using oxygen?\nIs there a working smoke detector or alarm in the home?\nIs the Patient using a pre\u2013paid electricity meter?\nDoes the crush resistant tubing need to be replaced?\nOxygen concentration Testing\nFilters checking and cleaning\nLocation where Equipment to be installed\nElectricity meter reading as at installation date\nAssessors Other Comments \/ Concerns \/ Other Potential Risks\nAssessor\u2019s Name (Print)\nAssessor Signature Date\ni36 Hardinge M, et al. Thorax 2015;70:i1\u2013i43. doi:10.1136\/thoraxjnl-2015-206865\nBTS Guidelines\ngroup.bmj.com\non June 19, 2016 - Published by\nhttp:\/\/thorax.bmj.com\/\nDownloaded from\nRisk Assessment Form (Wirral NHS Home Oxygen assessment service)*\nLocation\/Activity: Oxygen Therapy Assessment date:\nPatient\u2019s Full Name: Date of birth: NHS N\u00b0\nAssessor: Signature: Review date:\nRisk Description\/Source\nIF THE PATIENT HAS AN AIR FLOW PRESSURE RELIEVING MATTRESS YOU MUST DISCUSS THE POTENTIAL RISKS AND DOCUMENT IT\nRef Hazards Risks People at risk Current Control Measures L x C=R\nIs further action\nrequired (Y\/N)\n1. Smoking Fire\nFacial burns\nCommunity Nursing Staff\nPatients and carers\nPatients\n(1) Instruct patients, carers and visitors not to smoke in any\npart of the house where oxygen is used\n(2) Patient\/carer to sign \u201csmoking and oxygen\u201d advice form\n(3) Arrange for removal of any oxygen equipment not in\nregular use\n(4) Fire breaks never to be removed from tubing supplied by\noxygen provider\n(5) Ensure smoke detectors are fitted and in working order\n2. Exposure to naked flames from open\/\ngas fires\/candles and cooking\nappliances.\nExplosion and fire Community Nursing Staff\nPatients and carers\n(1) Advise patient to maintain a safe distance from fires\nand naked flame appliances as instructed by oxygen\nprovider\n(2) Oxygen must be positioned and stored as directed by\noxygen provider\n3. Kinking or entrapment of tubing in\/\nunder furniture, doors, wheels\nRestriction of or no Oxygen supply Patient (1) Check there are no kinks in the tubing\n(2) Check that the tubing is not trapped between furniture\nor trapped e.g. under bed wheels\n(3) Only tubing supplied by the oxygen provider is to be\nused on cylinders and concentrators\n(4) Encourage piped oxygen if there is excessive tubing\n4. Alcohol hand rubs\/gels Combustion Community nursing staff\nPatients and carers\n(1) Ensure hands are adequately dried after the use of\nalcohol gels.\n5 Use of oil based emollients Local burning of affected area Patient (1) Instruct patients (or carers) not to use oil based\nemollients on patients nostrils\n6. Patient\/Carers not aware on how to\nobtain replacement cylinders\nRunning out of oxygen Patient (1) Ensure patient has information leaflet from company\nsupplying oxygen\n(2) Check patient\/carer has contact details on how to\nobtain\/replace oxygen cylinder.\nHardinge\nM,\net\nal.\nThorax\n2015;70:i1\u2013i43.\ndoi:10.1136\/thoraxjnl-2015-206865\ni37\nBTS\nGuidelines\ngroup.bmj.com\non\nJune\n19,\n2016\n-\nPublished\nby\nhttp:\/\/thorax.bmj.com\/\nDownloaded\nfrom\nRef Hazards Risks People at risk Current Control Measures L x C=R\nIs further action\nrequired (Y\/N)\n7. Tubing Trips and falls Community Nursing Staff\nPatients and carers\n(1) Advise patients and carers to check position of tubing\ndaily to minimise risks of falls\n(2) Advise patients and carers to check position of tubing,\nparticularly if patient using a walking frame etc\n(3) Current oxygen tubing must be of an appropriate length\nto meet the needs of the patient.\n8. Power supply cut off to concentrator No oxygen supply Patient (1) Check patient has a back up cylinder\n(2) Educate patient not to use back up cylinder unless there\nis power failure to concentrator\n9 Unauthorised adjustment of flow rate\non oxygen equipment\nWorsening respiratory failure in oxygen sensitive\npatients\nPatient (1) Educate patient on the reason for oxygen\n(2) Inform patient\/carer of the prescribed flow rate and\nhours of use\n(3) Ensure patient\/carer understands how to operate\nequipment safely\n(4) Inform patient\/carer on the importance of not adjusting\noxygen flow rate without seeking appropriate clinical\nadvice and assessment\n(5) Very oxygen sensitive patients will be issued with an\nalert card and appropriate oxygen mask and tubing for\nuse in ambulance transfers.\n10 Non compliance with assessment and\/\nor review process\nRisks will not be identified or managed. Oxygen\nprescription may not be appropriate for the\npatient\u2019s clinical need.\nPatient (1) All except terminally ill patients should be formally\nassessed prior to commencing oxygen therapy.\n(2) Patients will be recalled for review according to national\nguidance\n(3) Assessment and review will be undertaken at a mutually\nconvenient time and place.\n11 Non compliance with oxygen\nprescription\nHypoxia remains untreated Patient (1) Patients will be educated on when and how to use\noxygen at the time of prescribing.\n(2) Reason for oxygen will be discussed at each review.\n(3) Significant carers, family and other HP\u2019s involved with\nthe patient to be educated on why oxygen has been\nprescribed.\n\u25a1 Green Low Risk (04) Managed by COPD and oxygen service=Acceptable risk. Routine review\n\u25a1 Yellow\/Amber Moderate Risk (5\u201312) Managed by Senior Managers=Action required\n\u25a1 Red High to extreme Risk (15\u201325) Managed by Director Level=Serious risk requiring immediate action.\ni38\nHardinge\nM,\net\nal.\nThorax\n2015;70:i1\u2013i43.\ndoi:10.1136\/thoraxjnl-2015-206865\nBTS\nGuidelines\ngroup.bmj.com\non\nJune\n19,\n2016\n-\nPublished\nby\nhttp:\/\/thorax.bmj.com\/\nDownloaded\nfrom\nRISK SCORING MATRIX\nLikelihood\nConsequence\nInsignificant 1 Minor 2 Moderate 3 Major 4 Catastrophic 5\nCertain 5 5 10 15 20 25\nLikely 4 4 8 12 16 20\nPossible 3 3 6 9 12 15\nUnlikely 2 2 4 6 8 10\nRare 1 1 2 3 4 5\nPRIORITY AND ACTION\nESCALATION PATHWAY\nLow risk \u2013 Green (0\u20134)\nContinue usual control measures, reinforce education, update documentation, see at next planned review.\nIncident form to be completed if the patient sustains injury or harm related to oxygen. Copy for WUTH and PCT\nMedium risk \u2013 Yellow (5\u201312)\nEnsure all current safety control measures are in place including \ufb01re service involvement\nImplement and reinforce control measures\nInform patient\u2019s GP and community nursing team\/matron if appropriate.\nNotify locality MDT for discussion and review\nInvolve carers\/next of kin in discussion of safety issues\nReview risk after 4 weeks\nIncident form to be completed if the patient sustains injury or harm related to oxygen. Copy for WUTH and PCT\nHigh risk \u2013 Red (15\u201325)\nEnsure all current safety control measures are in place including \ufb01re service involvement\nUrgent discussion with patient\u2019s GP\nUrgent discussion with community nursing team\/matron if appropriate\nInform next of kin, carers of the seriousness of the situation\nArrange for removal of oxygen and admission to hospital if removal of oxygen is likely to result in severe hypoxia\nIncident form to be completed if oxygen removed or the patient sustains injury or harm related to oxygen. Copy for WUTH\nand PCT.\nRisk\nColour\nRisk\nrating\nRisk\nlevel Identifier Action required\nGREEN 0-4 Low Control measures in place or risk of harm is\ninsignificant\nLong term action with routine review\nAMBER 5-12 Medium Likelihood of major harm if control measures not\nimplemented\nAction is needed in the medium term\nRED 15-25 High Significant probability of major harm Urgent action needed. Escalate to line manager, patient\u2019s GP and\nsenior manager.\nHardinge M, et al. Thorax 2015;70:i1\u2013i43. doi:10.1136\/thoraxjnl-2015-206865 i39\nBTS Guidelines\ngroup.bmj.com\non June 19, 2016 - Published by\nhttp:\/\/thorax.bmj.com\/\nDownloaded from\nRisk Assessment Action Plan\nPatient\u2019s Full Name: Date of birth: NHS N\u00b0\nLocation\/Activity: Assessment date:\nAssessor: Signature: Review date:\nRef Further Action Implemented Short Term, Medium Term, Long Term Responsible Person Revised Risk rating L x C=R\nAre further assessments required if so list.\ne.g. COSHH\n1 Arrange 6monthly review. Review risk assessment annually.\nCheck safety implications at every visit.\nCaseload Manager\n2 As above\n3 As above\n4 As above\n5 As above\n6 As above\n7 As above\n8 As above\n9 As above\n10 As above. Inform GP.\n11 As above.\ni40\nHardinge\nM,\net\nal.\nThorax\n2015;70:i1\u2013i43.\ndoi:10.1136\/thoraxjnl-2015-206865\nBTS\nGuidelines\ngroup.bmj.com\non\nJune\n19,\n2016\n-\nPublished\nby\nhttp:\/\/thorax.bmj.com\/\nDownloaded\nfrom\nAPPENDIX 5: HOME OXYGEN ORDER FORMS (HOOF) AND HOME OXYGEN CONSENT FORMS (HOCF) FORMS\nThe Home Oxygen Order Form (HOOF) form for use in England and Wales comes in two parts:\nPart A is used when the request is being made by non-specialist healthcare professionals and is usually for a temporary order pending\nreview by a Home Oxygen Assessment service.\nPart B should be used by Home Oxygen Assessment services once a patient has undergone formal assessment. It also allows for order-\ning of equipment in addition to the basic static concentrator and static cylinders.\nForms are available via the home oxygen supplier website relevant to each geographical area (or Part A HOOF is available from\nPrimary Care Commissioning website.\nhttp:\/\/www.pcc-cic.org.uk\/article\/home-oxygen-service-current-supply-contracts (accessed Jan 2015)\nhttp:\/\/www.pcc-cic.org.uk\/article\/home-oxygen-order-form (accessed Jan 2015)\nAPPENDIX 6: SAMPLE PATIENT INFORMATION LEAFLETS\nThere are many examples of excellent patient information lea\ufb02ets available from different Home Oxygen Assessment teams. The\nBritish Lung Foundation provides a wide range of information for patients with lung conditions: www.blf.org.uk\nA new publication \u2018Oxygen treatment\u2019 will be available from April 2015: www.blf.org.uk\/page\/oxygen-treatment\nThe booklet will be available to order from the BLF shop: Patient: http:\/\/shop.blf.org.uk\/products\/oxygen-booklet\nHCP: http:\/\/shop.blf.org.uk\/products\/oxygen-booklet-1\nHardinge M, et al. Thorax 2015;70:i1\u2013i43. doi:10.1136\/thoraxjnl-2015-206865 i41\nBTS Guidelines\ngroup.bmj.com\non June 19, 2016 - Published by\nhttp:\/\/thorax.bmj.com\/\nDownloaded from\nAPPENDIX 7 : PRACTICAL POINTS FOR REMOVAL OF HOME OXYGEN\nRemoval of home oxygen may be challenging and should be undertaken by experienced healthcare professionals. A multidisciplinary\nteam approach including all healthcare professionals directly involved with the patient\u2019s care agreeing a plan may help the process. If\nthis is not possible, communication of the removal plan to all relevant healthcare professionals is important.\nRemoval of home oxygen may not occur at one point but take time and multiple contacts. In order to remove home oxygen other\ninterventions to manage breathlessness should be considered as an alternative where appropriate e.g. pulmonary rehabilitation,\ndepression and anxiety management. The process may be stressful for the patient and their families or carers and should be handled\nsensitively.\nIt is helpful if the possibility of removal of home oxygen, and the circumstances in which this might occur, is raised with patients and\ntheir carers when home oxygen is \ufb01rst prescribed. This should be supported by written information.\nReasons for removal of home oxygen therapy:\n1. Clinical\nIf the patient no longer meets the criteria for home oxygen on reassessment in a stable clinical state, then the removal process\nshould be initiated. Consider the time and effort of removal in those patients with borderline arterial oxygen levels as they are\nlikely to deteriorate in time, and a further assessment may be useful before initiating removal.\n2. Patient adherence\nWhere patients do not use their prescribed oxygen for the period of time to gain clinical bene\ufb01t (eg 15 hours per day with\nLTOT), they should be advised of the importance of this. An agreement should be reached with patients of an agreed period over\nwhich to improve adherence and if adherence is still suboptimal the oxygen should be removed.\nPatients who do not use ambulatory oxygen therapy (AOT) despite leaving their house, or those who have AOT but do not leave\ntheir house, should again be similarly advised that this is a waste of NHS resources and an agreed period of time to improve\nadherence should be decided on, before reassessment. If there is no signi\ufb01cant improvement in AOT use, then it should be\nremoved.\n3. Safety\nIf there are clear safety issues around the use of home oxygen a risk assessment should be undertaken (see Appendix 4). Serious\nincidents such as \ufb01res involving oxygen should lead to serious consideration of the removal of oxygen. Altering \ufb02ow rates if not\nrecommended by home oxygen team can result in harm and falls may result from piped oxygen tubing. There may be interven-\ntions that can minimise the risks and these should be initiated e.g. smoking cessation support in smokers; oxygen tubing being\npiped in and \ufb01xed rather than loose to reduce the risk of trips and falls; locking concentrators to avoid alteration in \ufb02ow rates.\nFollowing initiation there should be a reassessment after a set agreed period.\nBefore removal of home oxygen you should be able to answer \u2018YES\u2019 to the following:\n\u2022 Has the patient been reassessed by a health professional experienced in managing home oxygen or part of the home oxygen assess-\nment team?\n\u2022 Is there a clear indication for removal?\n\u2022 Is the patient (and\/or signi\ufb01cant other) aware removal may occur?\n\u2022 Have all interventions to improve adherence or reduce risk been considered and implemented with an evaluation following\nimplementation?\n\u2022 Have appropriate alternative treatment strategies been considered and implemented as part of the removal process?\n\u2022 Have the wider health care team been part of the decision to remove home oxygen but if not informed of the decision prior to\nremoval?\ni42 Hardinge M, et al. Thorax 2015;70:i1\u2013i43. doi:10.1136\/thoraxjnl-2015-206865\nBTS Guidelines\ngroup.bmj.com\non June 19, 2016 - Published by\nhttp:\/\/thorax.bmj.com\/\nDownloaded from\nAPPENDIX 8: GUIDELINE GROUP MEMBERS\nName\nDr Maxine Hardinge, Chair Consultant Respiratory Physician Oxford University Hospitals NHS Trust\nJoe Annandale Respiratory Nurse Specialist, Hywel Dda University Health Board, Prince Philip Hospital, Llanelli Representing ARNS\nDr Simon Bourne Consultant Respiratory Physician Portsmouth NHS Trust Representing the Royal College of Physicians, London\nDr Brendan Cooper Consultant Clinical Scientist, Lung Function and Sleep, Queen Elizabeth Hospital Birmingham Representing ARTP\nLynn McDonnell Clinical Specialist Physiotherapist London Representing ACPRC\nAngela Evans Specialist Practitioner, Staffordshire and Stoke-on-Trent Partnership Trust Representing ARTP\nDr Daryl Freeman General Practitioner Representing PCRS-UK\nAngela Green Respiratory Physiotherapist Improvement Academy (Y&H AHSN) Bradford Teaching Hospitals NHS FT\nMr Colin Hawkey (dec) Patient\/carer representative: 2011\/2013\nDr Sabrine Hippolyte Respiratory Specialty Trainee London\nVikki Knowles Respiratory Nurse Specialist, Respiratory Care Team, Virgin Care, Surrey Representing PCRS \u2013UK\nMrs Joan Ling Patient\/carer representation: 2011\/2012\nProfessor William MacNee Professor of Respiratory Medicine Edinburgh\nKathy Pye Clinical Nurse Specialist Liverpool\nDr Jay Suntharalingam Consultant Respiratory Physician Bath\nDr Vandana Vora Consultant Palliative Care Physician, Sheffield Representing Association for Palliative Medicine\nDr Tom Wilkinson Consultant Respiratory Physician Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, Southampton\nHardinge M, et al. Thorax 2015;70:i1\u2013i43. doi:10.1136\/thoraxjnl-2015-206865 i43\nBTS Guidelines\ngroup.bmj.com\non June 19, 2016 - Published by\nhttp:\/\/thorax.bmj.com\/\nDownloaded from\noxygen use in adults: accredited by NICE\nBritish Thoracic Society guidelines for home\nThoracic Society Standards of Care Committee\nHome Oxygen Guideline Development Group, and on behalf of the British\nSuntharalingam, Vandana Vora, Tom Wilkinson, British Thoracic Society\nKnowles, William MacNee, Lynn McDonnell, Kathy Pye, Jay\nAngela Evans, Daryl Freeman, Angela Green, Sabrine Hippolyte, Vikki\nMaxine Hardinge, Joe Annandale, Simon Bourne, Brendan Cooper,\ndoi: 10.1136\/thoraxjnl-2015-206865\n2015 70: i1-i43\nThorax\nhttp:\/\/thorax.bmj.com\/content\/70\/Suppl_1\/i1\nUpdated information and services can be found at:\nThese include:\nMaterial\nSupplementary\n5.DC1.html\nhttp:\/\/thorax.bmj.com\/content\/suppl\/2015\/04\/21\/thoraxjnl-2015-20686\nSupplementary material can be found at:\nReferences\n#BIBL\nhttp:\/\/thorax.bmj.com\/content\/70\/Suppl_1\/i1\nThis article cites 148 articles, 47 of which you can access for free at:\nservice\nEmail alerting\nbox at the top right corner of the online article.\nReceive free email alerts when new articles cite this article. Sign up in the\nCollections\nTopic Articles on similar topics can be found in the following collections\n(1186)\nTB and other respiratory infections\n(1672)\nEpidemiologic studies\n(2)\nGuidelines, Recommendations and Consensus Statements\nNotes\nhttp:\/\/group.bmj.com\/group\/rights-licensing\/permissions\nTo request permissions go to:\nhttp:\/\/journals.bmj.com\/cgi\/reprintform\nTo order reprints go to:\nhttp:\/\/group.bmj.com\/subscribe\/\nTo subscribe to BMJ go to:\ngroup.bmj.com\non June 19, 2016 - Published by\nhttp:\/\/thorax.bmj.com\/\nDownloaded from","pure_content":"British Thoracic Society guidelines for home oxygen\nuse in adults\nMaxine Hardinge,1\nJoe Annandale,2\nSimon Bourne,3\nBrendan Cooper,4\nAngela Evans,5\nDaryl Freeman,6\nAngela Green,7\nSabrine Hippolyte,8\nVikki Knowles,9\nWilliam MacNee,10\nLynn McDonnell,11\nKathy Pye,12\nJay Suntharalingam,13\nVandana Vora,14\nTom Wilkinson,15\nBritish Thoracic Society Home Oxygen Guideline Development Group, on behalf of the\nBritish Thoracic Society Standards of Care Committee\n\u25b8 Additional material is\npublished online only. To view\nplease visit the journal online\n(http:\/\/dx.doi.org\/10.1136\/\nthoraxjnl-2015-206865).\nFor numbered af\ufb01liations see\nend of article.\nCorrespondence to\nDr Maxine Hardinge, Oxford\nCentre of Respiratory Medicine,\nChurchill Hospital, Oxford\nUniversity Hospitals NHS Trust,\nHeadington, Oxford OX3 7LJ,\nUK; maxine.hardinge@ouh.\nnhs.uk\nReceived 28 January 2015\nAccepted 29 January 2015\nTo cite: Hardinge M,\nAnnandale J, Bourne S,\net al. Thorax 2015;70:\ni1\u2013i43.\nABSTRACT\nThe British Thoracic Society (BTS) Home Oxygen\nGuideline provides detailed evidence-based guidance for\nthe use of home oxygen for patients out of hospital.\nAlthough the majority of evidence comes from the use of\noxygen in patients with chronic obstructive pulmonary\ndisease, the scope of the guidance includes patients\nwith a variety of long-term respiratory illnesses and other\ngroups in whom oxygen is currently ordered, such as\nthose with cardiac failure, cancer and end-stage\ncardiorespiratory disease, terminal illness or cluster\nheadache. It explores the evidence base for the use of\ndifferent modalities of oxygen therapy and patient-\nrelated outcomes such as mortality, symptoms and\nquality of life. The guideline also makes\nrecommendations for assessment and follow-up\nprotocols, and risk assessments, particularly in the\nclinically challenging area of home oxygen users who\nsmoke. The guideline development group is aware of the\npotential for confusion sometimes caused by the current\nnomenclature for different types of home oxygen, and\nrather than renaming them, has adopted the approach\nof clarifying those de\ufb01nitions, and in particular\nemphasising what is meant by long-term oxygen therapy\nand palliative oxygen therapy. The home oxygen\nguideline provides expert consensus opinion in areas\nwhere clinical evidence is lacking, and seeks to deliver\nimproved prescribing practice, leading to improved\ncompliance and improved patient outcomes, with\nconsequent increased value to the health service.\nSUMMARY OF RECOMMENDATIONS AND\nGOOD PRACTICE POINTS\nEvidence for use of long-term oxygen therapy\nin patients with chronic obstructive pulmonary\ndisease\n\u25b8 Patients with stable chronic obstructive pulmon-\nary disease (COPD) and a resting PaO2 \u22647.3 kPa\nshould be assessed for long-term oxygen therapy\n(LTOT) which offers survival bene\ufb01t and\nimproves pulmonary haemodynamics. (Grade A)\n\u25b8 LTOT should be ordered for patients with stable\nCOPD with a resting PaO2 \u22648 kPa with evi-\ndence of peripheral oedema, polycythaemia\n(haematocrit \u226555%) or pulmonary hyperten-\nsion. (Grade A)\n\u25b8 LTOT should be ordered for patients with\nresting hypercapnia if they ful\ufb01l all other criteria\nfor LTOT. (Grade B)\nEvidence for use of LTOT in other respiratory or\ncardiac disease\n\u25b8 LTOT should be ordered for patients with inter-\nstitial lung disease (ILD) with a resting PaO2\n\u22647.3 kPa. (Grade D)\n\u25b8 LTOT should be ordered for patients with ILD\nwith a resting PaO2 \u22648 kPa in the presence of\nperipheral oedema, polycythaemia (haematocrit\n\u226555%) or evidence of pulmonary hypertension.\n(Grade D)\nGood practice point\n\u25b8 Patients with ILD who experience severe breath-\nlessness could be considered for palliative\noxygen therapy (POT). (\u221a)\nLTOT in patients with cystic \ufb01brosis\n\u25b8 LTOT should be ordered for patients with cystic\n\ufb01brosis (CF) with a resting PaO2 \u22647.3 kPa.\n(Grade D)\n\u25b8 LTOT should be ordered for patients with CF\nwith a resting PaO2 \u22648 kPa in the presence of\nperipheral oedema, polycythaemia (haematocrit\n\u226555%) or evidence of pulmonary hypertension.\n(Grade D)\nLTOT in patients with pulmonary hypertension\n\u25b8 LTOT should be ordered for patients with\npulmonary hypertension, including idiopathic\npulmonary hypertension, when the PaO2 is\n\u22648 kPa. (Grade D)\nLTOT in patients with neuromuscular or chest wall\ndisorders\n\u25b8 Non-invasive ventilation (NIV) should be the\ntreatment of choice for patients with chest wall\nor neuromuscular disease causing type 2 respira-\ntory failure. Additional LTOT may be required\nin case of hypoxaemia not corrected with NIV\n.\n(Grade D)\nLTOT in patients with advanced cardiac failure\n\u25b8 LTOT should be ordered for patients with\nadvanced cardiac failure with a resting PaO2\n\u22647.3 kPa. (Grade D)\n\u25b8 LTOT should be ordered for patients with\nadvanced cardiac failure with a resting PaO2\n\u22648 kPa in the presence of peripheral oedema,\npolycythaemia (haematocrit \u226555%) or evidence\nof pulmonary hypertension on ECG or echocar-\ndiograph. (Grade D)\nHardinge M, et al. Thorax 2015;70:i1\u2013i43. doi:10.1136\/thoraxjnl-2015-206865 i1\nBTS Guidelines\ngroup.bmj.com\non June 19, 2016 - Published by\nhttp:\/\/thorax.bmj.com\/\nDownloaded from\nOutcomes of LTOT in patients who continue to smoke\n\u25b8 If LTOT is ordered for patients who are continuing to\nsmoke, the potential for more limited clinical bene\ufb01t should\nbe discussed with the patient. (Grade D)\nReferral and assessment of patients for LTOT\n\u25b8 Written and verbal information should be given to patients\nreferred to home oxygen assessment services at the time of\nreferral. (Grade D)\n\u25b8 Patients with a resting stable oxygen saturation (SpO2) of\n\u226492% should be referred for a blood gas assessment in order\nto assess eligibility for LTOT. (Grade C)\nGood practice point\n\u25b8 In patients with clinical evidence of peripheral oedema, polycy-\nthaemia (haematocrit \u226555%) or pulmonary hypertension,\nreferral for LTOTassessment may be considered at SpO2 levels\n\u226494% to identify patients with a resting PaO2 \u22648 kPa. (\u221a)\nReferral for home oxygen at hospital discharge\n\u25b8 Patients should undergo formal assessment for LTOT after a\nperiod of stability of at least 8 weeks from their last exacerba-\ntion. (Grade B)\nGood practice points\n\u25b8 Patients who have borderline saturations (ie 93\u201394%) should\nhave their oxygen saturations monitored at their annual\nreview with their general practitioner (GP) or practice nurse,\nor sooner if they experience an exacerbation in the interim.\n(\u221a)\n\u25b8 Patients who exacerbate frequently and are unable to achieve\na period of stability lasting 8 weeks may need to be assessed\nat an earlier stage after exacerbation. If LTOT is ordered for\nsuch patients, they should be counselled that in the future\nLTOT may no longer be required once they achieve a more\nstable state. (\u221a)\n\u25b8 Patients should not normally have LTOT ordered at the time of\nan acute exacerbation of their underlying condition. However, if\nhome oxygen is ordered (eg, at hospital discharge), it should be\nlimited to patients with an SpO2 of \u226492%, who are breathless,\nand unable to manage off oxygen. These patients should\nundergo a blood gases assessment and be counselled that in the\nfuture LTOT may not be required after formal reassessment. (\u221a)\n\u25b8 The date of the patient\u2019s last exacerbation should be included\nin the referral request to the home oxygen assessment\nservice. (\u221a)\nUse of pulse oximetry, arterial and capillary blood gases in\nassessment for LTOT\n\u25b8 Patients potentially requiring LTOT should not be assessed\nusing pulse oximetry alone. (Grade D)\nAssessment using arterial blood gases and capillary blood gases\n\u25b8 Patients being assessed for LTOT should undergo initial\nassessment for suitability using arterial blood gases (ABG)\nsampling. (Grade A)\n\u25b8 Patients assessed for LTOT during a period of apparent clin-\nical stability should undergo two ABG measurements at least\n3 weeks apart, before the need for LTOT can be con\ufb01rmed.\n(Grade B)\n\u25b8 Patients undergoing LTOT assessment should be reassessed\nwith ABG after oxygen titration is complete to determine\nwhether adequate oxygenation has been achieved without\nprecipitating respiratory acidosis and\/or worsening hypercap-\nnia. (Grade D)\n\u25b8 For oxygen titration during LTOT assessment, capillary blood\ngases (CBG) sampling can be used in place of ABG sampling\nfor re-measuring PaCO2 and pH at different oxygen \ufb02ow\nrates. (Grade A)\n\u25b8 For oxygen titration during LTOT assessment, cutaneous cap-\nnography can be used in place of ABG sampling for\nre-measuring PaCO2 alone but not pH at different oxygen\n\ufb02ow rates. (Grade A)\nGood practice points\n\u25b8 Patients undergoing a radial ABG should be assessed with an\nAllen\u2019s test \ufb01rst, to ensure they have a dual blood supply to\nthe hand from both radial and ulnar arteries. (\u221a)\n\u25b8 Patients undergoing a radial ABG should be consented for\nthe procedure with a discussion of possible risks. (\u221a)\n\u25b8 In many community commissioned home oxygen service\u2013\nassessment and review (HOS-AR) services it is not practical\nfor patients to undergo ABG sampling during LTOT assess-\nment. Under such circumstances, a combination of CBGs and\noximetry (but not capnography) could be used as an alterna-\ntive tool for initial assessment for LTOT, and after oxygen\ntitration is complete. Some patients may receive LTOT\nunnecessarily using this approach, but it is unlikely that any\npatient would be inappropriately denied LTOT. (\u221a)\nManagement of hypercapnia during LTOT assessment\n\u25b8 Patients with baseline hypercapnia should be monitored for\nthe development of respiratory acidosis and worsening\nhypercapnia using ABGs after each titration of \ufb02ow rate, as\nwell as an ABG after oxygen titration is complete. (Grade D)\nGood practice points\n\u25b8 Patients who develop a respiratory acidosis and\/or a rise in\nPaCO2 of >1 kPa (7.5 mm Hg) during an LTOT assessment\nmay have clinically unstable disease. These patients should\nundergo further medical optimisation and be reassessed after\n4 weeks. (\u221a)\n\u25b8 Patients who develop a respiratory acidosis and\/or a rise in\nPaCO2 of >1 kPa (7.5 mm Hg) during an LTOT assessment\non two repeated occasions, while apparently clinically stable,\nshould only have domiciliary oxygen ordered in conjunction\nwith nocturnal ventilatory support. (\u221a)\nLTOT hours of use\n\u25b8 LTOT should be ordered for a minimum of 15 h per day, and\nup to 24 h per day may be of additional bene\ufb01t. (Grade C)\nLTOT \ufb02ow rates\n\u25b8 Patients eligible for LTOT should be initiated on a \ufb02ow rate\nof 1 L\/min and titrated up in 1 L\/min increments until SpO2\n>90%. An ABG should then be performed to con\ufb01rm that a\ntarget PaO2 \u22658 kPa (60 mm Hg) at rest has been achieved.\n(Grade B)\n\u25b8 Non-hypercapnic patients initiated on LTOT should increase\ntheir \ufb02ow rate by 1 L\/min during sleep in the absence of any\ncontraindications. (Grade B)\n\u25b8 Patients initiated on LTOT who are active outdoors should\nreceive an ambulatory oxygen assessment to assess whether\ntheir \ufb02ow rate needs increasing during exercise. (Grade B)\nGood practice points\n\u25b8 Ambulatory and nocturnal oximetry may be performed to\nallow more accurate \ufb02ow rates to be ordered for exercise and\nsleep, respectively. (\u221a)\ni2 Hardinge M, et al. Thorax 2015;70:i1\u2013i43. doi:10.1136\/thoraxjnl-2015-206865\nBTS Guidelines\ngroup.bmj.com\non June 19, 2016 - Published by\nhttp:\/\/thorax.bmj.com\/\nDownloaded from\n\u25b8 Patients initiated on LTOT who have cognitive, visual or\ncoordination impairments, may not be able to safely manipu-\nlate their own \ufb02ow rates and should be maintained on a\nsingle \ufb02ow rate. (\u221a)\n\u25b8 Flow rates may be increased at 20 min intervals during an\noxygen titration until a target PaO2 is achieved. (\u221a)\nPatient education at time of assessment\n\u25b8 Patients initiated on LTOT should be provided with formal\neducation by a specialist home oxygen assessment team to\nensure compliance with therapy. (Grade D)\n\u25b8 Patients being commenced on home oxygen on discharge\nfrom hospital should be advised that home oxygen may be\nremoved if reassessment shows clinical improvement.\n(Grade D)\nFollow-up of LTOT patients\n\u25b8 LTOT patients should receive follow-up at 3 months after\nLTOT has been ordered, which should include assessment of\nblood gases and \ufb02ow rate to ensure LTOT is still indicated\nand therapeutic. (Grade A)\n\u25b8 LTOT patients should receive follow-up visits at 6\u2013\n12 months after their initial 3-month follow-up, which can\nbe either home based or in combination with hospital visits.\n(Grade D)\n\u25b8 Follow-up visits should be conducted by a specialist home\noxygen assessment team with the necessary skills to deliver\npatient education and manage withdrawal of home oxygen.\n(Grade D)\nGood practice point\n\u25b8 All patients for whom LTOT has been ordered should be\nvisited at home within 4 weeks by a specialist nurse or\nhealthcare professional with experience of domiciliary\noxygen therapy. The visit provides an opportunity to high-\nlight potential risks and should be used to reinforce educa-\ntion and offer support to the patient and carer. Compliance\nmay be checked, along with smoking status, symptoms of\nhypercapnia and oxygen saturations on oxygen to check that\noxygen is therapeutic. (\u221a)\nNocturnal oxygen therapy\n\u25b8 Nocturnal oxygen therapy (NOT) is not recommended in\npatients with COPD who have nocturnal hypoxaemia but\nwho fail to meet the criteria for LTOT. (Grade A)\nGood practice point\n\u25b8 Other causes of nocturnal desaturation in COPD should be\nconsidered such as obesity hypoventilation, respiratory\nmuscle weakness or obstructive sleep apnoea (OSA). (\u221a)\nNOT in patients with cardiac disease and nocturnal desaturation\n\u25b8 NOT can be ordered for severe heart failure patients who do\nnot ful\ufb01l indications for LTOT and have evidence of sleep\ndisordered breathing (SDB) leading to daytime symptoms,\nafter other causes of nocturnal desaturation have been\nexcluded (eg, obesity hypoventilation or OSA) and heart\nfailure treatment has been optimised. Treatment with modal-\nities of ventilatory support should also be considered.\n(Grade B)\nGood practice point\n\u25b8 If NOT is ordered for patients with severe heart failure, it\nshould be ordered at a low \ufb02ow rate of 1\u20132 L\/min and response\nshould be assessed by a reduction in symptoms of daytime\nsleepiness, and SDB indices as measured by an overnight oxim-\netry study. A blood gas assessment should be undertaken to\nexclude worsening hypercapnia and respiratory acidosis.\nTreatment with modalities of ventilatory support should be\nconsidered for patients who are hypercapnic. (\u221a)\nNOT in patients with CF\n\u25b8 NOT should not be given to patients with CF with nocturnal\nhypoxaemia alone who do not ful\ufb01l LTOT criteria. It can be\nconsidered in patients with evidence of established ventilatory\nfailure, where it should be given with NIV support. (Grade B)\nNOT in patients with ILD\n\u25b8 NOT should not be given to patients with ILD with nocturnal\nhypoxaemia alone, who do not ful\ufb01l LTOTcriteria. (Grade B)\nNOT in patients with neuromuscular weakness\n\u25b8 Patients with neuromuscular weakness affecting respiratory\nmuscles should not have NOTalone ordered. It can be consid-\nered in patients with evidence of established ventilatory failure,\nwhere it should be given with NIV support. (Grade B)\nNOT in patients with OSA, obesity hypoventilation syndrome\nor overlap syndrome\n\u25b8 Patients with OSA, obesity hypoventilation syndrome (OHS) or\noverlap syndrome should not have NOT alone ordered. It can\nbe considered in patients with evidence of established ventila-\ntory failure, where it should be given with NIV support.\n(Grade D)\nAmbulatory oxygen therapy\n\u25b8 AOT should not be routinely offered to patients who are not\neligible for LTOT. (Grade B)\n\u25b8 AOT should not be routinely offered to patients already on\nLTOT. (Grade D)\n\u25b8 Ambulatory oxygen therapy (AOT) assessment should only\nbe offered to patients already on LTOT if they are mobile\noutdoors. (Grade A)\n\u25b8 AOT should be offered to patients for use during exercise in\na pulmonary rehabilitation programme or during an exercise\nprogramme following a formal assessment demonstrating\nimprovement in exercise endurance. (Grade B)\nGood practice points\n\u25b8 Patients started on AOT should be reviewed regularly. If AOT\nwas started during an exacerbation or when unwell, an\ninitial review at 4\u20136 weeks to check it is still indicated is\nessential. (\u221a)\n\u25b8 Home visits may be useful to identify problems with equip-\nment or set-up. Further reviews should be carried out every\n6 months when stable, or sooner if the patient\u2019s clinical\nstatus changes. (\u221a)\n\u25b8 AOT therapy may offer patients with active lifestyles or\nactive treatment regimens (eg, CF) additional bene\ufb01ts. All\npatients should be assessed for AOT in the context of their\ndaily activity and therapies. (\u221a)\n\u25b8 It is recognised that there may be some patients, for example\nwith ILD and disabling breathlessness, who do not qualify\nfor LTOT but who do desaturate on exercise who may\nbene\ufb01t from AOT. Once all other medical interventions have\nbeen optimised, these patients could be considered for AOT\nfollowing formal assessment and continued provision follow-\ning demonstration of bene\ufb01t and compliance. (\u221a)\n\u25b8 Patients with high respiratory rates (common in CF and ILD)\nshould receive AOT at a selected \ufb02ow rate via a Venturi\nHardinge M, et al. Thorax 2015;70:i1\u2013i43. doi:10.1136\/thoraxjnl-2015-206865 i3\nBTS Guidelines\ngroup.bmj.com\non June 19, 2016 - Published by\nhttp:\/\/thorax.bmj.com\/\nDownloaded from\nmask, which exceeds their peak tidal and exertional inspira-\ntory \ufb02ow, and be supplied with home oxygen equipment\nwhich is able to deliver the required high \ufb02ow rates. (\u221a)\n\u25b8 AOT may be offered to LTOT patients who could otherwise\nnot achieve 15 h per day oxygen usage, or who are severely\nhypoxaemic and are too symptomatic to leave their\nhouse without supplemental oxygen but may need to do so,\nfor example to attend their GP or hospital appointments.\nFormal assessment is not required in these circumstances.\n(\u221a)\nPalliative oxygen therapy\n\u25b8 Patients with cancer or end-stage cardiorespiratory disease\nwho are experiencing intractable breathlessness should not\nreceive treatment with POT if they are non-hypoxaemic or\nhave mild levels of hypoxaemia above current LTOT thresh-\nolds (SpO2 \u226592%). (Grade A)\n\u25b8 Patients with cancer or end-stage cardiorespiratory disease who\nare experiencing intractable breathlessness should receive\nassessment for a trial of treatment with opiates from an appro-\npriately trained healthcare professional. (Grade A)\n\u25b8 Patients with cancer or end-stage cardiorespiratory disease who\nare experiencing intractable breathlessness should receive\nassessment for a trial of treatment with non-pharmacological\ntreatments including fan therapy from an appropriately trained\nhealthcare professional. (Grade D)\nGood practice point\n\u25b8 POT may on occasion be considered by specialist teams for\npatients with intractable breathlessness unresponsive to all other\nmodalities of treatment. In those instances, individual formal\nassessment of the effect of palliative oxygen on reducing breath-\nlessness and improving quality of life should be made. (\u221a)\nShort burst oxygen therapy\n\u25b8 Short burst oxygen therapy (SBOT) should not be ordered\nfor use prior to or following exercise in hypoxaemic or nor-\nmoxic patients with COPD. (Grade A)\n\u25b8 SBOT should not be ordered on discharge from hospital for\nnon-hypoxaemic patients with severe COPD. (Grade A)\nUse of SBOT in cluster headache\n\u25b8 SBOT delivering high \ufb02ow oxygen therapy (12 L\/min via a\nnon-rebreather mask) should be offered to treat acute attacks\nof cluster headache (CH). (Grade A)\nGood practice point\n\u25b8 Appropriate equipment will need to be provided in order to\nensure delivery of high \ufb02ow rate oxygen at 12 L\/min for CH\nusing a non-rebreather mask. Patients will usually have\nwarning of a CH attack, and so provision should be made\nfor urgent 4 h installation of home oxygen, if available,\nrather than a permanent home supply being provided. (\u221a)\nEquipment for home oxygen therapy\n\u25b8 Oxygen concentrators should be used to deliver LTOT at\n\ufb02ow rates of 4 L\/min or less. (Grade B)\n\u25b8 Portable oxygen should be delivered by whatever mode is\nbest suited to the individual needs of the patient to increase\nthe daily amount of oxygen used and activity levels in mobile\npatients. (Grade C)\nGood practice point\n\u25b8 The type of portable device selected should balance patient\nfactors with cost effectiveness, resources and safety. (\u221a)\nOxygen delivery\n\u25b8 Nasal cannulae should be considered as the \ufb01rst choice of\ndelivery device for patients requiring home oxygen therapy.\nAs an alternative some patients may bene\ufb01t from or prefer a\nVenturi mask system. (Grade D)\n\u25b8 Oxygen-conserving devices can be used in home oxygen\npatients requiring high \ufb02ow rates to increase the time the\ncylinder will last. (Grade B)\nGood practice points\n\u25b8 Venturi masks should be considered in patients in whom\nthere are concerns about existing or developing hypercapnic\nrespiratory failure, those with a high resting respiratory rate\nor those with cognitive problems. (\u221a)\n\u25b8 Oxygen-conserving devices should be considered in patients\nwho are active outside the home, following an ambulatory\noxygen assessment. (\u221a)\nHumidi\ufb01cation\n\u25b8 Humidi\ufb01cation of home oxygen should not be ordered for\nnon-tracheostomy patients. (Grade D)\nGood practice point\n\u25b8 Patients receiving oxygen via a tracheostomy should receive\nhumidi\ufb01ed oxygen. (\u221a)\nCarrying home oxygen\n\u25b8 Less able patients should be offered wheeled devices or back-\npacks if assessment shows they improve ambulation and\nquality of life. (Grade B)\nGood practice point\n\u25b8 When being transported in cars, cylinders should be secured\neither with a seat belt, or in the foot-well or car boot, possibly\nusing a cylinder box. Liquid oxygen should always be trans-\nported in an upright position. A warning triangle may be dis-\nplayed and insurance companies should be informed. (\u221a)\nSafety and home oxygen therapy\n\u25b8 Smoking cessation should be discussed and written education\ngiven to all patients prior to ordering home oxygen and at\neach subsequent review if the patient continues to smoke.\n(Grade C)\n\u25b8 Patients should be made aware in writing of the dangers of\nusing home oxygen within the vicinity of any naked \ufb02ame\nsuch as pilot lights, cookers, gas \ufb01res and candles. (Grade D)\n\u25b8 Patients and family members who continue to smoke in the\npresence of home oxygen should be warned of the associated\ndangers of smoking in the presence of oxygen. (Grade D)\nGood practice points\n\u25b8 Safety should be a factor when making decisions regarding\nthe ordering of oxygen. Education and written information\nshould be provided to the patient and family or carers\nregarding the safe use of oxygen and its equipment. (\u221a)\n\u25b8 The risks of prescribing oxygen to active smokers should be\nconsidered on a case-by-case basis: this should include a home\nvisit to assess the patient\u2019s home situation, attitude toward risks\nand smoking behaviour. Home oxygen assessment services may\ndecide not to prescribe home oxygen to smokers if the risks are\nin their judgement too high. Particular consideration needs to\nbe given to risks to children and risks to neighbours in multiple\noccupancy dwellings. A risk assessment tool should be used,\nand the health professional who is undertaking the risk assess-\nment may need to visit the home in conjunction with the local\ni4 Hardinge M, et al. Thorax 2015;70:i1\u2013i43. doi:10.1136\/thoraxjnl-2015-206865\nBTS Guidelines\ngroup.bmj.com\non June 19, 2016 - Published by\nhttp:\/\/thorax.bmj.com\/\nDownloaded from\n\ufb01re service and\/or the oxygen contractor. Where there is rea-\nsonable doubt, the therapy should not be prescribed. (\u221a)\n\u25b8 Patients who continue to smoke or live with other household\nsmokers should be informed that the home oxygen order\nwill be reviewed and evidence of increased risk may lead to\nwithdrawal of home oxygen therapy. (\u221a)\n\u25b8 Carbon monoxide monitoring and measuring urine cotinine\nmay help identify those patients who continue to smoke. (\u221a)\n\u25b8 Patients should be made aware that they should not use\ne-cigarettes and chargers within the vicinity of their home\noxygen. (\u221a)\n\u25b8 Oil-based emollients and petroleum jelly can support com-\nbustion in the presence of oxygen. Patients should be made\naware that only water-based products should be used on the\nhands and face or inside the nose while using oxygen. (\u221a)\n\u25b8 The oxygen supplier should be informed if the patient con-\ntinues to smoke in order for the engineer to consider it in\nthe home oxygen supplier risk assessment. (\u221a)\n\u25b8 Patients and family or carers should be instructed not to\nremove the \ufb01re breaks or to change \ufb02ow rate on their\noxygen equipment. Only oxygen tubing and connections\nsupplied by the oxygen company should be used. (\u221a)\n\u25b8 The local \ufb01re service should be made aware of patients who are\nusing oxygen at home and especially those who continue to\nsmoke in order for a home safety assessment to be carried out.\n(\u221a)\n\u25b8 Patients and carers should be aware that tubing should be\nchecked on a regular basis and repositioned as necessary to\nensure safety by preventing trips and falls. (\u221a)\nINTRODUCTION\nThe British Thoracic Society (BTS) Home Oxygen Guideline\nprovides detailed evidence-based guidance for the use of home\noxygen for patients out of hospital. Although the majority of\nevidence comes from the use of oxygen in patients with chronic\nobstructive pulmonary disease (COPD), the scope of the\nguidance includes patients with a variety of long-term respira-\ntory illnesses and other groups in whom oxygen is currently\nordered, such as those with cardiac failure, cancer and end-stage\ncardiorespiratory disease, terminal illness and cluster headache\n(CH). It explores the evidence base for the use of different\nmodalities of oxygen therapy and patient-related outcomes such\nas mortality, symptoms and quality of life. The guideline also\nmakes recommendations for assessment and follow-up proto-\ncols, and risk assessments, particularly in the clinically challen-\nging area of home oxygen users who smoke. The guideline\ndevelopment group is aware of the potential for confusion\nsometimes caused by the current nomenclature for different\ntypes of home oxygen, and rather than renaming them has\nadopted the approach of clarifying those de\ufb01nitions, and in par-\nticular emphasising what is meant by long-term oxygen therapy\n(LTOT) and palliative oxygen therapy (POT). The home oxygen\nguideline provides expert consensus opinion in areas where clin-\nical evidence is lacking, and seeks to deliver improved prescrib-\ning practice, leading to improved compliance and improved\npatient outcomes, with consequent increased value to the health\nservice.\nTarget audience for the guideline\nThis guideline is aimed at all healthcare practitioners who are\ninvolved in the care of patients who use home oxygen therapy:\nthis will include primary care clinicians (general practitioners\n(GPs), and practice and district nurses), those working in\ncommunity nursing or palliative care teams, integrated respira-\ntory teams, home oxygen assessment services and hospital spe-\ncialist teams in respiratory medicine, cardiology, neurology,\noncology, geratology and palliative care.\nGroups covered\nThe home oxygen guideline addresses the use of home oxygen\nin adults with\n\u25b8 chronic respiratory disease including COPD, pulmonary hyper-\ntension, pulmonary vascular disease, cystic \ufb01brosis (CF), inter-\nstitial lung disease (ILD), chest wall disease, neuromuscular\ndisease, and pulmonary malignancy\n\u25b8 cardiac disease including congestive cardiac failure and adult\ncongenital heart disease\n\u25b8 CH.\nIt will also consider special situations including:\n\u25b8 palliative and end-of-life care\n\u25b8 patients discharged from hospital pending a formal assess-\nment when stable\n\u25b8 smokers.\nScope of the guideline\nThe guideline considers the evidence base and makes recom-\nmendations for the use or restricted use of the following types\nof home oxygen therapy:\n\u25b8 long-term oxygen therapy (LTOT)\n\u25b8 nocturnal oxygen therapy (NOT)\n\u25b8 ambulatory oxygen therapy (AOT)\n\u25b8 palliative oxygen therapy (POT)\n\u25b8 short burst oxygen therapy (SBOT).\nThe guideline considers the evidence base and makes recom-\nmendations for referral, assessment (including the roles of oxim-\netry, arterial blood gases (ABGs) and capillary blood gases\n(CBGs)), and follow-up of patients for home oxygen therapy.\nThe guideline reviews the different equipment used to deliver\nhome oxygen therapy.\nFinally, the guideline reviews safety issues around home oxygen\ntherapy, in particular risks of \ufb01re, burns and smoke inhalation\nfrom \ufb02ammable sources such as smoking. It outlines the risk\nassessment processes which were put in place by the National\nFramework Agreement for home oxygen therapy (2010) which\noutlined responsibilities for home oxygen providers.\nAreas not covered by the guideline\nThe guideline development group was aware of existing BTS\nguidelines in related areas and the following areas therefore fall\noutside the scope of this guideline:\n\u25b8 home oxygen in children (younger than 18)\u2014home oxygen\nin children remains as a separate guideline.1\n\u25b8 home oxygen use during acute exacerbations of respiratory\ndisease\u2014this is covered by the BTS Guideline for Emergency\nOxygen Use in Adult Patients.2\n\u25b8 home oxygen use during air travel\u2014see the 2011 BTS guide-\nline on recommendations for managing passengers with\nstable respiratory disease planning air travel.3\nThe guideline development group were unable to cover all\ndisease groups individually, for example bronchiectasis and\nasthma among others. In these areas no disease speci\ufb01c evidence\nfor oxygen use was found.\nMethodology\nThis guideline is based on the best available evidence. The\nmethodology used to write the guideline adheres strictly to the\nHardinge M, et al. Thorax 2015;70:i1\u2013i43. doi:10.1136\/thoraxjnl-2015-206865 i5\nBTS Guidelines\ngroup.bmj.com\non June 19, 2016 - Published by\nhttp:\/\/thorax.bmj.com\/\nDownloaded from\ncriteria as set by the AGREE collaboration, which is available\nonline (http:\/\/www.agreetrust.org\/resource-centre\/agree-ii\/). The\nBTS Standards of Care Committee (SOCC) guideline produc-\ntion manual is available at http:\/\/www.brit-thoracic.org.uk\/\nguidelines-and-quality-standards\/\nClinical questions and literature search\nClinical questions were structured in the PICO (Patient,\nIntervention, Control, Outcome) format (see online supple-\nmentary appendix 9) to de\ufb01ne the scope of the guideline and\ninform the literature search.\nSystematic electronic database searches were conducted in\norder to identify potentially relevant studies for inclusion in the\nguideline. For each topic area the following databases were\nsearched: Ovid MEDLINE (including MEDLINE In-Process),\nOvid EMBASE, and the Cochrane Library (including the\nCochrane Database of Systematic Reviews and the Database of\nAbstracts of Reviews of Effects) from 1980.\nThe searches were \ufb01rst run in July 2012 and updated in\nJanuary 2014 (see online supplementary appendix 10 for the\nsearch strategy). Searches included a combination of indexed\nterms and free text terms and were limited to English language\npublications only. The initial search identi\ufb01ed 1392 potential\nabstracts and the second search 326 abstracts.\nAppraisal of the literature\nAppraisal was performed to be compliant with the AGREE col-\nlaboration. Four individuals (MH, SH, TW\n, JS) read the title\nand abstract of each article retrieved by the literature searches\nand decided whether the paper was de\ufb01nitely relevant, possibly\nrelevant or not relevant to the project. Criteria formulated for\ncategorising the abstracts into these three groups were:\n\u25b8 whether the study addressed the clinical question;\n\u25b8 whether the appropriate study type was used to produce the\nbest evidence to answer the clinical question;\n\u25b8 review articles were excluded;\n\u25b8 the abstract was in English;\n\u25b8 abstracts were not rejected on the basis of the journal of pub-\nlication, country in which the research was performed or\npublished, or the date of publication.\nThe full paper was obtained for all relevant or possibly rele-\nvant abstracts and allocated to the relevant section(s) of the\nguideline.\nThe \ufb01rst screening process identi\ufb01ed 511 of the initial 1392\nreference abstracts to be de\ufb01nitely or possibly relevant to the\nguideline. Two guideline reviewers per section independently\nreviewed the abstracts to identify papers to be appraised for the\nguideline. The two reviewers for each section then independ-\nently appraised each paper assigned to them using the Scottish\nIntercollegiate Guidelines Network (SIGN) critical appraisal\nchecklists. The reliability of the evidence in each individual\nstudy was graded using the SIGN critical appraisal check lists\nand is shown in the evidence tables (++, + or \u2212) (see online\nsupplementary appendix 11). The body of evidence for each\nrecommendation was summarised into evidence statements and\ngraded using the SIGN grading system (see table 1).\nDisagreements were resolved by discussion with the section\npartner. The second literature search in January 2014 yielded\n326 abstracts. Of these, 56 were identi\ufb01ed as de\ufb01nitely or pos-\nsibly relevant to the guideline. However, all of the pertinent\nabstracts from this search had been identi\ufb01ed by the guideline\ndevelopment group (GDG) in the meantime and already\nincorporated.\nConsidered judgement and grading of evidence\nThe GDG used the evidence tables to judge the body of evi-\ndence and grade recommendations for this guideline. Evidence\ntables are available in the online supplementary appendix 11.\nWhere evidence was lacking to answer the formulated clinical\nquestions, expert opinions were obtained through consensus.\nThe following were considered in grading of the\nrecommendations:\n\u25b8 the available volume of the body of evidence;\n\u25b8 how applicable the obtained evidence was in making recom-\nmendations for the de\ufb01ned target audience of this guideline;\n\u25b8 whether the evidence was generalisable to the target popula-\ntion for the guideline;\n\u25b8 whether there was clear consistency in the evidence obtained\nto support recommendations;\n\u25b8 what the implications of recommendations would be on clin-\nical practice in terms of resources and skilled expertise;\n\u25b8 cost-effectiveness was not reviewed in detail as in-depth eco-\nnomic analysis of recommendations falls beyond the scope of\nthis guideline.\nRecommendations were graded from A to D as indicated by the\nstrength of the evidence as shown in table 2. In line with SIGN\nguidance, evidence rated \u2018minus\u2019 was considered by the GDG in\ncontext but in the absence of other supporting evidence with a\n\u201cplus\u201d rating, any recommendation made was Grade D. Important\npractical points lacking any research evidence and not likely to be\nresearch evidence in the future, were highlighted as \u2018good practice\npoints\u2019.\nDrafting the guideline\nThe GDG corresponded regularly by email and meetings of the\nfull group were held in November 2011, February and\nNovember 2012, and March, April and September 2013 in add-\nition to a number of teleconferences. The BTS SOCC reviewed\nthe draft guideline in March 2014. The draft guideline was\nmade available online in July\/August 2014 for public consult-\nation and circulated to all the relevant stakeholders. The BTS\nSOCC re-reviewed the revised draft guideline in December\n2014 and \ufb01nal SOCC approval was granted in January 2015.\nThis BTS guideline will be reviewed within the next 5 years.\nTable 1 Key to evidence statements\nGrade Evidence\n1++ High quality meta-analyses, systematic reviews of RCTs, or RCTs with a\nvery low risk of bias\n1+ Well conducted meta-analyses, systematic reviews of RCTs, or RCTs\nwith a low risk of bias\n1\u2212 Meta-analyses, systematic reviews of RCTs, or RCTs with a high risk of\nbias\n2++ High quality systematic reviews of case\u2013control or cohort studies or\nhigh quality case\u2013control or cohort studies with a very low risk of\nconfounding, bias or chance and a high probability that the relationship\nis causal\n2+ Well conducted case\u2013control or cohort studies with a low risk of\nconfounding, bias or chance and a moderate probability that the\nrelationship is causal\n2\u2212 Case\u2013control or cohort studies with a high risk of confounding, bias or\nchance and a significant risk that the relationship is not causal\n3 Non-analytic studies, for example case reports, case series\n4 Expert opinion\nRCT, randomised control trial.\ni6 Hardinge M, et al. Thorax 2015;70:i1\u2013i43. doi:10.1136\/thoraxjnl-2015-206865\nBTS Guidelines\ngroup.bmj.com\non June 19, 2016 - Published by\nhttp:\/\/thorax.bmj.com\/\nDownloaded from\nDeclarations of interest\nAll members of the GDG made declarations of interest in line\nwith BTS policy and further details can be obtained on request\nfrom BTS. GDG members are listed in appendix 8.\nAcknowledgements\nThe guideline development group members are grateful to:\n\u25b8 Wirral NHS home oxygen assessment service for the\nexample of a Home Oxygen Risk Assessment form (see\nappendix 4);\n\u25b8 Oxford Health Foundation Trust home oxygen assessment\nservice for an example of an Ambulatory Oxygen Assessment\non which appendix 1 is based;\n\u25b8 The British Lung Foundation for patient information lea\ufb02ets\nreferred to in appendix 6;\n\u25b8 Barema (the Association for Anaesthetic and Respiratory\nDevice Suppliers) and BOC Healthcare for the photographs\nof home oxygen equipment used to illustrate online supple-\nmentary appendix 12.\nAudit and research recommendations\n1. Research to investigate which patients with particular disease\nphenotypes bene\ufb01t from LTOT: for example smokers com-\npared with ex-smokers, those with pulmonary hypertension,\nthose with COPD-driven cachexia and frequent exacerbators.\n2. Research to investigate long-term outcomes (survival) in dis-\neases other than COPD such as CF, ILD and bronchiectasis.\n3. Research to investigate delivery of oxygen during pulmonary\nrehabilitation and maintenance classes, assessing impact on\noutcomes such as exacerbations, exercise tolerance and\nquality of life.\n4. Longitudinal studies to assess the impact of LTOT on pul-\nmonary haemodynamics in COPD patients with pulmonary\nhypertension using both direct (eg, cardiac catheterisation)\nand indirect (eg, NT-proBNP\n, echocardiography) parameters,\nalong with quality of life and exercise tolerance outcomes.\n5. A robust assessment of risk assessment measures with the\naim of developing an integrated pathway for home oxygen\nteams and oxygen provider services to manage patients who\nsmoke.\n6. Research to investigate the role of palliative oxygen in com-\nparison with or used together with other measures such as\nopiates, fan therapy and cognitive behavioural therapy.\n7. Research to investigate and compare the use of ABG and\nCBG in predicting need for LTOT and risk of hypercapnia.\n8. Audit of assessment, ordering for and follow-up of home\noxygen patients to improve and maintain standards of care\nfrom home oxygen assessment teams.\nTable 2 Grades of recommendations\nGrade Type of evidence\nA At least one meta-analysis, systematic review or RCT rated as 1++ and\ndirectly applicable to the target population or\nA systematic review of RCTs or a body of evidence consisting principally\nof studies rated as 1+ directly applicable to the target population and\ndemonstrating overall consistency of results\nB A body of evidence including studies rated as 2++ directly applicable to\nthe target population and demonstrating overall consistency of results\nor\nExtrapolated evidence from studies rated as 1++ or 1+\nC A body of evidence including studies rated as 2+ directly applicable to\nthe target population and demonstrating overall consistency of results\nor\nExtrapolated evidence from studies rated as 2++\nD Evidence level 3 or 4 or\nExtrapolated evidence from studies rated as 2+\n\u221a Important practical points for which there is no research evidence, nor\nis there likely to be any research evidence. The guideline committee\nwishes to emphasise these as Good Practice Points.\nRCT, randomised control trial.\nGlossary\/Abbreviations and symbols\nAbbreviations\nABG Arterial blood gas\nAHI Apnoea hypopnoea index\nAOT Ambulatory oxygen therapy\nASV Adaptive servo ventilation\nBIPAP Bi-level positive airway pressure\nBTS British Thoracic Society\nCBG Capillary blood gas\nCCF Congestive cardiac failure\nCCH Chronic cluster headache\nCF Cystic fibrosis\nCH Cluster headache\nCO Carbon monoxide\nCO2 Carbon dioxide\nCOPD Chronic obstructive pulmonary disease\nCPAP Continuous positive airway pressure\nCRQ Chronic respiratory disease questionnaire\nCSA Central sleep apnoea\nCSB Cheyne-stokes breathing\nECH Episodic cluster headache\nECOG PS Eastern Cooperative Oncology Group Performance Status\nEEG Electroencephalography\nELBG Earlobe blood gas\nESS Epworth sleepiness scale\nFiO2 Fraction of inspired oxygen\nGDG Guideline development group\nGP General practitioner\nH Hypoxaemia\nHAD Hospital anxiety and depression scale\nHb Haemoglobin\nHO Home oxygen\nHOOF Home oxygen order form\nHOS-AR Home oxygen service \u2013 assessment and review\nIPAH Idiopathic Pulmonary Arterial Hypertension\nIOT Intermittent oxygen therapy\nILD Interstitial lung disease\nkPa kilo Pascal (unit of measurement of pressure) 1kPa= 7.5mmHg\nL\/min Litres per minute (unit of measure of flow rate of oxygen)\nLTOT Long term oxygen therapy\nLVEF Left ventricular ejection fraction\nm Meter (unit of measurement of length)\nmmHg millimetres of mercury (unit of measurement of pressure)\nMMSE Mini mental state examination\nMQoLQ Migraine quality of life questionnaire\nMRC Medical Research Council\nNH Non hypoxaemic\nNHYA New York Heart Association\nNIV Non-invasive ventilation\nNIPPV Non-invasive positive pressure ventilation\nNOT Nocturnal oxygen therapy\nNRS Numeric rating scale\nHardinge M, et al. Thorax 2015;70:i1\u2013i43. doi:10.1136\/thoraxjnl-2015-206865 i7\nBTS Guidelines\ngroup.bmj.com\non June 19, 2016 - Published by\nhttp:\/\/thorax.bmj.com\/\nDownloaded from\nPartial pressure units of measurement and conversion\nbetween them\n\u25b8 Partial pressures of oxygen and carbon dioxide are measured\nusing kilopascals (kPa) and millimetres of mercury (mm Hg)\nwhere:\n\u25b8 1 kPa=7.5 mm Hg, and 1 mm Hg=0.133 kPa.\nLONG-TERM OXYGEN THERAPY\nLTOT can be de\ufb01ned as oxygen used for at least 15 h per day in\nchronically hypoxaemic patients. Chronic hypoxaemia is\nde\ufb01ned as a PaO2 \u22647.3 kPa or, in certain clinical situations,\nPaO2 \u22648.0 kPa. LTOT is delivered via an oxygen concentrator\nand should be differentiated from the use of oxygen as a pallia-\ntive measure for symptomatic relief in breathless patients, which\nwill be discussed in the palliative oxygen therapy section. LTOT\naddresses speci\ufb01c physiological inclusion criteria as outlined\nbelow.\nEvidence for use of LTOT in patients with COPD\nSurvival bene\ufb01t in COPD patients with LTOT\nTwo landmark randomised controlled trials (RCTs) showed sur-\nvival bene\ufb01t of LTOT in patients with COPD and severe chronic\nhypoxaemia when used for at least 15 h daily.\nThe Nocturnal Oxygen Therapy Trial (NOTT) was the \ufb01rst\nRCT of LTOT in patients with COPD.4\nIt included 203 patients\nwith COPD in six US centres with PaO2 \u22647.33 kPa (55 mm Hg),\nor PaO2 <7.87 kPa (59 mm Hg) with a raised haematocrit, signs\nof right heart failure or P pulmonale. It compared the effects of\n12 h nocturnal oxygen (n=102) therapy with continuous oxygen\n(24 h; n=101) therapy on mortality, pulmonary haemodynamics\nand exercise capacity at 12 months. The treatment groups were\nwell matched. There was 1.94 times the mortality in the NOT\ngroup compared to the continuous oxygen therapy group. This\nsurvival bene\ufb01t was present in relatively normocapnic patients,\nand in those without a raised pulmonary arterial pressure (PAP)\nbut was more pronounced in patients with hypercapnia, severe\nair\ufb02ow limitation, lower oxygen saturations and in those with\nneuropsychological impairment. There was also a correlation\nbetween the mean reduction in PAP in the \ufb01rst 6 months of LTOT\nand survival at 8-year follow-up.\nThe UK MRC (Medical Research Council) domiciliary oxygen\ntrial studied 87 patients with chronic bronchitis and emphysema\nwho were hypoxaemic (PaO2 5.3\u20138.0 kPa), who were mostly\nhypercapnic and who had a previous documented episode of\noedema indicating cor pulmonale. Patients were randomised to\nno oxygen therapy or 15 h\/day at an inspired oxygen concentra-\ntion to achieve a PaO2 >8 kPa.5\nOver a 5-year follow-up period\nin the MRC trial, 19\/42 died in the LTOT (treatment) group\ncompared with 30\/45 in the control (no oxygen) group.\nSubsequent studies have con\ufb01rmed a survival bene\ufb01t of LTOT\nwhen given for at least 15 h\/day in the presence of chronic hyp-\noxaemia, irrespective of chronic hypercapnia or previous epi-\nsodes of oedema or pulmonary hypertension.6\u20138\nThis survival\nbene\ufb01t was not seen in patients with moderate hypoxaemia. No\nsigni\ufb01cant differences were found in survival rates between\npatients treated with LTOT and controls in a population of 135\npatients with advanced air\ufb02ow limitation (mean (SD) FEV1 0.83\n(0.28) L) and moderate hypoxaemia (PaO2 7.4\u20138.7 kPa, 56\u201365\nmm Hg) followed up for at least 3 years or until death.9\nWomen\nhave a worse prognosis on LTOT than men.10\nMost patients\ntreated with LTOT die as a result of respiratory failure.11\nNutritional depletion is an independent risk factor for mortality\nand hospitalisation in patients with COPD receiving LTOT.12\nEvidence for blood gas criteria for selection of\nCOPD patients for LTOT\nCriteria for ordering LTOT and ABG parameters derive from\nthe two previously described landmark RCTs.4 5\nThe NOTT\ntrial included COPD patients with PaO2 \u22647.33 kPa\n(\u226455 mm Hg) or PaO2 \u22648 kPa (60 mm Hg) with a raised haem-\natocrit, signs of right heart failure or P pulmonale on electrocar-\ndiogram.4\nThe UK MRC domiciliary oxygen trial studied\noutcomes in patients with chronic bronchitis and emphysema\nwho were hypoxaemic (PaO2 5.3\u20138 kPa), mostly hypercapnic\nand who had a previous documented episode of oedema indi-\ncating cor pulmonale.5\nLTOT in hypercapnic COPD patients\nFew RCTs have directly studied the impact of providing oxygen\nby comparing a priori hypercapnic and normocapnic patients\nwith COPD. In the MRC trial, an analysis of predictors of mor-\ntality demonstrated that raised red cell mass and baseline PaCO2\nwere predictors of mortality in both the treatment and placebo\narms.5\nLongitudinal analysis demonstrated that a rising PaCO2\nand falling PaO2 were associated with poor outcomes in both\narms. The authors concluded that there was no evidence of\noxygen toxicity with this treatment regimen. In contrast, a study\nof 228 patients given an oxygen concentrator who were fol-\nlowed up for a maximum of 5 years, and analysed in three\nOHS Obesity Hypoventilation Syndrome\nOT Oxygen therapy\nOSA Obstructive sleep apnoea\nO2 Oxygen\nPAP Pulmonary artery pressure\nPCO2 Carbon dioxide tension (partial pressure) in blood or alveolus\nPaCO2 Arterial carbon dioxide tension (partial pressure)\nPaO2 Arterial oxygen tension (partial pressure)\nPO2 Oxygen tension (partial pressure) in blood or alveolus\nPCU Palliative care unit\nPICO Patient Intervention Control Outcome\nPOT Palliative oxygen therapy\nPPH Primary pulmonary hypertension\npH Unit of measurement of acidity of blood\nQoL Quality of life\nREM Rapid eye movement stage of sleep\nSBOT Short burst oxygen therapy\nSD Standard deviation\nSDB Sleep disorder breathing\nSF-A Validated sleep quality questionnaire\nSF 36 Short form (36) health questionnaire\nSIGN Scottish Intercollegiate Guideline Network\nSaO2 Arterial oxygen saturation measured by arterial blood gas\nco-oximetry\nSpO2 Arterial oxygen saturation measured by pulse oximetry\nSOCC British Thoracic Society Standards of Care Committee\nVAS Visual analogue scale\nVE Minute ventilation\n6MWT 6 minute walk test\nSymbols\n> Greater than or above\n\u2264 Less than or below\n> Greater than or equal to\n\u2264 Less than or equal to\n% Percent\ni8 Hardinge M, et al. Thorax 2015;70:i1\u2013i43. doi:10.1136\/thoraxjnl-2015-206865\nBTS Guidelines\ngroup.bmj.com\non June 19, 2016 - Published by\nhttp:\/\/thorax.bmj.com\/\nDownloaded from\ngroups (n=55, no use of oxygen; n=112, use for <15 h per\nday; and n=61, use for >15 h per day) showed that median sur-\nvival at 2 years was better in the groups receiving oxygen com-\npared to the no use group.8\nBaseline PaCO2 was not shown to\nbe a predictor of mortality and did not predict differences in\nmortality between the groups. However, the NOTT trial\nshowed the survival bene\ufb01t in the treatment groups was more\napparent in patients with hypercapnia.4\nThe effect of supplementary oxygen on the chemical control\nof ventilation has the potential to increase CO2 levels in patients\nreceiving 24 h\/day oxygen. Fleetham et al13\nstudied 30 hypox-\naemic COPD patients (mean PaO2 6.9 kPa) who were rando-\nmised to 12 or 24 h oxygen therapy for 12 months. Patients\ngiven 24 h oxygen had a blunted CO2 response. There was no\nchange in the hypoxaemic response in either group.\nEffects of LTOT on pulmonary haemodynamics in COPD patients\nThe effect of LTOT on PAP are small. In the NOTT trial, sur-\nvival after 8 years was related to the decrease in mean PAP\nduring the \ufb01rst 6 months of treatment.14\nThis subgroup analysis\nalso showed improvement in PAP and stroke volume in patients\nwith 24 h of oxygen therapy per day compared to those given\nonly 12 h of oxygen per day. In the MRC trial, LTOT prevented\na rise in PAP of 0.4 kPa (3 mm Hg), seen in the control group,\nalthough a fall in PAP was not found.5\nA small intervention\nstudy measured PAP and left ventricular ejection fraction (LVEF)\nbefore and after 6 months of LTOT and showed a signi\ufb01cant fall\nin mean PAP\n.15\nEffects of LTOT on sleep in COPD patients\nPatients with COPD can develop nocturnal hypoxaemia due to\nventilation\u2013perfusion mismatch, decreased functional capacity\nand nocturnal hypoventilation particularly pronounced during\nREM sleep. This in turn can lead to poor sleep quality with\nsleep fragmentation. Use of LTOT has been demonstrated to\ncorrect nocturnal SaO2, decrease sleep latency and improve\nsleep quality evaluated by EEG.16\nEffects of LTOT on quality of life and neuropsychological\nfunction in COPD patients\nHealth-related quality of life is impaired in patients with COPD.\nIn one study, the administration of LTOT showed no bene\ufb01cial\neffects on quality of life compared to patients not ful\ufb01lling cri-\nteria for LTOT.17\nIn the NOTT study, minor improvements in\nneuropsychological function were achieved after 12 months of\nLTOT compared to NOT.18\nThere was only modest improve-\nment in neuropsychological scores after 6 months of treatment.\nAn observational study has shown improvement in mood after\n1 year of treatment with LTOT.19\nHowever, psychological\nchanges due to LTOT are dif\ufb01cult to separate from the effects of\nother therapies.\nLTOT in COPD patients and impact upon hospital admissions\nLack of provision of LTOT to hypoxaemic COPD patients with\nPaO2 <7.3 kPa is an independent risk factor for hospital admis-\nsion with a COPD exacerbation.20\nConversely, use of LTOT in\nmoderately hypoxaemic patients (PaO2 7.3\u20139.5 kPa) does not\nsigni\ufb01cantly reduce hospital admission rates or bed days when\ncomparing a 10-month period before and after LTOT treat-\nment.21\nThe MRC trial did not \ufb01nd any impact on hospitalisa-\ntion from treatment with LTOT.5\nOther effects of LTOT in COPD patients\nA further bene\ufb01t of LTOT may be in the improvement of renal\nblood \ufb02ow, reducing activation of the renin angiotensin system\nand thus salt and water retention. However, one study of LTOT\nshowed no overall bene\ufb01t on renal function after 6 months of\ntreatment.22\nSupplemental oxygen therapy reduces secondary polycythae-\nmia, as seen by a fall in haematocrit and red cell mass.5\nA study\nin COPD patients showed that LTOT patients with a low haem-\natocrit have worse survival than patients with high haematocrits\n(>0.55).23\nEvidence statements\n\u25b8 Patients whose clinical condition is stable with a resting PaO2\n\u22647.3 kPa have improved life expectancy when treated with\nLTOT for at least 15 h\/day. Evidence level 1+\n\u25b8 Patients with stable COPD and a resting PaO2 \u22648.0 kPa with\nevidence of cor pulmonale, polycythaemia and\/or pulmonary\nhypertension have improved outcomes with LTOT. Evidence\nlevel 1+\n\u25b8 Use of continuous oxygen therapy (24 h) offers additional\nsurvival bene\ufb01t compared to shorter durations (12\u201315 h) but\ncan contribute to higher PaCO2 levels. Evidence level 1\u2212\n\u25b8 Use of LTOT in hypercapnic respiratory patients with COPD\ndoes not lead to increased morbidity, mortality or healthcare\nutilisation. Evidence level 1+\nRecommendations\n\u25b8 Patients with stable COPD and a resting PaO2 \u22647.3 kPa\nshould be assessed for LTOT, which offers survival bene\ufb01t\nand improves pulmonary haemodynamics. (Grade A)\n\u25b8 LTOT should be ordered for patients with stable COPD with\na resting PaO2 \u22648 kPa with evidence of peripheral oedema,\npolycythaemia (haematocrit \u226555%) or pulmonary hyperten-\nsion. (Grade A)\n\u25b8 LTOT should be ordered for patients with resting hypercap-\nnia if they ful\ufb01l all other criteria for LTOT. (Grade B)\nEvidence for use of LTOT in patients with other respiratory\nor cardiac disease\nLTOT in patient with ILD\nChronic hypoxaemia can occur in patients with severe ILD. As\nwith other progressive respiratory conditions, the development of\nprogressive hypoxaemia may lead to poor tissue oxygenation and\nthe development of complications such as pulmonary hyperten-\nsion. This in turn can worsen prognosis. However, there are no\nRCTs reporting the effects of use of LTOT in these disorders.\nTherefore, recommendations for use are extrapolated from evi-\ndence in COPD patients. In clinical practice, patients with severe\nbreathlessness due to ILD may hyperventilate to maintain oxygen\nsaturations, and often desaturate abruptly on minimal exertion.\nClinical management varies, with some centres measuring oxygen\nsaturation over a 24 h period to assess \u2018hypoxaemic burden\u2019 and\nprescribing home oxygen accordingly. There is at present no evi-\ndence to support home oxygen provision on this basis.\nEvidence statement\n\u25b8 The use of LTOT in patients with ILD may improve survival\nand tissue oxygenation, and prevent complications associated\nwith hypoxaemia such as worsening pulmonary hyperten-\nsion. Evidence level 4\nRecommendations\n\u25b8 LTOT should be ordered for patients with ILD with a resting\nPaO2 \u22647.3 kPa. (Grade D)\n\u25b8 LTOT should be ordered for patients with ILD with a resting\nPaO2 \u22648 kPa in the presence of peripheral oedema,\nHardinge M, et al. Thorax 2015;70:i1\u2013i43. doi:10.1136\/thoraxjnl-2015-206865 i9\nBTS Guidelines\ngroup.bmj.com\non June 19, 2016 - Published by\nhttp:\/\/thorax.bmj.com\/\nDownloaded from\npolycythaemia (haematocrit \u226555%) or evidence of pulmon-\nary hypertension. (Grade D)\nGood practice point\n\u25b8 Patients with ILD who experience severe breathlessness could\nbe considered for POT. (\u221a)\nLTOT in patients with CF\nPatients with CF may develop chronic hypoxaemia with increas-\ning severity of their disease. A Cochrane review examined 11\npublished studies of oxygen therapy in CF but no studies exam-\nined the use of LTOT.24\nRecommendations for use are extrapo-\nlated from evidence in COPD patients.\nEvidence statement\n\u25b8 The use of LTOT in patients with CF may improve survival\nand tissue oxygenation, and prevent complications associated\nwith hypoxaemia such as worsening pulmonary hyperten-\nsion. Evidence level 4\nRecommendations\n\u25b8 LTOT should be ordered for patients with CF with a resting\nPaO2 \u22647.3 kPa. (Grade D)\n\u25b8 LTOT should be ordered for patients with CF with a resting\nPaO2 \u22648 kPa in the presence of peripheral oedema, polycy-\nthaemia (haematocrit \u226555%) or evidence of pulmonary\nhypertension. (Grade D)\nLTOT in patients with pulmonary hypertension\nPulmonary hypertension may occur in a number of pulmonary\nvascular disorders such as idiopathic pulmonary arterial hyper-\ntension (IPAH), pulmonary arterial hypertension associated with\nportal hypertension, pulmonary arterial hypertension associated\nwith connective tissues disease, drug-induced thromboembolism,\npulmonary arterial hypertension and chronic thromboembolic\npulmonary hypertension (CTEPH), which can all predispose to\nhypoxaemia. There is no evidence of the effectiveness of LTOT\nin RCTs in patients with pulmonary hypertension, with the\nexception of those patients who develop pulmonary hyperten-\nsion as a complication of their COPD. Thus, use of LTOT in\nnon-COPD patients with pulmonary hypertension is to improve\ntissue oxygenation and to prevent complications associated with\nhypoxaemia, such as worsening pulmonary hypertension, rather\nthan to afford a speci\ufb01c survival bene\ufb01t.\nEvidence statement\n\u25b8 The use of LTOT in patients with pulmonary hypertension\nmay improve tissue oxygenation and prevent complications\nassociated with hypoxaemia rather than lead to a speci\ufb01c sur-\nvival bene\ufb01t. Evidence level 4\nRecommendation\n\u25b8 LTOT should be ordered for patients with pulmonary hyper-\ntension, including idiopathic pulmonary hypertension, when\nthe PaO2 is \u22648 kPa. (Grade D)\nLTOT in patients with neuromuscular or chest wall disorders\nPatients with chest wall disease (kyphoscoliosis, thoracoplasty)\nand neuromuscular disorders develop nocturnal hypoventila-\ntion, which causes nocturnal hypoxaemia and leads to chronic\nrespiratory failure. Non-invasive ventilation (NIV) is the\ntreatment of choice in these patients, although LTOT may be\nrequired additionally, particularly in patients with severe restrict-\nive disease or where there is co-existing airways disease or\nobesity causing hypoxaemia which NIV alone does not correct\n(although there are no studies of this approach).\nEvidence statement\n\u25b8 LTOT can be used in addition to NIV in patients with neuro-\nmuscular or chest wall disorders, particularly where there is\nco-existing airways disease or obesity causing hypoxaemia\nwhich NIV alone does not correct. Evidence level 4\nRecommendation\n\u25b8 NIV should be the treatment of choice for patients with\nchest wall or neuromuscular disease causing type 2 respira-\ntory failure. Additional LTOT may be required in case of\nhypoxaemia not corrected with NIV\n. (Grade D)\nLTOT in patients with advanced cardiac failure\nSome patients with advanced cardiac failure may have resting hyp-\noxaemia although hypoxaemia is most consistently demonstrated\nduring sleep in these patients. There are studies of NOT in patients\nwith heart failure (see the section on nocturnal oxygen therapy)\nbut no studies of the effects of LTOT in patients with chronic\nheart failure. The use of LTOT in patients with advanced cardiac\nfailure and resting hypoxaemia may lead to improved tissue oxy-\ngenation and prevent complications associated with hypoxaemia\nsuch as worsening pulmonary hypertension.\nEvidence statement\n\u25b8 The use of LTOT in patients with advanced cardiac failure\nand resting hypoxaemia may improve survival, tissue oxygen-\nation and prevent complications associated with hypoxaemia.\nEvidence level 4\nRecommendations\n\u25b8 LTOT should be ordered for patients with advanced cardiac\nfailure with a resting PaO2 \u22647.3 kPa. (Grade D)\n\u25b8 LTOT should be ordered for patients with advanced cardiac\nfailure with a resting PaO2 \u22648 kPa in the presence of periph-\neral oedema, polycythaemia (haematocrit \u226555%) or evidence\nof pulmonary hypertension on ECG or echocardiograph.\n(Grade D)\nOutcomes of LTOT in patients who continue to smoke\nAccurate reports of individual smoking status can be dif\ufb01cult to\nobtain reliably in clinical practice. All trial data around smoking\ncome from trials conducted with COPD patients.25\nUnfortunately, the small numbers of patients included in the\nmain RCTs is not optimal in discriminating between the impact\nof LTOT on smokers and non-smokers.4 5\nThere are no rando-\nmised or cohort studies investigating LTOT according to\nsmoking status.\nCigarette smoking predisposes to secondary polycythaemia,\naccelerated decline in lung function and increased mortality in\nCOPD. Thus, the bene\ufb01cial effect of LTOT may be offset by\nraised carboxyhaemoglobin levels from continued cigarette\nsmoking.26\nThe MRC study did not exclude smokers but did\n\u2018urge all patients to give up smoking\u2019.5\nIn the LTOT group,\n52% of the patients were smokers (reduced to 44% at the end\nof the study). There were no recorded adverse events attribut-\nable to smoking in the MRC trial. There was an overall survival\nbene\ufb01t in patients given oxygen (bene\ufb01ts in smoking and non-\nsmoking populations were not reported separately).\nThe signi\ufb01cant risk associated with combining cigarette\nsmoking and oxygen therapy is reviewed in a later safety section\nof the guideline.\nEvidence statement\n\u25b8 Evidence is insuf\ufb01cient to determine adverse clinical out-\ncomes related to the effect of continuing smoking in LTOT\npatients compared to non-smokers. Evidence level 2+\ni10 Hardinge M, et al. Thorax 2015;70:i1\u2013i43. doi:10.1136\/thoraxjnl-2015-206865\nBTS Guidelines\ngroup.bmj.com\non June 19, 2016 - Published by\nhttp:\/\/thorax.bmj.com\/\nDownloaded from\nRecommendation\n\u25b8 If LTOT is ordered for patients who are continuing to\nsmoke, the potential for more limited clinical bene\ufb01t should\nbe discussed with the patient. (Grade D)\nReferral and assessment of patients for LTOT\nReferral to home oxygen assessment services provides the\nappropriate means for patients to be assessed for home oxygen\ntherapy. Patients should have a de\ufb01nite diagnosis and be medic-\nally optimised prior to referral for assessment by an oxygen\nservice. These services should have the appropriate clinical\nexpertise, equipment and access to appropriate support services\nto enable the patient to have the best available care and out-\ncomes, with the best use of resources. Guidance for commis-\nsioners in England and Wales has been published.27\nPatient information on referral for home oxygen assessment\nIn order to support a patient in understanding the implications of\nattending an assessment for home oxygen therapy, information is\noften given (whether verbal or written) at the time of referral.\nFailing to attend for initial assessment or reassessment could result\nin suboptimal treatment, poor clinical outcomes and wasted\nresources. There is a lack of published trial data on the impact of\nproviding information on LTOT to patients in any format.\nEvidence statement\n\u25b8 Provision of written and verbal information to patients at the\npoint of referral to home oxygen assessment services can\nimprove attendance at \ufb01rst referral. Evidence level 4\nRecommendation\n\u25b8 Written and verbal information should be given to patients\nreferred to home oxygen assessment services at the time of\nreferral. (Grade D)\nUse of oximetry as a screening tool for patient selection for LTOT\nMeasurement of oxygen saturation using a pulse oximeter is\nwidely available and presents a possible tool to be used for screen-\ning patients who might be candidates for LTOT. Studies have\nexamined the use of an SpO2 value of \u226492% as a cut-off point at\nwhich patients will be deemed suitable for referral to an oxygen\nassessment service because of known evidence around ABG cri-\nteria for LTOT. Roberts et al28\nstudied use of SpO2 levels alone or\nin combination with FEV1 in 113 COPD patients referred for\nLTOT, and showed that using an SpO2 level of \u226492% resulted in\n100% sensitivity but a speci\ufb01city of only 69% in identifying\npatients with a PaO2 <7.3 kPa. There was a particularly poor cor-\nrelation between SpO2 values between 85% and 90% and ABGs.\nA study using pulse oximetry in screening patients in general prac-\ntice for LTOT assessed 13 of 114 patients with a resting SpO2 of\n\u226492% and found three patients had a resting PaO2 <7.3 kPa.29\nWhen Medicare guidelines for oxygen assessments were validated,\nan SpO2 level of 85% was found to still miss patients who would\nhave required an oxygen assessment, but did demonstrate that at\nthis level an oxygen assessment was not necessary for a large pro-\nportion of patients.30\nEvidence statement\n\u25b8 An oxygen saturation (SpO2) level of \u226492% can be used\nsafely to identify patients for referral for LTOT. Evidence\nlevel 2+\nRecommendation\n\u25b8 Patients with a resting stable oxygen saturation (SpO2) of\n\u2264 92% should be referred for a blood gas assessment in\norder to assess eligibility for LTOT. (Grade C)\nGood practice point\n\u25b8 In patients with clinical evidence of peripheral oedema, polycy-\nthaemia (haematocrit \u226555%) or pulmonary hypertension,\nreferral for LTOTassessment may be considered at SpO2 levels\n\u226494% to identify patients with a resting PaO2 \u22648 kPa. (\u221a)\nReferral for home oxygen at hospital discharge\nIt is recognised that an exacerbation of a cardiorespiratory con-\ndition may result in temporary worsening of hypoxaemia which\nmay improve over time with recovery. However, the time course\nof recovery may be variable and undertaking an assessment for\nhome oxygen prior to optimal treatment and recovery could\nresult in the overprescribing of home oxygen and unnecessary\nrepeated assessments for the patient. However, clinicians are fre-\nquently faced with the practical dif\ufb01culty of managing patients\nwho, having been treated with oxygen during the acute phase of\ntheir illness, feel they require oxygen in order to be discharged\nsafely home. These patients are either normoxaemic at rest or\nremain hypoxaemic at the point of hospital discharge.\nSeveral studies have looked at the timing of assessment for\nLTOT. In an RCT of 546 COPD patients allowing for a 2-month\nperiod of clinical stability rather than prescribing LTOT immedi-\nately after exacerbation, resulted in a 36% absolute difference in\nthose given LTOT at 2 months, with about a 15% difference at\n1 year.31\nThere was no signi\ufb01cant difference in quality of life,\nmortality or use of community health resources between the\ntwo groups at 1 year. A subgroup analysis of the NOTT trial\nshowed that 184\/409 (45%) patients in what was thought to be\na clinically stable group on trial entry, subsequently improved\ntheir PaO2 to levels which excluded them from the trial after at\nleast a 4-week follow-up period.32\nObservational studies of\nhome oxygen patients (the majority having COPD) who were\nsupplied with LTOT from hospital discharge or during a period\nof clinical instability found that 30\u201358% of patients reassessed\n1\u20133 months later no longer met the criteria for LTOT.33\u201335\nIn a\nstudy in which ABGs were measured monthly in 77 COPD\npatients following hospitalisation, improvements in levels of\nhypoxaemia were seen at each time point, with 30% of patients\nno longer meeting the criteria for LTOT at 4 months.36\nLater\nwithdrawal of LTOT if no longer required can lead to patient\ndistress, and be challenging for staff to manage.37\nNo studies have de\ufb01ned criteria for safe discharge home from\nhospital without home oxygen pending a formal LTOTassessment.\nEvidence statement\n\u25b8 Patients referred for LTOT assessment after an exacerbation\nof COPD can show improvement in hypoxaemia with recov-\nery above the threshold for LTOT after an 8-week period.\nEvidence level 1+\nRecommendation\n\u25b8 Patients should undergo formal assessment for LTOT after a\nperiod of stability of at least 8 weeks from their last exacerba-\ntion. (Grade B)\nGood practice points\n\u25b8 Patients who have borderline saturations (ie, 93\u201394%)\nshould have their oxygen saturations monitored at their\nannual review with their GP or practice nurse, or sooner if\nthey experience an exacerbation in the interim. (\u221a)\n\u25b8 Patients who exacerbate frequently and are unable to achieve\na period of stability lasting 8 weeks may need to be assessed\nat an earlier stage after exacerbation. If LTOT is ordered for\nsuch patients, they should be counselled that in the future\nLTOT may no longer be required once they achieve a more\nstable state. (\u221a)\nHardinge M, et al. Thorax 2015;70:i1\u2013i43. doi:10.1136\/thoraxjnl-2015-206865 i11\nBTS Guidelines\ngroup.bmj.com\non June 19, 2016 - Published by\nhttp:\/\/thorax.bmj.com\/\nDownloaded from\n\u25b8 Patients should not normally have LTOT ordered at the time\nof an acute exacerbation of their underlying condition.\nHowever, if home oxygen is ordered (eg, at hospital dis-\ncharge), it should be limited to patients with an SpO2 of\n\u226492%, who are breathless and unable to manage off oxygen.\nThese patients should undergo a blood gases assessment and\nbe counselled that in the future LTOT may not be required\nafter formal reassessment. (\u221a)\n\u25b8 The date of the patient\u2019s last exacerbation should be included in\nthe referral request to the home oxygen assessment service. (\u221a)\nUse of pulse oximetry, ABGs and CBGs in assessment for LTOT\nAssessment using pulse oximetry alone\nMeasurement of oxygen saturations (SaO2) provides informa-\ntion on the percentage of available haemoglobin that is com-\nbined with oxygen (ie, oxyhaemoglobin). The relationship\nbetween oxygen saturations and the PO2 in blood (PaO2) is\ndescribed by the oxyhaemoglobin dissociation curve. This curve\nis very steep once PaO2 falls below 8 kPa (60 mm Hg) and thus\nsmall changes in PaO2 can greatly change oxygen saturations\u2014\nthis characteristic allows the use of SaO2 to give estimates of\nPaO2 in hypoxaemic patients.\nWhereas SaO2 is measured directly from blood using\nCO-oximetry, pulse oximetry (SpO2) measures oxygen saturations\nindirectly by comparing the absorbance of transmitted light before\nand during arterial pulsation at external sites such as earlobes or\n\ufb01ngertips. This non-invasive tool carries a number of advantages\nas SpO2 can be measured rapidly with portable equipment by staff\nwho are not necessarily skilled in arterial puncture. Conversely,\nthe ability of SaO2 and SpO2 to estimate PaO2 is in\ufb02uenced by\nchanges in the oxygen dissociation curve (eg, due to the presence\nof acidosis or changes in temperature), while oximetry alone\ncannot detect hypercapnia or acidosis.\nSeveral studies have examined the use of pulse oximetry alone\nto determine LTOT requirement. In the largest study, 846 stable\npatients with chronic lung disease (74.2% COPD) underwent\nLTOTassessment using both SaO2 (measured following ABG sam-\npling) and SpO2 measurements.38\nSpO2 overestimated SaO2 in the\npresence of hypercapnia (PaCO2 >6.4 kPa, 48 mm Hg), while\nagreement between SpO2 and SaO2 was also poor under hypoxae-\nmic conditions (PaO2 <7.2 kPa, 54 mm Hg). A smaller study of\n55 stable patients with chronic lung disease and a resting PaO2\n<8.65 kPa measured both PaO2 and SpO2 simultaneously on air\nat rest.30\nUsing SpO2 <88% as a threshold for prescribing LTOT\nwould have led to 24\u201357% being denied LTOT and 7\u201321% being\ntreated inappropriately, depending upon which brand of oximeter\nwas used. Similar \ufb01ndings were reported from a study of 100\npatients undergoing LTOT assessment, where using SpO2 alone\nwith a <88% threshold would have led to 56% of patients being\ninappropriately denied LTOT.35\nNo patient would have had LTOT\nordered unnecessarily.\nEvidence statement\n\u25b8 Pulse oximetry (SpO2) agrees poorly with ABG CO-oximetry\n(SaO2) and arterial oxygen tension (PaO2) and cannot be\nused alone to assess the need for LTOT. Evidence level 3\nRecommendation\n\u25b8 Patients potentially requiring LTOT should not be assessed\nusing pulse oximetry alone. (Grade D)\nABG and CBG\nABG sampling, performed via radial artery puncture, allows\nPaO2, PaCO2 and pH to be measured directly from arterial\nblood. Evidence for using ABGs to select patients for LTOT\ncomes from previously reviewed trials.4 5 36\nIn the NOTT trial,\nsubjects underwent ABG sampling on two occasions more than\n1 week apart during a 3-week observation period and were only\nrecruited if they ful\ufb01lled the criteria of resting PaO2 \u22647.33 kPa\n(55 mm Hg) or PaO2 \u22647.86 kPa (59 mm Hg) in the presence of\none of oedema, haematocrit \u226555% or P pulmonale on ECG on\nboth occasions.4\nIn the MRC trial, ABG measurements were\nrepeated more than 3 weeks apart in stable patients who were\nincluded if their resting PaO2 was between 5.3 kPa (40 mm Hg)\nand 8 kPa (60 mm Hg).5\nAlthough ABG sampling allows direct measurement of PaO2,\nit involves puncture of the radial artery and thus can be painful\nand can only be performed by trained healthcare professionals.\nThere may be other considerations to take into account, such as\na patient\u2019s past experience of ABG sampling and whether they\nare on anticoagulants. CBG sampling conversely only requires a\nsmall sample of blood (125 mL) from a relatively super\ufb01cial site\n(typically at the \ufb01ngertip or earlobe). It is therefore less invasive,\noften better tolerated and can be performed by a wider range of\nhealthcare professionals, although training and technique are\nstill important to obtain adequately \u2018arterialised\u2019 samples. The\ndifference in PO2 levels at an arterial level versus venous level\ncan be signi\ufb01cant, typically 8 kPa (60 mm Hg) at rest and up to\n10 kPa (75 mm Hg) during exercise.39\nTo help raise capillary\nPO2 to a level closer to arterial PO2, a number of manoeuvres\ncan be used prior to sampling, including the use of topical vaso-\ndilators and heat.\nA meta-analysis included 886 subjects from 29 studies.40\nThe\nstudies included both healthy subjects and patients with chronic\nlung disease under a number of situations, including high altitude.\nBoth earlobe CBGs and \ufb01ngertip CBGs were compared against\nABGs, and both gave accurate estimates of pH and PaCO2,\nalthough earlobe sampling gave a more accurate estimate for\nPaCO2. Earlobe CBGs were superior to \ufb01ngertip CBGs in estimat-\ning PaO2 but continued to underestimate PaO2 by a mean of\n0.32 kPa (2.4 mm Hg) difference (1.9\u20132.8), residual SE 0.8 kPa\n(6 mm Hg). The authors concluded that earlobe sampling gave a\nreasonable estimate of PaO2 unless precision was required.\nIn a comparison of simultaneous earlobe CBGs and radial ABGs\nfrom 40 patients with chronic lung disease, including 29 patients\nwith COPD,41\nthere was a good correlation between CBGs and\nABGs for estimating PaO2, with CBGs underestimating PaO2 by a\nmean of just 0.17 kPa, albeit with a relatively wide 95% CI\n(\u22121.09 kPa to +0.75 kPa). A subgroup analysis suggested that\nCBGs were more accurate in hypoxaemic patients, with CBGs\nunderestimating by <0.5 kPa in \u2018nearly all\u2019 patients with PaO2\n<8 kPa. In another study carrying out a comparison of simultan-\neous PaO2 and earlobe CBG measurements in 100 patients under-\ngoing LTOT assessment, CBGs alone would have resulted in 9\/55\n(ie, 16%) receiving LTOT inappropriately. No patients would have\nbeen denied LTOT.35\nConversely, patients found ABGs more\nuncomfortable than CBGs (p<0.0001).\nA repeat ABG after oxygen titration is completed allows\naccurate reassessment of PaO2, PaCO2 and pH, but can be\nuncomfortable for patients. Cutaneous capnography was used\nto reassess PaCO2 in comparison with ABGs in 20 subjects with\nchronic lung disease who received oxygen at gradually increas-\ning rates until SaO2 was >90%.42\nCapnography accurately esti-\nmated PaCO2 with minimal bias. Earlobe CBGs have also been\nshown to give accurate estimates of pH and PaCO2 that are\ncomparable to those achieved from ABGs.40\nNo studies were identi\ufb01ed which showed that ABGs provided\ninaccurate results due to patient hyperventilation secondary to\ni12 Hardinge M, et al. Thorax 2015;70:i1\u2013i43. doi:10.1136\/thoraxjnl-2015-206865\nBTS Guidelines\ngroup.bmj.com\non June 19, 2016 - Published by\nhttp:\/\/thorax.bmj.com\/\nDownloaded from\npain induced by the procedure. In clinical practice, many ser-\nvices routinely use local anaesthetic when performing radial\nABGs. There are also no outcome data comparing complication\nrates between radial ABGs and earlobe CBGs.\nEvidence statements\n\u25b8 ABG sampling, performed twice at least 3 weeks apart,\nduring a stable phase of their condition, identi\ufb01es patients\nwho may bene\ufb01t from LTOT. Evidence level 1++\n\u25b8 Both earlobe and \ufb01ngertip CBGs provide accurate estimates\nof arterial carbon dioxide tension and arterial pH during\nLTOT assessment and oxygen titration. Evidence level 1+\n\u25b8 Earlobe CBGs provide a more accurate estimate of arterial\noxygen tension than \ufb01ngertip CBGs. Evidence level 1+\n\u25b8 Use of earlobe CBGs alone for LTOT assessment leads to\nsome patients inappropriately receiving LTOT. Evidence\nlevel 3\n\u25b8 Patients tolerate earlobe CBG testing better than ABG sam-\npling. Evidence level 3\n\u25b8 During an LTOT assessment, cutaneous capnography can be\nused in place of ABG sampling for reassessing PaCO2 but not\npH after oxygen titration. Evidence level 3\nRecommendations\n\u25b8 Patients being assessed for LTOT should undergo initial\nassessment for suitability using ABG sampling. (Grade A)\n\u25b8 Patients assessed for LTOT during a period of apparent clin-\nical stability should undergo two ABG measurements at least\n3 weeks apart, before the need for LTOT can be con\ufb01rmed.\n(Grade B)\n\u25b8 Patients undergoing LTOT assessment should be reassessed\nwith ABG after oxygen titration is complete to determine\nwhether adequate oxygenation has been achieved without\nprecipitating respiratory acidosis and\/or worsening hypercap-\nnia. (Grade D)\n\u25b8 For oxygen titration during LTOT assessment, CBG sampling\ncan be used in place of ABG sampling for re-measuring\nPaCO2 and pH at different oxygen \ufb02ow rates. (Grade A)\n\u25b8 For oxygen titration during LTOT assessment, cutaneous cap-\nnography can be used in place of ABG sampling for\nre-measuring PaCO2 alone but not pH at different oxygen\n\ufb02ow rates. (Grade A)\nGood practice points\n\u25b8 Patients undergoing a radial ABG should be assessed with an\nAllen\u2019s test \ufb01rst, to ensure they have a dual blood supply to\nthe hand from both radial and ulnar arteries. (\u221a)\n\u25b8 Patients undergoing a radial ABG should be consented for\nthe procedure with a discussion of possible risks. (\u221a)\n\u25b8 In many community commissioned home oxygen service\u2014\nassessment and review (HOS-AR) services, it is not practical\nfor patients to undergo ABG sampling during LTOT assess-\nment. Under such circumstances, a combination of CBGs and\noximetry (but not capnography) could be used as an alterna-\ntive tool for initial assessment for LTOT, and after oxygen\ntitration is complete. Some patients may receive LTOT\nunnecessarily using this approach, but it is unlikely that any\npatient would be inappropriately denied LTOT. (\u221a)\nManagement of hypercapnia during LTOT assessment\nPatients with chronic lung disease may develop resting hyper-\ncapnia as the severity of their disease progresses. In such cases,\noxygen supplementation can cause suppression of existing\nhypoxaemic respiratory drive with consequent diminution of\nminute ventilation and worsening hypercapnia and V\/Q\nmismatch. This has the potential to lead to the development of\nrespiratory acidosis and progressive ventilatory failure.\nFew studies exist to support best practice where patients became\nacidotic or excessively hypercapnoeic during an LTOTassessment.\nNeither the MRC5\nnor the NOTT4\nstudies excluded patients with\nhypercapnia. In the MRC study, average PaCO2 ranged between\n7.1 and 7.3 kPa (53.2\u201354.9 mm Hg) for both control and treated\ngroups. Subjects received oxygen at 2 L\/min or higher if necessary\nto achieve PaO2 >8 kPa (60 mm Hg), and no hypercapnia-related\nissues during the assessment process were reported. Although the\nNOTT study did not explicitly exclude patients with hypercapnia,\npatients in both groups were mostly normocapnoeic (mean PaCO2\n5.7 kPa, 43 mm Hg).4\nAgain no hypercapnia-related issues during\nthe assessment process were reported. Chiang et al43\nstudied venti-\nlatory responses to CO2 stimulation in 26 COPD patients, 12 with\nresting hypercapnia, following oxygen supplementation with\n2 L\/min oxygen. Hypercapnic patients showed a rise in mean\nPCO2 from 7.1\u00b10.2 kPa to 7.8\u00b10.3 kPa without developing acid-\nosis and also a blunted response to CO2 stimulation. However,\nthere were no reported adverse clinical events during this short-\nterm study.\nEvidence statement\n\u25b8 Patients with baseline hypercapnia can undergo LTOT assess-\nment without adverse outcome but require monitoring of\npH and PCO2 levels during and at the end of assessment.\nEvidence level 4\nRecommendation\n\u25b8 Patients with baseline hypercapnia should be monitored for the\ndevelopment of respiratory acidosis and worsening hypercap-\nnia using ABGs after each titration of \ufb02ow rate, as well as ABG\nsampling after oxygen titration is complete. (Grade D)\nGood practice points\n\u25b8 Patients who develop a respiratory acidosis and\/or a rise in\nPaCO2 of >1 kPa (7.5 mm Hg) during an LTOT assessment\nmay have clinically unstable disease. These patients should\nundergo further medical optimisation and be reassessed after\n4 weeks. (\u221a)\n\u25b8 Patients who develop a respiratory acidosis and\/or a rise in\nPaCO2 of >1 kPa (7.5 mm Hg) during an LTOT assessment\non two repeated occasions, while apparently clinically stable,\nshould only have domiciliary oxygen ordered in conjunction\nwith nocturnal ventilatory support. (\u221a)\nUse of LTOT: hours of use and \ufb02ow rates\nLTOT hours of use\nThe bene\ufb01ts of LTOT are derived from normalisation of abnor-\nmal physiology driven by chronic hypoxaemia and have been\nachieved with use of LTOT for 15 h\/day.5\nTherefore, there is a\nhypothetical advantage of longer durations of oxygen therapy in\ncorrecting these abnormalities for greater periods of each day\nand particularly at night, when hypoxaemia may be more pro-\nfound during sleep. Comparison of the effects of 12 h NOT\nwith continuous oxygen (24 h) therapy in the NOTT study\ndemonstrated a 1.94 times higher mortality in the NOT group:\nthis survival bene\ufb01t may be offset by the practicalities of\nincreased oxygen use and the impact upon mobility.4\nIn a pragmatic 5-year follow-up study of 228 patients for\nwhom an oxygen concentrator was ordered, comparisons were\nmade between no oxygen use (n=55), oxygen use for <15 h\nper day (n=112) and oxygen use for >15 h per day (n=61).\nOverall survival at 2 years was better in the groups receiving\noxygen compared to the no oxygen group, but there was no dif-\nference between the oxygen groups.8\nHardinge M, et al. Thorax 2015;70:i1\u2013i43. doi:10.1136\/thoraxjnl-2015-206865 i13\nBTS Guidelines\ngroup.bmj.com\non June 19, 2016 - Published by\nhttp:\/\/thorax.bmj.com\/\nDownloaded from\nThere is no evidence base for duration of LTOT use in\nnon-COPD respiratory disease or cardiac disease.\nEvidence statements\n\u25b8 LTOT ordered for COPD patients for at least 15 h and up to\n24 h per day confers a mortality bene\ufb01t and improvement in\nphysiological indices. Evidence level 1+\n\u25b8 Use of LTOT for 24 h versus 12 h offers additional bene\ufb01ts\nespecially for COPD patients with more severe disease (higher\nPaCO2, higher haematocrit, higher pulmonary artery pressure\nand more neuropsychological impairment). Evidence level 2+\nRecommendation\n\u25b8 LTOT should be ordered for a minimum of 15 h per day, and\nup to 24 h per day may be of additional bene\ufb01t. (Grade C)\nLTOT \ufb02ow rates\nDaytime activity and LTOT \ufb02ow rates\nA \ufb02ow rate based on a single measure of oxygenation at rest may\nnot necessarily guarantee adequate oxygenation during\nday-to-day activities where oxygen requirements may \ufb02uctuate.\nAlthough transient hypoxaemia could temporarily increase both\npulmonary artery pressures and the risk of arrhythmias, it is\nunclear to what degree such \ufb02uctuations in oxygenation during\ndaily life can offset the potentially bene\ufb01cial effects of LTOT.\nPatients in the MRC study were started on a \ufb02ow rate of 2 L\/min,\nwhich was increased incrementally until a PaO2 >8 kPa\n(60 mm Hg) was achieved,5\nand patients in the NOTT trial\nstarted on a \ufb02ow rate of 1 L\/min, which was increased in 1 L\/min\nincrements up to a maximum of 4 L\/min until PaO2 >8 kPa\n(60 mm Hg) was achieved.4\nFlow rates were not altered to re\ufb02ect\nexercise. However, a number of studies suggest that determining\n\ufb02ow rates using a single measure of PaO2 at rest may not guaran-\ntee adequate oxygenation during exercise:44\u201347\nstable COPD\npatients receiving LTOT at a single \ufb02ow rate spent between 70%\nand 87% of the daytime with SpO2 >90% when performing\nday-to-day activities. Individual tailoring of \ufb02ow rates to suit\npatients\u2019 requirements during exercise, rest and sleep can reduce\nmedian oxygen \ufb02ow rate from 2.5 to 1.2 L\/min, while the per-\ncentage of time SpO2 was within the target range increased from\n24.8% to 52.8% (p=0.001).48\nNocturnal oxygen requirements and LTOT\nPatients can desaturate during sleep as a result of reduced minute\nventilation and impaired ventilatory responses and so oxygen\nrequirements overnight may also differ from those at rest when\nawake. Several studies have suggested that a \ufb02ow rate established\nfrom resting ABGs while awake may not allow adequate oxygen-\nation overnight with patients spending only between 72% and\n77% of the time with SpO2 >90% overnight.46 49 50\nPatients\nwith more severe COPD and worse daytime ABGs spent a signi\ufb01-\ncantly greater proportion of the night with hypoxaemia.51\nIn the\nNOTT study, oxygen was automatically increased by 1 L\/min\nduring sleep without reported adverse events.4\nNo data were\nfound with respect to other diagnostic patient groups.\nEvidence statements\n\u25b8 Patients for whom LTOT is ordered at a single \ufb02ow rate suf\ufb01-\ncient to achieve PaO2 >8 kPa (60 mm Hg) at rest demon-\nstrate a survival bene\ufb01t from LTOT. Evidence level 1+\n\u25b8 LTOT ordered at a single \ufb02ow rate to provide adequate oxy-\ngenation at rest may offer inadequate oxygenation during\nexercise and\/or sleep. Evidence level 3\n\u25b8 LTOT ordered for patients at different \ufb02ow rates for use\nduring sleep and exercise demonstrates a survival bene\ufb01t\nfrom LTOT. Evidence level 1+\nRecommendations\n\u25b8 Patients eligible for LTOT should be initiated on a \ufb02ow rate\nof 1 L\/min and titrated up in 1 L\/min increments until SpO2\n>90%. An ABG should then be performed to con\ufb01rm that a\ntarget PaO2 \u22658 kPa (60 mm Hg) at rest has been achieved.\n(Grade B)\n\u25b8 Non-hypercapnic patients initiated on LTOT should increase\ntheir \ufb02ow rate by 1 L\/min during sleep in the absence of any\ncontraindications. (Grade B)\n\u25b8 Patients initiated on LTOT who are active outdoors should\nreceive an ambulatory oxygen assessment to assess whether\ntheir \ufb02ow rate needs to increase during exercise. (Grade B)\nGood practice points\n\u25b8 Ambulatory and nocturnal oximetry may be performed to\nallow more accurate \ufb02ow rates to be ordered for use during\nexercise and sleep, respectively. (\u221a)\n\u25b8 Patients initiated on LTOT who have cognitive, visual or\ncoordination impairments, may not be able to safely manipu-\nlate their own \ufb02ow rates and should be maintained on a\nsingle \ufb02ow rate. (\u221a)\n\u25b8 Flow rates may be increased at 20 min intervals during an\noxygen titration until a target PaO2 is achieved. (\u221a)\nPatient education at time of assessment\nA few studies have evaluated the provision of patient education,\nusually in the form of verbal or written information, at the time\nof oxygen assessment. A comparison of patients who had\nreceived formal assessment with ABGs on two separate occa-\nsions together with education by a specialist respiratory team\nwith patients commencing LTOT in primary care, mostly on the\nbasis of oximetry alone, demonstrated a signi\ufb01cantly higher\ncompliance (82% vs 44%; p=0.002) and understanding of the\nrationale for treatment (93% vs 41%; p<0.00001).52\nThese\n\ufb01ndings were supported by a large case series of 930 patients in\nwhom education consisting of a home visit by a nurse or physio-\ntherapist was an important factor in those patients\u2019 compliance\nwith \u226515 h\/day of oxygen use.53\nOrdering LTOT on hospital\ndischarge does not prepare patients for a follow-up assessment\nor the implications of oxygen removal if they no longer meet\nthe criteria for LTOT:54\npsychological dependence on oxygen\ntherapy was reported as a major issue in these patients, causing\ndistress for patients and staff as well as requiring signi\ufb01cant\nresources and expertise to address.\nEvidence statements\n\u25b8 Patients initiated on LTOT without formal education exhibit\npoor compliance with therapy. Evidence level 2+\n\u25b8 Providing written information to patients commenced on\nhome oxygen in hospital does not prepare them for\nfollow-up or the implication of not meeting the criteria for\nLTOT. Evidence level 3\nRecommendations\n\u25b8 Patients initiated on LTOT should be provided with formal\neducation by a specialist home oxygen assessment team to\nensure compliance with therapy. (Grade D)\n\u25b8 Patients being commenced on home oxygen on discharge from\nhospital should be advised that home oxygen may be removed\nif reassessment shows clinical improvement. (Grade D)\nFollow-up of LTOT patients\nFollow-up of LTOT patients is necessary for a variety of\nreasons: to ensure that LTOT treatment is still required, that the\noxygen order is still adequate (and therefore that the potential\ni14 Hardinge M, et al. Thorax 2015;70:i1\u2013i43. doi:10.1136\/thoraxjnl-2015-206865\nBTS Guidelines\ngroup.bmj.com\non June 19, 2016 - Published by\nhttp:\/\/thorax.bmj.com\/\nDownloaded from\nfor healthcare gains such as survival are realised), that patients\nare compliant with treatment, and that any concerns or pro-\nblems are addressed. Although home oxygen patients may be a\nrelatively small group of lung disease patients in general, they\nare a very resource intensive group. Targeted follow-up of this\ngroup could provide signi\ufb01cant bene\ufb01ts in terms of cost effect-\nive healthcare utilisation.\nThe original MRC and NOTT LTOT studies both provided\ntitration of \ufb02ow rate at a 3-month follow-up appointment as\npart of their protocol.4 5\nCottrell et al55\nrandomised 50 LTOT\npatients to follow-up at 2, 6 or 12 months. They costed hospital\ninterventions given\/required over a 1-year period, and found\nthat the 2-monthly follow-up group had signi\ufb01cantly higher\nevaluation costs with no bene\ufb01t in terms of emergency depart-\nment or hospital visits, length of stay in hospital or mortality:\nthe only clinical bene\ufb01t shown was an improvement in the psy-\nchological component of the sickness impact pro\ufb01le.\nOther studies have focused on the setting for reassessment\nusing different models, some of which might now be called\n\u2018integrated respiratory services\u2019. Cross-sectional studies have\nreported \u2018added value\u2019 from reviewing patients in their homes,\nwhich included identifying and correcting problems with the\nconcentrator, humidi\ufb01er, the length of the patient\u2019s tubing and\nfactors impacting on the patient\u2019s usage.56 57\nIn a prospective\n10-year case\u2013control study in which 217 LTOT patients were\nrandomised to \u2018home care\u2019 (de\ufb01ned as 6-monthly hospital\nappointments and 2\u20133-monthly home visits) or standard care\n(management by hospital physician only), home care decreased\nexacerbation rates.58\nRandomisation of 122 LTOT patients to\nfollow-up with a hospital-based homecare programme (monthly\nphone call, home visits every 3 months, and home or hospital\nvisits on a demand basis) or conventional medical care, demon-\nstrated signi\ufb01cantly decreased costs in the homecare follow-up\ngroup, which was mainly due to a reduction in use of hospital\nresources, despite the cost of running the service itself.59\nReports from focus groups60\nand case series53\nhighlight the\nimportance of education from specialist nurses or physiothera-\npists in increasing compliance and addressing patient concerns.\nWithdrawal of home oxygen\nCase series in which LTOT patients have been followed up have\nshown that a signi\ufb01cant proportion of patients no longer required\noxygen as originally ordered.33 61\nIn addition, it has been well\nrecognised that compliance with LTOT can be poor and that with-\ndrawal of home oxygen through non-use is sometimes indicated.\nWithdrawal of LTOTcan be distressing to patients, challenging for\nstaff and entail a signi\ufb01cant use of resources.37\nSee appendix 7 for\na suggested protocol for withdrawal of home oxygen therapy.\nEvidence statements\n\u25b8 Follow-up of LTOT patients 3 months after starting LTOT,\ncan ensure that LTOT is still required and that the \ufb02ow rate\nis appropriate. Evidence level 1+\n\u25b8 Six-monthly follow-up has a similar effect to 2-monthly\nfollow-up in terms of healthcare utilisation but at decreased\ncost. Evidence level 3\n\u25b8 Home follow-up alone or in combination with hospital\nfollow-up is more effective than hospital follow-up. Evidence\nlevel 2+\n\u25b8 Follow-up with a specialist home oxygen assessment team\nincluding education improves compliance with LTOT.\nEvidence level 3\nRecommendations\n\u25b8 LTOT patients should receive follow-up at 3 months after\nLTOT is ordered, which should include assessment of blood\ngases and \ufb02ow rate to ensure LTOT is still indicated and\ntherapeutic. (Grade A)\n\u25b8 LTOT patients should receive follow-up visits at 6\u2013\n12 months after their initial 3-month follow-up, which can\nbe either home based or in combination with hospital or\nclinic visits. (Grade D)\n\u25b8 Follow-up visits should be conducted by a specialist home\noxygen assessment team with the necessary skills to deliver\npatient education and manage withdrawal of home oxygen.\n(Grade D)\nGood practice point\n\u25b8 All patients for whom LTOT has been ordered should be\nvisited at home within 4 weeks by a specialist nurse or\nhealthcare professional with experience of domiciliary\noxygen therapy. The visit provides an opportunity to high-\nlight potential risks and should be used to reinforce educa-\ntion and offer support to the patient and carer. Compliance\nmay be checked, along with smoking status, symptoms of\nhypercapnia and oxygen saturations on oxygen to check that\noxygen is therapeutic. (\u221a)\nNOCTURNAL OXYGEN THERAPY\nNOT is oxygen administered overnight alone without additional\noxygen therapy during awake or daytime hours. Before daytime\nresting hypoxaemia develops, many patients develop nocturnal\nor sleep time oxygen desaturation due to a combination of wor-\nsening V\/Q mismatch in a supine posture and lack of drive to\nventilatory muscles during sleep. This section refers to patients\nwho are either normoxic during the day, or have mild daytime\nhypoxaemia but do not ful\ufb01l LTOT criteria.\nNOT in COPD patients with nocturnal desaturation\nThe worsening of hypoxaemia during sleep in patients with\nadvanced COPD has been well established in many studies.\nThere is retrospective evidence that nocturnal desaturation is\nassociated with worse survival. The evidence as to whether\npatients who fail to meet the criteria for LTOT but are hypoxae-\nmic during sleep bene\ufb01t from NOT is assessed here.\nThere are only a small numbers of studies addressing this\npopulation of patients. Of these, three studies examined out-\ncomes over 2\u20133 years, and three studies looked at mortality.\nPatients were recruited from out-patients settings, largely in\nteaching hospitals. In a multicentre study, 76 patients with\nCOPD (obstructive sleep apnoea (OSA) excluded) were identi-\n\ufb01ed as having nocturnal desaturation but did not qualify for\nLTOT.62\nA total of 41 patients were randomised to receive NOT\nwhich was titrated to achieve saturations >90% throughout the\nnight. In the follow-up period, 22 patients went on to develop\nhypoxaemia requiring LTOT, 16 patients died (nine in the\nLTOT group), and there was no difference in the PAP (measured\nby cardiac catheter) between the two groups. A double-blind\ncrossover study63\nrandomised 23 patients with COPD and noc-\nturnal hypoxaemia to receive air or NOT over a 1-night period.\nNo difference was seen in the quality of sleep (assessed by ques-\ntionnaire and EEG) between the two groups. In six centres, 203\npatients diagnosed with COPD and signi\ufb01cant hypoxaemia\n(PaO2 <7.8 kPa, 59 mm Hg) were randomised to continuous\noxygen therapy (24 h) or NOT (12 h).4\nThe primary end point\nwas all cause mortality. There was a 1.94 times increase in \u2018all\ncause\u2019 mortality in the NOT group compared to the continuous\noxygen therapy group. A multicentre retrospective study investi-\ngated the data of patients from \ufb01ve centres who had polysomno-\ngraphy performed.64\nPatients had mild to moderate daytime\nHardinge M, et al. Thorax 2015;70:i1\u2013i43. doi:10.1136\/thoraxjnl-2015-206865 i15\nBTS Guidelines\ngroup.bmj.com\non June 19, 2016 - Published by\nhttp:\/\/thorax.bmj.com\/\nDownloaded from\nhypoxaemia with a PaO2 >60 mmg Hg (8 kPa) and evidence of\ndesaturation during sleep without signs of sleep apnoea. A total\nof 169 subjects with COPD (77 desaturators and 92 non-\ndesaturators) were analysed. The mean survival was signi\ufb01cantly\nless in the desaturator group (2.89\u00b11.7 years vs 3.7\u00b11.7 years;\np<0.003). Thirty-\ufb01ve of the desaturator group were reported to\nhave received some form of oxygen supplementation, however\nit was not clear how many hours this was for or if it was used\nnocturnally; on analysis it did not alter survival. In a double-\nblind study of 51 patients with moderate COPD and daytime\nPaO2 >60 mm Hg including 38 with desaturation, patients were\nallocated to receive NOT at 3 L\/min or room air.65\nAfter\n3 years, the NOT-treated group PAP had reduced by 0.49 kPa\n(3.7 mm Hg) and had increased in the air-treated group by\n0.52 kPa (3.9 mm Hg; p<0.02). There was no difference in\nmortality; however, only nine in the sham group and seven in\nthe oxygen group completed the study.\nEvidence statements\n\u25b8 Patients with mild daytime hypoxaemia and nocturnal hyp-\noxaemia have a worse survival compared to patients with no\nnocturnal desaturation. Evidence level 1+\n\u25b8 When administered to patients who are either normoxaemic\nor have baseline ABG levels above the threshold for LTOT,\nNOT alone does not show consistent improvements in\npulmonary haemodynamics leading to a survival advantage.\nEvidence level 1+\n\u25b8 No additional signi\ufb01cant bene\ufb01t in sleep quality is derived\nfrom nocturnal supplemental oxygen in patients with noctur-\nnal hypoxaemia. Evidence level 1\u2212\nRecommendation\n\u25b8 NOT is not recommended in patients with COPD who have\nnocturnal hypoxaemia but who fail to meet the criteria for\nLTOT. (Grade A)\nGood practice point\n\u25b8 Other causes of nocturnal desaturation in COPD should be\nconsidered such as obesity hypoventilation, respiratory\nmuscle weakness or OSA. (\u221a)\nNOT in patients with cardiac disease and\nnocturnal desaturation\nA variety of factors can contribute to the development of noc-\nturnal hypoxaemia in patients with heart failure: hypoventila-\ntion during sleep, reduced oxygen stores due to restricted lung\nvolumes, sleep disordered breathing (SDB) and impaired gas\nexchange due to ventilation\u2013perfusion mismatch. As previously,\nthis section refers to patients who are either normoxic during\nthe day, or have mild daytime hypoxaemia but do not ful\ufb01l\nLTOT criteria.\nSDB in heart failure is due to central sleep apnoea (CSA)\nassociated with Cheyne-Stokes respiration (CSR), often in com-\nbination with OSA. These frequently co-exist, and can be clinic-\nally dif\ufb01cult to differentiate. The presence of SDB is associated\nwith atrial \ufb01brillation and a worse New York Heart Association\n(NYHA) functional class. It is commoner in male patients, those\nover 60 years of age, and those with daytime hypocapnia\n(PaCO2 <5.06 kPa, 38 mm Hg). SDB in heart failure can have\nfew symptoms and come to light following reports by carers, or\npresents with symptoms of disrupted sleep such as increased\ndaytime sleepiness, poor subjective sleep quality, insomnia,\ninattention and poor concentration. Recurrent nocturnal desa-\nturations can lead to paroxysmal nocturnal dyspnoea, morning\nheadaches, nocturnal angina and arrhythmias. SDB is important\nin the context of heart failure as it can predict mortality and\nalso contribute to disease progression (through intermittent hyp-\noxaemia and arousals inducing adrenergic surges and negative\nintra-pleural pressure swings which increase left ventricular\ntransmural pressure leading to an increase in afterload). Some\ninternational guidelines on heart failure management advocate\nscreening for SDB in selected patients. Treatment approaches\nhave been to maximise treatment for the underlying cardiac\ndisorder, and to consider additional therapies which include\nNOT or ventilatory support such as continuous positive airways\npressure (CPAP), adaptive servo-ventilation (ASV) or NIV\n.\nThere are signi\ufb01cant limitations in the evidence of the impact\nof treatment of SDB on heart-related outcomes: most studies\nevaluate surrogate outcomes (blood pressure, cardiac function,\ncatecholamines) rather than clinically important outcomes\n(health-related quality of life, hospitalisation and mortality). In\naddition, the literature evaluating NOT against modalities of\nventilation is limited.\nEffect of NOT on SDB in severe cardiac disease\nSeveral studies examined the effects of low \ufb02ow oxygen (2\u2013\n4 L\/min delivered by nasal cannulae) on SDB in patients with\nmoderate to severe heart failure. In two non-randomised studies,\nSDB was assessed using the Apnoea Hyponoea Index (AHI) and\ntotal sleep time as outcome measures, thus including both central\nand obstructive apnoeas. One of these trials reported \ufb01ndings on\nin-patients with severe heart failure and CSR on a transplant\nwaiting list and showed that NOT led to a signi\ufb01cant improve-\nment in sleep quality after 1 night, which effect was sustained by\nuse over 1 month (AHI reduced from 57\u00b161 events\/h to 12\u00b117\nevents\/h).66\nIn the other non-RCT of patients with moderate to\nsevere heart failure (LVEF <45%), NOT signi\ufb01cantly reduced\ntotal AHI in 41% of patients (mainly reducing the CSA index)\nbut did not affect total sleep time.67\nTwo RCTs of moderate to\nsevere heart failure patients with CSR showed a reduction in\nCSR after 1 night of treatment with oxygen from 50.7\u00b112% to\n24.2\u00b15.4% of total sleep time and after 4 weeks from 33.6\n\u00b17.4% to 10.7\u00b13.9% of total sleep time, respectively.68 69\nIn\naddition, Staniforth et al69\nreported a reduction in CSAs from\n18.4\u00b14.1\/h to 3.8\u00b12.1\/h. Despite these improvements in sleep\nstudy parameters, no improvement in patient-reported symptom\nscores of sleep fragmentation were seen including the Epworth\nsleepiness scale and visual analogue scale (VAS),69\nor the SF-A\nsleep questionnaire.70\nEffect of NOT on cardiac function in severe cardiac disease\nStudies examined cardiac function using transthoracic echocar-\ndiograms, assessment of NYHA functional class and plasma or\nurinary neuropeptide levels. No studies assessed the effects on\nnocturnal angina. No change in left ventricular function was\nseen following NOT.66 67 71 72\nDespite no demonstrable\nimprovement in echocardiogram parameters, one study reported\na statistically signi\ufb01cant improvement in NYHA functional class\ncompared with an untreated control group after 52 weeks of\nNOT use.71\nNo studies demonstrated any effect on plasma or\nurinary neuropeptide levels. Two studies did not demonstrate\nany reduction in the frequency of ventricular arrhythmias\nduring sleep.67 73\nEffect of NOT on quality of life, activity and cognition in severe\ncardiac disease\nQuality of life assessed using a disease-speci\ufb01c questionnaire in a\n4-week crossover study showed no improvement,69\nwhereas a\ncase series also reporting after 4 weeks and using the Minnesota\nLiving with Heart Failure (MLHF) Questionnaire did show\ni16 Hardinge M, et al. Thorax 2015;70:i1\u2013i43. doi:10.1136\/thoraxjnl-2015-206865\nBTS Guidelines\ngroup.bmj.com\non June 19, 2016 - Published by\nhttp:\/\/thorax.bmj.com\/\nDownloaded from\nimprovement.74\nAnother study used the Dartmouth CO-OP\nFunctional Health Assessment Charts which showed no\nimprovement in daytime symptoms after 1 week.70\nExercise capacity was assessed in two case series of patients\nusing NOT for 4 weeks74\nand 3 months:72\nboth reported an\nimprovement in the 6-minute walk test (6MWT). Activity assessed\nby the Speci\ufb01c Activity Scale showed signi\ufb01cant improvement in a\n52-week RCT.71\nOne study examined effects on cognitive function in detail in\npatients receiving NOT using a variety of measures.69\nNo\nimprovements were seen after 4 weeks in this double-blind\ncross-over study. In contrast, Andreas et al used some similar\nmeasures which did demonstrate improvement after NOT.70\nEffect of NOT on healthcare utilisation or mortality\nNo studies evaluated the effects of NOT use on healthcare util-\nisation or mortality: most studies evaluate surrogate outcomes.\nEvidence statements\n\u25b8 Treatment of heart failure patients who are symptomatic\nfrom SDB with NOT leads to a reduction in SDB. Evidence\nlevel 1\u2212\n\u25b8 Treatment of symptomatic severe heart failure patients with\nNOT leads to modest improvement in exercise capacity.\nEvidence level 3\n\u25b8 Treatment of heart failure patients with NOT does not lead\nto improvement in quality of life, cognitive function, or\ncardiac function including ventricular arrhythmias. Evidence\nlevel 1+\nRecommendation\n\u25b8 NOT can be ordered for severe heart failure patients who do\nnot ful\ufb01l indications for LTOT, and have evidence of SDB\nleading to daytime symptoms, after other causes of nocturnal\ndesaturation have been excluded (eg, obesity hypoventilation\nor OSA) and heart failure treatment has been optimised.\nTreatment with modalities of ventilatory support should also\nbe considered. (Grade B)\nGood practice point\n\u25b8 If NOT is ordered for patients with severe heart failure, it\nshould be ordered at a low \ufb02ow rate of 1\u20132 L\/min and response\nshould be assessed by a reduction in symptoms of daytime\nsleepiness, and SDB indices as measured by an overnight oxim-\netry study. A blood gas assessment should be undertaken to\nexclude worsening hypercapnia and respiratory acidosis.\nTreatment with modalities of ventilatory support should be\nconsidered for patients who are hypercapnic. (\u221a)\nNOT in patients with other respiratory diseases and\nnocturnal desaturation\nUse of NOT in patients with CF\nPatients with CF develop progressive air\ufb02ow obstruction, venti-\nlatory failure and nocturnal desaturations with sleep fragmenta-\ntion (which may in addition result from cough). Development\nof nocturnal hypoxaemia and hypercapnia are known to be\npoor prognostic signs in patients with CF and use of NOT has\nbeen examined to see whether it will improve blood gas para-\nmeters and so improve prognosis. Four studies have examined\nthe use of NOT in adult patients with CF, of which two studies\nwere designed to evaluate the role of bi-level positive airway\npressure (BiPAP) and used NOT, with and without air, in their\ncontrol arm. All studies were single night studies of the varying\nmodalities of NOT and between them examined effects on sleep\nquality, blood gas parameters and ventilation. No studies\nexamined effects on pulmonary hypertension, quality of life,\nactivity and cognition, or healthcare utilisation.\nTwenty-eight patients with CF who received NOT were fol-\nlowed over 2 years.75\nNo statistically signi\ufb01cant improvement in\nsurvival, lung or cardiac outcomes was seen, although school and\nwork attendance had improved. However, actual hours of oxygen\nuse were low. In a small RCT of 10 patients with mean FEV1\n<25% predicted (four with daytime hypercapnia), patients who\nwere randomised to receive NOT over 2 nights rather than room\nair improved overnight oxygen saturation levels, but did not\nimprove sleep parameters.76\nTranscutaneous PCO2 rose in all\nstages of sleep, predominantly in REM sleep, but not to a level\nwhich was felt to be clinically signi\ufb01cant. A small study of six sub-\njects with mean FEV1 <29% predicted (two with daytime hyper-\ncapnia) reported results receiving room air, BiPAP or NOT over\n3 nights in random order.77\nNOT led to improved overnight oxy-\ngenation but no change in sleep quality. However, two patients\ndeveloped symptomatic hypercapnia which was not seen with\nBiPAP and NOT given together, where there was substantial\nimprovement in levels of hypercapnia. Another similar small study\nof 13 patients with mean FEV1 <32% predicted (six with daytime\nhypercapnia) showed a non-signi\ufb01cant rise in transcutaneous CO2\nwith NOTwhich improved with BiPAP\n.78\nEvidence statements\n\u25b8 Treatment of CF patients with NOT improves nocturnal oxy-\ngenation but there is no evidence of long-term bene\ufb01t on\nsurvival. Evidence level 1+\n\u25b8 Treatment of CF patients with NOT does not improve sleep\nquality. Evidence level 1+\n\u25b8 Treatment of CF patients with NOT can cause hypercapnia,\nwhich can be improved with provision of NIV along with\nNOT. Evidence level 1+\nRecommendation\n\u25b8 NOT should not be given to CF patients with nocturnal\nhypoxaemia alone who do not ful\ufb01l LTOT criteria. It can be\nconsidered in patients with evidence of established ventila-\ntory failure, where it should be given with NIV support.\n(Grade B)\nUse of NOT in patients with ILD\nPatients with ILD have been found to develop progressive day\nand night-time hypoxaemia, sleep disruption and poor sleep\nquality. Evidence is limited in this area and no studies have\nexamined the long-term use of nocturnal oxygen or its effects\non mortality, pulmonary haemodynamics or healthcare utilisa-\ntion in ILD. Only one study has prospectively examined the\neffect of NOT in patients with ILD compared with air.79\nThis\nwas a 2-night study comparing room air with NOT titrated at\n1\u20133 L\/min via nasal prongs to give an oxygen saturation reading\nof >90%. However, the study took place among long-term resi-\ndents of Mexico city who were therefore acclimatised to living\nat altitude (\u2018normal\u2019 control subjects had a mean PaO2 of\n6.7 kPa). They found that NOT corrected nocturnal hypox-\naemia, improved tachycardia and tachypnoea but that there was\nno change in sleep ef\ufb01ciency.\nEvidence statements\n\u25b8 Treatment of ILD patients with nocturnal episodic\nhypoxaemia, but without established daytime blood gas\nabnormalities, with NOT improves nocturnal oxygenation,\nbut there is no evidence of long-term bene\ufb01t on survival.\nEvidence level 1+\n\u25b8 Treatment of ILD patients with NOT does not improve sleep\nquality. Evidence level 1+\nHardinge M, et al. Thorax 2015;70:i1\u2013i43. doi:10.1136\/thoraxjnl-2015-206865 i17\nBTS Guidelines\ngroup.bmj.com\non June 19, 2016 - Published by\nhttp:\/\/thorax.bmj.com\/\nDownloaded from\nRecommendation\n\u25b8 NOT should not be given to patients with ILD with noctur-\nnal hypoxaemia alone, who do not ful\ufb01l LTOT criteria.\n(Grade B)\nUse of NOT in patients with neuromuscular weakness\nPatients with neuromuscular weakness can develop progressive\nweakness of all muscle groups including respiratory muscle weak-\nness. If this occurs, they may develop nocturnal desaturation, par-\nticularly during REM sleep, prior to developing daytime type 2\nrespiratory failure. No studies have examined the long-term use of\nnocturnal oxygen or its effects on mortality, pulmonary haemo-\ndynamics or healthcare utilisation in neuromuscular weakness.\nEvidence comes from one study which examined the use of NOT\nin patients with Duchenne muscular dystrophy, who had normal\ndaytime blood gases but evidence of episodic nocturnal hypox-\naemia.80\nNo bene\ufb01cial effect was found on sleep quality, but there\nwas a signi\ufb01cant worsening of the duration of hypopnoeas and\ncentral apnoeas. In addition, levels of hypercapnia were not moni-\ntored and the concern that NOT in the absence of NIV support\nmay worsen ventilatory failure remains.\nEvidence statement\n\u25b8 Treatment of patients with neuromuscular weakness and noc-\nturnal episodic hypoxaemia with NOT, without established\ndaytime blood gas abnormalities, does not improve sleep\nquality and worsens CSA. Evidence level 1+\nRecommendation\n\u25b8 Patients with neuromuscular weakness affecting respiratory\nmuscles should not have NOT alone ordered. It can be\nconsidered in patients with evidence of established ventila-\ntory failure, where it should be given with NIV support.\n(Grade B)\nUse of NOT in patients with Cheyne-Stokes respiration, obesity\nhypoventilation syndrome and overlap syndrome\nPatients with OSA experience recurrent episodic desaturation\nthroughout the night, which leads to sleep fragmentation, which\nusually manifests as daytime sleepiness. Treatment for moderate\nto severe OSA is with a combination of weight loss and CPAP\ntreatment. Some obese patients may develop obesity hypoventi-\nlation syndrome (OHS) de\ufb01ned as obesity with body mass index\n(BMI) >30 kg\/m2\nand awake hypercapnia in the absence of\nother causes of hypoventilation. In these patients there can be\nsustained nocturnal hypoxaemia. Some patients can develop an\n\u2018overlap syndrome\u2019 in which there is a combination of OHS and\nOSA (often with underlying lung disease such as COPD) with\nworsening daytime ventilatory failure.\nThere are no trials of home oxygen therapy in the treatment\nof OHS or overlap syndrome. Oxygen has been used as an\nadd-on therapy to NIV\n.\nRecommendation\n\u25b8 Patients with OSA, OHS or overlap syndrome should not\nhave NOT alone ordered. It can be considered in patients\nwith evidence of established ventilatory failure, where it\nshould be given with NIV support. (Grade D)\nAMBULATORY OXYGEN THERAPY\nAOT is de\ufb01ned as the use of supplemental oxygen during exer-\ncise and activities of daily living.81\nIn mobile patients who are\nnot suf\ufb01ciently hypoxaemic to qualify for LTOT but who\ndesaturate on exercise, AOT has historically been used to opti-\nmise saturations and short-term exercise capacity. AOT is also\noften supplied to LTOT users, either to allow those who are\nmobile outdoors to optimise their exercise capacity and achieve\ntheir recommended hours per day usage, or to enable more\nimmobile patients to leave the house in a wheelchair\/scooter on\noccasion, for example for hospital appointments. In some\npatient groups such as those with CF, AOT may be used to\nmaintain an exercise regime or to enable effective airways\nclearance.\nAOT in patients not eligible for LTOT\nThere are a number of hypothetical bene\ufb01ts from the use of\nAOT in patients who are not hypoxaemic at rest but who desat-\nurate on exercise, including increased oxygen transport, allow-\ning greater utilisation of oxygen by exercising muscles, delayed\nonset of inspiratory muscle fatigue, reduction in symptoms of\ndyspnoea and improved right ventricular function.\nStudies that have examined the use of AOT in non-LTOT\nusers can be divided into those which have assessed the acute\nimpact of AOT on exercise capacity during a single assessment,\nthose studying the potential bene\ufb01ts of AOT during an exercise\ntraining programme, and those that have examined the potential\nlonger term bene\ufb01ts of AOT on activity levels and quality of life.\nUse of AOT during exercise\nA Cochrane review of single assessment cross-over studies on\nthe short-term impact of AOT versus placebo air on exercise\ncapacity in moderate to severe COPD patients, reported that\nAOT signi\ufb01cantly improved all outcomes of endurance exercise\ncapacity (distance, time, number of steps) and that maximal\nexercise work rate also increased.82\nBene\ufb01ts in terms of reduced\nbreathlessness, levels of oxygenation and minute ventilation at\nthe time that the placebo test ended were also reported.\nHowever, the clinical signi\ufb01cance of the size of improvement\nseen in these single assessment studies is unclear.83\nThe addition of supplemental oxygen during exercise training\nmay allow patients who normally desaturate on exercise to toler-\nate higher levels of activity and therefore gain more from train-\ning. A meta- analysis included three RCTs examining the use of\nAOT during exercise training in COPD patients using compar-\nable outcome measures.84\nAlthough there were signi\ufb01cant\nimprovements in two parameters (constant power exercise time\nand constant power exercise end-of-test Borg score), there was\nno bene\ufb01cial effect from oxygen-supplemented training in a\nnumber of other parameters including maximal exercise out-\ncomes, functional exercise outcomes (6MWT), shuttle walk\ndistance, health-related quality of life and oxygenation status.\nA recent single-blinded RCTexamined use of AOT in a pulmon-\nary rehabilitation programme in 51 \u2018oxygen responders\u2019 who\nwere selected based on whether they had >10% improvement in\nexercise capacity when using AOT at baseline.85\nSigni\ufb01cant\nimprovements in walking distance as measured by an endurance\nshuttle walking test pre- and post-course (490 m, 95% CI 228 to\n750; p\u22640.001) were shown for those who had used AOT during\npulmonary rehabilitation. This area has also been reviewed in the\nBTS Guideline on Pulmonary Rehabilitation in Adults 2013.86\nIn a study of CF patients with advanced lung disease and\nnormal resting oxygen saturations, patients could exercise for\nlonger periods using supplemental oxygen during graded exer-\ncise tests.87\nIn a Cochrane review of AOT in CF, six studies eval-\nuated oxygen supplementation during exercise. Oxygenation\nimproved, but mild hypercapnia resulted and participants receiv-\ning oxygen therapy were able to exercise for a signi\ufb01cantly\ni18 Hardinge M, et al. Thorax 2015;70:i1\u2013i43. doi:10.1136\/thoraxjnl-2015-206865\nBTS Guidelines\ngroup.bmj.com\non June 19, 2016 - Published by\nhttp:\/\/thorax.bmj.com\/\nDownloaded from\nlonger duration.24\nEvidence for an effect of AOT on daily activ-\nity is lacking, but in clinical practice use of AOT to support\nexercise, physiotherapy and activities of daily living in patients\nwith CF is commonplace.\nLong-term impact of AOT\nThere are limited data on whether the symptomatic bene\ufb01ts out-\nweigh the practical dif\ufb01culties associated with using AOT in\neveryday life.\nA large parallel double-blinded 12-week RCT randomised\n143 COPD patients to use of AOT versus a control group using\ncompressed air.88\nThere were no signi\ufb01cant improvements in\nthe AOT group in terms of dyspnoea, quality of life or func-\ntional capacity, although only 50 patients were shown to desat-\nurate (de\ufb01ned in this case as SpO2 <88%). Average cylinder\nusage in both groups was low at just 40 min\/day, and 46% of\nthe AOT group reported they would prefer to cease using\noxygen therapy altogether at the end of the study. A number of\nsmaller studies (ie, n=20\u201345 patients) have examined the short-\nterm bene\ufb01ts of AOT in either crossover or parallel blinded\nstudies, lasting between 6 and 10 weeks.89\u201393\nModest statistic-\nally signi\ufb01cant improvements were seen in exercise capacity93\nand in health-related quality of life.89\nHowever, the majority\nfailed to show any sustained bene\ufb01t from AOT in a number of\nvariables, including dyspnoea, exercise capacity, St. George\u2019s\nRespiratory Questionnaire (SGRQ), health-related quality of\nlife, activity levels, distance walked or time away from home.\nAOT in patients eligible for LTOT\nAOT is often ordered for LTOT patients, or those who require\noxygen 24 h per day, to allow those who regularly mobilise out-\ndoors to leave the house and maintain their oxygen saturations\nwithin desired levels. Conversely for patients who require LTOT\nor are dependent on oxygen 24 h per day, but are not able to\nmobilise outdoors, AOT may assist them to leave the house on\nan occasional basis, for example for hospital appointments.\nRe-analysis of data from the NOTT study4 94\nshowed that in\nLTOT patients, AOT increased the chances of patients achieving\nthe 15 oxygen hours per day threshold, which has been shown\nto confer survival bene\ufb01ts, a \ufb01nding supported by other\nstudies.95\nHowever, AOT may prove burdensome for LTOT\npatients and not improve quality of life or exercise capacity. A\n1-year double-blinded crossover trial in 24 LTOT patients allo-\ncated them to one of: standard therapy of LTOT via an oxygen\nconcentrator only, standard therapy plus AOT, or standard\ntherapy plus ambulatory compressed air. Use of AOT did not\nimprove any of the primary outcome measures, including\nquality of life, exercise tolerance or daily duration of oxygen\nuse, and the trial was stopped prematurely after an interim ana-\nlysis.96\nHowever, patients were expected to collect their oxygen\ncylinders from the hospital themselves, which is likely to have\nhad an impact on usage.\nSome patients \ufb01nd the weight of standard cylinders prohibits\nuse, and so lightweight cylinders may be considered. Use of\nlightweight cylinders for AOT in comparison with \u2018normal\u2019\nweight cylinders had no impact on the hours of use or on activ-\nity levels, both of which were low at randomisation and\nthroughout the study in a 6-month unblinded RCT of 17 LTOT\npatients.97\nPoor compliance with AOT may result from lack of\ninformation provision, perceived unreliability of the delivery\nsystem, system weight, self-consciousness in public, and carer\nissues surrounding managing and using AOTequipment.98\nAssessment for AOT\nOxygen saturation (SpO2) measured from a \ufb01nger probe or the\nearlobe, is frequently used in clinical practice during exercise to\nassess patients and their response to AOT. When oximetry in 20\nCOPD patients performing 6MWTs with AOT both non-\ninvasively using ear-oximetry (SpO2) and invasively using\nCO-oximetry (SaO2) was compared,97\n\ufb02ow rates were incremen-\ntally increased until both SaO2 and SpO2 were >90%. Signi\ufb01cant\ndifferences were noted between SpO2 and SaO2 readings, which\nwould potentially have led to different \ufb02ow rates being ordered\nin 50% of subjects. For patients with a high respiratory rate, for\nexample those with CF or ILD, assessment using Venturi oxygen\nat a \ufb02ow rate suf\ufb01cient to exceed the patient\u2019s peak tidal (and\nexertional) inspiratory \ufb02ow can offer advantages over oxygen\ntherapy delivered by nasal cannulae. If total gas \ufb02ow exceeds the\npatient\u2019s inspiratory \ufb02ow rate, a Venturi mask will deliver an\naccurate oxygen concentration which may decrease the work of\nbreathing and facilitate CO2 control.99\nSee the section on equip-\nment for information on oxygen conservers.\nEvidence statements\n\u25b8 AOT has been shown to improve survival in patients on\nLTOT by helping them to achieve 15 h per day usage.\nEvidence level 1++\n\u25b8 AOT acutely increases exercise capacity in laboratory-based\nexercise tests in patients who are not eligible for LTOT but\nwho desaturate during exercise. Evidence level 1+\n\u25b8 Long-term use of AOT has not been shown to confer any\nsustained bene\ufb01ts in dyspnoea, exercise capacity, functional\ncapacity, time away from home or quality of life in patients\nwho are not eligible for LTOT. Evidence level 1+\n\u25b8 AOT has not been shown to improve quality of life, exercise\ntolerance or oxygen usage in patients on LTOT. Evidence\nlevel 1\u2212\n\u25b8 AOT leads to improvement in walking distance when given in a\npulmonary rehabilitation programme setting to patients who\nhave demonstrated a >10% improvement in exercise capacity\nwhen using AOTat baseline assessment. Evidence level 1\u2212\nRecommendations\n\u25b8 AOT should not be routinely offered to patients who are not\neligible for LTOT. (Grade B)\n\u25b8 AOT should not be routinely offered to patients already on\nLTOT. (Grade D)\n\u25b8 AOT assessment should only be offered to patients already\non LTOT if they are mobile outdoors. (Grade A)\n\u25b8 AOT should be offered to patients for use during exercise in\na pulmonary rehabilitation programme or during an exercise\nprogramme following a formal assessment demonstrating\nimprovement in exercise endurance. (Grade B)\nGood practice points\n\u25b8 Patients started on AOT should be reviewed regularly. If AOT\nwas started during an exacerbation or when unwell, an initial\nreview at 4\u20136 weeks to check it is still indicated is essential.\n(\u221a)\n\u25b8 Home visits may be useful to identify problems with equip-\nment or set-up. Further reviews should be carried out every\n6 months when stable, or sooner if the patient\u2019s clinical\nstatus changes. (\u221a)\n\u25b8 AOT therapy may offer patients with active lifestyles or\nactive treatment regimens (eg, CF) additional bene\ufb01ts. All\npatients should be assessed for AOT in the context of their\ndaily activity and therapies. (\u221a)\n\u25b8 It is recognised that there may be some patients, for example\nwith ILD and disabling breathlessness, who do not qualify\nHardinge M, et al. Thorax 2015;70:i1\u2013i43. doi:10.1136\/thoraxjnl-2015-206865 i19\nBTS Guidelines\ngroup.bmj.com\non June 19, 2016 - Published by\nhttp:\/\/thorax.bmj.com\/\nDownloaded from\nfor LTOT but who do desaturate on exercise, who may\nbene\ufb01t from AOT. Once all other medical interventions\nhave been optimised, these patients could be considered for\nAOT following formal assessment and AOT use could con-\ntinue following demonstration of bene\ufb01t and compliance.\n(\u221a)\n\u25b8 Patients with high respiratory rates (common in CF and ILD)\nshould receive AOT at a \ufb02ow rate via a Venturi mask, which\nexceeds their peak tidal and exertional inspiratory \ufb02ow, and\nbe supplied with home oxygen equipment which is able to\ndeliver the required high \ufb02ow rates. (\u221a)\n\u25b8 AOT may be offered to LTOT patients who could otherwise\nnot achieve 15 h per day oxygen usage, or who are severely\nhypoxaemic and are too symptomatic to leave their house\nwithout supplemental oxygen but may need to do so, for\nexample to attend GP or hospital appointments. Formal\nassessment is not required in these circumstances. (\u221a)\nFor suggested patient selection criteria and an AOT assessment\nprocedure for AOT during pulmonary rehabilitation, see appen-\ndix 1.\nPALLIATIVE OXYGEN THERAPY\nThe term \u2018palliative oxygen therapy\u2019 (POT) refers to the use of\noxygen to relieve the sensation of refractory persistent breath-\nlessness in advanced disease or life-limiting illness irrespective of\nunderlying pathology where all reversible causes have been or\nare being treated optimally.\nDyspnoea is common in patients with advanced life-limiting\nillness of all types. Breathlessness is a subjective sensation which\narises from a complex interaction of physiological and psycho-\nlogical stimuli and processing.100\nA number of small studies\nhave demonstrated the bene\ufb01t of non-pharmacological techni-\nques such as breathing control\/pacing, acupuncture101 102\nor a\nhand-held fan,103\nwhile the evidence supporting pharmaco-\nlogical management, principally opioids, is well established.104\nThis section discusses the role of home oxygen in the manage-\nment of intractable breathlessness in patients with advanced\ncancer or end-stage cardiorespiratory disease. The evidence\nreviewed dates from subsequent studies since the publication of a\nreport of the Expert Working Group of the Scienti\ufb01c Committee\nof the Association of Palliative Medicine on the use of oxygen in\nthe palliation of breathlessness in 2004.105\nHowever, as most par-\nticipants in studies had an Eastern Cooperative Oncology Group\n(ECOG) performance status of 2 or 3, this population might not\nbe representative of the sickest patients in palliative care.\nEffects of POT in comparison with air\nThe studies reviewed excluded patients with cognitive impair-\nment106 107\nand those with a prognosis of <1 month.107\nOxygen\nwas delivered by nasal cannula or mask, and \ufb02ow rate varied\nfrom 2 to 5 L\/min. Studies also varied regarding duration of\noxygen therapy, ranging from 15 min106\nand 60 min108\nto\n15 h.107\nOxygen was delivered at rest in two studies,106 109\non\nexertion in one108\nand continuously for 15 h in another study.107\nNo studies looked at life expectancy, but one study reported\nquality of life.107\nA double-blind crossover study randomised 51 patients with\nadvanced cancer, 17 of whom were hypoxaemic (SpO2 <90%)\nto 15 min of either air or palliative oxygen.106\nPatients (whether\nhypoxaemic at baseline or not) improved symptomatically with\nboth air and oxygen, but there were no signi\ufb01cant differences\nbetween the treatments. A systematic review and meta-analysis\nof the ef\ufb01cacy of palliative oxygen for relief of dyspnoea in\nhypoxaemic (mean SpO2 88%) or non-hypoxaemic cancer\npatients included 134 patients.108\nAlthough palliative oxygen\nwas administered in a variety of ways (nasal cannula or mask;\nrest or 6MWT; \ufb02ow rate 3\u20135 L\/min), there was no improvement\nin dyspnoea. A double-blind RCT compared air with palliative\noxygen (2 L\/min for 15 h per day for 7 days from a concentra-\ntor) in 239 patients with cancer or end-stage cardiorespiratory\ndisease.107\nThere was no statistically signi\ufb01cant difference\nbetween the two groups in breathlessness (measured twice\ndaily), frequency of side effects, or change in quality of life\nbetween groups. Finally, a cohort study failed to demonstrate\nany symptomatic bene\ufb01t over 2 weeks of the provision of home\npalliative oxygen as measured by routine recording of breath-\nlessness with each clinical encounter with a specialist commu-\nnity palliative care team.110\nEffects of POT in comparison with other therapies such as\nopiates, fan therapy and cognitive behaviour therapy\nThere are no reported studies comparing POT with fan therapy,\ncognitive behavioural therapy or other techniques for symptom-\natic relief of breathlessness.\nOne study assessed the effects of oxygen and opioid treatment\non ventilation and palliation of dyspnoea in hypoxaemic (SpO2\n<90%) and non-hypoxaemic (SpO2 \u226590%) palliative care\npatients (either opioid-naive or pre-treated with strong opioids)\nin a prospective non-randomised study.109\nWhereas opioid\nadministration resulted in a signi\ufb01cant decrease in the intensity\nof dyspnoea in hypoxaemic or in non-hypoxaemic patients,\nnasal oxygen therapy did not. There was no signi\ufb01cant correl-\nation between intensity of dyspnoea and SpO2, and no signi\ufb01-\ncant difference between hypoxaemic or non-hypoxaemic\npatients with regard to transcutaneous CO2 increase or SpO2\ndecrease after administration of opioids.\nEvidence statements\n\u25b8 Measurements of oxygenation do not correlate well with the\nsubjective experience of dyspnoea in patients with cancer or\nend-stage cardiorespiratory disease. Evidence level 2+\n\u25b8 Hypoxaemic patients do not experience a signi\ufb01cant differ-\nence in symptoms between air and POT despite having\nimproved oxygen saturations when administered oxygen.\nEvidence level 2+\n\u25b8 Non-hypoxaemic patients or those with mild levels of hypox-\naemia who would not normally qualify for LTOT do not\nexperience symptomatic bene\ufb01t with POT compared with air.\nEvidence level 1++\n\u25b8 Opioids are signi\ufb01cantly better than POT in reducing the\nintensity of dyspnoea in non-hypoxaemic or hypoxaemic\npatients. Evidence level 1+\nRecommendations\n\u25b8 Patients with cancer or end-stage cardiorespiratory disease\nwho are experiencing intractable breathlessness should not\nreceive treatment with POT if they are non-hypoxaemic or\nhave mild levels of hypoxaemia above current LTOT thresh-\nolds (SpO2 \u226592%). (Grade A)\n\u25b8 Patients with cancer or end-stage cardiorespiratory\ndisease who are experiencing intractable breathlessness\nshould receive assessment for a trial of treatment with\nopiates from an appropriately trained healthcare profes-\nsional. (Grade A)\n\u25b8 Patients with cancer or end-stage cardiorespiratory disease\nwho are experiencing intractable breathlessness should\nreceive assessment for a trial of treatment with non-\npharmacological treatments including fan therapy, from an\nappropriately trained healthcare professional. (Grade D)\ni20 Hardinge M, et al. Thorax 2015;70:i1\u2013i43. doi:10.1136\/thoraxjnl-2015-206865\nBTS Guidelines\ngroup.bmj.com\non June 19, 2016 - Published by\nhttp:\/\/thorax.bmj.com\/\nDownloaded from\nGood practice point\n\u25b8 POT may on occasion be considered by specialist teams for\npatients with intractable breathlessness unresponsive to all\nother modalities of treatment. In those instances, individual\nformal assessment of the effect of palliative oxygen on redu-\ncing breathlessness and improving quality of life should be\nmade. (\u221a)\nFor suggested patient selection criteria and a protocol for POT\nassessment, see appendix 3.\nSHORT BURST OXYGEN THERAPY\nSBOT is typically given to patients for the relief of breathless-\nness not relieved by any other treatments. It is used intermit-\ntently at home for short periods, for example 10\u201320 min at a\ntime. Oxygen used in this way has traditionally been ordered\nfor non-hypoxaemic patients and used for subjective relief of\ndyspnoea prior to exercise for oxygenation or after exercise for\nrelief of dyspnoea and recovery from exertion.\nUse of SBOT in respiratory disease\nThe studies reviewed were limited to patients with COPD and\nincluded normoxic and hypoxaemic patients with moderate to\nsevere disease. Two studies examined oxygen delivery before\nand after exercise, while four studies administered oxygen after\nexercise. One study that examined the bene\ufb01t of oxygen after\nexercise included patients given LTOT,111\nhowever hypoxaemic\nand non-hypoxaemic patients were not analysed separately.\nThere were no studies that speci\ufb01cally examined the bene\ufb01ts of\nSBOT ordered for hypoxaemic patients alone.\nIn order to examine the effect of supplemental oxygen before\nand after exercise in stable COPD patients with moderate to severe\ndisease who demonstrated exercise desaturation, Nandi et al112\nundertook two double-blind randomised studies. In the \ufb01rst study,\n34 subjects received either cylinder air or oxygen 28% at a \ufb02ow\nrate of 4 L\/min for 10 min before a 6MWT. In the second study,\n18 subjects received either cylinder air or cylinder oxygen for\n5 min immediately after a 6MWT. Those that took part in both\nstudies did so on different days. Distance walked, oxygen satura-\ntions and breathlessness as measured by a VAS were recorded as\nwas time to recovery. No difference was found in distance walked,\nsubjective breathlessness or recovery time when oxygen was admi-\nnistered prior to exercise. Nor was there any signi\ufb01cant difference\nin distance walked, recovery time or breathlessness when oxygen\nwas administered following exercise. The authors concluded that\nno recommendation could be made to support a useful therapeutic\nrole for SBOT.\nSimilarly, SBOTwas not found to have any effect on perform-\nance when administered before and after exercise in 22 non-\nhypoxaemic COPD patients with moderate to severe disease.113\nSubjects undertook four 6MWTs at each of two sessions.\nCylinder air or oxygen was randomly administered prior to the\n\ufb01rst two walk tests and during recovery following the \ufb01nal two\ntests. The group found no signi\ufb01cant difference in distance\nwalked or breathlessness as measured by the Borg score for air\nand oxygen given prior to exercise and no signi\ufb01cant difference\nin mean time to resting Borg score when oxygen was given after\nexercise.\nAnother study compared oxygen, air, fan and no treatment in\n34 stable patients with moderate to severe COPD who were\nshort of breath on minimal exertion and who were not hypox-\naemic (SaO2 \u226493% at rest).114\nPatients undertook an exercise\nstep test on four occasions and after each test were given either\noxygen 4 L\/min from a face mask, air from a face mask, air\nfrom a fan, or no intervention. Fourteen patients desaturated on\nexercise below 90%. Oxygen therapy had no signi\ufb01cant effect\non Borg scores even for those patients who desaturated. Oxygen\nsaturation rose more quickly and to a higher level when the\noxygen mask was used compared with other treatments\n(p<0.009), but this increase of 2% had no effect on subjective\nbreathlessness as measured by the Borg score.\nPatients were asked to choose whether they received treatment\nbefore or after exercise in a study that examined 22 stable COPD\npatients with moderate to severe disease.111\nSubjects were studied\nat home undertaking an activity of choice (mean resting SaO2\n93.1% (range 82\u201398%)). All had domiciliary oxygen ordered for\nthem and 50% were on LTOT. In this double-blind study, cylinder\nair or oxygen was randomly administered after exercise.\nInterestingly, all subjects chose after exercise. The exercise was\nrepeated after a rest period and the alternative treatment adminis-\ntered. There was no difference in recovery times with oxygen com-\npared with air. Five patients were able to correctly identify oxygen\nfrom air on both occasions. This group had shorter subjective and\nobjective recovery times when compared with the rest of the\ngroup, although this did not reach statistical signi\ufb01cance.\nA reduced recovery time as measured by a VAS was associated\nwith oxygen use compared with compressed air or placebo in a\nstudy of 19 subjects with stable severe COPD (mean (SD) PaO2\n8.05 (1.52) kPa).115\nSubjects undertook three step tests to\nmaximal dyspnoea and then were administered either cylinder\noxygen 67% via a mask, cylinder air at the same \ufb02ow for\n20 min, or no mask in random order. The results were not\nfound to be reproducible when the seven responders were\nre-tested after a time lapse of between 1 week and 1 month.\nIn a study undertaken by Stevenson and Calverley, 18 stable\nCOPD patients were included, none of whom were hypoxaemic at\nrest, although six patients did desaturated on exercise (range\n88\u201396%).116\nPatients attended on two occasions at least 1 week\napart. At each visit, patients performed a maximal cardiorespira-\ntory exercise test following which they randomly received either\nair or oxygen (FiO2 0.4) in a single-blind crossover fashion. At one\nvisit the subject remained instrumented during recovery, while at\nthe other visit the mouthpiece and nose clips were replaced with a\nVenturi mask at a \ufb02ow rate of 10 L\/min. The results revealed that\nfollowing exercise, administration of oxygen when compared with\ncompressed air was associated with a reduced ventilatory effort\nand dynamic hyperin\ufb02ation resolution was shorter; however, there\nwas no reduction of breathlessness as measured by the Borg score\nat any time during recovery between oxygen and air inhalation,\nnor did oxygen in\ufb02uence the rate at which symptoms were\nresolved. The authors concluded that the routine use of oxygen to\naid recovery of symptoms after exercise does not appear to be\njusti\ufb01ed.\nHealthcare utilisation and quality of life were measured in a ran-\ndomised double-blind placebo-controlled trial in patients with\nmoderate to severe disease following an admission to hospital with\nan exacerbation of COPD.117\nA total of 78 non-hypoxaemic\npatients were recruited and were randomised to cylinder air, cylin-\nder oxygen or usual care for 6 months following discharge from\nhospital. The subjects who were randomised to cylinder air or\ncylinder oxygen were instructed to use it at 2 L\/min via nasal can-\nnulae as needed for relief of distressing or limiting breathlessness.\nCylinder use was self-recorded in patient diaries. Healthcare util-\nisation was assessed by number of COPD-related readmissions and\nunscheduled emergency department or primary care visits.\nQuality of life was measured using the Chronic Respiratory\nDisease Questionnaire (CRQ), the Hospital Anxiety and\nDepression Scale (HAD) and the Medical Outcomes Study Short\nHardinge M, et al. Thorax 2015;70:i1\u2013i43. doi:10.1136\/thoraxjnl-2015-206865 i21\nBTS Guidelines\ngroup.bmj.com\non June 19, 2016 - Published by\nhttp:\/\/thorax.bmj.com\/\nDownloaded from\nForm (SF-36). There was no signi\ufb01cant difference between patient\ngroups in any of the health-related quality of life measures apart\nfrom the emotions domain of the CRQ for the usual care group.\nHospital readmission and healthcare utilisation were high.\nHowever, there was no signi\ufb01cant difference between groups.\nCylinder use was initially high but fell rapidly within weeks in\nboth the cylinder air and oxygen groups. The authors conclude\nthat these results do not offer any support for the use of SBOTon\ndischarge from hospital following an acute exacerbation of COPD.\nEvidence statements\n\u25b8 SBOT does not improve exercise tolerance or reduce breath-\nlessness when administered either before or following exer-\ncise to hypoxaemic or non-hypoxaemic patients with\nmoderate to severe COPD. Evidence level 1++\n\u25b8 SBOT does not improve health-related quality of life or\nreduce healthcare utilisation when ordered for patients fol-\nlowing an acute exacerbation of COPD. Evidence level 1++\nRecommendations\n\u25b8 SBOT should not be ordered for use prior to or following\nexercise in hypoxaemic or normoxic patients with COPD.\n(Grade A)\n\u25b8 SBOT should not be ordered on discharge from hospital for\nnon-hypoxaemic patients with severe COPD. (Grade A)\nUse of SBOT in CH\nCH pain is the most severe of the primary headache syndromes.\nIt is characterised by periodic attacks of strictly unilateral pain\nassociated with ipsilateral cranial autonomic symptoms. The\nmajority of patients have episodic cluster headache (ECH), with\ncluster periods that typically occur in a circannual rhythm, while\n10% have the chronic form (CCH), with no signi\ufb01cant remis-\nsions between cluster periods. High \ufb02ow oxygen therapy is used\nto relieve pain and is delivered usually from static oxygen cylin-\nders in the patient\u2019s home.\nIn a double-blind randomised, placebo-controlled cross-over\ntrial, 109 adults were treated for CH attacks with either 100%\noxygen (12 L\/min) or inhaled air, given via a facial mask for\n15 min at the start of an attack. Fifty-seven patients with ECH\nand 19 with CCH were available for the analysis.118\nOxygen was\nsigni\ufb01cantly superior to placebo in elimination of pain or provi-\nsion of \u2018adequate pain relief\u2019 at 15 min in 78% of patients (vs\n20% with air). In a case series of 52 randomly selected out-\npatients with either active ECH or CCH, 100% oxygen was\nadministered through a facial mask at a rate of 7 L\/min for\n15 min at the onset of each of 10 cluster attacks.119\nOverall, 75%\nof patients obtained signi\ufb01cant relief (de\ufb01ned as complete or\nalmost complete reduction of pain in seven of 10 attacks within\n15 min) from cluster pain. These \ufb01ndings were supported by a\ndouble-blind crossover study of 19 patients where use of SBOT\n(6 L\/min via non-rebreather face masks for 15 min) produced sig-\nni\ufb01cantly higher average relief scores for all oxygen-treated\npatients.120\nA case report of three patients unresponsive to\noxygen given at 7\u201310 L\/min reported complete or near complete\nalleviation of headache after 100% oxygen at a rate of 14\u201315\nL\/min.121\nNon-responders to SBOT have more often smoked in\nthe past (p=0.014), had longer CH attacks (p=0.049), and\nreported more inter-ictal headache (p=0.02) than responders.122\nA single-blind crossover trial of 50 patients has compared sub-\nlingual ergotamine tartrate to SBOT (100% oxygen via a face\nmask, at a rate of 7 L\/min for 15 min) for symptomatic relief of\ncluster attacks showed no statistical difference between treat-\nment groups.119\nNICE (National Institute of Health and Care Excellence) guide-\nlines on the diagnosis and management of headaches in young\npeople and adults, published in September 2012, recommend\noxygen and\/or a subcutaneous or nasal triptan for the acute treat-\nment of CH.123\nIt is recommended that oxygen should be given at\na \ufb02ow rate of at least 12 L\/min with a non-rebreather mask and a\nreservoir bag arranged as home oxygen. (NICE refers to ambula-\ntory oxygen in this context which differs from the de\ufb01nition of\nambulatory oxygen used in this guideline).\nEvidence statement\n\u25b8 SBOT delivering high \ufb02ow oxygen (12 L\/min via a non-\nrebreather mask) is an effective symptomatic treatment for\nacute CH attacks. Evidence level 1+\nRecommendation\n\u25b8 SBOT delivering high \ufb02ow oxygen therapy (12 L\/min via a\nnon-rebreather mask) should be offered to treat acute attacks\nof CH. (Grade A)\nGood practice point\n\u25b8 Appropriate equipment will need to be provided in order to\nensure delivery of high \ufb02ow rate oxygen at 12 L\/min for CH\nusing a non-rebreather mask. Patients will usually have\nwarning of a CH attack, and so provision should be made\nfor urgent 4 h installation of home oxygen, if available,\nrather than a permanent home supply being provided. (\u221a)\nEQUIPMENT FOR HOME OXYGEN THERAPY\nThe equipment for home oxygen therapy can be divided into\nthree categories: oxygen source (concentrators, cylinders and\nliquid oxygen), oxygen delivery (cannulae, masks, conservers\nand tracheal devices) and supplementary equipment (humidi\ufb01ers\nand equipment to carry oxygen). Please see online supplemen-\ntary appendix 12 for illustrations and further details of equip-\nment types.\nOxygen source: concentrators, cylinders and liquid oxygen \u2013\ndescription and indications for use\nHome oxygen can be delivered from cylinders, concentrators or\nas liquid oxygen. Each of these oxygen sources can be static or\nportable, and the source selected is dependent upon the mobil-\nity and clinical circumstances of the patient, along with the costs\nof installation and supply as determined by the oxygen provider.\nThere are few published studies comparing the different modes\nof oxygen source in different clinical situations. Some studies\nhave compared similar devices, but many of these are now out-\ndated and technology has superseded them.\nConcentrators\nThe most common device for LTOT delivery is an oxygen con-\ncentrator which can either be \ufb01xed in a room in the house or is\nportable to go with the patient around the home, outside the\nhome and in the workplace. An oxygen concentrator is an elec-\ntrically driven device which takes room air and passes it through\na \ufb01ltering system, removing nitrogen, to supply an oxygen-\nenriched gas mixture (usually 85\u201395% oxygen).\nPerformance of oxygen concentrators can vary depending on\nthe technology used.124\u2013130\nThe maximum oxygen concentra-\ntion delivered by an oxygen concentrator is 96%,124\nbut there\ncan be a difference in performance between devices depending\nupon \ufb02ow rate. In a study that assessed a number of oxygen\nconcentrators, all concentrators were found to deliver suf\ufb01cient\noxygen to achieve target oxygen saturation levels above 92% at\n\ufb02ow rates of 2 L\/min, of 85\u201394% at 3 L\/min and of 69\u201385% at\n4 L\/min depending upon the device.126\nThis can result in\ni22 Hardinge M, et al. Thorax 2015;70:i1\u2013i43. doi:10.1136\/thoraxjnl-2015-206865\nBTS Guidelines\ngroup.bmj.com\non June 19, 2016 - Published by\nhttp:\/\/thorax.bmj.com\/\nDownloaded from\npatients not receiving their oxygen as ordered.131\nIn another\nseries of 2400 oxygen concentrator users, where the \ufb02ow rate\nwas 2 L\/min or less in 79% of users, the mean\u00b1SD oxygen sat-\nuration achieved was 92\u00b16%.127\nIt is current clinical practice to\nuse a combination of two oxygen concentrators joined via a\nT-piece to deliver high \ufb02ow rates, for example 12 L\/min when\nrequired, although there is no clinical trial evidence to support\nthis practice and it is unknown whether the equipment used per-\nforms adequately in this way.\nHome concentrators\nHome concentrators will be installed and regularly maintained\nby oxygen provider companies. In order to reduce risk of falls\nfrom tripping over long lengths of tubing, they may be \u2018piped\nin\u2019 to the home with appropriate tubing to areas where the\npatient will use the oxygen (bedroom, living room). All concen-\ntrators should have \ufb01re breaks inserted into the tubing\u2014one at\nthe patient end and one at the machine end\u2014to reduce the risk\nof potentially catastrophic \ufb01res (see the section on safety and\nhome oxygen). Oxygen concentrators can deliver \ufb02ow rates of\nup to 4 L\/min, adjustable in 0.5 L\/min increments. Where low\n\ufb02ow is needed, for example in paediatric, NIV use and oxygen-\nsensitive patients, \ufb02ow metres that reduce \ufb02ow can be added to\nthe standard concentrator. High \ufb02ow oxygen concentrators can\ndeliver \ufb02ow rates of 8 L\/min. For very high \ufb02ows, concentrators\ncan be joined via a T-piece and each concentrator must be set to\nthe same \ufb02ow, for example 12 L\/min required would need two\nhigh \ufb02ow concentrators both set at 6 L\/min, although there is\nno research evidence to support their use in this way. This\noption may not be available and it is suggested that home\noxygen teams check with their oxygen supplier. Concentrators\nare recommended for patients using oxygen for more than 1.4 h\na day.132\nPractical considerations for patients are the need to\nchange \ufb01lters weekly, regular servicing of the machine, the\nwarm-up period of the machine and the noise of the device. A\nnew development is a concentrator which can be used to re\ufb01ll\nsmall portable cylinders at home, known as a \u2018home \ufb01ll\u2019 oxygen\nsystem.\nTransportable and portable concentrators\nTransportable concentrators are similar to home concentrators\nbut smaller in size and more portable with a typical weight\nbeing 4.5\u20138.6 kg. They come with batteries as well as a mains\nattachment, allowing use outside as well as inside the home.\n(Inside the home, a transportable concentrator can be used as a\nstandard concentrator as well as ful\ufb01lling the patient\u2019s ambula-\ntory needs.) The battery for use outside the home does limit the\ntime they can be used without recharging and will depend on\nthe \ufb02ow rate and whether the pulsed mode is used. They can be\nused and charged in cars. Most are now approved for use on\ncommercial aircraft, although patients are currently advised not\nto take their supplied equipment out of the country as it will\nnot be supported by the oxygen supplier in the event of a mal-\nfunction when abroad. Current models are available that deliver\nup to 3 L\/min continuous oxygen and 6 L\/min pulsed oxygen,\nand come with a power adapter to plug into an electrical\nsource, or a battery back-up.\nPortable concentrators are somewhat lighter than transport-\nable concentrators, with a typical weight being 3.3\u20134.5 kg. The\nmajority of portable oxygen concentrators provide pulsed\noxygen only. Therefore, they are not suitable for use when\nsleeping. It should be noted that some portable concentrators\nhave numerical settings, for example number 2 does not equate\nto 2 L\/min, and some do not alarm when they malfunction.\nCylinder oxygen\nA cylinder is a strengthened metal container containing com-\npressed gas held under high pressure safely for use via its regula-\ntor (tap). Oxygen cylinders come in a range of sizes and hence\ncapacity, ranging from small portable cylinders to large static\ncylinders (see online supplementary appendix 12), and are\ncolour coded to distinguish them from other medical gases.\nCurrently, oxygen cylinders are white with writing denoting the\ncontent down the side, and black with white shoulder: all\nmedical oxygen cylinders will be white bodied by 2025. The\n\ufb02ow rate can be \ufb01xed or variable depending on patient require-\nments. All systems containing compressed gases in the UK are\nsubject to the Pressure Systems Safety Regulations 2000 (SI\n2000 No 128), which are intended to prevent the risk of injury\nfrom pressurised systems.\nHistorically, static cylinders have usually been used to deliver\nshort burst or palliative oxygen in the home but now \ufb01nd their\nmain use as back-up cylinders if there is a power cut or concen-\ntrator failure or in the treatment of CH patients. Lightweight\ncylinders (example weight 8 kg\/3.6 lb) and standard ambulatory\ncylinders (example weight 3.2 kg\/7 lb) are available for ambula-\ntory use.\nLiquid oxygen\nLiquid oxygen is oxygen that is cooled so that it condenses from\na gas to a liquid which can be stored in insulated containers.\nLiquid oxygen is generally stored in large Dewar \ufb02asks with a\ndecanting system to deliver it to smaller portable Dewar \ufb02asks.\nThe length of time these can last will depend on the \ufb02ow pro-\nvided and the size of the Dewar \ufb02ask. Users need to be trained\nto connect the two containers to reduce problems of gas\nleakage and also to prevent users received cold burns through\ninappropriate handing of the device. Choices between these\ndevices should take account of individual patient\u2019s dexterity,\nvisual acuity and strength. Liquid oxygen Dewar \ufb02asks can only\nbe installed on a ground \ufb02oor due to venting and safety\nconsiderations.\nComparison of different oxygen sources in clinical trials\nThe majority of clinical trials in this area focus on delivery of\nportable oxygen either to facilitate use of ambulatory oxygen or\nto use as a method of delivery of LTOT with home oxygen con-\ncentrators. There are six methods of delivering portable oxygen:\nliquid, home \ufb01ll cylinder, portable cylinder, lightweight cylinder,\nportable and transportable oxygen concentrator.\nUse of portable oxygen to deliver ambulatory oxygen\nSeveral small RCTs have compared different modalities of port-\nable oxygen97 133 134\nin short-term or exercise test-based\nstudies. Comparison of standard portable cylinders with light-\nweight cylinders97\nand safe-\ufb01ll portable cylinders133\nshowed no\ndifference in activity levels (which were low), oxygen saturation,\nBorg score or 6MWT between the different modalities. In a\ncomparison of four different methods of supplying portable\noxygen (liquid, home \ufb01ll cylinder, portable concentrator and\nlightweight cylinder) in 44 patients with stable severe COPD,\nthere were no differences between oxygen saturation, distance\nwalked or time used.134\nCylinder oxygen was least favoured by\npatients and liquid oxygen was most favoured with the lowest\nlong-term costs. Despite a lack of improvement in quality of life\nin this study, the patients using liquid oxygen in comparison\nwith portable cylinders spent signi\ufb01cantly longer outside the\nhouse and used their oxygen more.135\nIn another study of\nHardinge M, et al. Thorax 2015;70:i1\u2013i43. doi:10.1136\/thoraxjnl-2015-206865 i23\nBTS Guidelines\ngroup.bmj.com\non June 19, 2016 - Published by\nhttp:\/\/thorax.bmj.com\/\nDownloaded from\npatients with severe COPD comparing continuous \ufb02ow liquid\noxygen with a portable concentrator, there was no signi\ufb01cant\ndifference in use or level of oxygenation. The \ufb02ow rate of\noxygen needed on ambulation was an average of three times\nhigher than at rest.136\nUse of portable oxygen to deliver LTOT\nSmall RCTs and an observational study have examined the use\nof portable oxygen in contributing to the delivery of LTOT.\nPortable devices compared with home-based LTOT alone\nimproved oxygen usage.95\nUse of liquid oxygen with or instead\nof a concentrator can increase daily use of oxygen137\u2013139\nand\nimprove quality of life,137\nbut overall costs can be higher.137 138\nStatic cylinder use\nA survey of patients using static oxygen cylinders at home found\nthat most had a diagnosis of COPD and used oxygen regularly\nfor short-term relief of breathlessness, with 58% using their\noxygen at least once a day. On average these patients used three\ncylinders each per month.140\nEvidence statements\n\u25b8 Portable oxygen provides greater oxygen daily usage and\nimproved quality of life than static concentrators alone.\nEvidence level 1\u2212\n\u25b8 There is no conclusive difference in activity levels or utilisa-\ntion between different methods of portable oxygen, but\npatient preference is generally for liquid oxygen. Evidence\nlevel 1\u2212\n\u25b8 Lightweight cylinders do not improve walking distance or\noxygen utilisation and may lead to increased costs. Evidence\nlevel 1\u2212\n\u25b8 Oxygen concentrators are the most cost-effective way to\ndeliver LTOT, but can have variable ef\ufb01ciency depending on\n\ufb02ow rates, particularly above 4 L\/min. Evidence level 2++\nRecommendations\n\u25b8 Oxygen concentrators should be used to deliver LTOT at\n\ufb02ow rates of 4 L\/min or less. (Grade B)\n\u25b8 Portable oxygen should be delivered by whatever mode is\nbest suited to the individual needs of the patient to increase\nthe daily amount of oxygen used and activity levels in mobile\npatients. (Grade C)\nGood practice point\n\u25b8 The type of portable device selected should balance patient\nfactors with cost effectiveness, resources and safety. (\u221a)\nOxygen delivery: nasal cannulae and masks,\noxygen-conserving devices and trans-tracheal devices\u2013\ndescription and indications for use\nMethods of home oxygen delivery depend upon the patient\u2019s\nrequirements and the setting for delivery of care. Interfaces used\nfor home oxygen fall into two main categories: nasal cannulae\nand face masks using the Venturi system. Trans-tracheal delivery\nis rarely used but will be brie\ufb02y described. In addition, oxygen-\nconserving devices may be used to facilitate oxygen delivery.\nMost home oxygen tubing has a \u2018\ufb01re break\u2019 inserted at the\npatient end of the tubing just before the nasal cannula or mask:\nthis is a thermal fuse which when triggered will stop the oxygen\nsupply in the event of \ufb01re.\nNasal cannulae and masks\nNasal cannulae are the most common interface for oxygen\ndelivery. This is largely the result of a compromise between\npatient comfort and tolerance when using oxygen for 15 h\/day\nand the need for controlled oxygen concentration delivery.\nNasal cannulae are usually lightweight, soft plastic\/silicone\ntipped tubing that are dual-pronged and sit in the nostrils, held\nin position by looping the tubing over the pinna of the ears, and\nallow oxygen delivery continuously into the nose. The nasal\ncannula delivers a low \ufb02ow of oxygen entrained in a larger\nvolume of atmospheric air so that each litre per minute of\noxygen \ufb02ow adds about 3\u20134% to the inspired oxygen concentra-\ntion. The respiratory rate as well as underlying disease process\nwill determine the actual oxygen delivery. However, a small\nnon-randomised trial showed that oxygen delivery with nasal\ncannulae can be very variable, with individual inspired oxygen\nconcentrations varying between 24% and 35% with the same\n\ufb02ow rate of 2 L\/min.141\nHigh \ufb02ow nasal cannulae are used in\ncritically unwell patients and not appropriate to the home\noxygen population.\nOxygen masks are minimal volume, made of clear, soft plastic\nand held over the nose and mouth with elasticated straps for\ncomfort. Venturi masks are designed to deliver accurate concen-\ntrations of oxygen when used with certain \ufb02ow rates. They are\nfavoured for delivery of controlled oxygen concentrations\nwhere this is clinically important, such as in patients with hyper-\ncapnic respiratory failure requiring LTOT. Other patient factors\nmay be relevant such as confused or demented patients where\n\ufb02ows might be altered in error.\nOther interfaces such as the OxyArm have been developed\nallowing minimal head contact but no facial contact, and the\npotential for use in both nose and mouth breathers, and in\npatients with high respiratory rates. When used in stable COPD\npatients requiring LTOT over a 4-week period, nasal cannulae\nand OxyArm gave similar oxygen delivery, but fewer patients\npreferred the OxyArm due to dislodgement and reduced\nmobility.142\nOxygen-conserving devices\nOxygen-conserving devices deliver oxygen during inspiration\nonly and, by reducing oxygen wasted during expiration, enable\ncylinders to last longer compared to constant \ufb02ow. This can\nreduce costs by reducing the number of home deliveries. Most\noxygen delivery systems now have conservers \ufb01tted as standard.\nEach model of conserver will have very different speci\ufb01cations\nchosen by the manufacturers to suit the device and are not able\nto be changed by the users. This high degree of variability\nmeans that they are not truly comparable from one make or\nmodel to another. Reservoir cannulae are a form of oxygen-\nconserving device but are rarely used in home oxygen services;\ninformation about them can be found in the BTS Emergency\nOxygen guidelines. Historical studies performed prior to con-\nservers becoming standard equipment have not been reviewed.\nMost studies have agreed that conservers can reduce oxygen\nusage by as much as 50%.126 143 144\nThe demand oxygen deliv-\nery system produced only a small increase in walk distance\nwithout elevation of oxygen saturation, but was inferior to con-\ntinuous \ufb02ow oxygen in most of the measured variables when\ncompared directly.145\nHowever, it has been suggested that\noxygen-conserving devices vary in their ability to maintain SaO2\nlevels during exercise146 147\nand that some patients (particularly\nthose who mouth breathe) may struggle to trigger them, and\ntherefore patients should have ambulatory assessments before\nbeing issued with them. The evidence for the use of nocturnal\noxygenation using a pulsed-dose oxygen-conserving device com-\npared to continuous \ufb02ow is limited.148\nContinuous oxygen was\ncompared with pulsed oxygen delivery at two different settings\nand showed no clinical difference. The evidence for the use of\ni24 Hardinge M, et al. Thorax 2015;70:i1\u2013i43. doi:10.1136\/thoraxjnl-2015-206865\nBTS Guidelines\ngroup.bmj.com\non June 19, 2016 - Published by\nhttp:\/\/thorax.bmj.com\/\nDownloaded from\npulse dose conservers at night is at best very poor and requires\nmore research.\nTrans-tracheal oxygen\nThis form of oxygen can be used but rarely in the home setting\nand requires dedicated support from a trained team. Oxygen is\ndelivered via a catheter inserted percutaneously between the\nsecond and third tracheal rings. By reducing anatomical dead\nspace, it allows lower levels of oxygen to be required than nasal\ncannulae, and reduces the work of breathing. Serious complica-\ntions can include catheter displacement, obstruction of the cath-\neter by mucous, and infection.\nEvidence statements\n\u25b8 Nasal cannulae can be used to deliver home oxygen at low\n\ufb02ow rates and are acceptable to patients. Evidence level 4\n\u25b8 Nasal cannulae provide variable inspired concentrations of\noxygen when used at the same \ufb02ow rate in different patients.\nEvidence level 4\n\u25b8 Oxygen-conserving devices reduce total oxygen usage.\nEvidence level 1+\n\u25b8 Oxygen-conserving devices vary in their ability to maintain\nSaO2 levels during exercise, and some patients struggle to\ntrigger them. Evidence level 1+\nRecommendations\n\u25b8 Nasal cannulae should be considered as the \ufb01rst choice of\ndelivery device for patients requiring home oxygen therapy.\nAs an alternative, some patients may bene\ufb01t from or prefer a\nVenturi mask system. (Grade D)\n\u25b8 Oxygen-conserving devices can be used in home oxygen\npatients requiring high \ufb02ow rates to increase the time the\ncylinder will last. (Grade B)\nGood practice points\n\u25b8 Venturi masks should be considered in patients in whom\nthere are concerns about existing or developing hypercapnic\nrespiratory failure, those with a high resting respiratory rate\nor those with cognitive problems. (\u221a)\n\u25b8 Oxygen-conserving devices should be considered in patients\nwho are active outside the home, following an ambulatory\noxygen assessment. (\u221a)\nOther equipment: trolleys and backpacks, humidi\ufb01ers\u2013\ndescription and indications for use\nPatient compliance with treatment is greatly improved with sup-\nplementary equipment which may help address practical issues\naround home oxygen provision.\nHumidi\ufb01cation\nOxygen is sometimes humidi\ufb01ed in an attempt to prevent a\ndrying effect of oxygen if delivered at high \ufb02ow rates or in\npatients with excessive chest secretions such as those with CF or\nbronchiectasis. Systems are available for the humidi\ufb01cation of\nsupplemental oxygen by bubbling oxygen through sterile water.\nWhereas nebulised saline given in single doses can help airways\nclearance in the presence of thick secretions, there is no\nevidence to support the use of continuous humidi\ufb01cation and\nthe effect on patient comfort is negligible.147 148\nSome studies\nconclude the risks of infection contraindicate its use.149 150\nFor\npatients with a tracheostomy tube, natural mechanisms to warm\nand moisturise inspired gases have been bypassed. It is therefore\nessential to humidify any supplemental oxygen being delivered\nto the tracheostomised patient to help maintain a patent trache-\nostomy tube, reduce the build-up of secretions within the inner\ntube or the tracheostomy itself, and minimise any subjective dis-\ncomfort that the patient may experience. However, there are no\ntrial data to evaluate this approach. More detail about the use of\noxygen in tracheostomy patients is given in the BTS emergency\noxygen guideline.2\nEvidence statement\n\u25b8 There is no evidence of patient bene\ufb01t from use of humidi-\n\ufb01ed oxygen. Evidence level 3\nRecommendation\n\u25b8 Humidi\ufb01cation of home oxygen should not be ordered for\nnon-tracheostomy patients. (Grade D)\nGood practice point\n\u25b8 Patients receiving oxygen via a tracheostomy should receive\nhumidi\ufb01ed oxygen. (\u221a)\nCarrying home oxygen: trolleys and backpacks\nPatients can bene\ufb01t from the provision of trolleys, wheeled carts\nor backpacks to enable them to carry home oxygen equipment.\nThis may be necessary because of the weight of the equipment\nwhen carried or to provide greater convenience. Less able\npatients \ufb01nd trolleys and wheeled carts easier to use than back-\npacks.149 150\nStudies have shown that their use can improve\npatient quality of life, distance walked and symptoms during\nexercise in patients who are habitually mobile.\nEvidence statement\n\u25b8 Trolleys or wheeled devices to enable patients to carry home\noxygen can improve patient quality of life, distance walked\nand symptoms during exercise in patients who can walk\nmore than 300 m. Evidence level 1+\nRecommendation\n\u25b8 Less able patients should be offered wheeled devices or back-\npacks if assessment shows they improve ambulation and\nquality of life. (Grade B)\nGood practice point\n\u25b8 When being transported in cars, cylinders should be secured\neither with a seat belt, or in the foot-well or car boot, possibly\nusing a cylinder box. Liquid oxygen should always be trans-\nported in an upright position. A warning triangle may be dis-\nplayed and insurance companies should be informed. (\u221a)\nSAFETY AND HOME OXYGEN THERAPY\nSmoking and home oxygen therapy\nThere is increasing recognition of the signi\ufb01cant risks of \ufb01re and\npersonal injury associated with smoking and the use of home\noxygen therapy. LTOT patients can be enabled to achieve smoking\ncessation,52\nbut despite these necessary interventions, many\npatients with respiratory disease, and especially COPD, continue\nto smoke. In addition, the clinician\u2019s assessment of smoking status\nrelies mainly on patients\u2019 testimony and evidence has shown that\nthis can be inaccurate.61\nThere have been no high quality trials to\nenable an objective assessment of the risks and bene\ufb01ts of the use\nof home oxygen in those who continue to smoke. However, there\nis emerging evidence from case reports of the risks of continued\nsmoking and oxygen use. A study in four American states from\n2000 to 2007 documented 38 fatalities associated with smoking\nand oxygen therapy, and 16 non-fatal injuries reported which\nincluded harm to two \ufb01re-\ufb01ghters and one policeman.151\nOf the\nfatalities, 34 (89%) were using LTOTand smoking at the time the\n\ufb01re began, three were household members of smokers receiving\nLTOT, and one was a non-smoker with LTOT who was uninten-\ntionally ignited by a family member who was smoking. Two retro-\nspective case series of patients admitted to burns units reported\nHardinge M, et al. Thorax 2015;70:i1\u2013i43. doi:10.1136\/thoraxjnl-2015-206865 i25\nBTS Guidelines\ngroup.bmj.com\non June 19, 2016 - Published by\nhttp:\/\/thorax.bmj.com\/\nDownloaded from\nharm caused by smoking while using home oxygen.152 153\nOf 27\npatients over a 7-year period who were identi\ufb01ed with burns dir-\nectly attributed to home oxygen use, 24 were smoking while using\noxygen, two were lighting pilot lights, and one was lighting his\nwife\u2019s cigarette.152\nOf 21 patients in a 12-year period who experi-\nenced partial thickness burn injuries, 57% sustained inhalation\ninjury, \ufb01ve (22%) required intubation and mechanical ventilation,\nand two died during hospitalisation.153\nIn addition, 86 home\noxygen-related burn injuries were documented in a retrospective\nstudy designed to compare the outcome characteristics of patients\nadmitted to a burns unit who had been intubated compared with\nthose who had not been intubated.154\nLighting a cigarette was the\ncause of the majority of injuries (87%), while exposure to other\nnaked \ufb02ame sources accounted for others (lighting a cooker 5%,\nelectrical spark 5%, candles 2%, and other open \ufb02ames 1%).\nThere are an increasing number of anecdotal reports of e-cigarettes\nand chargers causing \ufb01re-related incidents if used in the vicinity of\nhome oxygen.\nNo studies were identi\ufb01ed that examined improvements in\nsafety if smoking status in home oxygen patients was monitored\neither by urinary cotinine measurements or CO (carbon monox-\nide) monitoring compared to no monitoring.\nRole of risk assessments\nRecognition of the danger of \ufb01re and personal injury caused by\nsmoking and home oxygen use has led to pragmatic approaches\nto individual assessment of risks on a case-by-case basis. A risk\nassessment may be conducted by the home oxygen assessment\nservice and the \ufb01re and rescue service according to local proto-\ncols. Home oxygen suppliers carry out a formal risk assessment\ntwice under the current UK National Framework Agreement:\nonce at the time of taking the order and a \ufb01eld-based assessment\nat the patient\u2019s location when the order is delivered. Further\nrisk assessment should then take place every 6 months there-\nafter. See appendix 4 for examples of risk assessment tools.\nSome home oxygen services have adopted the practice of\nasking patients to sign a disclaimer acknowledging the risks of\nbehaviours such as smoking near home oxygen.\nResponsibilities of the oxygen supplier\nCertain responsibilities around risk assessment are outlined in\nthe National Framework Agreement for home oxygen services\n(December 2000, transitioned to NHS England 2013), which\noutlines the contractual obligations of home oxygen supply\ncompanies in England and Wales. In Scotland, a national home\noxygen service was established by Health Facilities Scotland in\n2012, and the single contracted supplier is also obliged to carry\nout a similar risk assessment prior to oxygen installation.\nThese risk assessment obligations for home oxygen suppliers\nin England are:\n\u25b8 A desk risk assessment should be conducted upon receipt of\na home oxygen order to ensure that the oxygen equipment\nordered matches the requirements and the equipment can be\ndelivered safely.\n\u25b8 The supplier shall ensure that a \ufb01eld-based risk assessment is\ncarried out at the time of installation to verify whether the\nrequirement of the home oxygen order form (HOOF) can be\nsupplied safely and in accordance with the requirements. See\nappendix 5 for details of HOOF forms.\n\u25b8 A \ufb01eld-based risk assessment must be conducted in each\npatient\u2019s primary and\/or secondary location every 6 months\nafter the initial \ufb01eld-based risk assessment to ensure that risk\nis monitored on an ongoing basis. The supplier shall \ufb01le a\ncopy of such \ufb01eld-based risk assessment and provide it to the\nclinical commissioning group home oxygen service lead\nwhere risk has been identi\ufb01ed\n\u25b8 The \ufb01eld-based risk assessment will identify potential \ufb01re-\nrelated risk in the patient\u2019s home. During this assessment,\nthe supplier shall check for the presence of an operational\nsmoke detector or alarm. In the event that a smoke detector\nor \ufb01re alarm is not present, the supplier shall inform the\nlocal \ufb01re authorities of this fact, together with any speci\ufb01c\n\ufb01re risks that have been identi\ufb01ed.\n\u25b8 The concentrator and any cylinders are positioned with suf\ufb01-\ncient ventilation and at a safe distance from any naked \ufb02ame,\ncooking or heating appliance.\n\u25b8 Oxygen equipment should be placed in a position where it\nwill not cause an obstruction to patients or family members,\nespecially those who may have mobility or sight impairment.\n\u25b8 A \ufb01xed installation should be considered to \ufb01x tubing and\nreduce trip hazard.\n\u25b8 A second concentrator may be necessary in larger properties\nor if patients have dif\ufb01culty using the stairs.\n\u25b8 Verbal and written information should be given to the patient\nor carer regarding the use of the equipment provided.\n\u25b8 The engineer should be satis\ufb01ed that the patient can use the\nprovided oxygen equipment safely.\n\u25b8 The oxygen concentrator must be checked regularly to ensure\nthe \ufb01lters are cleaned, the \ufb02ow metres are accurate, and the\nconcentrator delivers oxygen at the correct concentration.\n\u25b8 The oxygen contractor should inform the assessment service\nof any safety issues concerning the patient and the oxygen\nequipment and its use.\n\u25b8 The data collected by the oxygen contractor related to safety\nsuch as \ufb01re and accidents as a result of oxygen equipment\nand its use in the home, should be made available to oxygen\nassessment services.\nRole of the \ufb01re and rescue service\nAlthough this is not mandatory for the \ufb01re and rescue service, a\ncommunity \ufb01re safety of\ufb01cer may visit to discuss \ufb01re safety,\nsmoke alarms and safe exit routes in the event of a \ufb01re.\nTrips and falls\nPatients with home oxygen often have mobility or sight impair-\nment, and equipment and tubing can jeopardise safety. No\nstudies were found that examined the number of accidents that\noccurred as the result of home oxygen equipment or tubing.\nEvidence statements\n\u25b8 Serious burns, inhalation injury or death can be caused by\nusing oxygen while smoking or using oxygen near a naked\n\ufb02ame. Evidence level 3\n\u25b8 Patients who are educated regarding the dangers of smoking\nand using oxygen are more likely to quit smoking. Evidence\nlevel 2+\nRecommendations\n\u25b8 Smoking cessation should be discussed and written education\ngiven to all patients prior to ordering home oxygen and at\neach subsequent review if the patient continues to smoke.\n(Grade C)\n\u25b8 Patients should be made aware in writing of the dangers of\nusing home oxygen within the vicinity of any naked\n\ufb02ame such as pilot lights, cookers, gas \ufb01res and candles.\n(Grade D)\n\u25b8 Patients and family members who continue to smoke in the\npresence of home oxygen should be warned of the associated\ndangers of smoking in the presence of oxygen. (Grade D)\ni26 Hardinge M, et al. Thorax 2015;70:i1\u2013i43. doi:10.1136\/thoraxjnl-2015-206865\nBTS Guidelines\ngroup.bmj.com\non June 19, 2016 - Published by\nhttp:\/\/thorax.bmj.com\/\nDownloaded from\nGood practice points\n\u25b8 Safety should be a factor when making decisions regarding\nordering home oxygen. Education and written information\nshould be provided to the patient and their family or carers\nregarding the safe use of oxygen and its equipment. (\u221a)\n\u25b8 The risks of prescribing oxygen to active smokers should be\nconsidered on a case-by-case basis: this should include a\nhome visit to assess the patient\u2019s home situation, attitude\ntoward risks and smoking behaviour. Home oxygen assess-\nment services may decide not to prescribe home oxygen to\nsmokers if the risks are in their judgement too high.\nParticular consideration needs to be given to risks to children\nand risks to neighbours in multiple occupancy dwellings.\nA risk assessment tool should be used, and the health profes-\nsional who is undertaking the risk assessment may need to\nvisit the home in conjunction with the local \ufb01re service\nand\/or the oxygen contractor. Where there is reasonable\ndoubt, the therapy should not be prescribed. (\u221a)\n\u25b8 Patients who continue to smoke or live with other household\nsmokers should be informed that the order for home oxygen\nwill be reviewed and evidence of increased risk may lead to\nwithdrawal of home oxygen therapy. (\u221a)\n\u25b8 Carbon monoxide monitoring and measuring urine cotinine\nmay help identify those patients who continue to smoke. (\u221a)\n\u25b8 Patients should be made aware that they should not use\ne-cigarettes and chargers within the vicinity of their home\noxygen. (\u221a)\n\u25b8 Oil-based emollients and petroleum jelly can support com-\nbustion in the presence of oxygen. Patients should be made\naware that only water-based products should be used on the\nhands and face or inside the nose while using oxygen. (\u221a)\n\u25b8 The oxygen supplier should be informed if the patient con-\ntinues to smoke in order for the engineer to consider it in\nthe home oxygen supplier risk assessment. (\u221a)\n\u25b8 Patients and family or carers should be instructed not to\nremove the \ufb01re breaks or to change the \ufb02ow rate on their\noxygen equipment. Only oxygen tubing and connections\nsupplied by the oxygen company should be used. (\u221a)\n\u25b8 The local \ufb01re service should be made aware of patients who\nare using oxygen at home and especially those who continue\nto smoke in order for a home safety assessment to be carried\nout. (\u221a)\n\u25b8 Patients and carers should be aware that tubing should be\nchecked on a regular basis and repositioned as necessary to\nensure safety by preventing trips and falls. (\u221a)\nCONCLUSION\nThis guideline has reviewed the indications for the ordering\nand provision of home oxygen. It has con\ufb01rmed which patients\nwill bene\ufb01t from LTOT, how they should be assessed and mon-\nitored, focusing on dif\ufb01cult clinical situations such as hospital\ndischarge and management of hypercapnia. It has outlined\nrecommended \ufb02ow rates and duration of use, along with a\nreview of all modalities of equipment used to deliver home\noxygen. It has given recommendations for use of NOT in\npatients with advanced cardiac disease who are symptomatic\nfrom SDB and for use of SBOT in acute CH alone. It has\nrecommended use of AOT is limited to patients with evidence\nof improvement of exercise tolerance when using AOT as part\nof a pulmonary rehabilitation programme. Finally, it has con-\nsidered in detail the safety aspects of home oxygen delivery,\nparticularly in the challenging area of risk assessment in con-\ntinuing smokers.\nAuthor af\ufb01liations\n1\nOxford Centre of Respiratory Medicine, Oxford University Hospitals NHS Trust,\nOxford, UK\n2\nHywel Dda University Health Board, Prince Philip Hospital, Llanelli, UK\n3\nPortsmouth NHS Trust, Portsmouth, UK\n4\nLung Function and Sleep, Queen Elizabeth Hospital Birmingham, Birmingham, UK\n5\nStaffordshire and Stoke-on-Trent Partnership Trust, Staffordshire, UK\n6\nMundesley Medical Centre, Mundesley, UK\n7\nImprovement Academy (Y&H AHSN) Bradford Teaching Hospitals NHS FT,\nWake\ufb01eld, UK\n8\nRoyal Brompton Hospital, London, UK\n9\nRespiratory Care Team, Virgin Care, Surrey, UK\n10\nUniversity of Edinburgh, Edinburgh, UK\n11\nDepartment of Physiotherapy, Guy\u2019s and St Thomas\u2019 NHS Foundation Trust, St\nThomas\u2019 Hospital, London, UK\n12\nAintree University Hospital, Liverpool, UK\n13\nRespiratory Department, Royal United Hospital, Bath, UK\n14\nNorthern General Hospital, Shef\ufb01eld, UK\n15\nClinical and Experimental Medicine, Faculty of Medicine, University of\nSouthampton, Southampton, UK\nContributors MH, as chair of the guideline development group oversaw the\ndevelopment of the guideline, adhering to British Thoracic Society guideline\nmethodology, and is responsible for the \ufb01nal guideline document. JA, SB, BC, AE,\nDF, AG, SH, VK, WM, LM, KP, JS, VV, TW, all members of the British Thoracic\nSociety Home Oxygen Guideline Development Group, were responsible for\ndevelopment of the scope of the guideline, review of evidence, drafting text and\nrecommendations.\nCompeting interests All guideline group members completed the BTS declaration\nof interest form in line with BTS policy, and copies of all declarations are available\non the BTS website or on request from BTS Head Of\ufb01ce.\nProvenance and peer review Not commissioned; internally peer reviewed.\nREFERENCES\n1 Balfour-Lynn IM, Field DJ, Gringras P, et al. BTS guidelines for home oxygen in\nchildren. Thorax 2009;64(Suppl 2):ii1\u201326.\n2 O\u2019Driscoll BR, Howard LS, Davison AG, et al. BTS guideline for emergency oxygen\nuse in adult patients. Thorax 2008;63(Suppl 6):vi1\u201368.\n3 Ahmedzai S, Balfour-Lynn IM, Bewick T, et al. 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A crossover study of short burst oxygen\ntherapy (SBOT) for the relief of exercise-induced breathlessness in severe COPD.\nBMC Pulm Med 2011;11:23.\n115 Evans TW, Waterhouse JC, Carter A, et al. Short burst oxygen treatment for\nbreathlessness in chronic obstructive airways disease. Thorax 1986;41:611\u201315.\n116 Stevenson NJ, Calverley PM. Effect of oxygen on recovery from maximal\nexercise in patients with chronic obstructive pulmonary disease. Thorax\n2004;59:668\u201372.\n117 Eaton T, Fergusson W, Kolbe J, et al. Short-burst oxygen therapy for COPD\npatients: a 6-month randomised, controlled study. Eur Respir J 2006;27:697\u2013704.\n118 Cohen AS, Burns B, Goadsby PJ. High-\ufb02ow oxygen for treatment of cluster\nheadache: a randomized trial. JAMA 2009;302:2451\u20137.\n119 Kudrow L. Response of cluster headache attacks to oxygen inhalation. Headache\n1981;21:1\u20134.\n120 Fogan L. Treatment of cluster headache. A double-blind comparison of oxygen v\nair inhalation. Arch Neurol 1985;42:362\u20133.\n121 Rozen TD. High oxygen \ufb02ow rates for cluster headache. Neurology 2004;63:593.\n122 Backx APM, Haane DYP, De Ceuster L, et al. Cluster headache and oxygen: is it\npossible to predict which patients will be relieved? A retrospective cross-sectional\ncorrelation study. J Neurol 2010;257:1533\u201342.\n123 NICE. NICE Guideline for the diagnosis and management of headaches in young\npeople and adults. NICE, 2012.\n124 Johns DP, Rochford PD, Streeton JA. Evaluation of six oxygen concentrators.\nThorax 1985;40:806\u201310.\n125 Hall LW, Kellagher RE, Fleet KJ. A portable oxygen generator. Anaesthesia\n1986;41:516\u201318.\n126 Gould GA, Scott W, Hayhurst MD, et al. Technical and clinical assessment of\noxygen concentrators. Thorax 1985;40:811\u201316.\n127 [No authors listed]. Home controls of a sample of 2,414 oxygen concentrators.\nSous-Commission Technique ANTADIR. Eur Respir J 1991;4:227\u201331.\n128 Burioka N, Takano K, Hoshino E, et al. Clinical utility of a newly developed\npressure swing adsorption-type oxygen concentrator with a membrane humidi\ufb01er.\nRespiration 1997;64:268\u201372.\n129 Burioka N, Takano K, Suyama H, et al. Ef\ufb01cacy of newly developed pressure swing\nadsorption type oxygen concentrator with membrane humidi\ufb01er: comparison with\nconventional oxygen concentrator with bubble water humidi\ufb01er. Intern Med\n1997;36:861\u20134.\n130 Pesce LI, Bassi GN, Santovito A. Clinical usefulness of a new portable oxygen\nconcentrator. Monaldi Arch Chest Dis 1994;49:444\u20136.\n131 Shiner RJ, Zaretsky U, Mirali M, et al. Evaluation of domiciliary long-term oxygen\ntherapy with oxygen concentrators. Isr J Med Sci 1997;33:23\u20139.\n132 Jackson M, Shneerson J. An evaluation of the use of concentrators for domiciliary\noxygen supply for less than 8 h day-1. Respir Med 1998;92:250\u20135.\n133 Cuvelier A, Nuir JF, Chakroun N, et al. Re\ufb01llable oxygen cylinders may be an\nalternative for ambulatory oxygen therapy in COPD. Chest 2002;122:451\u20136.\n134 Strickland SL, Hogan TM, Hogan RG, et al. A randomized multi-arm\nrepeated-measures prospective study of several modalities of portable oxygen\nHardinge M, et al. Thorax 2015;70:i1\u2013i43. doi:10.1136\/thoraxjnl-2015-206865 i29\nBTS Guidelines\ngroup.bmj.com\non June 19, 2016 - Published by\nhttp:\/\/thorax.bmj.com\/\nDownloaded from\ndelivery during assessment of functional exercise capacity. Respir Care\n2009;54:344\u20139.\n135 Lock SH, Blower G, Prynne M, et al. Comparison of liquid and gaseous oxygen for\ndomiciliary portable use. Thorax 1992;47:98\u2013100.\n136 Nasilowski J, Przybylowski T, Zielinski J, et al. Comparing supplementary oxygen\nbene\ufb01ts from a portable oxygen concentrator and a liquid oxygen portable device\nduring a walk test in COPD patients on long-term oxygen therapy. Respir Med\n2008;102:1021\u20135.\n137 Andersson A, Str\u00f6m K, Brodin H, et al. Domiciliary liquid oxygen versus\nconcentrator treatment in chronic hypoxaemia: a cost-utility analysis. Eur Respir J\n1998;12:1284\u20139.\n138 Katsenos S, Charisis A, Daskalopoulos G, et al. Long-term oxygen therapy in\nchronic obstructive pulmonary disease: the use of concentrators and liquid oxygen\nsystems in north-western Greece. Respiration 2006;73:777\u201382.\n139 Czajkowska-Malinowska M, Poltyn B, Ciesielska A, et al. Comparison of the\nresults of long term oxygen therapy in patients treated sequentially using\nstationary or a portable source of oxygen. Pneumonol Alergol Pol\n2012;80:308\u201316.\n140 Okubadejo AA, Paul EA, Wedzicha JA. Domiciliary oxygen cylinders: indications,\nprescription and usage. Respir Med 1994;88:777\u201385.\n141 Bazuaye EA, Stone TN, Corris PA, et al. Variability of inspired oxygen\nconcentration with nasal cannulas. Thorax 1992;47:609\u201311.\n142 Paul J, Otvos T. Comparison of nasal cannulas and the OxyArm in patients\nrequiring chronic domiciliary oxygen therapy. Can Respir J 2006;13:421\u20136.\n143 Domingo C, Roig J, Coll R, et al. Evaluation of the use of three different devices\nfor nocturnal oxygen therapy in COPD patients. Respiration 1996;63:230\u20135.\n144 Moore-Gillon JC, George RJ, Geddes DM. An oxygen conserving nasal cannula.\nThorax 1985;40:817\u201319.\n145 Roberts CM, Bell J, Wedzicha JA. Comparison of the ef\ufb01cacy of a demand oxygen\ndelivery system with continuous low \ufb02ow oxygen in subjects with stable COPD and\nsevere oxygen desaturation on walking. Thorax 1996;51:831\u20134.\n146 Braun SR, Spratt G, Scott GC, et al. Comparison of six oxygen delivery systems for\nCOPD patients at rest and during exercise. Chest 1992;102:694\u20138.\n147 Marti S, Pajares V, Morante F, et al. Are oxygen-conserving devices effective for\ncorrecting exercise hypoxemia? Respir Care 2013;58:1606\u201313.\n148 Chatburn RL, Lewarski JS, McCoy RW. Nocturnal oxygenation using a pulsed-dose\noxygen-conserving device compared to continuous \ufb02ow. Respir Care\n2006;51:252\u20136.\n149 Leggett RJ, Flenley DC. Portable oxygen and exercise tolerance in patients with\nchronic hypoxic cor pulmonale. BMJ 1977;2:84\u20136.\n150 Crisafulli E, Costi S, De BF, et al. Effects of a walking aid in COPD patients\nreceiving oxygen therapy. Chest 2007;131:1068\u201374.\n151 Centers for Disease Control and Prevention. Fatal \ufb01res associated with smoking\nduring long-term oxygen therapy\u2014Maine, Massachusetts, New Hampshire, and\nOklahoma, 2000\u20132007. MMWR Morb Mortal Wkly Rep 2008;57:852\u20134.\n152 Robb BW, Hungness ES, Hershko DD, et al. Home oxygen therapy: adjunct or risk\nfactor? Burn Care Rehabil 2003;24:403\u20136; discussion 02.\n153 Chang TT, Lipinski CA, Sherman HF. A hazard of home oxygen therapy. Burn Care\nRehabil 2001;22:71\u20134; discussion 70\u20131.\n154 Amani H, Lozano DD, Blome-Eberwein S. Brother, have you got a light? Assessing\nthe need for intubation in patients sustaining burn injury secondary to home\noxygen therapy. J Burn Care Res 2012;33:e280\u20135.\ni30 Hardinge M, et al. Thorax 2015;70:i1\u2013i43. doi:10.1136\/thoraxjnl-2015-206865\nBTS Guidelines\ngroup.bmj.com\non June 19, 2016 - Published by\nhttp:\/\/thorax.bmj.com\/\nDownloaded from\nAPPENDIX 1: PROTOCOL FOR AMBULATORY OXYGEN THERAPY ASSESSMENT\nAIMS OF ASSESSMENT FOR EACH PATIENT\n(1) To determine if there is desaturation on exercise, de\ufb01ned as a drop in SpO2 of \u22654% to<90%\n(2) To determine the most appropriate device and setting to correct exercise desaturation\nCONSIDERATIONS\n\u2022 This protocol is designed to be generic and can be adapted for any valid and repeatable walking test.\n\u2022 A 6 Minute Walking Test (6MWT) should be performed over a 30m course (cones 29m apart), but it is recognised that due to a\nlack of space a modi\ufb01ed 10m-6MWT (cones 9m apart) may be used as an alternative (1, 2). Incremental and Endurance Shuttle\nWalking Tests (ESWT) are performed over a 10m course (cones 9m apart). There is some evidence to show that endurance tests,\nsuch as the ESWT, may be more sensitive than standard tests (3, 4).\n\u2022 Desaturation during baseline endurance shuttle walking test (ESWT) has been found to predict required \ufb02ow rate (see annex 1).\nThis is unlikely to predict as robustly when desaturations produced during other walking tests are used but may give some\nguidance.\n\u2022 A practice walk test should be performed and without one the improvement in walking distance from air to oxygen is likely to be\noverestimated.\n\u2022 Local policy and individual patient capabilities will affect the maximum number of tests performed in one appointment. Two\nappointments may be required to titrate oxygen fully.\n\u2022 It is not possible to correct SpO2 in every patient to >90% using 6 litres per minute (lpm) oxygen or the maximum settings on\nother devices. In this situation discussion with patient and their consultant may help determine if a higher \ufb02ow rate may be suit-\nable. Portability and \/ or duration of use declines considerably above 6 lpm.\n\u2022 Authors have described a dose response to oxygen i.e. for each increase in \ufb02ow rate there is an increase in exercise performance\n(3). Those whose performance has not improved on oxygen should therefore be trialled on a higher \ufb02owrate \/ setting.\n\u2022 Carrying the cylinder \/ device negates the effect of the oxygen but wheeling it does not (5). Therefore patients must have AOT\n\ufb02ow rate \/ setting titrated while carrying \/ wheeling the oxygen device as they plan to use it in everyday life.\n\u2022 Different oxygen devices weigh different amounts and oxygen conservers vary in sensitivity and functionality which result in\ndevices responding differently to different patients (6). Patients must have the \ufb02ow \/ setting titrated on the device that they are to\nbe prescribed.\nEQUIPMENT REQUIRED\n\u2022 Long, \ufb02at, corridor at least 32m long (12m for modi\ufb01ed\n6MWT)\n\u2022 2 cones\n\u2022 2 chairs (placed beyond each cone)\n\u2022 Stopwatch\/CD & CD player\n\u2022 Ambulatory oxygen equipment (hired\/supplied\nby oxygen provider)\n\u2022 Nasal cannulae\n\u2022 Pulse oximeter\n\u2022 Modi\ufb01ed BORG breathlessness scale\n\u2022 Oxygen risk assessment\n\u2022 Patient information lea\ufb02ets\nPREPARATION\n\u2022 Explain the purpose of AO\n\u2022 Outline the AO assessment process\n\u2022 Gain informed consent for assessment\n\u2022 Con\ufb01rm indication for AO (including outdoor mobility)\n\u2022 Complete risk assessment\n\u2022 Ensure 20 mins rest before walking test (included in dis-\ncussion time)\n\u2022 Set up walking test circuit\n\u2022 Read \/ play test instructions\n\u2022 Ask if the patient has any questions\n\u2022 Perform practice test\n\u2022 Ensure further 20 mins rest before retest\nDEMONSTRATING A POSITIVE IMPROVEMENT WITH AO\n2 out of 3 of the markers below are required to show that the patient bene\ufb01ts from AO.\n\u2022 SpO2s \u226590% throughout\n\u2022 \u2265 10% increase in walking distance from baseline (7)\n\u2022 Improvement in BORG of at least 1 point from baseline (8)\nFOLLOW-UP\n8 week review:\nCheck patient\u2019s concordance with the oxygen order (call the oxygen delivery company to determine their usage) and compare this\nwith the patient\u2019s diary card when they attend. Discuss any discrepancies or issues highlighted.\nTroubleshoot any device issues. Review device and oxygen order as required.\nAnnual review:\nReassess using current prescription and adjust \ufb02ow rate and device as required.\nHardinge M, et al. Thorax 2015;70:i1\u2013i43. doi:10.1136\/thoraxjnl-2015-206865 i31\nBTS Guidelines\ngroup.bmj.com\non June 19, 2016 - Published by\nhttp:\/\/thorax.bmj.com\/\nDownloaded from\ni32 Hardinge M, et al. Thorax 2015;70:i1\u2013i43. doi:10.1136\/thoraxjnl-2015-206865\nBTS Guidelines\ngroup.bmj.com\non June 19, 2016 - Published by\nhttp:\/\/thorax.bmj.com\/\nDownloaded from\nANNEX 1\nSuggested AO \ufb02ow rates according to baseline ESWT desaturations (9):\nOxygen saturation range (%) Suggested AO flow rate (l\/min)\n86-89 3\n80-85 4\n74-79 5\n73 or below 6\nReferences\n(1) Beekman E, Mesters I, Gosselink R, Klaassen MPM, Hendriks EJM, Van Schayck OCP\n, De Bie RA. The \ufb01rst reference equations\nfor the 6-minute walking distance over a 10 metre course. Thorax 2014. http:\/\/thorax.bmj.com\/content\/early\/2014\/04\/23\/\nthoraxjnl-2014-205228\n(2) Crapo RO, Casaburi R, Coates AL, et al (2002) American Thoracic Society Statement \u2013 Guidelines for the six-minute walk test.\nAmerican Journal of Respiratory and Critical Care Medicine. 166 p 111\u2013117. http:\/ajrccm.atsjournals.org\/cgi\/content\/full\/166\/1\/\n111 [accessed 02\/07\/2007]\n(3) Davidson AC, Leach R, George RJD, Geddes DM. 1988. Supplemental oxygen and exercise ability in chronic obstructive airways\ndisease. Thorax, 43: 965\u2013971.\n(4) Ambulatory oxygen therapy assessment: a comparative study of incremental shuttle and 6-minute walking tests A. Lewko,\nJ. Marshall, R. Garrod Physiotherapy \u2013 December 2007 (Vol. 93, Issue 4, Pages 261-266, DOI: 10.1016\/j.\nphysio.2007.03.002).\n(5) Leggett RJE, Flenley DC. 1977. Portable oxygen and exercise tolerance in patients with chronic hypoxic cor pulmonale. British\nMedical Journal, ii: 84\u201386.\n(6) Bliss PL, McCoy RW\n, Adams AB. 1999. A bench Study Comparison of Demand Oxygen Delivery Systems and Continuous Flow\nOxygen. Respiratory Care, 44 (8): 925\u2013931.\n(7) Dyer F, Callaghan J, Cheema K, Bott J. Ambulatory oxygen improves the effectiveness of pulmonary rehabilitation in selected\npatients with chronic obstructive pulmonary disease. Chronic Respiratory Disease 2012;9:83\u201391\n(8) Ries AL. Minimally Clinically Important Difference for the UCSD Shortness of Breath Questionnaire, Borg Scale, and Visual\nAnalog Scale. Journal of Chronic Obstructive Pulmonary Disease 2005; 2 (1) 105\u2013110.\n(9) Cornish L, Dyer F, Cheema K, Bott J. Is it possible to predict ambulatory oxygen (AO) requirements? Thorax 2013;68:Suppl 3\nA92 doi:10.1136\/thoraxjnl-2013-204457.188\nHardinge M, et al. Thorax 2015;70:i1\u2013i43. doi:10.1136\/thoraxjnl-2015-206865 i33\nBTS Guidelines\ngroup.bmj.com\non June 19, 2016 - Published by\nhttp:\/\/thorax.bmj.com\/\nDownloaded from\nAPPENDIX 2: ASSESSMENT REFERRAL FORM\ni34 Hardinge M, et al. Thorax 2015;70:i1\u2013i43. doi:10.1136\/thoraxjnl-2015-206865\nBTS Guidelines\ngroup.bmj.com\non June 19, 2016 - Published by\nhttp:\/\/thorax.bmj.com\/\nDownloaded from\nAPPENDIX 3: ASSESSMENT PROTOCOL FOR PALLIATIVE OXYGEN\nThere is no consensus for the correct clinical assessment strategy for the use of oxygen in palliative care, although multiple\ntools exist for assessing dyspnoea. This assessment protocol is suggested best practice by the guideline group and applies to\npatients with cancer or end stage cardio-respiratory disease who are experiencing intractable breathlessness, who are hypoxae-\nmic with resting SpO2<92% or who are normoxaemic but in whom all other approaches have been exhausted. The Numerical\nRating Scale score is recommended as this approach was used in evidence sited. First ensure patient is on maximum treatment\nfor underlying diseases where possible and reversible causes for breathlessness have been or are being treated optimally.\n\u2022 As distress from breathlessness can be multi-dimensional, ensure psycho-social factors have been assessed and addressed.\n\u2022 Trial of non-pharmacological measures including teaching of breathing relaxation and life modifying strategies by involving physio\nand occupational therapists.\n\u2022 Trial of hand held fan before consideration of oxygen therapy.\n\u2022 Assess response to opioids if they have been tried.\n\u2022 Check SpO2 using pulse oximetry at rest and\/ or after exertion.\nThe subjective severity and intensity of breathlessness should therefore be recorded regularly to evaluate the degree of suffering\ncaused and the effect of treatment. A numerical rating scale (NRS) from 0 to 10 has been found useful for this purpose (0=no short-\nness of breath, 10=worst shortness of breath imaginable). Treatment should focus on patients with dyspnoea scores (NRS) of \u22654,\nand especially those with scores \u22657. Recurrent assessment with standardized scales is prudent, especially when using an N-of-1\napproach, as it is dif\ufb01cult to predict which patients will bene\ufb01t (1).\nPRESCRIPTION\nAs distress from breathlessness is not correlated to degree of hypoxemia, the \ufb02ow rates for symptom relief in the studies identi\ufb01ed\nrange from 2\u20135 litres\/min. It is suggested therefore that oxygen \ufb02ow rates be determined by symptom score on an individual basis\nrather than SpO2 reading. Additional consideration needs to be given to potential risks of hypercapnia if oxygen is given at higher\n\ufb02ow rates.\nEQUIPMENT\nConcentrator or cylinder as determined by patient\u2019s needs.\nFOLLOW UP\nOxygen therapy like any pharmacological intervention should be best considered on trial basis and be reviewed regularly while balan-\ncing between bene\ufb01ts and risks.\nMost bene\ufb01t is likely to occur in the \ufb01rst 24 hours, and nearly all symptomatic and functional improvements within the \ufb01rst 3 days\nof use (1). Follow-up and assessment of response should \ufb01t with these timescales.\n1. Nonoyama ML, Brooks D, Guyatt GH, et al. Effect of oxygen on health quality of life in patients with chronic obstructive\npulmonary disease with transient exertional hypoxemia. Am J Respir Crit Care Med 2007;176(4):343\u20139\nHardinge M, et al. Thorax 2015;70:i1\u2013i43. doi:10.1136\/thoraxjnl-2015-206865 i35\nBTS Guidelines\ngroup.bmj.com\non June 19, 2016 - Published by\nhttp:\/\/thorax.bmj.com\/\nDownloaded from\nAPPENDIX 4: RISK ASSESSMENT TOOLS*\n*The risk assessment templates provided have not been validated.\nFIELD BASED RISK ASSESSMENT REPORT TEMPLATE AS USED BY HOME OXYEN PROVIDER COMPANY\nWritten con\ufb01rmation that the risk assessment has been conducted at the Patient\u2019s home at the due date and report of the \ufb01ndings\nof the assessment shall include, but not necessarily be limited to, the following information:-\nPatient Name Patient Number\nPatient Address Job Type\nPotential Risks YES NO Comments \/ Observations\nInitial Desk Based Assessment Completed\nProperty Access\nSuitable parking, good surface condition and safe access to property\nSuitable access using path\/stairs (not too steep or narrow)\nIs a Lift\/Escalator available?\nPatient \/ Carer\nAre there any language barriers, does the Patient\/carer understand the safety demonstration?\nDoes the Patient\/carer understand and are they able to operate the Equipment provided?\nDoes Patient \/ Carer smoke or is there evidence of smoking in the Patient\u2019s residence?\nIs any other Equipment used in combination with the oxygen therapy Equipment?\nIs the Patient able to replace the filter autonomously?\nOxygen Equipment usage and storage\nIs Equipment used \/ stored in Workshop, Garage or Kitchen?\nIs Equipment used \/ stored within 3m of open flame 1.5m of electrical appliance, flammable material,\nPaint, oils or grease?\nIs usage \/ storage area safe, suitable, clean and adequately ventilated in relation to the Patients safety\nand the safety of other people that have authorised access to the location?\nIs usage\/storage etc adequate where there is more than one Patient using Oxygen e.g. care homes\nCan Equipment be located to allow a maximum of 15m free line without causing obstructions\/hazards\nwhen in use?\nIf delivery is made in the absence of Patient\/carer, has suitable, safe, secure storage been agreed?\nConcentrator installations \u2013 Has mains outlet socket passed safety test?\nDoes the Patient need to use stairs in the property\nCan the Patient safely climb stairs whilst using oxygen?\nIs there a working smoke detector or alarm in the home?\nIs the Patient using a pre\u2013paid electricity meter?\nDoes the crush resistant tubing need to be replaced?\nOxygen concentration Testing\nFilters checking and cleaning\nLocation where Equipment to be installed\nElectricity meter reading as at installation date\nAssessors Other Comments \/ Concerns \/ Other Potential Risks\nAssessor\u2019s Name (Print)\nAssessor Signature Date\ni36 Hardinge M, et al. Thorax 2015;70:i1\u2013i43. doi:10.1136\/thoraxjnl-2015-206865\nBTS Guidelines\ngroup.bmj.com\non June 19, 2016 - Published by\nhttp:\/\/thorax.bmj.com\/\nDownloaded from\nRisk Assessment Form (Wirral NHS Home Oxygen assessment service)*\nLocation\/Activity: Oxygen Therapy Assessment date:\nPatient\u2019s Full Name: Date of birth: NHS N\u00b0\nAssessor: Signature: Review date:\nRisk Description\/Source\nIF THE PATIENT HAS AN AIR FLOW PRESSURE RELIEVING MATTRESS YOU MUST DISCUSS THE POTENTIAL RISKS AND DOCUMENT IT\nRef Hazards Risks People at risk Current Control Measures L x C=R\nIs further action\nrequired (Y\/N)\n1. Smoking Fire\nFacial burns\nCommunity Nursing Staff\nPatients and carers\nPatients\n(1) Instruct patients, carers and visitors not to smoke in any\npart of the house where oxygen is used\n(2) Patient\/carer to sign \u201csmoking and oxygen\u201d advice form\n(3) Arrange for removal of any oxygen equipment not in\nregular use\n(4) Fire breaks never to be removed from tubing supplied by\noxygen provider\n(5) Ensure smoke detectors are fitted and in working order\n2. Exposure to naked flames from open\/\ngas fires\/candles and cooking\nappliances.\nExplosion and fire Community Nursing Staff\nPatients and carers\n(1) Advise patient to maintain a safe distance from fires\nand naked flame appliances as instructed by oxygen\nprovider\n(2) Oxygen must be positioned and stored as directed by\noxygen provider\n3. Kinking or entrapment of tubing in\/\nunder furniture, doors, wheels\nRestriction of or no Oxygen supply Patient (1) Check there are no kinks in the tubing\n(2) Check that the tubing is not trapped between furniture\nor trapped e.g. under bed wheels\n(3) Only tubing supplied by the oxygen provider is to be\nused on cylinders and concentrators\n(4) Encourage piped oxygen if there is excessive tubing\n4. Alcohol hand rubs\/gels Combustion Community nursing staff\nPatients and carers\n(1) Ensure hands are adequately dried after the use of\nalcohol gels.\n5 Use of oil based emollients Local burning of affected area Patient (1) Instruct patients (or carers) not to use oil based\nemollients on patients nostrils\n6. Patient\/Carers not aware on how to\nobtain replacement cylinders\nRunning out of oxygen Patient (1) Ensure patient has information leaflet from company\nsupplying oxygen\n(2) Check patient\/carer has contact details on how to\nobtain\/replace oxygen cylinder.\nHardinge\nM,\net\nal.\nThorax\n2015;70:i1\u2013i43.\ndoi:10.1136\/thoraxjnl-2015-206865\ni37\nBTS\nGuidelines\ngroup.bmj.com\non\nJune\n19,\n2016\n-\nPublished\nby\nhttp:\/\/thorax.bmj.com\/\nDownloaded\nfrom\nRef Hazards Risks People at risk Current Control Measures L x C=R\nIs further action\nrequired (Y\/N)\n7. Tubing Trips and falls Community Nursing Staff\nPatients and carers\n(1) Advise patients and carers to check position of tubing\ndaily to minimise risks of falls\n(2) Advise patients and carers to check position of tubing,\nparticularly if patient using a walking frame etc\n(3) Current oxygen tubing must be of an appropriate length\nto meet the needs of the patient.\n8. Power supply cut off to concentrator No oxygen supply Patient (1) Check patient has a back up cylinder\n(2) Educate patient not to use back up cylinder unless there\nis power failure to concentrator\n9 Unauthorised adjustment of flow rate\non oxygen equipment\nWorsening respiratory failure in oxygen sensitive\npatients\nPatient (1) Educate patient on the reason for oxygen\n(2) Inform patient\/carer of the prescribed flow rate and\nhours of use\n(3) Ensure patient\/carer understands how to operate\nequipment safely\n(4) Inform patient\/carer on the importance of not adjusting\noxygen flow rate without seeking appropriate clinical\nadvice and assessment\n(5) Very oxygen sensitive patients will be issued with an\nalert card and appropriate oxygen mask and tubing for\nuse in ambulance transfers.\n10 Non compliance with assessment and\/\nor review process\nRisks will not be identified or managed. Oxygen\nprescription may not be appropriate for the\npatient\u2019s clinical need.\nPatient (1) All except terminally ill patients should be formally\nassessed prior to commencing oxygen therapy.\n(2) Patients will be recalled for review according to national\nguidance\n(3) Assessment and review will be undertaken at a mutually\nconvenient time and place.\n11 Non compliance with oxygen\nprescription\nHypoxia remains untreated Patient (1) Patients will be educated on when and how to use\noxygen at the time of prescribing.\n(2) Reason for oxygen will be discussed at each review.\n(3) Significant carers, family and other HP\u2019s involved with\nthe patient to be educated on why oxygen has been\nprescribed.\n\u25a1 Green Low Risk (04) Managed by COPD and oxygen service=Acceptable risk. Routine review\n\u25a1 Yellow\/Amber Moderate Risk (5\u201312) Managed by Senior Managers=Action required\n\u25a1 Red High to extreme Risk (15\u201325) Managed by Director Level=Serious risk requiring immediate action.\ni38\nHardinge\nM,\net\nal.\nThorax\n2015;70:i1\u2013i43.\ndoi:10.1136\/thoraxjnl-2015-206865\nBTS\nGuidelines\ngroup.bmj.com\non\nJune\n19,\n2016\n-\nPublished\nby\nhttp:\/\/thorax.bmj.com\/\nDownloaded\nfrom\nRISK SCORING MATRIX\nLikelihood\nConsequence\nInsignificant 1 Minor 2 Moderate 3 Major 4 Catastrophic 5\nCertain 5 5 10 15 20 25\nLikely 4 4 8 12 16 20\nPossible 3 3 6 9 12 15\nUnlikely 2 2 4 6 8 10\nRare 1 1 2 3 4 5\nPRIORITY AND ACTION\nESCALATION PATHWAY\nLow risk \u2013 Green (0\u20134)\nContinue usual control measures, reinforce education, update documentation, see at next planned review.\nIncident form to be completed if the patient sustains injury or harm related to oxygen. Copy for WUTH and PCT\nMedium risk \u2013 Yellow (5\u201312)\nEnsure all current safety control measures are in place including \ufb01re service involvement\nImplement and reinforce control measures\nInform patient\u2019s GP and community nursing team\/matron if appropriate.\nNotify locality MDT for discussion and review\nInvolve carers\/next of kin in discussion of safety issues\nReview risk after 4 weeks\nIncident form to be completed if the patient sustains injury or harm related to oxygen. Copy for WUTH and PCT\nHigh risk \u2013 Red (15\u201325)\nEnsure all current safety control measures are in place including \ufb01re service involvement\nUrgent discussion with patient\u2019s GP\nUrgent discussion with community nursing team\/matron if appropriate\nInform next of kin, carers of the seriousness of the situation\nArrange for removal of oxygen and admission to hospital if removal of oxygen is likely to result in severe hypoxia\nIncident form to be completed if oxygen removed or the patient sustains injury or harm related to oxygen. Copy for WUTH\nand PCT.\nRisk\nColour\nRisk\nrating\nRisk\nlevel Identifier Action required\nGREEN 0-4 Low Control measures in place or risk of harm is\ninsignificant\nLong term action with routine review\nAMBER 5-12 Medium Likelihood of major harm if control measures not\nimplemented\nAction is needed in the medium term\nRED 15-25 High Significant probability of major harm Urgent action needed. Escalate to line manager, patient\u2019s GP and\nsenior manager.\nHardinge M, et al. Thorax 2015;70:i1\u2013i43. doi:10.1136\/thoraxjnl-2015-206865 i39\nBTS Guidelines\ngroup.bmj.com\non June 19, 2016 - Published by\nhttp:\/\/thorax.bmj.com\/\nDownloaded from\nRisk Assessment Action Plan\nPatient\u2019s Full Name: Date of birth: NHS N\u00b0\nLocation\/Activity: Assessment date:\nAssessor: Signature: Review date:\nRef Further Action Implemented Short Term, Medium Term, Long Term Responsible Person Revised Risk rating L x C=R\nAre further assessments required if so list.\ne.g. COSHH\n1 Arrange 6monthly review. Review risk assessment annually.\nCheck safety implications at every visit.\nCaseload Manager\n2 As above\n3 As above\n4 As above\n5 As above\n6 As above\n7 As above\n8 As above\n9 As above\n10 As above. Inform GP.\n11 As above.\ni40\nHardinge\nM,\net\nal.\nThorax\n2015;70:i1\u2013i43.\ndoi:10.1136\/thoraxjnl-2015-206865\nBTS\nGuidelines\ngroup.bmj.com\non\nJune\n19,\n2016\n-\nPublished\nby\nhttp:\/\/thorax.bmj.com\/\nDownloaded\nfrom\nAPPENDIX 5: HOME OXYGEN ORDER FORMS (HOOF) AND HOME OXYGEN CONSENT FORMS (HOCF) FORMS\nThe Home Oxygen Order Form (HOOF) form for use in England and Wales comes in two parts:\nPart A is used when the request is being made by non-specialist healthcare professionals and is usually for a temporary order pending\nreview by a Home Oxygen Assessment service.\nPart B should be used by Home Oxygen Assessment services once a patient has undergone formal assessment. It also allows for order-\ning of equipment in addition to the basic static concentrator and static cylinders.\nForms are available via the home oxygen supplier website relevant to each geographical area (or Part A HOOF is available from\nPrimary Care Commissioning website.\nhttp:\/\/www.pcc-cic.org.uk\/article\/home-oxygen-service-current-supply-contracts (accessed Jan 2015)\nhttp:\/\/www.pcc-cic.org.uk\/article\/home-oxygen-order-form (accessed Jan 2015)\nAPPENDIX 6: SAMPLE PATIENT INFORMATION LEAFLETS\nThere are many examples of excellent patient information lea\ufb02ets available from different Home Oxygen Assessment teams. The\nBritish Lung Foundation provides a wide range of information for patients with lung conditions: www.blf.org.uk\nA new publication \u2018Oxygen treatment\u2019 will be available from April 2015: www.blf.org.uk\/page\/oxygen-treatment\nThe booklet will be available to order from the BLF shop: Patient: http:\/\/shop.blf.org.uk\/products\/oxygen-booklet\nHCP: http:\/\/shop.blf.org.uk\/products\/oxygen-booklet-1\nHardinge M, et al. Thorax 2015;70:i1\u2013i43. doi:10.1136\/thoraxjnl-2015-206865 i41\nBTS Guidelines\ngroup.bmj.com\non June 19, 2016 - Published by\nhttp:\/\/thorax.bmj.com\/\nDownloaded from\nAPPENDIX 7 : PRACTICAL POINTS FOR REMOVAL OF HOME OXYGEN\nRemoval of home oxygen may be challenging and should be undertaken by experienced healthcare professionals. A multidisciplinary\nteam approach including all healthcare professionals directly involved with the patient\u2019s care agreeing a plan may help the process. If\nthis is not possible, communication of the removal plan to all relevant healthcare professionals is important.\nRemoval of home oxygen may not occur at one point but take time and multiple contacts. In order to remove home oxygen other\ninterventions to manage breathlessness should be considered as an alternative where appropriate e.g. pulmonary rehabilitation,\ndepression and anxiety management. The process may be stressful for the patient and their families or carers and should be handled\nsensitively.\nIt is helpful if the possibility of removal of home oxygen, and the circumstances in which this might occur, is raised with patients and\ntheir carers when home oxygen is \ufb01rst prescribed. This should be supported by written information.\nReasons for removal of home oxygen therapy:\n1. Clinical\nIf the patient no longer meets the criteria for home oxygen on reassessment in a stable clinical state, then the removal process\nshould be initiated. Consider the time and effort of removal in those patients with borderline arterial oxygen levels as they are\nlikely to deteriorate in time, and a further assessment may be useful before initiating removal.\n2. Patient adherence\nWhere patients do not use their prescribed oxygen for the period of time to gain clinical bene\ufb01t (eg 15 hours per day with\nLTOT), they should be advised of the importance of this. An agreement should be reached with patients of an agreed period over\nwhich to improve adherence and if adherence is still suboptimal the oxygen should be removed.\nPatients who do not use ambulatory oxygen therapy (AOT) despite leaving their house, or those who have AOT but do not leave\ntheir house, should again be similarly advised that this is a waste of NHS resources and an agreed period of time to improve\nadherence should be decided on, before reassessment. If there is no signi\ufb01cant improvement in AOT use, then it should be\nremoved.\n3. Safety\nIf there are clear safety issues around the use of home oxygen a risk assessment should be undertaken (see Appendix 4). Serious\nincidents such as \ufb01res involving oxygen should lead to serious consideration of the removal of oxygen. Altering \ufb02ow rates if not\nrecommended by home oxygen team can result in harm and falls may result from piped oxygen tubing. There may be interven-\ntions that can minimise the risks and these should be initiated e.g. smoking cessation support in smokers; oxygen tubing being\npiped in and \ufb01xed rather than loose to reduce the risk of trips and falls; locking concentrators to avoid alteration in \ufb02ow rates.\nFollowing initiation there should be a reassessment after a set agreed period.\nBefore removal of home oxygen you should be able to answer \u2018YES\u2019 to the following:\n\u2022 Has the patient been reassessed by a health professional experienced in managing home oxygen or part of the home oxygen assess-\nment team?\n\u2022 Is there a clear indication for removal?\n\u2022 Is the patient (and\/or signi\ufb01cant other) aware removal may occur?\n\u2022 Have all interventions to improve adherence or reduce risk been considered and implemented with an evaluation following\nimplementation?\n\u2022 Have appropriate alternative treatment strategies been considered and implemented as part of the removal process?\n\u2022 Have the wider health care team been part of the decision to remove home oxygen but if not informed of the decision prior to\nremoval?\ni42 Hardinge M, et al. Thorax 2015;70:i1\u2013i43. doi:10.1136\/thoraxjnl-2015-206865\nBTS Guidelines\ngroup.bmj.com\non June 19, 2016 - Published by\nhttp:\/\/thorax.bmj.com\/\nDownloaded from\nAPPENDIX 8: GUIDELINE GROUP MEMBERS\nName\nDr Maxine Hardinge, Chair Consultant Respiratory Physician Oxford University Hospitals NHS Trust\nJoe Annandale Respiratory Nurse Specialist, Hywel Dda University Health Board, Prince Philip Hospital, Llanelli Representing ARNS\nDr Simon Bourne Consultant Respiratory Physician Portsmouth NHS Trust Representing the Royal College of Physicians, London\nDr Brendan Cooper Consultant Clinical Scientist, Lung Function and Sleep, Queen Elizabeth Hospital Birmingham Representing ARTP\nLynn McDonnell Clinical Specialist Physiotherapist London Representing ACPRC\nAngela Evans Specialist Practitioner, Staffordshire and Stoke-on-Trent Partnership Trust Representing ARTP\nDr Daryl Freeman General Practitioner Representing PCRS-UK\nAngela Green Respiratory Physiotherapist Improvement Academy (Y&H AHSN) Bradford Teaching Hospitals NHS FT\nMr Colin Hawkey (dec) Patient\/carer representative: 2011\/2013\nDr Sabrine Hippolyte Respiratory Specialty Trainee London\nVikki Knowles Respiratory Nurse Specialist, Respiratory Care Team, Virgin Care, Surrey Representing PCRS \u2013UK\nMrs Joan Ling Patient\/carer representation: 2011\/2012\nProfessor William MacNee Professor of Respiratory Medicine Edinburgh\nKathy Pye Clinical Nurse Specialist Liverpool\nDr Jay Suntharalingam Consultant Respiratory Physician Bath\nDr Vandana Vora Consultant Palliative Care Physician, Sheffield Representing Association for Palliative Medicine\nDr Tom Wilkinson Consultant Respiratory Physician Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, Southampton\nHardinge M, et al. Thorax 2015;70:i1\u2013i43. doi:10.1136\/thoraxjnl-2015-206865 i43\nBTS Guidelines\ngroup.bmj.com\non June 19, 2016 - Published by\nhttp:\/\/thorax.bmj.com\/\nDownloaded from\noxygen use in adults: accredited by NICE\nBritish Thoracic Society guidelines for home\nThoracic Society Standards of Care Committee\nHome Oxygen Guideline Development Group, and on behalf of the British\nSuntharalingam, Vandana Vora, Tom Wilkinson, British Thoracic Society\nKnowles, William MacNee, Lynn McDonnell, Kathy Pye, Jay\nAngela Evans, Daryl Freeman, Angela Green, Sabrine Hippolyte, Vikki\nMaxine Hardinge, Joe Annandale, Simon Bourne, Brendan Cooper,\ndoi: 10.1136\/thoraxjnl-2015-206865\n2015 70: i1-i43\nThorax\nhttp:\/\/thorax.bmj.com\/content\/70\/Suppl_1\/i1\nUpdated information and services can be found at:\nThese include:\nMaterial\nSupplementary\n5.DC1.html\nhttp:\/\/thorax.bmj.com\/content\/suppl\/2015\/04\/21\/thoraxjnl-2015-20686\nSupplementary material can be found at:\nReferences\n#BIBL\nhttp:\/\/thorax.bmj.com\/content\/70\/Suppl_1\/i1\nThis article cites 148 articles, 47 of which you can access for free at:\nservice\nEmail alerting\nbox at the top right corner of the online article.\nReceive free email alerts when new articles cite this article. Sign up in the\nCollections\nTopic Articles on similar topics can be found in the following collections\n(1186)\nTB and other respiratory infections\n(1672)\nEpidemiologic studies\n(2)\nGuidelines, Recommendations and Consensus Statements\nNotes\nhttp:\/\/group.bmj.com\/group\/rights-licensing\/permissions\nTo request permissions go to:\nhttp:\/\/journals.bmj.com\/cgi\/reprintform\nTo order reprints go to:\nhttp:\/\/group.bmj.com\/subscribe\/\nTo subscribe to BMJ go to:\ngroup.bmj.com\non June 19, 2016 - Published by\nhttp:\/\/thorax.bmj.com\/\nDownloaded from","is_draft":"0","editor_type":"4","file_path":"\/docker_production\/zgvd51\/article\/t6wrT2XK\/article_file\/2015 BTS\u6210\u4eba\u5bb6\u5ead\u6c27\u6c14\u4f7f\u7528\u6307\u5357.pdf","add_time":"1757143010","update_time":"1757143078"},"pure_content":"British Thoracic Society guidelines for home oxygen\nuse in adults\nMaxine Hardinge,1\nJoe Annandale,2\nSimon Bourne,3\nBrendan Cooper,4\nAngela Evans,5\nDaryl Freeman,6\nAngela Green,7\nSabrine Hippolyte,8\nVi"},{"id":"610661","string_id":"Tl4sV95l","status":"1","parent_id":"610654","slug":"2019-ATS-lin-chuang-shi-jian-zhi-nan-er-tong-jia-ting-yang-liao","order":"0","name":"2019 ATS\u4e34\u5e8a\u5b9e\u8df5\u6307\u5357 \u513f\u7ae5\u5bb6\u5ead\u6c27\u7597","type":"2","cover":"","cover_alt":"","desc":null,"website":"","contact":"","seo_title":"","seo_keyword":"","seo_desc":"","share_switch":"0","share_code":"","author":"","published_time":"1757143079","add_time":"1757143011","update_time":"1757143079","corp_auth_id":"0","verify_code_auth_id":"0","editor_type":"4","file_type":"pdf","auth_id":"[\"610661\", \"610654\"]","content":{"content_id":"610661","content":"AMERICAN THORACIC SOCIETY\nDOCUMENTS\nHome Oxygen Therapy for Children\nAn Of\ufb01cial American Thoracic Society Clinical Practice Guideline\nDon Hayes, Jr., Kevin C. Wilson, Katelyn Krivchenia, Stephen M. M. Hawkins, Ian M. Balfour-Lynn, David Gozal,\nHoward B. Panitch, Mark L. Splaingard, Lawrence M. Rhein, Geoffrey Kurland, Steven H. Abman, Timothy M. Hoffman,\nChristopher L. Carroll, Mary E. Cataletto, Dmitry Tumin, Eyal Oren, Richard J. Martin, Joyce Baker, Gregory R. Porta,\nDeborah Kaley, Ann Gettys, and Robin R. Deterding; on behalf of the American Thoracic Society Assembly on\nPediatrics\nTHIS OFFICIAL CLINICAL PRACTICE GUIDELINE OF THE AMERICAN THORACIC SOCIETY WAS APPROVED DECEMBER 2018\nBackground: Home oxygen therapy is often required in children\nwith chronic respiratory conditions. This document provides an\nevidence-based clinical practice guideline on the implementation,\nmonitoring, and discontinuation of home oxygen therapy for the\npediatric population.\nMethods: A multidisciplinary panel identi\ufb01ed pertinent questions\nregarding home oxygen therapy in children, conducted systematic\nreviews of the relevant literature, and applied the Grading of\nRecommendations, Assessment, Development, and Evaluation\napproach to rate the quality of evidence and strength of clinical\nrecommendations.\nResults: After considering the panel\u2019s con\ufb01dence in the estimated\neffects, the balance of desirable (bene\ufb01ts) and undesirable (harms\nand burdens) consequences of treatment, patient values and\npreferences, cost, and feasibility, recommendations were developed\nfor or against home oxygen therapy speci\ufb01c to pediatric lung and\npulmonary vascular diseases.\nConclusions: Although home oxygen therapy is commonly\nrequired in the care of children, there is a striking lack of\nempirical evidence regarding implementation, monitoring, and\ndiscontinuation of supplemental oxygen therapy. The panel\nformulated and provided the rationale for clinical recommendations\nfor home oxygen therapy based on scant empirical evidence,\nexpert opinion, and clinical experience to aid clinicians in the\nmanagement of these complex pediatric patients and identi\ufb01ed\nimportant areas for future research.\nKeywords: children; home; hypoxemia; oxygen\nAn Executive Summary of this document is available at http:\/\/www.atsjournals.org\/doi\/suppl\/10.1164\/rccm.201812-2276ST.\nORCID IDs: 0000-0002-6734-6052 (D.H.); 0000-0003-4429-2263 (K.C.W.); 0000-0002-0754-3863 (I.M.B.-L.); 0000-0001-8195-6036 (D.G.);\n0000-0001-8440-283X (H.B.P.); 0000-0002-1361-4947 (M.L.S.); 0000-0001-7817-3516 (E.O.).\nYou may print one copy of this document at no charge. However, if you require more than one copy, you must place a reprint order. Domestic reprint orders:\namy.schriver@sheridan.com; international reprint orders: louisa.mott@springer.com.\nCorrespondence and requests for reprints should be addressed to Don Hayes, Jr., M.D., M.S., The Ohio State University, Nationwide Children\u2019s Hospital, 700\nChildren\u2019s Drive, Columbus, OH 43205. E-mail: hayes.705@osu.edu.\nThis article has an online supplement, which is accessible from this issue\u2019s table of contents at www.atsjournals.org.\nAm J Respir Crit Care Med Vol 199, Iss 3, pp e5\u2013e23, Feb 1, 2019\nCopyright \u00a9 2019 by the American Thoracic Society\nDOI: 10.1164\/rccm.201812-2276ST\nInternet address: www.atsjournals.org\nAmerican Thoracic Society Documents e5\nContents\nSummary of Recommendations\nCystic Fibrosis\nBronchopulmonary Dysplasia\nSleep-disordered Breathing\nSickle Cell Disease\nPulmonary Hypertension without\nCongenital Heart Disease\nPulmonary Hypertension with\nCongenital Heart Disease\nInterstitial Lung Disease\nImplementation\nIntroduction\nMethods\nDe\ufb01nition of Hypoxemia\nChildren Younger Than 1 Year Old\nChildren Aged 1 Year Old and\nOlder\nConsequences of Untreated\nHypoxemia\nPulmonary Circulation\nNeurodevelopment and\nCognition\nSleep\nGrowth\nIndications for HOT\nQuestion 1: Should Children with\nCystic Fibrosis Complicated by\nChronic Hypoxemia Be Treated\nwith HOT?\nQuestion 2: Should Children with\nBronchopulmonary Dysplasia\nComplicated by Chronic\nHypoxemia Be Treated with\nHOT?\nQuestion 3: Should Children with\nSleep-disordered Breathing\nComplicated by Chronic\nHypoxemia Be Treated with\nHOT?\nQuestion 4: Should Children with\nSickle Cell Disease Complicated\nby Chronic Hypoxemia Be\nTreated with HOT?\nQuestion 5: Should Children with\nPulmonary Hypertension\nwithout Congenital Heart\nDisease Be Treated with HOT?\nQuestion 6: Should Children with\nPulmonary Hypertension with\nCongenital Heart Disease Be\nTreated with HOT?\nQuestion 7: Should Children with\nInterstitial Lung Disease\nComplicated by Chronic\nHypoxemia Be Treated with\nHOT?\nProviding HOT\nEquipment\nMonitoring\nHome Safety\nFollow-up\nDiscontinuation of HOT\nAssessing Readiness\nWeaning of HOT\nSuccessful Discontinuation of\nHOT\nConclusions\nSummary of\nRecommendations\nCystic Fibrosis\nd For patients with cystic \ufb01brosis\ncomplicated by severe chronic hypoxemia,\nwe recommend that home oxygen therapy\nbe prescribed (strong recommendation, very\nlow-quality evidence).\nd For patients with cystic \ufb01brosis who\nhave both mild chronic hypoxemia and\ndyspnea on exertion, we suggest that\nhome oxygen therapy be prescribed\n(conditional recommendation, very low-\nquality evidence).\nBronchopulmonary Dysplasia\nd For patients with bronchopulmonary\ndysplasia complicated by chronic\nhypoxemia, we recommend that home\noxygen therapy be prescribed (strong\nrecommendation, very low-quality\nevidence).\nSleep-disordered Breathing\nd For patients with sleep-disordered\nbreathing complicated by severe\nnocturnal hypoxemia who cannot tolerate\npositive airway pressure therapy or are\nawaiting surgical treatment of sleep-\ndisordered breathing, we suggest that\nhome oxygen therapy be prescribed\n(conditional recommendation, very\nlow-quality evidence).\nSickle Cell Disease\nd For patients with sickle cell disease\ncomplicated by severe chronic\nhypoxemia, we suggest that home\noxygen therapy be prescribed\n(conditional recommendation, very\nlow-quality evidence).\nPulmonary Hypertension without\nCongenital Heart Disease\nd For patients with pulmonary\nhypertension without congenital heart\ndisease complicated by chronic\nhypoxemia, we recommend that home\noxygen therapy be prescribed (strong\nrecommendation, very low-quality\nevidence).\nPulmonary Hypertension with\nCongenital Heart Disease\nd For patients with pulmonary\nhypertension with congenital heart\ndisease complicated by chronic\nhypoxemia, supplemental oxygen will\nimpact hemodynamics and physiology;\nwe recommend that home oxygen\ntherapy NOT be initiated in these\nchildren, regardless of previous\nreparative or palliative congenital\nheart surgery, until there has\nbeen consultation with a pediatric\npulmonologist or cardiologist who\nhas expertise in the management of\npulmonary hypertension in this clinical\nsetting (strong recommendation, very\nlow-quality evidence).\nInterstitial Lung Disease\nd For patients with interstitial lung disease\ncomplicated by severe chronic hypoxemia,\nwe recommend that home oxygen therapy\nbe prescribed (strong recommendation, very\nlow-quality evidence).\nd For patients with interstitial lung\ndisease who have mild chronic\nhypoxemia and either dyspnea on\nexertion or desaturation during sleep\nor exertion, we suggest that home\noxygen therapy be prescribed\n(conditional recommendation, very\nlow-quality evidence).\nImplementation\nd The expert panel unanimously agreed\nthat optimal implementation of the\nabove recommendations consists of all\nof the following:\n\u2218 Oxygen therapy to maintain an oxygen\nsaturation as measured by pulse\noximetry in an acceptable range\nAMERICAN THORACIC SOCIETY DOCUMENTS\ne6 American Journal of Respiratory and Critical Care Medicine Volume 199 Number 3 | February 1 2019\naccording to age and respiratory\ncondition as outlined in this document\n\u2218 Use of oxygen equipment that is of the\nappropriate size, developmental stage,\nand \ufb02ow rate to function properly\n\u2218 Oxygen therapy monitoring by pulse\noximetry in the home\nIntroduction\nHome oxygen therapy (HOT) is used to\nmaintain health by addressing physiologic\nand metabolic requirements for children\nwith chronic lung and pulmonary vascular\ndiseases. Enabling a child to receive HOT also\nconfers psychological advantages by allowing\nthe child to remain within the family unit at\nhome, reducing healthcare costs compared\nwith hospitalization. Despite children having\nsigni\ufb01cantly different pulmonary physiology\nfrom adults and additional requirements for\noptimal lung growth and development,\nindications for funding HOT as determined\nby the Centers for Medicare and Medicaid\nServices (CMS) are the same for pediatric\nand adult patients. These include 1) PaO2\nless than 55 mm Hg (,7.33 kPa); 2)\noxygen saturation as measured by pulse\noximetry (SpO2\n) less than 88%; or 3) PaO2\n55\u201359 mm Hg (7.33\u20137.87 kPa) or SpO2\n89% accompanied by cor pulmonale, a\nhematocrit greater than 55%, or a history of\nedema (1). The basis of these indications\nby CMS is predicated on seminal studies\nin adult patients with chronic obstructive\npulmonary disease showing reductions in\nmortality with continuous oxygen therapy\n(2, 3). Despite the lack of pediatric patients\nin these historic studies performed over 35\nyears ago, CMS coverage determination for\nHOT is the same for pediatric patients of all\nages compared with adult patients.\nRecognizing the need for clinical\nguidance regarding HOT speci\ufb01cally for\nchildren, the American Thoracic Society\n(ATS) convened a task force of specialists in\npediatric and neonatal medicine, respiratory\ntherapy, nursing, and population health,\ntogether with parents, to conduct systematic\nreviews and use available evidence to inform\nrecommendations for the use of HOT in\nchronic lung and pulmonary vascular\ndiseases of childhood.\nThe target audience of this guideline is\nclinicians who manage children with diseases\ncomplicated by chronic hypoxemia. This\ngroup includes pediatric pulmonologists,\npediatric cardiologists, neonatologists, general\npediatricians and family practitioners,\nemergency medicine and primary care\nclinicians, other healthcare professionals, and\npolicy makers. Clinicians, patients, third-party\npayers, stakeholders, or the courts should never\nview the recommendations contained in this\nguideline as dictates. Though evidence-based\nguidelines can summarize the best available\nevidence regarding the effects of an intervention\nin a given patient population, they cannot take\ninto account all of the unique clinical\ncircumstances that may arise when managing a\npatient, and as such their implementation is at\nthe discretion of each treating clinician.\nMethods\nThis clinical practice guideline was developed\nin accordance with policies and procedures\nof the ATS. See the online supplement for\na detailed description of the methods.\nThe meaning of strong and conditional\nrecommendations is described in Table 1.\nDe\ufb01nition of Hypoxemia\nWith an immense medical literature\non hypoxemia, the panel focused this\ndocument on the treatment of sustained\nlow SpO2\nlevels, or \u201cchronic hypoxemia,\u201d\nand HOT for speci\ufb01c respiratory conditions\nof childhood. With unanimous agreement,\nthe panel determined that a low SpO2\nfor a\nduration of 2 weeks was suf\ufb01cient evidence\nfor chronic hypoxemia in a child with one\nof these respiratory conditions if otherwise\nclinically stable, thus achieving a threshold\nwhere HOT should be considered. One\ncaveat is that growth and development may\nresult in clinical resolution of chronic\nhypoxemia in some pediatric patients.\nTo de\ufb01ne hypoxemia, we conducted a\nsystematic search for data about normal\noxygenation in children that identi\ufb01ed 1,711\narticles, most of which were excluded by\nreview of their title and abstract (see Table\nE1 in the online supplement). We selected\n31 studies that measured oxygenation in\nhealthy children to inform our decision\nmaking (4\u201333). Of note, the studies\nenrolled subjects with different age ranges.\nFor analysis, we decided to categorize\nchildren as younger than 1 year old or\n1 year old and older. See Table 2 for\nnormative values of oxyhemoglobin\nsaturations in healthy children during\nwakefulness and sleep that originated from\nwork described in the paragraphs below.\nFor the purpose of this document, the term\n\u201cdesaturation\u201d will represent oxyhemoglobin\ndesaturation.\nChildren Younger Than 1 Year Old\nChildren younger than 1 year old had\na mean SpO2\nof 97.8% (SD, 61.4%)\n(27, 29, 32) and a median SpO2\nof 98.7%,\nwith a range from 97.9% to 99.8% (8, 9,\n14, 15, 27, 29, 31, 32), during wakefulness.\nDesaturation events were common during\nthe initial 48 hours of life. One study\nreported that 5% of the time was spent with\na mean SpO2\nless than 92.5% (63.9%) and\n10% of the time was spent with a mean SpO2\nTable 1. Meanings of the Strength of the Recommendations\nA Strong Recommendation Conveys . . . A Conditional Recommendation Conveys . . .\nIt is the right course of action for .95% of patients. It is the right course of action for .50% of patients but may not be right for a sizable\nminority.\n\u201cJust do it. Don\u2019t waste your time thinking about it,\njust do it.\u201d\n\u201cSlow down, think about it, discuss it with the patient.\u201d\nYou would be willing to tell a colleague that he or she\ndid the wrong thing if he or she did not follow the\nrecommendation.\nYou would NOT be willing to tell a colleague that he or she did the wrong thing if he\nor she did not follow the recommendation because there is clinical equipoise.\nThe recommended course of action may make a\ngood performance metric.\nThe recommended course of action would NOT make a good performance metric.\nAMERICAN THORACIC SOCIETY DOCUMENTS\nAmerican Thoracic Society Documents e7\nless than 95.3% (62.9%) (32); another\nreported that 3\u20134% of the time was spent\nwith SpO2\nof 90% or less (27). With respect\nto duration, studies estimated that 26% of\nneonates had desaturations to less than or\nequal to 80% for a median duration of 9.3\nseconds (31), 92% had desaturations to less\nthan or equal to 88% for more than 20\nseconds (24), and 100% had desaturations\nto less than or equal to 88% for more\nthan 10 seconds (27). Desaturation events\ndiminished with age. At an age of 1 month,\ninfants had desaturations to SpO2\nless than\nor equal to 80% a median of 0.9 times\nper hour (range, 0 to 15.1) for a median\nduration of 1.2 seconds (range, 0.3 to 2.2 s)\n(15); at ages of 6 weeks, 3 months, and 6\nmonths, infants had desaturations to a SpO2\nless than or equal to 80% a median of 0.7,\n0.4, and 0.5 times per hour (9); and at an\nage of 1.4 years (range, 1.1 to 1.9 yr), infants\nhad desaturations of greater than or equal to\n3% a median of 0.1 times per hour (range,\n0 to 2.2) (14). During sleep, mean SpO2\ndecreased to 96.3% (61.3%) (19) with\nepisodes of desaturation that reached a nadir\nat a mean of 86% (61.5%) (19) or a median\nof 85.5% with a range from 83% to 88%\n(8, 13). Infants 2 weeks, 3 months, and\n6 months old spent 5% of sleep time with\na median SpO2\nless than 92% (73\u201399%),\n96% (83\u201398%), and 95.5% (69\u201399%),\nrespectively, and spent 10% of sleep time\nwith a median SpO2\nless than 96% (77\u2013\n99%), 97% (86\u2013100%), and 97% (75\u201399%),\nrespectively (7).\nChildren Aged 1 Year Old and Older\nChildren aged 1 year old and older had a\nmean SpO2\nof 97.6% (60.7%) (16, 24, 32,\n33) and a median SpO2\nof 97.5%, with a\nrange from 97% to 98% (14, 16, 18, 24),\nduring wakefulness. During sleep, the mean\nSpO2\nremained 97.8% (60.7%) (33), with\nepisodes of desaturation that reached a\nnadir at a mean of 94.6% (63.1%) (16, 20,\n22, 23, 25, 26, 33) and a median of 93%,\nwith a range from 91% to 94% (16, 18,\n20, 21, 23). Desaturation events were\ninfrequent. Children had desaturations\ngreater than or equal to 3% or greater than\nor equal to 4% a mean of 0.6 times per hour\n(61.0) (16, 23, 26, 33) and a median of\n0.4 times per hour (range, 0.1\u20130.8) (14, 16,\n18, 23). The mean duration of desaturation\nevents was 0.3 seconds (60.1 s), and the\nmedian duration was 0 seconds (range, 0 to\n5.8 s) (23), with less than 1% of sleep spent\nwith a SpO2\nless than 95% (16) and less than\n0.03% of sleep spent with a SpO2\nless than\n90% (16, 33). Clusters of desaturation\noccurred with a mean frequency of 0.1\nclusters per hour (60.2) and a median\nfrequency of 0 clusters per hour (range,\n0\u20130.7) (23).\nOxygen saturation is lower among\nnormal children of all age groups living at a\nhigh altitude. Children 1 year old and\nyounger living at 2,560 and 3,200 m had\nmedian SpO2\nof 92% and 87%, respectively,\naccording to two studies (5, 6), whereas\nanother study found that those living at\naltitudes of 1,371, 2,073, 2,393, 2,405, and\n2,484 m had SpO2\nranges of 95\u201396.7%,\n93.9\u201395.4%, 91.8\u201393.4%, 93.4\u201396.1%, and\n93.7\u201396.2%, respectively (28). Children\nolder than 1 year old residing at an altitude\nof roughly 1,600 m had a median SpO2\nof\n95.4% (range, 93.1\u201396.9%) and a median\nnadir SpO2\nof 86% (range, 81\u201389%) (17),\nwhereas those living at roughly 4,000 m had\na mean SpO2\nof 87.4% (SD not estimable)\nand a mean nadir SpO2\nof 80% (SD, 67.5%)\n(11, 18). Desaturation events were more\nfrequent at high altitude than at sea level,\nbut they were less common among older\nchildren. Children 1\u20136 years old living at\n1,600 m had desaturations greater than or\nequal to 4% a median of 4.0 times per hour\n(17), whereas children older than 6 years\nold living at 4,000 m had desaturations\ngreater than or equal to 4% a median of\n1.6 times per hour (18). Owing to lack of\nstudies, adjustments for targeted saturation\nlevels in children at altitude cannot be\nadequately addressed in this guideline.\nWith these studies as background and a\nprimary objective of identifying potentially\nharmful hypoxemia while ensuring that\nvirtually no normal children are determined to\nhave abnormal oxygenation, the panel de\ufb01ned\nhypoxemia at or near sea level as follows:\nd In children younger than 1 year old,\nhypoxemia was de\ufb01ned as spending 5%\nof the recording time with SpO2\nless than\nor equal to 90% or, if measurements\nare taken intermittently, obtaining three\nindependent measurements of SpO2\nless\nthan or equal to 90%.\nd In children aged 1 year old and older,\nhypoxemia was de\ufb01ned as spending\n5% of the time with SpO2\nless than or\nequal to 93% or, if measurements are\ntaken intermittently, obtaining three\nindependent measurements of SpO2\nless\nthan or equal to 93%.\nAdditional conclusions from the panel\nincluded the following:\nd Pulse oximetry is suf\ufb01cient for\ndiagnosing hypoxemia in pediatric\npatients because arterial blood analysis\nfor PaO2\nis not practical for routine\nmonitoring, owing to technical dif\ufb01culty\nin children and the pain associated with\nthe arterial stick.\nd On very rare occasions, an arterial\nblood gas for PaO2\nmay be required\nto assess for hypoxemia in a child,\nspeci\ufb01cally when pulse oximetry may\nnot accurately measure SpO2\n, including\naltered hemoglobin states (e.g.,\ncarboxyhemoglobin, methemoglobin)\nor in diseases affecting hemoglobin,\nsuch as sickle cell disease (SCD).\nd Intermittent pulse oximetry appears\nsuitable with the different thresholds\nre\ufb02ecting greater variability of SpO2\namong healthy children younger than\n1 year old, particularly the youngest\nchildren, with this left at the discretion\nof the treating clinician according to\nthe clinical scenario of the patient.\nd In a child, three intermittent measurements,\nif abnormal, can diagnose hypoxemia,\nbut normal intermittent measurements\ncannot exclude it; this can be\nTable 2. Normative Values\nWakefulness Sleep Desaturation Nadir\nMean (6SD) Median (Range) Mean (6SD) Median (Range) Mean (6SD) Median (Range)\nChildren ,1 yr old 97.8% (61.4%) 98.7% (97.9\u201399.8%) 96.3% (61.3%) Not reported 86% (61.5%) 85.5% (83\u201388%)\nChildren >1 yr old 97.6% (60.7%) 97.5% (97\u201398%) 97.8% (60.7%) Not reported 94.6% (63.1%) 93% (91\u201394%)\nAMERICAN THORACIC SOCIETY DOCUMENTS\ne8 American Journal of Respiratory and Critical Care Medicine Volume 199 Number 3 | February 1 2019\ndone only by continuous oximetric\nmonitoring, which includes a period\nof sleep. More advanced evaluation with\npolysomnography may be needed on a\ncase-by-case basis at the discretion of the\ntreating clinician.\nd Averaging time for pulse oximetry\nmeasurements should take into account\nthe age of the child, the underlying\nrespiratory condition, and the current\nclinical scenario.\nd A duration of 2 weeks de\ufb01nes chronicity\nof hypoxemia in a child.\nd Hypoxemia in a child should account\nfor anticipated SpO2\nmeasurement\nalterations according to altitude.\nConsequences of Untreated\nHypoxemia\nThe pathobiology of hypoxemia\nencompasses a large body of work in the\nmedical literature, which we expect will\ncontinue to expand rapidly. Moreover, we\nenvision future research will better delineate\nthe effects of hypoxemia at the cellular and\nmolecular levels (34, 35). We brie\ufb02y review\nin this section the potential consequences of\nhypoxemia that pediatric patients may\nexperience, with the caveat that expanding\nresearch in this area may in\ufb02uence these\nrecommendations. Intermittent hypoxemia\noccurs more frequently in children with\nlung disease and has been associated with\ndeleterious consequences on pulmonary\ncirculation, neurodevelopment, cognition,\nsleep, and growth (36). Lower basal\noxygen saturation in children is associated\nwith more episodes of spontaneous\ndesaturations (37), placing them at even\nfurther risk for complications of\nhypoxemia.\nPulmonary Circulation\nChronic alveolar hypoxia elicits pulmonary\nvasoconstriction leading to pulmonary\nhypertension (PH), particularly in\nchildren with respiratory disorders, such\nas sleep-disordered breathing (SDB),\nbronchopulmonary dysplasia (BPD), cystic\n\ufb01brosis (CF), and SCD. Previous work in\nanimal models, including neonatal models,\nde\ufb01ned oxygen levels that induce hypoxic\npulmonary vasoconstriction (38\u201341).\nCompared with adults (42), children with\nSDB and intermittent hypoxemia are at\nincreased risk for PH (43). Intermittent\nhypoxemia adversely affects alveolar and\nvascular development in infants with BPD\n(44, 45). Correction of the hypoxemia\nin neonates with BPD and PH using\nsupplemental oxygen can ameliorate\nphysiologic complications (45\u201348),\nwith HOT resolving right ventricular\nhypertrophy when SpO2\nis maintained\nabove 94\u201395% (49). In CF, continuous\nhypoxemia during wakefulness and other\nphysiologic factors is associated with the\ndevelopment of PH independent of lung\nfunction (50, 51). Nocturnal hypoxemia\nand SDB appear to be in\ufb02uential in the\ndevelopment of PH in SCD (52, 53).\nHemolysis, hypercoagulability, ischemia-\nreperfusion injury, oxidative stress,\nin\ufb02ammation, and genetic susceptibility\nare additional factors that impact the\ndevelopment of PH (54). Although the\nresponse to mild levels of alveolar hypoxia\nmay have minimal effects in many children,\nothers may have adverse effects at similar\nlevels of inspired oxygen with regard to\nheightened pulmonary vascular reactivity\nor remodeling, as re\ufb02ected in infants with\nBPD (46), young adults with a history\nof perinatal asphyxia (55), and others.\nSuch susceptibility has been demonstrated\nin experimental studies of genetic rat\nstrains (56) or endothelial nitric oxide\nsynthase\u2013de\ufb01cient mice (57), in which\neven mild chronic alveolar hypoxia elicits\nstriking PH. These \ufb01ndings suggest\nthat genetic, epigenetic, and disease\npathobiology can increase the risk\nfor pulmonary vascular disease even at\nlevels that would be considered mild in\nnonsusceptible individuals.\nNeurodevelopment and Cognition\nThe adverse cognitive and behavioral\noutcomes of hypoxemia in children with\nobstructive sleep apnea (OSA) have been\nextensively investigated and published\nelsewhere. Those data highlight the effects\nof hypoxemia on brain development and\nsubsequent functioning as major concerns\nin children. For example, a post hoc analysis\nof a large international trial including\n1,019 premature infants surviving to a\npostmenstrual age of 36 weeks found\nthat prolonged hypoxemic episodes of\nmore than 1 minute were associated\nwith increased risk of death or adverse\nneurodevelopmental outcome at 18\nmonths (58). However, in a multicenter,\ndouble-blind, randomized, controlled\ntrial of 358 infants born at less than\n30 weeks of gestation who continued to\nreceive supplemental oxygen at 32\nweeks postmenstrual age, no signi\ufb01cant\ndevelopmental bene\ufb01t was seen at 1 year\nwhen children with measured SpO2\nof\n91\u201394% were compared with those with\nSpO2\nof 95\u201398% (59).\nA previous systematic review of\n55 studies investigating children with\ncongenital heart disease (CHD), SDB,\nasthma, and chronic ventilatory impairment\nand infants with respiratory instability\nidenti\ufb01ed that chronic intermittent\nhypoxemia negatively in\ufb02uences\ndevelopment, behavior, and academic\nachievement (60). In 995 school-aged\nchildren in fourth to sixth grades who\nunderwent overnight pulse oximetric\nstudies, hypoxemia was associated with\nimpaired performance in mathematics (61).\nIn the assessment of hypoxemia and the\neffects on cognition, investigators often\nstudy populations at high altitudes. A\nrecent study found that short- and long-\nterm exposures to high altitude at 3,500 m\nnegatively affected executive function,\nmemory, and processing speed in children\nand adolescents (62). However, we found\nno studies that assessed the effect of\ntreatment on clinical outcomes.\nIn children with CHD undergoing\nsurgical repair, cerebral tissue oxygenation\nappears to be an important determinant\nof cognitive development (63). Newborns\nwith unrepaired CHD may have decreased\ncerebral oxygen delivery owing to chronic\nhypoxemia, so brain growth and\ndevelopment can be adversely affected\nwithout surgical intervention (64). In\nchildren with CF and hypoxemia, nocturnal\nHOT improved school attendance and\nperformance (65, 66). Early research in\nSCD showed that hypoxemia is associated\nwith episodic memory issues (67).\nSleep\nOlder studies have identi\ufb01ed that exposure\nto hypoxemia during sleep predisposes\ninfants to increased periodic breathing,\nhypoventilation, and central apneas and\nplaces those individuals at increased\nrisk for brief resolved unexplained\nevents (BRUEs) (formerly apparent life-\nthreatening events) (68, 69). Risk factors\nfor more severe BRUEs in premature\ninfants include central apnea longer than\n30 seconds, SpO2\nless than 80% for 10\nseconds, bradycardia to less than 50\u201360\nbeats per minute for 10 seconds, and upper\nrespiratory infection symptoms (70, 71).\nAMERICAN THORACIC SOCIETY DOCUMENTS\nAmerican Thoracic Society Documents e9\nIn 91 premature infants with previous\nBRUEs, unsuspected SpO2\nless than 95%\nevents (range, 80\u201393%) had occurred in\n25% of the cohort (72).\nIn a comparison of premature\ninfants with and without BPD who were\nrecently weaned from supplemental\noxygen (,7 d), children with BPD had\nsigni\ufb01cantly lower SpO2\nand experienced\nsigni\ufb01cantly more central apnea that\nresolved with supplemental oxygen\nuse (73). In one study of infants with\nBPD, an SpO2\nof 90% was associated\nwith sleep fragmentation with less REM\nsleep that improved with supplemental\noxygen administration (74), whereas\nanother study showed no change in sleep\narchitecture in infants with BPD whose\nSpO2\nwas greater than 93% (75).\nSome patients with CF have SDB\nassociated with bone and soft tissue\nstructural alterations of the upper airway\nand chronic rhinosinusitis (76, 77).\nEarlier studies established sleep-related\nhypoventilation as the primary factor\nassociated with nocturnal hypoxemia in CF\n(78\u201381). More recent research comparing\nchildren with CF with healthy control\nindividuals who were matched for age and\nbody mass index found that mean SpO2\nand\nnadir SpO2\nwere signi\ufb01cantly lower in the\nCF group (82, 83). Using polysomnography\nin pediatric and young adult patients with\nCF and normal healthy control subjects,\nFEV1 less than 64% predicted sleep-related\ndesaturation with good sensitivity and\nspeci\ufb01city (84).\nIn SCD, studies have established\nthat clinical outcomes are worse in the\nsetting of hypoxemia and SDB (85\u201389),\nwith more severe reductions in SpO2\noccurring in children who have both SCD\nand OSA (85, 90). However, reductions in\nSpO2\npersisted in some children with SCD\ndespite adenotonsillectomy (91, 92),\nsuggesting that other factors may\ncontribute to hypoxemia in SCD.\nSupporting this point, hemoglobin SS is\nassociated with more severe nocturnal\nhypoxemia than is hemoglobin SC (91),\nand treatment of patients with SCD with\nhydroxyurea is associated with\nimprovement in hypoxemia (93, 94).\nConcerns exist for severe nocturnal\nhypoxemia in children with CHD because\nthese patients can have continuous low SpO2\nand potentially reduced cerebral blood \ufb02ow.\nInfants and older children with CHD can\npresent with SDB (95\u201398), whereas patients\nwith acyanotic CHD are often obese,\nplacing them at greater risk for OSA (99).\nChildren with Eisenmenger syndrome can\nhave signi\ufb01cant nocturnal hypoxemia\nbecause of SDB, especially with higher\nhemoglobin concentrations (100). Reductions\nin SpO2\ncan occur during sleep in children\nwith CHD, independent of whether they\nhave PH, sleep disturbances, or signi\ufb01cant\narrhythmias (101). Surgical correction of\ncongenital cardiac lesions can increase\nthe risk for SDB in patients with CHD,\nso close monitoring is needed for this\nhigh-risk group (95, 102).\nFor children with interstitial lung\ndisease (ILD), nocturnal hypoxemia is\nvery common with sustained reductions of\nSpO2\nduring sleep and throughout REM\nsleep periods (103). Moreover, the ATS\nguideline for ILD in children reported\nhypoxemia as an important component of\nthe diagnostic evaluation of pediatric\npatients with suspected ILD, and it\nrecommends routine measurement of\nSpO2\nby pulse oximetry in all aspects of\nlife, including sleep and during feeding,\nfor infants (104).\nGrowth\nIn infants with BPD, improved growth\noccurs when SpO2\nduring sleep is greater\nthan 92% compared with SpO2\nof 88\u201391%\n(105). A second study in premature infants\nwith BPD found promotion of growth\nwhen SpO2\nwas maintained above 93%\nwith supplemental oxygen (106). In both\nof these studies, a negative effect on growth\nwas seen when supplemental oxygen\nwas stopped (105, 106). However, the\npreviously discussed trial in infants\nborn at less than 30 weeks of gestation\nfound no growth bene\ufb01t associated with\nhigher SpO2\n(59).\nAlthough nutritional support can\nimprove pulmonary status in CF (107), it is\nnot clear whether treatment of hypoxemia\nimproves nutritional status. Hypoxemia in\nthe CF population increases the risk for PH,\nreduced exercise ability, and loss of skeletal\nmuscle strength, all of which are associated\nwith poor nutritional status (108). When\ncompared with healthy control individuals,\nthe body mass index of patients with\nCF with moderate to severe lung disease\ndid not correlate with exercise-induced\nhypoxemia. In another study, compared\nwith healthy control subjects, the nutritional\nstatus of subjects with CF was not\nassociated with hypoxemia or hypercapnia\nduring exercise or sleep, whereas air\ufb02ow\nobstruction was the single correlate to\nsleep-related hypoxemia and hypercapnia\n(109).\nRelative to asymptomatic children with\nacyanotic CHD, children with cyanotic\nCHD have shorter stature and leaner body\nmass associated with adipose hypocellularity\n(110). In the setting of hypoxemia, early\ndevelopment of heart failure produces\ntissue changes that handicap growth (111).\nAmong the CHD patient population, the\nrisk for malnutrition and growth failure is\ngreatest in those with cyanotic CHD and\nPH (112).\nIn children with neuroendocrine cell\nhyperplasia of infancy, a recent study\nevaluating growth trajectory and oxygen use\nfound that some subjects had improvement\nin growth velocity with the initiation of\nsupplemental oxygen (113). With growth\nand maturation, some children with\nchronic pulmonary disorders requiring\nHOT will have a limited duration of\ntreatment (114).\nIndications for HOT\nOur systematic search of the literature\nidenti\ufb01ed 952 articles, most of which\nwere excluded by review of their title and\nabstract (Table E2). Table 3 provides a\nsummary of the \ufb01nal recommendations by\nthe panel, with details of the evidence base\noutlined in the following sections for each\npediatric respiratory condition.\nQuestion 1: Should Children with\nCystic Fibrosis Complicated by\nChronic Hypoxemia Be Treated with\nHOT?\nEvidence base. We identi\ufb01ed no studies that\ndirectly compared home oxygen with no\noxygen in children with CF complicated by\nchronic hypoxemia, possibly because of\nconcerns about the safety of having such\na control group. We therefore selected\neight studies that indirectly addressed the\nquestion by comparing use of either short-\nterm oxygen or nocturnal home oxygen with\nno oxygen in children with CF complicated\nby chronic hypoxemia (65, 80, 115\u2013120).\nSeven trials were randomized crossover\ntrials (80, 115\u2013120), and the remaining trial\nwas a randomized trial with parallel groups\n(65). All trials enrolled children or young\nadults with both CF (mean age, 22 to 27 yr)\nAMERICAN THORACIC SOCIETY DOCUMENTS\ne10 American Journal of Respiratory and Critical Care Medicine Volume 199 Number 3 | February 1 2019\nand chronic hypoxemia (mean SpO2\nin the\nmid-80% range; mean PaO2\n, ,65 mm Hg\n[,8.67 kPa]; or desaturations to ,90%).\nThree trials compared an FIO2\nof 0.30\u20130.39\nwith an FIO2\nof 0.21 administered into the\nbreathing circuit during an exercise test\n(116, 119, 120); three trials compared an\nFIO2\nof 0.30\u20130.31 with an FIO2\nof 0.21\nadministered by nasal cannula or through a\ncontinuous positive airway pressure device\nduring a sleep study (80, 117, 118);\none trial compared being in a naturally\nhigh-oxygen environment below sea level\nwith being at sea level (115); and one\ntrial compared nocturnal HOT titrated\nto an awake PaO2\ngreater than 70 mm Hg\n(.9.33 kPa) with a nocturnal FIO2\nof 0.21\nadministered by nasal cannula during\nsleep. All trials were small, ranging from 6\nto 28 patients.\nMeta-analyses revealed that short-term\noxygen use increased exercise duration\n(mean difference [MD], 11.04 min; 95%\ncon\ufb01dence interval [CI], 10.21 to 11.88\nmin) and postexercise oxygen saturation\n(MD, 17%; 95% CI, 12.23% to 111.81%);\nthere was also a trend toward a higher peak\nexercise oxygen saturation (MD, 17.19%;\n95% CI, 22.51% to 116.89%). Single\nstudies revealed that short-term oxygen\nTable 3. Summary of Recommendations for Home Oxygen Therapy in Children with Strength of the Recommendation and Level of\nEvidence\nPediatric Respiratory\nCondition Recommendation\nStrength of Recommendation and\nLevel of Evidence\nCystic \ufb01brosis For patients with cystic \ufb01brosis complicated by\nsevere chronic hypoxemia, we recommend that\nhome oxygen therapy be prescribed.\nStrong recommendation, very low-quality\nevidence\nFor patients with cystic \ufb01brosis who have both mild\nchronic hypoxemia and dyspnea on exertion, we\nsuggest that home oxygen therapy be prescribed.\nConditional recommendation, very low-quality\nevidence\nBronchopulmonary dysplasia For patients with bronchopulmonary dysplasia\ncomplicated by chronic hypoxemia, we\nrecommend that home oxygen therapy be\nprescribed.\nStrong recommendation, very low-quality\nevidence\nSleep-disordered breathing For patients with sleep-disordered breathing\ncomplicated by severe nocturnal hypoxemia\nwho cannot tolerate positive airway pressure\ntherapy or are awaiting surgical treatment of\nsleep-disordered breathing, we suggest that\nhome oxygen therapy be prescribed.\nConditional recommendation, very low-quality\nevidence\nSickle cell disease For patients with sickle cell disease complicated by\nsevere chronic hypoxemia, we suggest that\nhome oxygen therapy be prescribed.\nConditional recommendation, very low-quality\nevidence\nPulmonary hypertension\nwithout congenital heart\ndisease\nFor patients with pulmonary hypertension without\ncongenital heart disease complicated by chronic\nhypoxemia, we recommend that home oxygen\ntherapy be prescribed.\nStrong recommendation, very low-quality\nevidence\nPulmonary hypertension with\ncongenital heart disease\nFor patients with pulmonary hypertension with\ncongenital heart disease complicated by chronic\nhypoxemia, supplemental oxygen will impact\nhemodynamics and physiology; we recommend\nthat home oxygen therapy NOT be initiated in\nthese children, regardless of previous reparative\nor palliative congenital heart surgery, until\nthere has been consultation with a pediatric\npulmonologist or cardiologist who has expertise\nin the management of pulmonary hypertension in\nthis clinical setting.\nStrong recommendation, very low-quality\nevidence\nInterstitial lung disease For patients with interstitial lung disease\ncomplicated by severe chronic hypoxemia, we\nrecommend that home oxygen therapy be\nprescribed.\nStrong recommendation, very low-quality\nevidence\nFor patients with interstitial lung disease who have\nmild chronic hypoxemia and either dyspnea on\nexertion or desaturation during sleep or exertion,\nwe suggest that home oxygen therapy be\nprescribed.\nConditional recommendation, very low-quality\nevidence\nAMERICAN THORACIC SOCIETY DOCUMENTS\nAmerican Thoracic Society Documents e11\nuse mitigated oxygen desaturation during\nexercise (25% vs. 212%; MD, 17%; 95%\nCI, 12.48% to 111.52%) (113), improved\noxygen saturation during REM sleep (90%\nvs. 79%; MD, 111%; 95% CI, 14.38% to\n117.62%) and non-REM (NREM) sleep\n(94% vs. 88%; MD, 16%; 95% CI, 11.36%\nto 110.64%) (118), reduced sleep latency\n(18 vs. 24 min; MD, 26 min; 95% CI,\n20.25 to 211.75 min) (118), and improved\nschool attendance at 6 months (71% vs.\n21%; relative risk, 3.3; 95% CI, 1.16 to 9.59)\nand 12 months (91% vs. 20%; relative risk,\n4.55; 95% CI, 1.30 to 15.9) (65). There were\ntrends toward more REM sleep time (18%\nvs. 13%; MD, 16%; 95% CI, 20.93% to\n112.93%) and a lower arousal index (6 vs.\n8.1 arousals\/h; MD, 22.1 arousals\/h; 95%\nCI, 24.57 to 10.37 arousals\/h). There\nwere no differences in mortality (65),\ngrowth (65), total sleep time (118),\nrespiratory function (65), or right ventricular\nfunction (65).\nThe panel had very low con\ufb01dence that\nthe estimated effects described above would\nbe the same for HOT in patients with CF\ncomplicated by chronic hypoxemia, because\nthe evidence from which the estimates were\nderived was indirect (i.e., the question\nwas about HOT, but the estimates were\nfrom trials that used short-term oxygen or\nnocturnal HOT) and the trials were all small\nwith few events.\nBene\ufb01ts. In patients with CF who have\nchronic hypoxemia, short-term oxygen\nuse increased exercise duration, increased\npostexercise oxygen saturation, mitigated\noxygen desaturation during exercise,\nimproved oxygen saturation during REM\nand NREM sleep, and reduced sleep latency;\nthere was also a trend toward increased\npeak exercise oxygen saturation, increased\nREM sleep time, and a decreased arousal\nindex. Nocturnal HOT improved school\nattendance at 6 and 12 months.\nHarms. No harms were reported in any\nof the trials.\nConclusions. Despite having very low\ncon\ufb01dence in the estimated effects, the panel\nwas certain that the bene\ufb01ts of HOT exceed\nthe harms, burdens, and cost in patients\nwith CF with severe chronic hypoxemia\n(SpO2\n, ,90%). This was based on the large\nnumber of bene\ufb01cial outcomes and absence\nof harmful outcomes, decades of clinical\nexperience collectively managing thousands\nof such patients, and recognition that\nprolonged chronic hypoxemia contributes\nto serious health consequences such as\nPH and cor pulmonale. The panel also\nconcluded that the bene\ufb01ts of HOT\nlikely exceed the harms, burden, and\ncost in patients with CF who have mild\nhypoxemia (SpO2\n, 90\u201393%) that is chronic,\naccompanied by sequelae of hypoxemia\n(e.g., dyspnea on exertion, PH, cor\npulmonale), or that occurs in the context of\nan exacerbation requiring antibiotics.\nWhat others are saying. Clinical\npractice guidelines of the British Thoracic\nSociety (BTS) published in 2009\nrecommended HOT for hypoxemic children\nwith CF as \u201ca means to improve school\nattendance\u201d and to \u201cobtain symptomatic\nrelief\u201d (121). Those guidelines further\nrecommended monitoring carbon dioxide\nconcentrations when the oxygen therapy is\ninitiated.\nATS recommendations.\nd For patients with CF complicated\nby severe chronic hypoxemia, we\nrecommend that HOT be prescribed\n(strong recommendation, very low-quality\nevidence). Severe chronic hypoxemia is\nde\ufb01ned as either 1) greater than or equal\nto 5% of recording time spent with an\nSpO2\nless than 90% if measurements are\nobtained by continuous recording or\n2) at least three separate \ufb01ndings of an\nSpO2\nless than 90% if measurements are\nobtained intermittently.\nd For patients with CF who have both\nmild chronic hypoxemia and dyspnea\non exertion, we suggest that HOT be\nprescribed (conditional recommendation,\nvery low-quality evidence). Mild chronic\nhypoxemia is de\ufb01ned as either 1) greater\nthan or equal to 5% of recording\ntime spent with an SpO2\n90\u201393%\nif measurements are obtained by\ncontinuous recording or 2) at least\nthree separate \ufb01ndings of an SpO2\n90\u201393% if measurements are obtained\nintermittently.\nQuestion 2: Should Children with\nBronchopulmonary Dysplasia\nComplicated by Chronic Hypoxemia\nBe Treated with HOT?\nEvidence base. We identi\ufb01ed 11 observational\nstudies that compared HOT with no\noxygen therapy in children whose BPD\nwas complicated by chronic hypoxemia.\nTen of the studies were excluded because\nthere was an unacceptable risk of bias\nowing to the patients receiving HOT being\nmore severely ill than the patients in the\nno-oxygen group. The remaining study\nwas selected for analysis (105).\nThe study enrolled 63 infants with\nBPD who were receiving HOT but had\nan SpO2\ngreater than or equal to 92% in\nroom air. The infants were admitted for\ncontinuous pulse oximetry in room air\nduring sleep and then categorized into\nthree groups: those who 1) maintained an\nSpO2\ngreater than or equal to 92%, 2) had\ndesaturations to 88\u201391% for more than\n1 hour, or 3) had desaturations to less\nthan 88% for more than 1 hour. Those\nwho maintained an SpO2\ngreater than or\nequal to 92% or had desaturations to\n88\u201391% had their supplemental oxygen\ndiscontinued, whereas those who had\ndesaturations to less than 88% had their\nsupplemental oxygen continued. For the\ngroups whose oxygen was discontinued,\nvarious growth parameters were measured\nbefore and after discontinuation of\noxygen and compared. Because the issue\nbeing addressed concerns children with\nchronic hypoxemia, our analysis focused\non the 14 infants who had desaturations\nto 88\u201391% during sleep. The study\nrevealed that the rate of weight gain\nwas greater while the infants were\nreceiving supplemental oxygen than\nafter discontinuation (15.9 g\/kg\/d vs.\n3.7 g\/kg\/d; MD, 12.2 g\/kg\/d; 95% CI, 7.22\nto 17.18 g\/kg\/d).\nThe panel supplemented this study\nwith indirect evidence. Two studies enrolled\npatients with BPD who had ongoing high\noxygen requirements: one compared\nhemodynamics measured by right heart\ncatheterization during the inhalation of 80%\noxygen for 10 minutes with those measured\nduring the inhalation of room air for\n10 minutes (45), and the other compared\nhemodynamics measured during the\ninhalation oxygen targeting a PaO2\ngreater\nthan 120 mm Hg (.16 kPa) with those\nmeasured during the inhalation oxygen\ntargeting a PaO2\nof 55 to 120 mm Hg\n(7.33\u201316 kPa) (122). Meta-analysis found\nthat oxygen administration was associated\nwith lower mean pulmonary artery pressure\n(MD, 210.03 mm Hg [21.34 kPa]; 95% CI,\n216.41 to 23.64 mm Hg [22.19 to 20.49\nkPa]). Another study enrolled patients\nwith BPD who required oxygen to keep\ntheir SpO2\nabove 90% and compared\npolysomnography results while subjects\nbreathed either an extra 0.25 L\/min of\nsupplemental oxygen or their baseline\namount of oxygen (74). The higher amount\nAMERICAN THORACIC SOCIETY DOCUMENTS\ne12 American Journal of Respiratory and Critical Care Medicine Volume 199 Number 3 | February 1 2019\nof oxygen was associated with increased\ntotal sleep duration, increased REM sleep\nduration, and decreased REM arousals,\nalthough the values of each were not\nreported.\nThe panel had very low con\ufb01dence that\nthe estimated effects described above are\nthe same for HOT in patients with BPD\ncomplicated by chronic hypoxemia. The\ndirect evidence was derived from a single,\nsmall observational study. The indirect\nevidence derived estimates from small\nobservational studies that used short-term\noxygen or nocturnal HOT rather than\nHOT.\nBene\ufb01ts. In patients with BPD who\nhave chronic hypoxemia, HOT increased\nthe growth rate, short-term oxygen use\ndecreased the mean pulmonary artery\npressure, and nocturnal oxygen administration\nimproved sleep duration and decreased\narousals.\nHarms. No harms were reported in any\nof the studies.\nConclusions. The panel emphasized\nthat patients with chronic hypoxemia\ndue to BPD generally reach a phase in\ntheir medical care when they face two\nalternatives: receive long-term oxygen in\nthe hospital or at home. This occurs when\nother medical issues have stabilized but\naltered oxygenation levels are only slowly\nimproving. The panel was certain, despite\nits very low con\ufb01dence in the estimated\neffects, that the bene\ufb01ts of HOT exceed the\nharms, burdens, and cost. In addition to\nimproved growth, lower pulmonary artery\npressure, improved sleep duration, and\nfewer arousals from sleep, it enables the\npatient and family to be at home and\ndiminishes the likelihood of harm by\npreventing the nosocomial and iatrogenic\nconsequences of hospitalization. The\nstrength of the panel\u2019s recommendation is\nstrong because its primary intention is to\nprevent the harmful effects of prolonged\nhospitalization.\nWhat others are saying. The BTS\nclinical practice guidelines recommended\nHOT for infants with chronic neonatal\nlung disease, including BPD, because BTS\nsimilarly concluded that HOT improves\nmultiple clinical outcomes, is preferable to a\nprolonged hospital stay for quality of life and\npsychological impact, and enables earlier\ndischarge from the hospital (121). In the more\nrecent guidelines for pediatric PH published\nas a combined effort by the ATS with\nthe American Heart Association (AHA),\nsupplemental oxygen therapy was graded as\nreasonable to avoid episodic or sustained\nhypoxemia with a suggested goal of\nmaintaining SpO2\nbetween 92% and 95% in\nchildren with established BPD and\nPH (123).\nATS recommendation.\nd For patients with BPD complicated by\nchronic hypoxemia, we recommend\nthat HOT be prescribed (strong\nrecommendation, very low-quality\nevidence). Chronic hypoxemia is de\ufb01ned\nas either 1) greater than or equal to 5% of\nrecording time spent with an SpO2\nless\nthan or equal to 93% if measurements\nare obtained by continuous recording\nor 2) at least three separate \ufb01ndings\nof an SpO2\nless than or equal to 93%\nif measurements are obtained\nintermittently.\nQuestion 3: Should Children with\nSleep-disordered Breathing\nComplicated by Chronic Hypoxemia\nBe Treated with HOT?\nEvidence base. We identi\ufb01ed two studies\nthat compared nocturnal oxygen with no\noxygen therapy in children with SDB\ncomplicated by nocturnal hypoxemia\n(124, 125). One study was a randomized\ncrossover trial that enrolled children (mean\nage, 5 yr) who had suspected OSA plus\ndesaturation during sleep to less than 92%\n(124); the other study was an observational\nstudy that enrolled children (mean age,\n4.3 yr) who had tonsillar hypertrophy\nand desaturations during sleep to less\nthan 90% (125). Both studies compared\nthe effects of supplemental oxygen\nwith room air during sleep; one study\nprovided oxygen at a rate of 1 L\/min\n(124), and the other provided oxygen at a\nrate needed to keep the patient\u2019s SpO2\nabove\n95% (125).\nThe apnea index was the only outcome\nmeasured by both studies; when pooled by\nmeta-analysis, oxygen use during sleep was\nassociated with no change in the apnea\nindex (MD, 23 events\/h; 95% CI, 212.92\nto 16.68 events\/h). In single studies,\noxygen use during sleep was associated with\na higher mean SpO2\n(MD, 18.2%; 95% CI,\n15.58% to 110.82%), nadir SpO2\n(MD,\n120.7%; 95% CI, 111.29% to 130.11%),\nand nadir SpO2\nduring REM sleep (MD,\n19%; 95% CI, 11.57% to 116.43%). It was\nalso associated with trends toward a higher\nmean SpO2\nduring REM sleep (MD, 14%;\n95% CI, 20.16% to 18.16%), mean SpO2\nduring NREM sleep (MD, 13%; 95% CI,\n20.39% to 16.39%), and nadir SpO2\nduring\nNREM sleep (MD, 14%; 95% CI, 20.47%\nto 18.47%). There was no difference in the\nhypopnea index (MD, 23.8 events\/h; 95%\nCI, 219.32 to 111.72 events\/h) or changes\nin overall end-tidal PCO2 levels, although\nPCO2 increased signi\ufb01cantly in a few patients.\nThe panel\u2019s con\ufb01dence in the accuracy\nof these estimated effects in the patient\npopulation of interest to them was very low.\nThere was indirectness of the intervention\nbecause the question is about HOT\nprovided chronically at night, but the\nstudies used oxygen provided during a\nsingle night. There was also indirectness of\noutcomes because those assessed were all\nshort-term physiologic measures rather\nthan the long-term clinical outcomes that\nthe panel would have preferred. In addition,\nthe studies were small, and there was a risk\nof bias, because neither study reported\nenrolling consecutive patients and one\nstudy was not blinded.\nBene\ufb01ts. In patients with SDB with\nnocturnal desaturation, HOT during sleep\nincreased both the mean and nadir SpO2\nduring sleep.\nHarms. No harms were reported in any\nof the studies.\nConclusions. The panel concluded that\nthe bene\ufb01ts of HOT likely exceed the harms,\nburdens, and cost for the majority of\npatients with severe nocturnal hypoxemia\ndue to SDB who either cannot tolerate\npositive airway pressure therapy or are\nawaiting surgical treatment of their SDB.\nAlthough the studies above merely show\nthat giving oxygen increases oxygenation,\nthere is abundant evidence that improving\nnocturnal oxygenation by other means,\nsuch as positive airway pressure, mitigates\nadverse cardiopulmonary consequences of\nnocturnal hypoxemia in children. The panel\nhad no reason to suspect that relief of\nnocturnal hypoxemia by oxygen or positive\nairway pressure will lead to different\nconsequences.\nWhat others are saying. The BTS\nclinical practice guidelines emphasized\nthat positive airway pressure is the\ntherapy of choice for children with OSA;\nhowever, for children in whom application\nof positive airway pressure is not\npossible, the BTS recommended HOT\nbut urged monitoring of CO2 levels\nduring the initiation of oxygen therapy\n(121).\nAMERICAN THORACIC SOCIETY DOCUMENTS\nAmerican Thoracic Society Documents e13\nATS recommendation.\nd For patients with SDB complicated\nby severe nocturnal hypoxemia who\ncannot tolerate positive airway pressure\ntherapy or are awaiting surgical\ntreatment of SDB, we suggest that\nHOT be prescribed (conditional\nrecommendation, very low-quality\nevidence). Severe nocturnal hypoxemia is\nde\ufb01ned as greater than or equal to 5% of\nrecording time spent with a SpO2\nless\nthan 90% during sleep.\nQuestion 4: Should Children with\nSickle Cell Disease Complicated by\nChronic Hypoxemia Be Treated with\nHOT?\nEvidence base. Many studies reported\nassociations between hypoxemia and\noutcomes such as stroke and pain crises, but\nthey were excluded because they did not\ncompare use of oxygen with no oxygen\ntherapy. We identi\ufb01ed two observational\nstudies that evaluated patients before,\nduring, and after receiving supplemental\noxygen (126, 127). Both studies enrolled\npatients with SCD, but neither reported the\nages of the patients or the degree of\nchronic hypoxemia. One study of three\npatients administered oxygen at 5 L\/min\nby nasal prongs (126), and the other\nstudy of four patients administered\n70\u2013100% oxygen continuously for 8 to 20\ndays (127).\nMeasures of oxygenation increased\nduring oxygen therapy. In one study, the\nPaO2\nranged from 72 to 83 mm Hg (9.60 to\n11.07 kPa) before receiving supplemental\noxygen and from 146 to 175 mm Hg (19.47\nto 23.33 kPa) while receiving oxygen (126).\nIn the other study, which reported a single\nrepresentative patient only, the SpO2\nwas\n89% before the initiation of oxygen, 100%\nduring administration, and 83% after\ndiscontinuation (127). In both studies, the\nnumber and percentage of sickle cells\ndecreased during oxygen administration,\nalthough this was not accompanied by\nless hemolysis. The amount of sickle cells\nrebounded when the oxygen was discontinued,\nwith six of seven patients rebounding to\nhigher-than-baseline levels and the remaining\npatient rebounding to baseline levels (126,\n127). One study was terminated early because\ntwo of three patients developed pain crises\nafter discontinuation of the supplemental\noxygen, although none of the four patients in\nthe other study experienced a pain crisis (126).\nThe panel\u2019s con\ufb01dence in the accuracy\nof these estimated effects in the patient\npopulation of interest to them was very low.\nThere was indirectness of the intervention\nbecause the oxygen was provided at much\nhigher levels than current norms. In\naddition, there was a risk of bias for\nmultiple reasons: The studies were not\nblinded, did not report enrolling consecutive\npatients, and did not report all of the data\nthat were collected.\nBene\ufb01ts. Oxygen therapy increased\noxygenation and decreased the amount of\nsickle cells.\nHarms. After discontinuation of\ncontinuous oxygen, the amount of sickle\ncells rebounded to higher-than-baseline\nlevels, and some patients developed a pain\ncrisis.\nConclusions. The panel acknowledged\nthat the studies described above raise serious\nconcerns about the potential for harm if\noxygen is discontinued in patients with\nSCD. However, the panel had very low\ncon\ufb01dence in the \ufb01ndings owing to the\nstudies\u2019 small size (only seven patients\ntotal) and publication age (cointerventions\nwere different in 1944 and 1984).\nMoreover, the panel has collectively used\noxygen in hundreds of patients with SCD\nfor a variety of reasons without increases\nin sickle cell crises or acute chest\nsyndrome upon discontinuation, and it was\nconcerned about the untoward effects of\nallowing severe chronic hypoxemia to go\nunabated.\nWhat others are saying. The BTS\nclinical practice guidelines recommended\nHOT for children with SCD and persistent\nnocturnal hypoxemia to reduce stroke and\npain crises (121). Although the National\nHealth Service guidelines on SCD and\nthalassemia do not speci\ufb01cally make\nrecommendations related to supplemental\noxygen use, the need for guidance in the\ndelivery of oxygen therapy was suggested\n(128). In an evidence-based summary\nof the management of SCD, long-term\noxygen therapy was not addressed,\nbut maintenance of SpO2\nabove 95%\nwas strongly recommended during\nacute chest syndrome, and exchange\ntransfusion was recommended when\nthe SpO2\ndropped below 90% (129). In\npatients with SCD with concomitant\nPH, the pediatric PH guidelines\nsuggested optimization of therapies\nwith no speci\ufb01cs about oxygen therapy\n(123).\nATS recommendation.\nd For patients with SCD complicated by\nsevere chronic hypoxemia, we suggest\nthat HOT be prescribed (conditional\nrecommendation, very low-quality\nevidence). Severe chronic hypoxemia is\nde\ufb01ned as either 1) greater than or equal\nto 5% of recording time spent with an\nSpO2\nless than 90% if measurements are\nobtained by continuous recording or 2)\nat least three separate \ufb01ndings of an SpO2\nless than 90% if measurements are\nobtained intermittently.\nQuestion 5: Should Children with\nPulmonary Hypertension without\nCongenital Heart Disease Be Treated\nwith HOT?\nEvidence base. We identi\ufb01ed no studies\nthat compared the effects of HOT with\nno oxygen therapy in children with PH\ncomplicated by chronic hypoxemia. The\npanel discussed whether to review indirect\nevidence from adults but judged adults\nwith PH to be too indirect a population\nto inform recommendations in children.\nInstead, the panel decided to inform its\nrecommendations with their collective\nnonsystematic clinical observations derived\nfrom caring for many such patients over\nseveral decades. Nonsystematic clinical\nobservations give very low con\ufb01dence in the\nestimated effects.\nConclusions. The panel emphasized\nthat empirical evidence comparing HOT\nwith no oxygen therapy will never be\nforthcoming, because withholding HOT\nin such patients is ethically questionable.\nThe panel\u2019s collective clinical experience\nsuggests that children with chronic\nhypoxemia due to PH are less dyspneic\nand more active when receiving HOT.\nAlthough harmful consequences of HOT\nare infrequent, there can be effects on\nquality of life. Most important, the panel\nwas particularly certain about the\npotential of HOT to bene\ufb01t patients by\nmitigating the undesirable consequences\nof chronic hypoxemia because it directly\ninterrupts the vicious cycle of PH causing\nhypoxemia, which in turn worsens\nthe PH.\nWhat others are saying. The BTS\nclinical practice guidelines recommended\nHOT for children with idiopathic PH\ncomplicated by sleep-associated desaturations,\nfor children with idiopathic PH who have\nsevere hypoxemia, and for PH secondary to\nAMERICAN THORACIC SOCIETY DOCUMENTS\ne14 American Journal of Respiratory and Critical Care Medicine Volume 199 Number 3 | February 1 2019\npulmonary disease. They recommended\nagainst HOT for PH associated with cardiac\neffects, owing to lack of good evidence (121).\nIn comparison, the combined ATS and\nAHA guidelines on pediatric PH reported\nthat treatment of hypoxemia with oxygen\ntherapy was reasonable in children with\nPH who had an SpO2\nless than 92%, especially\nif associated with any concomitant lung\ndisease (123).\nATS recommendation.\nd For patients with PH without CHD\ncomplicated by chronic hypoxemia, we\nrecommend that HOT be prescribed\n(strong recommendation, very low-quality\nevidence). Chronic hypoxemia is de\ufb01ned\nas either 1) greater than or equal to 5% of\nrecording time spent with an SpO2\nless\nthan or equal to 93% if measurements are\nobtained by continuous recording or 2) at\nleast three separate \ufb01ndings of an SpO2\nless than or equal to 93% if measurements\nare obtained intermittently.\nQuestion 6: Should Children with\nPulmonary Hypertension with\nCongenital Heart Disease Be Treated\nwith HOT?\nEvidence base. We identi\ufb01ed no studies\nthat compared the effects of HOT with\nno oxygen therapy exclusively in children\nwith CHD. The only relevant study was\na nonrandomized trial of supplemental\noxygen for patients with PH in which 13\nof the 15 patients had CHD (130). Nine\npatients were assigned to receive HOT for\nat least 12 hours per day, and six patients\nwere assigned no HOT. The patients were\nfollowed for up to 5 years. Baseline values\nrevealed a trend toward higher SpO2\nin the\nHOT group (15%; 24.43% to 114.43%), a\ntrend toward lower pulmonary vascular\nresistance in the HOT group (27 mm\nHg\/min\/m2\n\/L; 95% CI, 13.67 to 217.67 mm\nHg\/min\/m2\n\/L), and no difference in the\npulmonary artery pressure. Mortality was\nlower among children who received HOT\n(0% vs. 83%; relative risk not estimable).\nExercise capacity and symptoms were\nreportedly measured by questionnaire, but\nthe results were not described. The study\nprovided very low con\ufb01dence in its estimated\neffects.\nBene\ufb01ts. HOT was associated with\nlower mortality and trends toward\ndecreased pulmonary vascular resistance\nand increased pulmonary blood \ufb02ow.\nHarms. No harms were reported in the\nstudy.\nConclusions. The panel acknowledged\nthat the evidence favored HOT but had very\nlow con\ufb01dence in the estimated effects,\nowing to the study design, potential bias,\nand imprecision. They also expressed\nconcern that in some patients with\nunrepaired CHD and signi\ufb01cant left-to-\nright shunt, increased pulmonary blood \ufb02ow\ncan be harmful rather than bene\ufb01cial.\nGenerally speaking, they strongly believed\nthat the \ufb01ne balance between the potential\nfor either bene\ufb01cial or harmful effects\ndictates that such patients be evaluated and\ntreated by clinicians with experience in\nmanaging such complicated patients. In\nchildren with surgically repaired CHD,\nhowever, concerns of high pulmonary blood\n\ufb02ow would not persist, and the effects\nof oxygen therapy to avoid hypoxemia,\nespecially in the setting of PH, are likely\ngreater than potential adverse effects.\nWhat others are saying. The BTS\nclinical practice guidelines recommended\nagainst HOT for cyanotic CHD unless\naccompanied by other respiratory problems.\nThey similarly recommended against HOT\nfor acyanotic CHD (121). The combined\nATS and AHA guidelines on pediatric PH\ndid not address oxygen therapy in children\nwith CHD and chronic hypoxemia (123).\nATS recommendation.\nd For patients with PH with CHD\ncomplicated by chronic hypoxemia,\nsupplemental oxygen will impact\nhemodynamics and physiology; we\nrecommend that HOT NOT be\ninitiated in these children, regardless\nof previous reparative or palliative\ncongenital heart surgery, until there\nhas been consultation with a pediatric\npulmonologist or cardiologist who\nhas expertise in the management\nof PH in this clinical setting (strong\nrecommendation, very low-quality\nevidence).\nQuestion 7: Should Children with\nInterstitial Lung Disease Complicated\nby Chronic Hypoxemia Be Treated\nwith HOT?\nEvidence base. We identi\ufb01ed no studies that\ncompared the effects of HOT with no oxygen\ntherapy in children with ILD complicated\nby chronic hypoxemia. The panel discussed\nwhether to review indirect evidence from adults\nbut judged adults with ILD to be too indirect\na population to inform recommendations in\nchildren. Instead, the panel decided to inform\nits recommendations with their collective\nnonsystematic clinical observations.\nNonsystematic clinical observations give\nvery low con\ufb01dence in the estimated effects.\nConclusions. The panel again\nemphasized that empirical evidence\ncomparing oxygen use with no oxygen\ntherapy will never be forthcoming, because\nwithholding HOT in such patients is ethically\nquestionable. The panel was certain that the\nbene\ufb01ts of HOT exceed the harms, burdens,\nand cost in patients with ILD with severe\nchronic hypoxemia (SpO2\n, ,90%). This was\nbased on the large number of bene\ufb01cial\noutcomes that they have observed in\ntheir clinical practices and the absence of\nharmful outcomes, decades of clinical\nexperience in managing many such patients,\nand recognition that prolonged chronic\nhypoxemia can contribute to serious health\nconsequences such as PH and cor pulmonale.\nThe panel also concluded that the bene\ufb01ts of\nHOT likely exceed the harms, burden, and\ncost in patients with ILD who have mild\nhypoxemia (SpO2\n90\u201393%) that is chronic,\naccompanied by sequelae of hypoxemia\n(e.g., dyspnea on exertion), or associated with\ndesaturation during sleep or exertion.\nWhat others are saying. The BTS\nclinical practice guidelines recommended\nHOT for children with ILD complicated\nby chronic hypoxemia who are otherwise\nready for hospital discharge (121). Although\nspeci\ufb01c recommendations for oxygen therapy\nwere not addressed, the recent guideline\non ILD in children recommended routine\nmeasurement of SpO2\nfor pediatric patients by\npulse oximetry, with supplemental oxygen\npotentially indicated during the day, during\nthe night, and with exercise for all children as\nwell as during feeding for infants (104).\nATS recommendations.\nd For patients with ILD complicated\nby severe chronic hypoxemia, we\nrecommend that HOT be prescribed\n(strong recommendation, very low-quality\nevidence). Severe chronic hypoxemia is\nde\ufb01ned as either 1) greater than or equal\nto 5% of recording time spent with an\nSpO2\nless than 90% if measurements are\nobtained by continuous recording or 2)\nat least three separate \ufb01ndings of an SpO2\nless than 90% if measurements are obtained\nintermittently.\nd For patients with ILD who have both\nmild chronic hypoxemia and either\ndyspnea on exertion or desaturation\nAMERICAN THORACIC SOCIETY DOCUMENTS\nAmerican Thoracic Society Documents e15\nduring sleep or exertion, we suggest\nthat HOT be prescribed (conditional\nrecommendation, very low-quality\nevidence). Mild chronic hypoxemia is\nde\ufb01ned as either 1) greater than or equal\nto 5% of recording time spent with\nan SpO2\n90\u201393% if measurements are\nobtained by continuous recording or 2)\nat least three separate \ufb01ndings of an SpO2\n90\u201393% if measurements are obtained\nintermittently.\nProviding HOT\nEvidence-based data that address the\noptimal modalities of home oxygen\ndelivery and monitoring in the pediatric\npopulation are limited. Although an in-\ndepth discussion of speci\ufb01c delivery and\nmonitoring methods is beyond the scope of\nthis guideline, panel members identi\ufb01ed\nimportant considerations for equipment\nchoice, including the patient\u2019s age, size,\nand developmental stage, as well as the\nrequired \ufb02ow rate. Furthermore, equipment\nchoices should remain under appropriate\nsupervision.\nEquipment\nd All children require access to age-\nappropriate equipment and supplies\nthat will meet their supplemental\noxygen needs. These items should be\nreimbursed by insurers to ensure safe\nand effective delivery of oxygen in the\nhome. The prescriber should recognize\nthat there is currently signi\ufb01cant geographic\nvariability in access to and reimbursement\nfor pediatric patient\u2013speci\ufb01c equipment.\nd Oxygen concentrators are one of the\nmost commonly used delivery systems\nin the home and may be stationary or\nportable, whereas tanks may be more\nreadily available according to local\npreferences. The stationary devices are\nlarge and require reliable sources of\nelectricity. In areas where power outages\nare common, backup generators or\nalternative sources of oxygen are\nrequired. There are various types of\nconcentrators available, with \ufb02ows most\ncommonly ranging from 1 to 5 L\/min,\nproviding up to FIO2\n0.95 (131).\nd Children require access to low-\ufb02ow\ndelivery systems. Low-\ufb02ow meters\nshould be used to deliver \ufb02ows ranging\nfrom 0.1 to 1 L\/min for infants and\nyoung children (121). Some equipment\ncompanies have low-\ufb02ow concentrators\navailable to provide oxygen at 0.1 L\/min\nwithout the use of a \ufb02owmeter.\nd Size-adequate oxygen cylinders can be\nused in infants and small children as\nthe primary source of home oxygen if\n\ufb02ow rates are low (,0.3 L\/min) and\nif the duration of oxygen therapy is\nexpected to be limited to a few months\n(121).\nd Portability of equipment is an important\nconcern for pediatric patients. Continuous\n\ufb02ow portable concentrators are small\nand may be battery operated to allow\nfor increased mobility. Adaptation for\nstrollers and\/or wheelchairs should be\nconsidered (132). Lightweight cylinders\nallow for easier mobility, though\nthey do not last as long as standard\ncylinders outside the home. If using\na stationary oxygen system (e.g.,\nconcentrator, tanks) at home, a\nportable system is necessary to allow\nfor travel to school, medical visits, and\nso forth.\nd Pulse oxygen delivery systems (also\ncalled \u201coxygen conserver devices\u201d)\nare used in adult patients to restrict\noxygen administration to the period of\ninspiration, thereby avoiding the waste of\noxygen delivery during exhalation and\nassuring a consistent dose of oxygen per\nbreath, regardless of respiratory rate.\nVarying by device, this technology relies\non pressure, volume, or time to trigger\noxygen release (131). Because of higher\nrespiratory rates and low inspiratory\nvolumes in children, pulse oxygen\ndelivery systems should not be used\nin infants or young children, although\nthey can be considered for use in\nadolescents (121).\nd Humidi\ufb01cation of the oxygen circuit\nshould be provided for \ufb02ow rates above\n1 L\/min and can be achieved through\ncold bubble or heated humidi\ufb01cation\ndevices (121). A bene\ufb01t to humidi\ufb01cation\nof low-\ufb02ow oxygen therapy (,1 L\/min)\nhas not been clearly established (133).\nd The addition of humidi\ufb01cation (or\nother modi\ufb01cations to the original\ncircuit) may alter \ufb02ow delivery.\nAppropriate equipment (such as a gas\n\ufb02owmeter device) should be available\nfor families to monitor \ufb02ow delivery.\nd Home oxygen is typically delivered\nvia nasal cannula in the pediatric\npopulation. The delivered FIO2\nis\ndependent on the \ufb02ow through the\nprongs, the level of entrainment, and\nthe child\u2019s tidal volume, with the delivered\nFIO2\nranging from 0.22 to 0.95 at a\nmaximum \ufb02ow of 2 L\/min (134, 135).\nCannulae should be appropriately secured\nto the face to prevent skin breakdown and\nshould be replaced as often as weekly if\nrequired. The prescribers should be\nproactive in delineating the appropriate\noxygen delivery interface to minimize the\nrisk of equipment-related complications,\nwith special attention to maintaining skin\nintegrity. Older patients or those not\ntolerating nasal cannulas with a higher\noxygen \ufb02ow rates may opt for the use of\nan appropriate oxygen mask, although\nmore variability in FIO2\nbased on mask\npositioning and patient tidal volume may\nbe present (134).\nd Increased storage ef\ufb01ciency and\nportability have made liquid oxygen an\nattractive option for the adult population\n(131). Liquid oxygen cannot currently be\ndelivered using continuous \ufb02ows less\nthan 0.25 L\/min (121) and may not\nbe readily available. Storage of liquid\noxygen is not ef\ufb01cient for those needing\nintermittent supplemental oxygen.\nd The high-\ufb02ow nasal cannula has the\nability to deliver much higher \ufb02ow\nrates at varying oxygen concentrations.\nAlthough not routinely used in the\npediatric home setting, there are reports\nof successful cases using outpatient high-\n\ufb02ow nasal cannulas for hypoxemia\nsecondary to OSA (136) and tracheomalacia\n(137).\nMonitoring\nArterial blood gas measurements are not\nroutinely used to assess oxygenation in\nclinically stable children with chronic\ndiseases, owing to pain and discomfort\nfrom arterial puncture. Pulse oximetry\nis the primary method of monitoring\nSpO2\nin the pediatric population. The\noximeter measures red and infrared\nlight absorption of oxygenated and\ndeoxygenated hemoglobin to estimate the\nSpO2\n(138). Oximetric measurements have\ngenerally been shown to correlate at 2\u20133%\nabove measured arterial saturation, with\naccuracy worsening when SpO2\nmeasures\nbelow 90% (139). Some limitations to\naccurate SpO2\ndeterminations with pulse\noximeters include improper probe\nplacement, movement artifact, nail color,\nambient light, reduced distal extremity\nAMERICAN THORACIC SOCIETY DOCUMENTS\ne16 American Journal of Respiratory and Critical Care Medicine Volume 199 Number 3 | February 1 2019\nperfusion, hypothermia, skin pigmentation,\nand dysfunctional hemoglobin (134, 140).\nThe use of in-home pulse oximetry for\nlong-term monitoring of HOT in children\nis unanimously endorsed by the panel.\nSuch monitoring can alert caregivers to\ninterruptions in oxygen delivery that may\nsuggest clinical deterioration or the need\nfor clinical intervention such as airway\nsuctioning, patient repositioning, and so\nforth (141\u2013146). The panelists recognize the\nlimitations of the literature on in-home\npulse oximetry use in the care of children,\nso further research is recommended to\nidentify best practice of this valuable\nmedical equipment that has its own\ndrawbacks. During times of illness,\npulse oximetry can provide important\ninformation to the caregiver, potentially\ndecreasing the need for visits to the\nemergency department (147). The presence\nof a pulse oximeter can also identify\nreduced SpO2\nduring periods of exertion or\nduring infant feeding. However, concerns\nregarding home oximetry monitoring\ninclude the nuisance of frequent alarms,\nincreased caregiver anxiety, and the\npotential for overreliance by caregivers on\nnormal SpO2\nversus overall clinical status\n(121). Because SpO2\nis only one facet of a\npatient\u2019s clinical status, pediatric patients\nwith increased work of breathing and\npotential hypoventilation need to be\nassessed by a clinician, regardless of SpO2\n.\nWith the panel recommending the\nmonitoring of children on HOT with\npulse oximetry in the home, appropriate\ncaregiver training is required for its use and\napplication. Such training should include an\nunderstanding of when to apply the pulse\noximeter and how to interpret the\nmeasurements obtained. It is of great\nimportance that pediatric patient\u2013speci\ufb01c\nsensors be prescribed by healthcare providers.\nHome Safety\nAssurance of safety and support of all\nchildren and adolescents on HOT should be\na priority. Home caregiver education should\naddress appropriate management of the\nequipment and skills to interpret and\nrespond to abnormal SpO2\nmeasurements\nwhile applying these data to the clinical\nstatus of the child. Education regarding\nthe risks of smoking and open \ufb02ames in\nthe home, as well as the use of oil-based\nproducts or other fuels near the oxygen\nsource, should be provided (121, 134,\n140). The focus on the dangers of smoke\nexposure should include the \ufb02ammability\nof compressed oxygen and the known\nharms that inhaled smoke imparts to\ngrowing infants and children. The\npanel recommends documentation of\ncompetency in the delivery of HOT to\na child once all home caregivers have\ncompleted education. It is also imperative\nto ensure access to reliable electricity and a\ntelephone in case of emergencies (121).\nCommunication between the prescribing\nhealthcare provider, durable medical\nequipment agency, and other key parties is\nimportant to provide appropriate care to\nthese medically complex patients.\nFollow-up\nRegular follow-up with a healthcare\nprovider is required for children on\nHOT, because repeated assessment of\noxygen needs and changes in respiratory\nstatus should be performed. An outpatient\ncontinuous pulse oximetry study (nocturnal\nor daytime) can provide a more complete\nand objective assessment of SpO2\nthan what\ncan be obtained by parental report and\nevaluation in a clinic setting. In addition to\nSpO2\n, feeding patterns and growth, together\nwith activity tolerance, should be assessed.\nAny concern of hypoventilation\nshould be investigated with capillary\nblood gas analysis or serum bicarbonate\ndetermination, which are widely available,\nor with end-tidal or transcutaneous\nCO2 measurements, which are often\nimmediately available in hospital settings\nbut not readily available in an outpatient\nsetting or in the home. Although each of\nthese methods has its limitations (148),\nthey all have the potential for more\nwidespread use in the future. Depending\non the clinical scenario, a more de\ufb01nitive\nevaluation with polysomnography may be\nnecessary.\nDiscontinuation of HOT\nAlthough some conditions may warrant\ninde\ufb01nite HOT, improvements in\nrespiratory function that occur with age,\nmaturation, treatment, clinical course, and\nso forth can lead to an opportunity to wean\n(progressively decrease) or discontinue\n(stop altogether) HOT. Improvements in\nrespiratory status amenable to weaning\nof oxygen therapy are most applicable\nto infants with chronic lung disease of\nprematurity, but a standardized approach\nmay nonetheless be helpful in other\npopulations. Criteria for the justi\ufb01cation\nand initiation of HOT are outlined by CMS,\nbut weaning or discontinuation is not.\nAlthough many healthcare providers reduce\nor wean supplemental oxygen in the\noutpatient setting gradually and with the\nguidance of nocturnal oxygen assessments\n(121, 149\u2013152), there are no widely\naccepted, evidence-based guidelines, and\nfew report using a standardized protocol\n(149). The panel unanimously agrees\nthat a large, prospective trial comparing\nweaning strategies is needed. Nonetheless, we\ndescribe a consensus-based approach to\nidentifying patient readiness for weaning and\ndiscontinuation of HOT, the process for\ndoing so, and the monitoring necessary\nto determine its safety and tolerance. The\nuse, weaning, or discontinuation of other\ntherapies (e.g., diuretics in BPD) is outside the\nscope of this guideline, although providers are\ncautioned to avoid making multiple abrupt\nchanges in treatment at one time.\nAssessing Readiness\nAs previously mentioned, the measurement\nof arterial blood for PaO2\nis not practical\nfor routine outpatient monitoring of a\nchild\u2019s respiratory status; therefore, pulse\noximetry to monitor SpO2\nis standard for\nthe purposes of analyzing gas exchange. A\nchild may be considered appropriate for\nweaning of HOT if the following criteria\nare met, which are based on this panel\u2019s\nconsensus opinion and shaped by an earlier\nsurvey of pediatric pulmonologists (150):\nd Reassuring medical examination by a\nquali\ufb01ed healthcare provider that takes\ninto account the child\u2019s underlying\nmedical condition(s), gestational age,\ncondition-speci\ufb01c growth charts, home\naltitude, and so forth; ideally, the\nexamination should meet these criteria:\n\u2218 Period of relatively stable health (no\ncurrent or recent acute illness)\n\u2218 Age- and condition-appropriate\ngrowth, including positive trends in\nweight gain, linear growth, and head\ncircumference\n\u2218 Meeting developmental milestones as\nexpected for clinical condition, where\nfactors that may in\ufb02uence development,\nsuch as prematurity, concurrent\nsyndrome, perinatal neurodevelopmental\ninsult, and so forth, must be considered\n\u2218 Acceptably low frequency and\/or severity\nof illnesses requiring hospitalization\nAMERICAN THORACIC SOCIETY DOCUMENTS\nAmerican Thoracic Society Documents e17\n\u2218 Physical examination not suggestive of\nimpaired respiratory function (breathing\neffort, respiratory rate, and so forth are\nas expected for clinical course)\nd Reassuring objective measurement of\noxygenation, in which the following\nshould be considered:\n\u2218 Oxygen saturation measured at steady\nstate (not \u201cspot checked\u201d) by continuous\npulse oximetry in room air meets\npatient-speci\ufb01c goal.\n\u2218 Unfortunately, wakeful pulse oximetry\ndid not correlate with nocturnal\noxygenation in a population of premature\ninfants with BPD (121). Brief pulse\noximetry during wakefulness alone may\nbe appropriate for some patients, whereas\nothers may require monitoring during\nfeeding and\/or while asleep with an\novernight, in-home pulse oximetry study.\n\u2218 In general, the same oxygenation goals\nthat prompted initiation of HOT should\nbe used.\nd Depending on the underlying process,\nconsider an echocardiogram to demonstrate\nabsence of or improvement in \ufb01ndings\nsuggestive of PH or right heart strain (e.g.,\nnormal or improving estimation of right\nventricular pressure, lack of ventricular\nseptal \ufb02attening)\nWeaning of HOT\nOnce readiness for weaning of HOT is\ndetermined, it is suggested either to decrease\noxygen \ufb02ow rate gradually or to withdraw its\nuse during certain periods of the day. Some\nchildren may tolerate a reduction from\naround-the-clock home oxygen to nocturnal\nuse only, whereas infants and other children\nwith special circumstances may need to\ncontinue HOT with certain daytime activities\n(e.g., car rides, naps, during feeding).\nWhen gradually decreasing the oxygen\n\ufb02ow rate, it is practical to wean by halving\nbecause conventional home oxygen delivery\ndevices easily allow for this (1 L\/min to\n0.5 L\/min then 0.25 L\/min, and so forth)\nbefore room air challenges. We suggest\nweaning the \ufb02ow rate gradually over the\ncourse of weeks while frequently monitoring\nfor adverse effects. This should include\nregular (weekly to monthly) visits with a\nquali\ufb01ed healthcare provider to assess the\nchild as outlined above.\nSuccessful Discontinuation of HOT\nOnce the child has tolerated weaning\nHOT to a suf\ufb01ciently low \ufb02ow rate, then\ndiscontinuation can be considered. Preterm\nneonates with BPD had more successful\nroom air challenges and clinical stability at\n6 months postdischarge if previously stable\nreceiving less than or equal to 20 ml\/kg\/min\nof oxygen (153). By consensus, the panel\nrecommended that room air challenges be\nconsidered for clinically stable children\nunder 1 year of age receiving less than\n0.1 L\/min and children up to preschool age\nreceiving 0.1\u20130.25 L\/min. By extrapolation,\na \ufb02ow rate less than 0.25\u20130.5 L\/min could\nbe considered for school-age and older\nchildren. With HOT occurring in terms\nof \ufb02ow rate, it is not pertinent to wean or\ndiscontinue oxygen use on the basis of FIO2\n.\nOnce a patient is considered ready\nfor discontinuation of nighttime HOT\naltogether, then an in-home, room air,\nnocturnal pulse oximetry study should be\nperformed using appropriate pediatric\nequipment and reference ranges as outlined\nin this document. Healthcare providers\nshould encourage families to maintain\naccessibility to HOT for several months after\ndiscontinuation, particularly through the\nwinter season, when viral illnesses are\nprevalent. This allows for ample opportunity\nto determine whether the withdrawal of\nHOT was well timed, in addition to how well\nrespiratory illnesses are tolerated without\nsupplemental oxygen.\nAs suggested when assessing for\npatient readiness to wean HOT, it is\nnecessary to monitor responses to each\nchange repeatedly. Given the chronicity of\nthese respiratory conditions, changes should\nbe made on a weeks to months basis,\nas opposed to more quickly, so that\nsubtle deterioration is not missed and\nsuboptimal therapy is promptly reversed.\nThe factors to monitor re\ufb02ect those assessed\nwhen considering patient readiness and\ninclude patient growth, development,\ncardiorespiratory status, and stability of\nhealth (e.g., handling of respiratory illnesses,\ntravel to altitude).\nHOT and its necessary equipment are\noften burdensome and costly. However,\nhome caregivers and healthcare providers\nare reminded that the processes treated\nby HOT are chronic in nature, its use is\nlow risk, and patience is often rewarded.\nConversely, weaning HOT too soon or too\nabruptly can lead to patient and home\ncaregiver stress.\nConclusions\nDespite widespread use of HOT in children\nfor various lung and pulmonary vascular\ndiseases, there is a striking paucity of data\nregarding its implementation, ef\ufb01cacy,\nmonitoring, and discontinuation. With\nlimited evidence, the panel provides\nrecommendations based on expert opinion\nand experiences associated with patient-\nimportant outcomes that will aid clinicians\nin the management of complex pediatric\npatients requiring HOT. Future research\nshould address important areas including\nSpO2\nlevels associated with optimal growth\nand development and the identi\ufb01cation of\nbest practice for weaning and discontinuing\nHOT in children. n\nThis official clinical practice guideline was prepared by an ad hoc subcommittee of the ATS Assembly on Pediatrics.\nMembers of the subcommittee are as\nfollows:\nDON HAYES, JR., M.D., M.S., M.ED.1\n(Co-Chair)\nROBIN R. DETERDING, M.D.2\n(Co-Chair)\nSTEVEN H. ABMAN, M.D.2\n*\u2021\nJOYCE BAKER, M.B.A., R.R.T.-N.P.S.,\nA.E.-C.2x\nIAN M. BALFOUR-LYNN, M.D.3jj\nCHRISTOPHER L. CARROLL, M.D.4{\nMARY E. CATALETTO, M.D.5\n**\nANN GETTYS\n\u2021\u2021\nDAVID GOZAL, M.D., M.B.A.6\n*xx\nSTEPHEN M. M. HAWKINS, M.D.2jjjj\nTIMOTHY M. HOFFMAN, M.D.7{{\nDEBORAH KALEY, R.N., M.S.N., A.E.-C.8\n***\nKATELYN KRIVCHENIA, M.D.1\u2021\u2021\u2021\nGEOFFREY KURLAND, M.D.9\n*\nRICHARD J. MARTIN, M.D.10xxx\nEYAL OREN, PH.D., M.S.11\n**\nHOWARD B. PANITCH, M.D.12\n*\nGREGORY R. PORTA\n13\u2021\u2021\nLAWRENCE M. RHEIN, M.D., M.P.H.14\n*xxx\nMARK L. SPLAINGARD, M.D.1\n*xx\nDMITRY TUMIN, PH.D.1jjjjjj\nKEVIN C. WILSON, M.D.15,16\n**{{{\nAMERICAN THORACIC SOCIETY DOCUMENTS\ne18 American Journal of Respiratory and Critical Care Medicine Volume 199 Number 3 | February 1 2019\n*Pediatric pulmonary representative.\n\u2021\nPulmonary hypertension representative.\nx\nRespiratory therapy representative.\njj\nInternational representative.\n{\nPediatric critical care representative.\n**Methodologist.\n\u2021\u2021\nPatient representative.\nxx\nSleep medicine representative.\njjjj\nPediatric sleep medicine fellow representative.\n{{\nPediatric cardiology representative.\n***Nursing representative.\n\u2021\u2021\u2021\nPediatric pulmonary fellow representative.\nxxx\nNeonatology representative.\njjjjjj\nSociology and population health\nrepresentative.\n{{{\nProject manager.\n1\nDepartment of Pediatrics, The Ohio State\nUniversity College of Medicine, Nationwide\nChildren\u2019s Hospital, Columbus, Ohio;\n2\nDepartment of Pediatrics, University of\nColorado School of Medicine, Children\u2019s\nHospital Colorado, Denver, Colorado;\n3\nPediatric Respiratory Medicine, Royal\nBrompton Hospital, London, United\nKingdom; 4\nDepartment of Pediatrics,\nConnecticut Children\u2019s Medical Center,\nHartford, Connecticut; 5\nDepartment of\nPediatrics, Stony Brook University School\nof Medicine, Stony Brook, New York;\n6\nDepartment of Child Health, University of\nMissouri School of Medicine, Columbia,\nMissouri; 7\nDepartment of Pediatrics, University\nof North Carolina School of Medicine, Chapel\nHill, North Carolina; 8\nLucile Packard Children\u2019s\nHospital at Stanford, Palo Alto, California;\n9\nDepartment of Pediatrics, University of\nPittsburgh School of Medicine, Children\u2019s\nHospital of Pittsburgh, Pittsburgh,\nPennsylvania; 10\nDepartment of Pediatrics,\nCase Western Reserve University School of\nMedicine, Cleveland, Ohio; 11\nDivision of\nEpidemiology and Biostatistics, San Diego\nState University School of Public Health, San\nDiego, California; 12\nDepartment of Pediatrics,\nUniversity of Pennsylvania Perelman School of\nMedicine, Children\u2019s Hospital of Philadelphia,\nPhiladelphia, Pennsylvania; 13\nChildren\u2019s\nInterstitial Lung Disease Foundation Inc.,\nCincinnati, Ohio; 14\nDepartment of Pediatrics,\nUniversity of Massachusetts Medical School,\nWorcester, Massachusetts; 15\nDepartment\nof Medicine, Boston University School of\nMedicine, Boston, Massachusetts; and\n16\nAmerican Thoracic Society, New York,\nNew York\nAuthor Disclosures: R.R.D. served on an\nadvisory committee for Boehringer Ingelheim\nand ListenMD; served as a speaker for\nNovartis; received royalties from Elsevier\nPublishing; held a patent for a Personalized\nHealth Care Wearable Sensor System; had\npatents pending for Systems and Methods for\nDetermining Vital Information with a Computing\nDevice, for a Pediatric Nasal Endoscope, for a\nRespiration Rate Measurement System, and\nfor a Tongue Localization, Teeth Interaction,\nand Detection System; served as consultant\nfor, and had ownership or investment interests\nand other intellectual property with,\nTripleEndoscopy Inc.; and had ownership or\ninvestment interests and royalties, licensing\nfees, or other sales proceeds with Now\nVitals Inc. S.H.A. received research support\nfrom Shire Pharmaceuticals and United\nTherapeutics; and served on an advisory\ncommittee for Shire Pharmaceuticals. M.E.C.\nserved as editor-in-chief for and received\nan honorarium from Pediatric Allergy,\nImmunology, and Pulmonology; served as an\nassociate editor for the American Academy of\nPediatrics, Pediatric Pulmonology: A Manual\nfor Primary Care; and served as an editor for\nStatPearls. R.J.M. served on a data safety\nmonitoring board for CareFusion and Windtree\nTherapeutics. H.B.P. served on an advisory\ncommittee for Philips Respironics; and\nreceived royalties from UpToDate. K.C.W.\nreported employment by the American\nThoracic Society as Chief of Documents and\nPatient Education and Documents Editor and\nderived salary support from these roles, and\nas such he has a personal financial interest\nin the quality of all ATS clinical practice\nguidelines. D.H., J.B., I.M.B.-L., C.L.C., A.G.,\nD.G., S.M.M.H., T.M.H., D.K., K.K., G.K., E.O.,\nG.R.P., L.M.R., M.L.S., and D.T. reported\nno relationships with relevant commercial\ninterests.\nAcknowledgment: This official document\nwas prepared by a subcommittee of the\nAssembly on Pediatrics. The members of the\nclinical practice guideline panel on home oxygen\ntherapy for children thank Kimberly Lawrence\nfor the excellent and thoughtful job she did in\norganizing this panel, which was invaluable for the\ngeneration of this document.\nReferences\n1. Centers for Medicare & Medicaid Services. National coverage\ndetermination (NCD) for home use of oxygen [accessed 2018\nMay 8]. Available from: https:\/\/www.cms.gov\/medicare-coverage-\ndatabase\/details\/ncd-details.aspx?NCDId=169&ncdver=\n1&DocID=240.2&SearchType=Advanced&bc=IAAAABAAAAAA&.\n2. Nocturnal Oxygen Therapy Trial Group. 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Montgomery M, Wiebicke W, Bibi H, Pagtakhan RD, Pasterkamp H.\nHome measurement of oxygen saturation during sleep in patients\nwith cystic \ufb01brosis. Pediatr Pulmonol 1989;7:29\u201334.\n142. Uyan ZS, Ozdemir N, Ersu R, Akpinar I, Keskin S, Cakir E, et al.\nFactors that correlate with sleep oxygenation in children with cystic\n\ufb01brosis. Pediatr Pulmonol 2007;42:716\u2013722.\n143. Ge\u0301linas JF, Davis GM, Arlegui C, Co\u0302te\u0301 A. Prolonged, documented\nhome-monitoring of oxygenation in infants and children. Pediatr\nPulmonol 2008;43:288\u2013296.\nAMERICAN THORACIC SOCIETY DOCUMENTS\ne22 American Journal of Respiratory and Critical Care Medicine Volume 199 Number 3 | February 1 2019\n144. O\u0308hman A, Stro\u0308mvall-Larsson E, Nilsson B, Mellander M. Pulse\noximetry home monitoring in infants with single-ventricle physiology\nand a surgical shunt as the only source of pulmonary blood \ufb02ow.\nCardiol Young 2013;23:75\u201381.\n145. Needleman JP, Franco ME, Varlotta L, Reber-Brodecki D, Bauer N,\nDampier C, et al. Mechanisms of nocturnal oxyhemoglobin\ndesaturation in children and adolescents with sickle cell disease.\nPediatr Pulmonol 1999;28:418\u2013422.\n146. Barratt CW, Vyas H, Hayes-Gill BR, Crowe JA, Flatman D. Detection\nof previously unrecognized daytime desaturation in children with\nchronic lung disease. J Med Eng Technol 2007;31:101\u2013108.\n147. Allen J, Zwerdling R, Ehrenkranz R, Gaultier C, Geggel R, Greenough\nA, et al.; American Thoracic Society. Statement on the care of the\nchild with chronic lung disease of infancy and childhood. Am J\nRespir Crit Care Med 2003;168:356\u2013396.\n148. Smallwood CD, Walsh BK. Noninvasive monitoring of oxygen and\nventilation. Respir Care 2017;62:751\u2013764.\n149. Fitzgerald DA, Massie RJ, Nixon GM, Jaffe A, Wilson A, Landau LI,\net al.; Thoracic Society of Australia and New Zealand. Infants with\nchronic neonatal lung disease: recommendations for the use of\nhome oxygen therapy. Med J Aust 2008;189:578\u2013582.\n150. Palm K, Simoneau T, Sawicki G, Rhein L. Assessment of current\nstrategies for weaning premature infants from supplemental\noxygen in the outpatient setting. Adv Neonatal Care 2011;11:\n349\u2013356.\n151. Silva DT, Hagan R, Sly PD. Home oxygen management of neonatal\nchronic lung disease in Western Australia. J Paediatr Child Health\n1995;31:185\u2013188.\n152. Yeh J, McGrath-Morrow SA, Collaco JM. Oxygen weaning after\nhospital discharge in children with bronchopulmonary dysplasia.\nPediatr Pulmonol 2016;51:1206\u20131211.\n153. Simoes EA, Rosenberg AA, King SJ, Groothuis JR. Room air challenge:\nprediction for successful weaning of oxygen-dependent infants.\nJ Perinatol 1997;17:125\u2013129.\nAMERICAN THORACIC SOCIETY DOCUMENTS\nAmerican Thoracic Society Documents e23","pure_content":"AMERICAN THORACIC SOCIETY\nDOCUMENTS\nHome Oxygen Therapy for Children\nAn Of\ufb01cial American Thoracic Society Clinical Practice Guideline\nDon Hayes, Jr., Kevin C. Wilson, Katelyn Krivchenia, Stephen M. M. Hawkins, Ian M. Balfour-Lynn, David Gozal,\nHoward B. Panitch, Mark L. Splaingard, Lawrence M. Rhein, Geoffrey Kurland, Steven H. Abman, Timothy M. Hoffman,\nChristopher L. Carroll, Mary E. Cataletto, Dmitry Tumin, Eyal Oren, Richard J. Martin, Joyce Baker, Gregory R. Porta,\nDeborah Kaley, Ann Gettys, and Robin R. Deterding; on behalf of the American Thoracic Society Assembly on\nPediatrics\nTHIS OFFICIAL CLINICAL PRACTICE GUIDELINE OF THE AMERICAN THORACIC SOCIETY WAS APPROVED DECEMBER 2018\nBackground: Home oxygen therapy is often required in children\nwith chronic respiratory conditions. This document provides an\nevidence-based clinical practice guideline on the implementation,\nmonitoring, and discontinuation of home oxygen therapy for the\npediatric population.\nMethods: A multidisciplinary panel identi\ufb01ed pertinent questions\nregarding home oxygen therapy in children, conducted systematic\nreviews of the relevant literature, and applied the Grading of\nRecommendations, Assessment, Development, and Evaluation\napproach to rate the quality of evidence and strength of clinical\nrecommendations.\nResults: After considering the panel\u2019s con\ufb01dence in the estimated\neffects, the balance of desirable (bene\ufb01ts) and undesirable (harms\nand burdens) consequences of treatment, patient values and\npreferences, cost, and feasibility, recommendations were developed\nfor or against home oxygen therapy speci\ufb01c to pediatric lung and\npulmonary vascular diseases.\nConclusions: Although home oxygen therapy is commonly\nrequired in the care of children, there is a striking lack of\nempirical evidence regarding implementation, monitoring, and\ndiscontinuation of supplemental oxygen therapy. The panel\nformulated and provided the rationale for clinical recommendations\nfor home oxygen therapy based on scant empirical evidence,\nexpert opinion, and clinical experience to aid clinicians in the\nmanagement of these complex pediatric patients and identi\ufb01ed\nimportant areas for future research.\nKeywords: children; home; hypoxemia; oxygen\nAn Executive Summary of this document is available at http:\/\/www.atsjournals.org\/doi\/suppl\/10.1164\/rccm.201812-2276ST.\nORCID IDs: 0000-0002-6734-6052 (D.H.); 0000-0003-4429-2263 (K.C.W.); 0000-0002-0754-3863 (I.M.B.-L.); 0000-0001-8195-6036 (D.G.);\n0000-0001-8440-283X (H.B.P.); 0000-0002-1361-4947 (M.L.S.); 0000-0001-7817-3516 (E.O.).\nYou may print one copy of this document at no charge. However, if you require more than one copy, you must place a reprint order. Domestic reprint orders:\namy.schriver@sheridan.com; international reprint orders: louisa.mott@springer.com.\nCorrespondence and requests for reprints should be addressed to Don Hayes, Jr., M.D., M.S., The Ohio State University, Nationwide Children\u2019s Hospital, 700\nChildren\u2019s Drive, Columbus, OH 43205. E-mail: hayes.705@osu.edu.\nThis article has an online supplement, which is accessible from this issue\u2019s table of contents at www.atsjournals.org.\nAm J Respir Crit Care Med Vol 199, Iss 3, pp e5\u2013e23, Feb 1, 2019\nCopyright \u00a9 2019 by the American Thoracic Society\nDOI: 10.1164\/rccm.201812-2276ST\nInternet address: www.atsjournals.org\nAmerican Thoracic Society Documents e5\nContents\nSummary of Recommendations\nCystic Fibrosis\nBronchopulmonary Dysplasia\nSleep-disordered Breathing\nSickle Cell Disease\nPulmonary Hypertension without\nCongenital Heart Disease\nPulmonary Hypertension with\nCongenital Heart Disease\nInterstitial Lung Disease\nImplementation\nIntroduction\nMethods\nDe\ufb01nition of Hypoxemia\nChildren Younger Than 1 Year Old\nChildren Aged 1 Year Old and\nOlder\nConsequences of Untreated\nHypoxemia\nPulmonary Circulation\nNeurodevelopment and\nCognition\nSleep\nGrowth\nIndications for HOT\nQuestion 1: Should Children with\nCystic Fibrosis Complicated by\nChronic Hypoxemia Be Treated\nwith HOT?\nQuestion 2: Should Children with\nBronchopulmonary Dysplasia\nComplicated by Chronic\nHypoxemia Be Treated with\nHOT?\nQuestion 3: Should Children with\nSleep-disordered Breathing\nComplicated by Chronic\nHypoxemia Be Treated with\nHOT?\nQuestion 4: Should Children with\nSickle Cell Disease Complicated\nby Chronic Hypoxemia Be\nTreated with HOT?\nQuestion 5: Should Children with\nPulmonary Hypertension\nwithout Congenital Heart\nDisease Be Treated with HOT?\nQuestion 6: Should Children with\nPulmonary Hypertension with\nCongenital Heart Disease Be\nTreated with HOT?\nQuestion 7: Should Children with\nInterstitial Lung Disease\nComplicated by Chronic\nHypoxemia Be Treated with\nHOT?\nProviding HOT\nEquipment\nMonitoring\nHome Safety\nFollow-up\nDiscontinuation of HOT\nAssessing Readiness\nWeaning of HOT\nSuccessful Discontinuation of\nHOT\nConclusions\nSummary of\nRecommendations\nCystic Fibrosis\nd For patients with cystic \ufb01brosis\ncomplicated by severe chronic hypoxemia,\nwe recommend that home oxygen therapy\nbe prescribed (strong recommendation, very\nlow-quality evidence).\nd For patients with cystic \ufb01brosis who\nhave both mild chronic hypoxemia and\ndyspnea on exertion, we suggest that\nhome oxygen therapy be prescribed\n(conditional recommendation, very low-\nquality evidence).\nBronchopulmonary Dysplasia\nd For patients with bronchopulmonary\ndysplasia complicated by chronic\nhypoxemia, we recommend that home\noxygen therapy be prescribed (strong\nrecommendation, very low-quality\nevidence).\nSleep-disordered Breathing\nd For patients with sleep-disordered\nbreathing complicated by severe\nnocturnal hypoxemia who cannot tolerate\npositive airway pressure therapy or are\nawaiting surgical treatment of sleep-\ndisordered breathing, we suggest that\nhome oxygen therapy be prescribed\n(conditional recommendation, very\nlow-quality evidence).\nSickle Cell Disease\nd For patients with sickle cell disease\ncomplicated by severe chronic\nhypoxemia, we suggest that home\noxygen therapy be prescribed\n(conditional recommendation, very\nlow-quality evidence).\nPulmonary Hypertension without\nCongenital Heart Disease\nd For patients with pulmonary\nhypertension without congenital heart\ndisease complicated by chronic\nhypoxemia, we recommend that home\noxygen therapy be prescribed (strong\nrecommendation, very low-quality\nevidence).\nPulmonary Hypertension with\nCongenital Heart Disease\nd For patients with pulmonary\nhypertension with congenital heart\ndisease complicated by chronic\nhypoxemia, supplemental oxygen will\nimpact hemodynamics and physiology;\nwe recommend that home oxygen\ntherapy NOT be initiated in these\nchildren, regardless of previous\nreparative or palliative congenital\nheart surgery, until there has\nbeen consultation with a pediatric\npulmonologist or cardiologist who\nhas expertise in the management of\npulmonary hypertension in this clinical\nsetting (strong recommendation, very\nlow-quality evidence).\nInterstitial Lung Disease\nd For patients with interstitial lung disease\ncomplicated by severe chronic hypoxemia,\nwe recommend that home oxygen therapy\nbe prescribed (strong recommendation, very\nlow-quality evidence).\nd For patients with interstitial lung\ndisease who have mild chronic\nhypoxemia and either dyspnea on\nexertion or desaturation during sleep\nor exertion, we suggest that home\noxygen therapy be prescribed\n(conditional recommendation, very\nlow-quality evidence).\nImplementation\nd The expert panel unanimously agreed\nthat optimal implementation of the\nabove recommendations consists of all\nof the following:\n\u2218 Oxygen therapy to maintain an oxygen\nsaturation as measured by pulse\noximetry in an acceptable range\nAMERICAN THORACIC SOCIETY DOCUMENTS\ne6 American Journal of Respiratory and Critical Care Medicine Volume 199 Number 3 | February 1 2019\naccording to age and respiratory\ncondition as outlined in this document\n\u2218 Use of oxygen equipment that is of the\nappropriate size, developmental stage,\nand \ufb02ow rate to function properly\n\u2218 Oxygen therapy monitoring by pulse\noximetry in the home\nIntroduction\nHome oxygen therapy (HOT) is used to\nmaintain health by addressing physiologic\nand metabolic requirements for children\nwith chronic lung and pulmonary vascular\ndiseases. Enabling a child to receive HOT also\nconfers psychological advantages by allowing\nthe child to remain within the family unit at\nhome, reducing healthcare costs compared\nwith hospitalization. Despite children having\nsigni\ufb01cantly different pulmonary physiology\nfrom adults and additional requirements for\noptimal lung growth and development,\nindications for funding HOT as determined\nby the Centers for Medicare and Medicaid\nServices (CMS) are the same for pediatric\nand adult patients. These include 1) PaO2\nless than 55 mm Hg (,7.33 kPa); 2)\noxygen saturation as measured by pulse\noximetry (SpO2\n) less than 88%; or 3) PaO2\n55\u201359 mm Hg (7.33\u20137.87 kPa) or SpO2\n89% accompanied by cor pulmonale, a\nhematocrit greater than 55%, or a history of\nedema (1). The basis of these indications\nby CMS is predicated on seminal studies\nin adult patients with chronic obstructive\npulmonary disease showing reductions in\nmortality with continuous oxygen therapy\n(2, 3). Despite the lack of pediatric patients\nin these historic studies performed over 35\nyears ago, CMS coverage determination for\nHOT is the same for pediatric patients of all\nages compared with adult patients.\nRecognizing the need for clinical\nguidance regarding HOT speci\ufb01cally for\nchildren, the American Thoracic Society\n(ATS) convened a task force of specialists in\npediatric and neonatal medicine, respiratory\ntherapy, nursing, and population health,\ntogether with parents, to conduct systematic\nreviews and use available evidence to inform\nrecommendations for the use of HOT in\nchronic lung and pulmonary vascular\ndiseases of childhood.\nThe target audience of this guideline is\nclinicians who manage children with diseases\ncomplicated by chronic hypoxemia. This\ngroup includes pediatric pulmonologists,\npediatric cardiologists, neonatologists, general\npediatricians and family practitioners,\nemergency medicine and primary care\nclinicians, other healthcare professionals, and\npolicy makers. Clinicians, patients, third-party\npayers, stakeholders, or the courts should never\nview the recommendations contained in this\nguideline as dictates. Though evidence-based\nguidelines can summarize the best available\nevidence regarding the effects of an intervention\nin a given patient population, they cannot take\ninto account all of the unique clinical\ncircumstances that may arise when managing a\npatient, and as such their implementation is at\nthe discretion of each treating clinician.\nMethods\nThis clinical practice guideline was developed\nin accordance with policies and procedures\nof the ATS. See the online supplement for\na detailed description of the methods.\nThe meaning of strong and conditional\nrecommendations is described in Table 1.\nDe\ufb01nition of Hypoxemia\nWith an immense medical literature\non hypoxemia, the panel focused this\ndocument on the treatment of sustained\nlow SpO2\nlevels, or \u201cchronic hypoxemia,\u201d\nand HOT for speci\ufb01c respiratory conditions\nof childhood. With unanimous agreement,\nthe panel determined that a low SpO2\nfor a\nduration of 2 weeks was suf\ufb01cient evidence\nfor chronic hypoxemia in a child with one\nof these respiratory conditions if otherwise\nclinically stable, thus achieving a threshold\nwhere HOT should be considered. One\ncaveat is that growth and development may\nresult in clinical resolution of chronic\nhypoxemia in some pediatric patients.\nTo de\ufb01ne hypoxemia, we conducted a\nsystematic search for data about normal\noxygenation in children that identi\ufb01ed 1,711\narticles, most of which were excluded by\nreview of their title and abstract (see Table\nE1 in the online supplement). We selected\n31 studies that measured oxygenation in\nhealthy children to inform our decision\nmaking (4\u201333). Of note, the studies\nenrolled subjects with different age ranges.\nFor analysis, we decided to categorize\nchildren as younger than 1 year old or\n1 year old and older. See Table 2 for\nnormative values of oxyhemoglobin\nsaturations in healthy children during\nwakefulness and sleep that originated from\nwork described in the paragraphs below.\nFor the purpose of this document, the term\n\u201cdesaturation\u201d will represent oxyhemoglobin\ndesaturation.\nChildren Younger Than 1 Year Old\nChildren younger than 1 year old had\na mean SpO2\nof 97.8% (SD, 61.4%)\n(27, 29, 32) and a median SpO2\nof 98.7%,\nwith a range from 97.9% to 99.8% (8, 9,\n14, 15, 27, 29, 31, 32), during wakefulness.\nDesaturation events were common during\nthe initial 48 hours of life. One study\nreported that 5% of the time was spent with\na mean SpO2\nless than 92.5% (63.9%) and\n10% of the time was spent with a mean SpO2\nTable 1. Meanings of the Strength of the Recommendations\nA Strong Recommendation Conveys . . . A Conditional Recommendation Conveys . . .\nIt is the right course of action for .95% of patients. It is the right course of action for .50% of patients but may not be right for a sizable\nminority.\n\u201cJust do it. Don\u2019t waste your time thinking about it,\njust do it.\u201d\n\u201cSlow down, think about it, discuss it with the patient.\u201d\nYou would be willing to tell a colleague that he or she\ndid the wrong thing if he or she did not follow the\nrecommendation.\nYou would NOT be willing to tell a colleague that he or she did the wrong thing if he\nor she did not follow the recommendation because there is clinical equipoise.\nThe recommended course of action may make a\ngood performance metric.\nThe recommended course of action would NOT make a good performance metric.\nAMERICAN THORACIC SOCIETY DOCUMENTS\nAmerican Thoracic Society Documents e7\nless than 95.3% (62.9%) (32); another\nreported that 3\u20134% of the time was spent\nwith SpO2\nof 90% or less (27). With respect\nto duration, studies estimated that 26% of\nneonates had desaturations to less than or\nequal to 80% for a median duration of 9.3\nseconds (31), 92% had desaturations to less\nthan or equal to 88% for more than 20\nseconds (24), and 100% had desaturations\nto less than or equal to 88% for more\nthan 10 seconds (27). Desaturation events\ndiminished with age. At an age of 1 month,\ninfants had desaturations to SpO2\nless than\nor equal to 80% a median of 0.9 times\nper hour (range, 0 to 15.1) for a median\nduration of 1.2 seconds (range, 0.3 to 2.2 s)\n(15); at ages of 6 weeks, 3 months, and 6\nmonths, infants had desaturations to a SpO2\nless than or equal to 80% a median of 0.7,\n0.4, and 0.5 times per hour (9); and at an\nage of 1.4 years (range, 1.1 to 1.9 yr), infants\nhad desaturations of greater than or equal to\n3% a median of 0.1 times per hour (range,\n0 to 2.2) (14). During sleep, mean SpO2\ndecreased to 96.3% (61.3%) (19) with\nepisodes of desaturation that reached a nadir\nat a mean of 86% (61.5%) (19) or a median\nof 85.5% with a range from 83% to 88%\n(8, 13). Infants 2 weeks, 3 months, and\n6 months old spent 5% of sleep time with\na median SpO2\nless than 92% (73\u201399%),\n96% (83\u201398%), and 95.5% (69\u201399%),\nrespectively, and spent 10% of sleep time\nwith a median SpO2\nless than 96% (77\u2013\n99%), 97% (86\u2013100%), and 97% (75\u201399%),\nrespectively (7).\nChildren Aged 1 Year Old and Older\nChildren aged 1 year old and older had a\nmean SpO2\nof 97.6% (60.7%) (16, 24, 32,\n33) and a median SpO2\nof 97.5%, with a\nrange from 97% to 98% (14, 16, 18, 24),\nduring wakefulness. During sleep, the mean\nSpO2\nremained 97.8% (60.7%) (33), with\nepisodes of desaturation that reached a\nnadir at a mean of 94.6% (63.1%) (16, 20,\n22, 23, 25, 26, 33) and a median of 93%,\nwith a range from 91% to 94% (16, 18,\n20, 21, 23). Desaturation events were\ninfrequent. Children had desaturations\ngreater than or equal to 3% or greater than\nor equal to 4% a mean of 0.6 times per hour\n(61.0) (16, 23, 26, 33) and a median of\n0.4 times per hour (range, 0.1\u20130.8) (14, 16,\n18, 23). The mean duration of desaturation\nevents was 0.3 seconds (60.1 s), and the\nmedian duration was 0 seconds (range, 0 to\n5.8 s) (23), with less than 1% of sleep spent\nwith a SpO2\nless than 95% (16) and less than\n0.03% of sleep spent with a SpO2\nless than\n90% (16, 33). Clusters of desaturation\noccurred with a mean frequency of 0.1\nclusters per hour (60.2) and a median\nfrequency of 0 clusters per hour (range,\n0\u20130.7) (23).\nOxygen saturation is lower among\nnormal children of all age groups living at a\nhigh altitude. Children 1 year old and\nyounger living at 2,560 and 3,200 m had\nmedian SpO2\nof 92% and 87%, respectively,\naccording to two studies (5, 6), whereas\nanother study found that those living at\naltitudes of 1,371, 2,073, 2,393, 2,405, and\n2,484 m had SpO2\nranges of 95\u201396.7%,\n93.9\u201395.4%, 91.8\u201393.4%, 93.4\u201396.1%, and\n93.7\u201396.2%, respectively (28). Children\nolder than 1 year old residing at an altitude\nof roughly 1,600 m had a median SpO2\nof\n95.4% (range, 93.1\u201396.9%) and a median\nnadir SpO2\nof 86% (range, 81\u201389%) (17),\nwhereas those living at roughly 4,000 m had\na mean SpO2\nof 87.4% (SD not estimable)\nand a mean nadir SpO2\nof 80% (SD, 67.5%)\n(11, 18). Desaturation events were more\nfrequent at high altitude than at sea level,\nbut they were less common among older\nchildren. Children 1\u20136 years old living at\n1,600 m had desaturations greater than or\nequal to 4% a median of 4.0 times per hour\n(17), whereas children older than 6 years\nold living at 4,000 m had desaturations\ngreater than or equal to 4% a median of\n1.6 times per hour (18). Owing to lack of\nstudies, adjustments for targeted saturation\nlevels in children at altitude cannot be\nadequately addressed in this guideline.\nWith these studies as background and a\nprimary objective of identifying potentially\nharmful hypoxemia while ensuring that\nvirtually no normal children are determined to\nhave abnormal oxygenation, the panel de\ufb01ned\nhypoxemia at or near sea level as follows:\nd In children younger than 1 year old,\nhypoxemia was de\ufb01ned as spending 5%\nof the recording time with SpO2\nless than\nor equal to 90% or, if measurements\nare taken intermittently, obtaining three\nindependent measurements of SpO2\nless\nthan or equal to 90%.\nd In children aged 1 year old and older,\nhypoxemia was de\ufb01ned as spending\n5% of the time with SpO2\nless than or\nequal to 93% or, if measurements are\ntaken intermittently, obtaining three\nindependent measurements of SpO2\nless\nthan or equal to 93%.\nAdditional conclusions from the panel\nincluded the following:\nd Pulse oximetry is suf\ufb01cient for\ndiagnosing hypoxemia in pediatric\npatients because arterial blood analysis\nfor PaO2\nis not practical for routine\nmonitoring, owing to technical dif\ufb01culty\nin children and the pain associated with\nthe arterial stick.\nd On very rare occasions, an arterial\nblood gas for PaO2\nmay be required\nto assess for hypoxemia in a child,\nspeci\ufb01cally when pulse oximetry may\nnot accurately measure SpO2\n, including\naltered hemoglobin states (e.g.,\ncarboxyhemoglobin, methemoglobin)\nor in diseases affecting hemoglobin,\nsuch as sickle cell disease (SCD).\nd Intermittent pulse oximetry appears\nsuitable with the different thresholds\nre\ufb02ecting greater variability of SpO2\namong healthy children younger than\n1 year old, particularly the youngest\nchildren, with this left at the discretion\nof the treating clinician according to\nthe clinical scenario of the patient.\nd In a child, three intermittent measurements,\nif abnormal, can diagnose hypoxemia,\nbut normal intermittent measurements\ncannot exclude it; this can be\nTable 2. Normative Values\nWakefulness Sleep Desaturation Nadir\nMean (6SD) Median (Range) Mean (6SD) Median (Range) Mean (6SD) Median (Range)\nChildren ,1 yr old 97.8% (61.4%) 98.7% (97.9\u201399.8%) 96.3% (61.3%) Not reported 86% (61.5%) 85.5% (83\u201388%)\nChildren >1 yr old 97.6% (60.7%) 97.5% (97\u201398%) 97.8% (60.7%) Not reported 94.6% (63.1%) 93% (91\u201394%)\nAMERICAN THORACIC SOCIETY DOCUMENTS\ne8 American Journal of Respiratory and Critical Care Medicine Volume 199 Number 3 | February 1 2019\ndone only by continuous oximetric\nmonitoring, which includes a period\nof sleep. More advanced evaluation with\npolysomnography may be needed on a\ncase-by-case basis at the discretion of the\ntreating clinician.\nd Averaging time for pulse oximetry\nmeasurements should take into account\nthe age of the child, the underlying\nrespiratory condition, and the current\nclinical scenario.\nd A duration of 2 weeks de\ufb01nes chronicity\nof hypoxemia in a child.\nd Hypoxemia in a child should account\nfor anticipated SpO2\nmeasurement\nalterations according to altitude.\nConsequences of Untreated\nHypoxemia\nThe pathobiology of hypoxemia\nencompasses a large body of work in the\nmedical literature, which we expect will\ncontinue to expand rapidly. Moreover, we\nenvision future research will better delineate\nthe effects of hypoxemia at the cellular and\nmolecular levels (34, 35). We brie\ufb02y review\nin this section the potential consequences of\nhypoxemia that pediatric patients may\nexperience, with the caveat that expanding\nresearch in this area may in\ufb02uence these\nrecommendations. Intermittent hypoxemia\noccurs more frequently in children with\nlung disease and has been associated with\ndeleterious consequences on pulmonary\ncirculation, neurodevelopment, cognition,\nsleep, and growth (36). Lower basal\noxygen saturation in children is associated\nwith more episodes of spontaneous\ndesaturations (37), placing them at even\nfurther risk for complications of\nhypoxemia.\nPulmonary Circulation\nChronic alveolar hypoxia elicits pulmonary\nvasoconstriction leading to pulmonary\nhypertension (PH), particularly in\nchildren with respiratory disorders, such\nas sleep-disordered breathing (SDB),\nbronchopulmonary dysplasia (BPD), cystic\n\ufb01brosis (CF), and SCD. Previous work in\nanimal models, including neonatal models,\nde\ufb01ned oxygen levels that induce hypoxic\npulmonary vasoconstriction (38\u201341).\nCompared with adults (42), children with\nSDB and intermittent hypoxemia are at\nincreased risk for PH (43). Intermittent\nhypoxemia adversely affects alveolar and\nvascular development in infants with BPD\n(44, 45). Correction of the hypoxemia\nin neonates with BPD and PH using\nsupplemental oxygen can ameliorate\nphysiologic complications (45\u201348),\nwith HOT resolving right ventricular\nhypertrophy when SpO2\nis maintained\nabove 94\u201395% (49). In CF, continuous\nhypoxemia during wakefulness and other\nphysiologic factors is associated with the\ndevelopment of PH independent of lung\nfunction (50, 51). Nocturnal hypoxemia\nand SDB appear to be in\ufb02uential in the\ndevelopment of PH in SCD (52, 53).\nHemolysis, hypercoagulability, ischemia-\nreperfusion injury, oxidative stress,\nin\ufb02ammation, and genetic susceptibility\nare additional factors that impact the\ndevelopment of PH (54). Although the\nresponse to mild levels of alveolar hypoxia\nmay have minimal effects in many children,\nothers may have adverse effects at similar\nlevels of inspired oxygen with regard to\nheightened pulmonary vascular reactivity\nor remodeling, as re\ufb02ected in infants with\nBPD (46), young adults with a history\nof perinatal asphyxia (55), and others.\nSuch susceptibility has been demonstrated\nin experimental studies of genetic rat\nstrains (56) or endothelial nitric oxide\nsynthase\u2013de\ufb01cient mice (57), in which\neven mild chronic alveolar hypoxia elicits\nstriking PH. These \ufb01ndings suggest\nthat genetic, epigenetic, and disease\npathobiology can increase the risk\nfor pulmonary vascular disease even at\nlevels that would be considered mild in\nnonsusceptible individuals.\nNeurodevelopment and Cognition\nThe adverse cognitive and behavioral\noutcomes of hypoxemia in children with\nobstructive sleep apnea (OSA) have been\nextensively investigated and published\nelsewhere. Those data highlight the effects\nof hypoxemia on brain development and\nsubsequent functioning as major concerns\nin children. For example, a post hoc analysis\nof a large international trial including\n1,019 premature infants surviving to a\npostmenstrual age of 36 weeks found\nthat prolonged hypoxemic episodes of\nmore than 1 minute were associated\nwith increased risk of death or adverse\nneurodevelopmental outcome at 18\nmonths (58). However, in a multicenter,\ndouble-blind, randomized, controlled\ntrial of 358 infants born at less than\n30 weeks of gestation who continued to\nreceive supplemental oxygen at 32\nweeks postmenstrual age, no signi\ufb01cant\ndevelopmental bene\ufb01t was seen at 1 year\nwhen children with measured SpO2\nof\n91\u201394% were compared with those with\nSpO2\nof 95\u201398% (59).\nA previous systematic review of\n55 studies investigating children with\ncongenital heart disease (CHD), SDB,\nasthma, and chronic ventilatory impairment\nand infants with respiratory instability\nidenti\ufb01ed that chronic intermittent\nhypoxemia negatively in\ufb02uences\ndevelopment, behavior, and academic\nachievement (60). In 995 school-aged\nchildren in fourth to sixth grades who\nunderwent overnight pulse oximetric\nstudies, hypoxemia was associated with\nimpaired performance in mathematics (61).\nIn the assessment of hypoxemia and the\neffects on cognition, investigators often\nstudy populations at high altitudes. A\nrecent study found that short- and long-\nterm exposures to high altitude at 3,500 m\nnegatively affected executive function,\nmemory, and processing speed in children\nand adolescents (62). However, we found\nno studies that assessed the effect of\ntreatment on clinical outcomes.\nIn children with CHD undergoing\nsurgical repair, cerebral tissue oxygenation\nappears to be an important determinant\nof cognitive development (63). Newborns\nwith unrepaired CHD may have decreased\ncerebral oxygen delivery owing to chronic\nhypoxemia, so brain growth and\ndevelopment can be adversely affected\nwithout surgical intervention (64). In\nchildren with CF and hypoxemia, nocturnal\nHOT improved school attendance and\nperformance (65, 66). Early research in\nSCD showed that hypoxemia is associated\nwith episodic memory issues (67).\nSleep\nOlder studies have identi\ufb01ed that exposure\nto hypoxemia during sleep predisposes\ninfants to increased periodic breathing,\nhypoventilation, and central apneas and\nplaces those individuals at increased\nrisk for brief resolved unexplained\nevents (BRUEs) (formerly apparent life-\nthreatening events) (68, 69). Risk factors\nfor more severe BRUEs in premature\ninfants include central apnea longer than\n30 seconds, SpO2\nless than 80% for 10\nseconds, bradycardia to less than 50\u201360\nbeats per minute for 10 seconds, and upper\nrespiratory infection symptoms (70, 71).\nAMERICAN THORACIC SOCIETY DOCUMENTS\nAmerican Thoracic Society Documents e9\nIn 91 premature infants with previous\nBRUEs, unsuspected SpO2\nless than 95%\nevents (range, 80\u201393%) had occurred in\n25% of the cohort (72).\nIn a comparison of premature\ninfants with and without BPD who were\nrecently weaned from supplemental\noxygen (,7 d), children with BPD had\nsigni\ufb01cantly lower SpO2\nand experienced\nsigni\ufb01cantly more central apnea that\nresolved with supplemental oxygen\nuse (73). In one study of infants with\nBPD, an SpO2\nof 90% was associated\nwith sleep fragmentation with less REM\nsleep that improved with supplemental\noxygen administration (74), whereas\nanother study showed no change in sleep\narchitecture in infants with BPD whose\nSpO2\nwas greater than 93% (75).\nSome patients with CF have SDB\nassociated with bone and soft tissue\nstructural alterations of the upper airway\nand chronic rhinosinusitis (76, 77).\nEarlier studies established sleep-related\nhypoventilation as the primary factor\nassociated with nocturnal hypoxemia in CF\n(78\u201381). More recent research comparing\nchildren with CF with healthy control\nindividuals who were matched for age and\nbody mass index found that mean SpO2\nand\nnadir SpO2\nwere signi\ufb01cantly lower in the\nCF group (82, 83). Using polysomnography\nin pediatric and young adult patients with\nCF and normal healthy control subjects,\nFEV1 less than 64% predicted sleep-related\ndesaturation with good sensitivity and\nspeci\ufb01city (84).\nIn SCD, studies have established\nthat clinical outcomes are worse in the\nsetting of hypoxemia and SDB (85\u201389),\nwith more severe reductions in SpO2\noccurring in children who have both SCD\nand OSA (85, 90). However, reductions in\nSpO2\npersisted in some children with SCD\ndespite adenotonsillectomy (91, 92),\nsuggesting that other factors may\ncontribute to hypoxemia in SCD.\nSupporting this point, hemoglobin SS is\nassociated with more severe nocturnal\nhypoxemia than is hemoglobin SC (91),\nand treatment of patients with SCD with\nhydroxyurea is associated with\nimprovement in hypoxemia (93, 94).\nConcerns exist for severe nocturnal\nhypoxemia in children with CHD because\nthese patients can have continuous low SpO2\nand potentially reduced cerebral blood \ufb02ow.\nInfants and older children with CHD can\npresent with SDB (95\u201398), whereas patients\nwith acyanotic CHD are often obese,\nplacing them at greater risk for OSA (99).\nChildren with Eisenmenger syndrome can\nhave signi\ufb01cant nocturnal hypoxemia\nbecause of SDB, especially with higher\nhemoglobin concentrations (100). Reductions\nin SpO2\ncan occur during sleep in children\nwith CHD, independent of whether they\nhave PH, sleep disturbances, or signi\ufb01cant\narrhythmias (101). Surgical correction of\ncongenital cardiac lesions can increase\nthe risk for SDB in patients with CHD,\nso close monitoring is needed for this\nhigh-risk group (95, 102).\nFor children with interstitial lung\ndisease (ILD), nocturnal hypoxemia is\nvery common with sustained reductions of\nSpO2\nduring sleep and throughout REM\nsleep periods (103). Moreover, the ATS\nguideline for ILD in children reported\nhypoxemia as an important component of\nthe diagnostic evaluation of pediatric\npatients with suspected ILD, and it\nrecommends routine measurement of\nSpO2\nby pulse oximetry in all aspects of\nlife, including sleep and during feeding,\nfor infants (104).\nGrowth\nIn infants with BPD, improved growth\noccurs when SpO2\nduring sleep is greater\nthan 92% compared with SpO2\nof 88\u201391%\n(105). A second study in premature infants\nwith BPD found promotion of growth\nwhen SpO2\nwas maintained above 93%\nwith supplemental oxygen (106). In both\nof these studies, a negative effect on growth\nwas seen when supplemental oxygen\nwas stopped (105, 106). However, the\npreviously discussed trial in infants\nborn at less than 30 weeks of gestation\nfound no growth bene\ufb01t associated with\nhigher SpO2\n(59).\nAlthough nutritional support can\nimprove pulmonary status in CF (107), it is\nnot clear whether treatment of hypoxemia\nimproves nutritional status. Hypoxemia in\nthe CF population increases the risk for PH,\nreduced exercise ability, and loss of skeletal\nmuscle strength, all of which are associated\nwith poor nutritional status (108). When\ncompared with healthy control individuals,\nthe body mass index of patients with\nCF with moderate to severe lung disease\ndid not correlate with exercise-induced\nhypoxemia. In another study, compared\nwith healthy control subjects, the nutritional\nstatus of subjects with CF was not\nassociated with hypoxemia or hypercapnia\nduring exercise or sleep, whereas air\ufb02ow\nobstruction was the single correlate to\nsleep-related hypoxemia and hypercapnia\n(109).\nRelative to asymptomatic children with\nacyanotic CHD, children with cyanotic\nCHD have shorter stature and leaner body\nmass associated with adipose hypocellularity\n(110). In the setting of hypoxemia, early\ndevelopment of heart failure produces\ntissue changes that handicap growth (111).\nAmong the CHD patient population, the\nrisk for malnutrition and growth failure is\ngreatest in those with cyanotic CHD and\nPH (112).\nIn children with neuroendocrine cell\nhyperplasia of infancy, a recent study\nevaluating growth trajectory and oxygen use\nfound that some subjects had improvement\nin growth velocity with the initiation of\nsupplemental oxygen (113). With growth\nand maturation, some children with\nchronic pulmonary disorders requiring\nHOT will have a limited duration of\ntreatment (114).\nIndications for HOT\nOur systematic search of the literature\nidenti\ufb01ed 952 articles, most of which\nwere excluded by review of their title and\nabstract (Table E2). Table 3 provides a\nsummary of the \ufb01nal recommendations by\nthe panel, with details of the evidence base\noutlined in the following sections for each\npediatric respiratory condition.\nQuestion 1: Should Children with\nCystic Fibrosis Complicated by\nChronic Hypoxemia Be Treated with\nHOT?\nEvidence base. We identi\ufb01ed no studies that\ndirectly compared home oxygen with no\noxygen in children with CF complicated by\nchronic hypoxemia, possibly because of\nconcerns about the safety of having such\na control group. We therefore selected\neight studies that indirectly addressed the\nquestion by comparing use of either short-\nterm oxygen or nocturnal home oxygen with\nno oxygen in children with CF complicated\nby chronic hypoxemia (65, 80, 115\u2013120).\nSeven trials were randomized crossover\ntrials (80, 115\u2013120), and the remaining trial\nwas a randomized trial with parallel groups\n(65). All trials enrolled children or young\nadults with both CF (mean age, 22 to 27 yr)\nAMERICAN THORACIC SOCIETY DOCUMENTS\ne10 American Journal of Respiratory and Critical Care Medicine Volume 199 Number 3 | February 1 2019\nand chronic hypoxemia (mean SpO2\nin the\nmid-80% range; mean PaO2\n, ,65 mm Hg\n[,8.67 kPa]; or desaturations to ,90%).\nThree trials compared an FIO2\nof 0.30\u20130.39\nwith an FIO2\nof 0.21 administered into the\nbreathing circuit during an exercise test\n(116, 119, 120); three trials compared an\nFIO2\nof 0.30\u20130.31 with an FIO2\nof 0.21\nadministered by nasal cannula or through a\ncontinuous positive airway pressure device\nduring a sleep study (80, 117, 118);\none trial compared being in a naturally\nhigh-oxygen environment below sea level\nwith being at sea level (115); and one\ntrial compared nocturnal HOT titrated\nto an awake PaO2\ngreater than 70 mm Hg\n(.9.33 kPa) with a nocturnal FIO2\nof 0.21\nadministered by nasal cannula during\nsleep. All trials were small, ranging from 6\nto 28 patients.\nMeta-analyses revealed that short-term\noxygen use increased exercise duration\n(mean difference [MD], 11.04 min; 95%\ncon\ufb01dence interval [CI], 10.21 to 11.88\nmin) and postexercise oxygen saturation\n(MD, 17%; 95% CI, 12.23% to 111.81%);\nthere was also a trend toward a higher peak\nexercise oxygen saturation (MD, 17.19%;\n95% CI, 22.51% to 116.89%). Single\nstudies revealed that short-term oxygen\nTable 3. Summary of Recommendations for Home Oxygen Therapy in Children with Strength of the Recommendation and Level of\nEvidence\nPediatric Respiratory\nCondition Recommendation\nStrength of Recommendation and\nLevel of Evidence\nCystic \ufb01brosis For patients with cystic \ufb01brosis complicated by\nsevere chronic hypoxemia, we recommend that\nhome oxygen therapy be prescribed.\nStrong recommendation, very low-quality\nevidence\nFor patients with cystic \ufb01brosis who have both mild\nchronic hypoxemia and dyspnea on exertion, we\nsuggest that home oxygen therapy be prescribed.\nConditional recommendation, very low-quality\nevidence\nBronchopulmonary dysplasia For patients with bronchopulmonary dysplasia\ncomplicated by chronic hypoxemia, we\nrecommend that home oxygen therapy be\nprescribed.\nStrong recommendation, very low-quality\nevidence\nSleep-disordered breathing For patients with sleep-disordered breathing\ncomplicated by severe nocturnal hypoxemia\nwho cannot tolerate positive airway pressure\ntherapy or are awaiting surgical treatment of\nsleep-disordered breathing, we suggest that\nhome oxygen therapy be prescribed.\nConditional recommendation, very low-quality\nevidence\nSickle cell disease For patients with sickle cell disease complicated by\nsevere chronic hypoxemia, we suggest that\nhome oxygen therapy be prescribed.\nConditional recommendation, very low-quality\nevidence\nPulmonary hypertension\nwithout congenital heart\ndisease\nFor patients with pulmonary hypertension without\ncongenital heart disease complicated by chronic\nhypoxemia, we recommend that home oxygen\ntherapy be prescribed.\nStrong recommendation, very low-quality\nevidence\nPulmonary hypertension with\ncongenital heart disease\nFor patients with pulmonary hypertension with\ncongenital heart disease complicated by chronic\nhypoxemia, supplemental oxygen will impact\nhemodynamics and physiology; we recommend\nthat home oxygen therapy NOT be initiated in\nthese children, regardless of previous reparative\nor palliative congenital heart surgery, until\nthere has been consultation with a pediatric\npulmonologist or cardiologist who has expertise\nin the management of pulmonary hypertension in\nthis clinical setting.\nStrong recommendation, very low-quality\nevidence\nInterstitial lung disease For patients with interstitial lung disease\ncomplicated by severe chronic hypoxemia, we\nrecommend that home oxygen therapy be\nprescribed.\nStrong recommendation, very low-quality\nevidence\nFor patients with interstitial lung disease who have\nmild chronic hypoxemia and either dyspnea on\nexertion or desaturation during sleep or exertion,\nwe suggest that home oxygen therapy be\nprescribed.\nConditional recommendation, very low-quality\nevidence\nAMERICAN THORACIC SOCIETY DOCUMENTS\nAmerican Thoracic Society Documents e11\nuse mitigated oxygen desaturation during\nexercise (25% vs. 212%; MD, 17%; 95%\nCI, 12.48% to 111.52%) (113), improved\noxygen saturation during REM sleep (90%\nvs. 79%; MD, 111%; 95% CI, 14.38% to\n117.62%) and non-REM (NREM) sleep\n(94% vs. 88%; MD, 16%; 95% CI, 11.36%\nto 110.64%) (118), reduced sleep latency\n(18 vs. 24 min; MD, 26 min; 95% CI,\n20.25 to 211.75 min) (118), and improved\nschool attendance at 6 months (71% vs.\n21%; relative risk, 3.3; 95% CI, 1.16 to 9.59)\nand 12 months (91% vs. 20%; relative risk,\n4.55; 95% CI, 1.30 to 15.9) (65). There were\ntrends toward more REM sleep time (18%\nvs. 13%; MD, 16%; 95% CI, 20.93% to\n112.93%) and a lower arousal index (6 vs.\n8.1 arousals\/h; MD, 22.1 arousals\/h; 95%\nCI, 24.57 to 10.37 arousals\/h). There\nwere no differences in mortality (65),\ngrowth (65), total sleep time (118),\nrespiratory function (65), or right ventricular\nfunction (65).\nThe panel had very low con\ufb01dence that\nthe estimated effects described above would\nbe the same for HOT in patients with CF\ncomplicated by chronic hypoxemia, because\nthe evidence from which the estimates were\nderived was indirect (i.e., the question\nwas about HOT, but the estimates were\nfrom trials that used short-term oxygen or\nnocturnal HOT) and the trials were all small\nwith few events.\nBene\ufb01ts. In patients with CF who have\nchronic hypoxemia, short-term oxygen\nuse increased exercise duration, increased\npostexercise oxygen saturation, mitigated\noxygen desaturation during exercise,\nimproved oxygen saturation during REM\nand NREM sleep, and reduced sleep latency;\nthere was also a trend toward increased\npeak exercise oxygen saturation, increased\nREM sleep time, and a decreased arousal\nindex. Nocturnal HOT improved school\nattendance at 6 and 12 months.\nHarms. No harms were reported in any\nof the trials.\nConclusions. Despite having very low\ncon\ufb01dence in the estimated effects, the panel\nwas certain that the bene\ufb01ts of HOT exceed\nthe harms, burdens, and cost in patients\nwith CF with severe chronic hypoxemia\n(SpO2\n, ,90%). This was based on the large\nnumber of bene\ufb01cial outcomes and absence\nof harmful outcomes, decades of clinical\nexperience collectively managing thousands\nof such patients, and recognition that\nprolonged chronic hypoxemia contributes\nto serious health consequences such as\nPH and cor pulmonale. The panel also\nconcluded that the bene\ufb01ts of HOT\nlikely exceed the harms, burden, and\ncost in patients with CF who have mild\nhypoxemia (SpO2\n, 90\u201393%) that is chronic,\naccompanied by sequelae of hypoxemia\n(e.g., dyspnea on exertion, PH, cor\npulmonale), or that occurs in the context of\nan exacerbation requiring antibiotics.\nWhat others are saying. Clinical\npractice guidelines of the British Thoracic\nSociety (BTS) published in 2009\nrecommended HOT for hypoxemic children\nwith CF as \u201ca means to improve school\nattendance\u201d and to \u201cobtain symptomatic\nrelief\u201d (121). Those guidelines further\nrecommended monitoring carbon dioxide\nconcentrations when the oxygen therapy is\ninitiated.\nATS recommendations.\nd For patients with CF complicated\nby severe chronic hypoxemia, we\nrecommend that HOT be prescribed\n(strong recommendation, very low-quality\nevidence). Severe chronic hypoxemia is\nde\ufb01ned as either 1) greater than or equal\nto 5% of recording time spent with an\nSpO2\nless than 90% if measurements are\nobtained by continuous recording or\n2) at least three separate \ufb01ndings of an\nSpO2\nless than 90% if measurements are\nobtained intermittently.\nd For patients with CF who have both\nmild chronic hypoxemia and dyspnea\non exertion, we suggest that HOT be\nprescribed (conditional recommendation,\nvery low-quality evidence). Mild chronic\nhypoxemia is de\ufb01ned as either 1) greater\nthan or equal to 5% of recording\ntime spent with an SpO2\n90\u201393%\nif measurements are obtained by\ncontinuous recording or 2) at least\nthree separate \ufb01ndings of an SpO2\n90\u201393% if measurements are obtained\nintermittently.\nQuestion 2: Should Children with\nBronchopulmonary Dysplasia\nComplicated by Chronic Hypoxemia\nBe Treated with HOT?\nEvidence base. We identi\ufb01ed 11 observational\nstudies that compared HOT with no\noxygen therapy in children whose BPD\nwas complicated by chronic hypoxemia.\nTen of the studies were excluded because\nthere was an unacceptable risk of bias\nowing to the patients receiving HOT being\nmore severely ill than the patients in the\nno-oxygen group. The remaining study\nwas selected for analysis (105).\nThe study enrolled 63 infants with\nBPD who were receiving HOT but had\nan SpO2\ngreater than or equal to 92% in\nroom air. The infants were admitted for\ncontinuous pulse oximetry in room air\nduring sleep and then categorized into\nthree groups: those who 1) maintained an\nSpO2\ngreater than or equal to 92%, 2) had\ndesaturations to 88\u201391% for more than\n1 hour, or 3) had desaturations to less\nthan 88% for more than 1 hour. Those\nwho maintained an SpO2\ngreater than or\nequal to 92% or had desaturations to\n88\u201391% had their supplemental oxygen\ndiscontinued, whereas those who had\ndesaturations to less than 88% had their\nsupplemental oxygen continued. For the\ngroups whose oxygen was discontinued,\nvarious growth parameters were measured\nbefore and after discontinuation of\noxygen and compared. Because the issue\nbeing addressed concerns children with\nchronic hypoxemia, our analysis focused\non the 14 infants who had desaturations\nto 88\u201391% during sleep. The study\nrevealed that the rate of weight gain\nwas greater while the infants were\nreceiving supplemental oxygen than\nafter discontinuation (15.9 g\/kg\/d vs.\n3.7 g\/kg\/d; MD, 12.2 g\/kg\/d; 95% CI, 7.22\nto 17.18 g\/kg\/d).\nThe panel supplemented this study\nwith indirect evidence. Two studies enrolled\npatients with BPD who had ongoing high\noxygen requirements: one compared\nhemodynamics measured by right heart\ncatheterization during the inhalation of 80%\noxygen for 10 minutes with those measured\nduring the inhalation of room air for\n10 minutes (45), and the other compared\nhemodynamics measured during the\ninhalation oxygen targeting a PaO2\ngreater\nthan 120 mm Hg (.16 kPa) with those\nmeasured during the inhalation oxygen\ntargeting a PaO2\nof 55 to 120 mm Hg\n(7.33\u201316 kPa) (122). Meta-analysis found\nthat oxygen administration was associated\nwith lower mean pulmonary artery pressure\n(MD, 210.03 mm Hg [21.34 kPa]; 95% CI,\n216.41 to 23.64 mm Hg [22.19 to 20.49\nkPa]). Another study enrolled patients\nwith BPD who required oxygen to keep\ntheir SpO2\nabove 90% and compared\npolysomnography results while subjects\nbreathed either an extra 0.25 L\/min of\nsupplemental oxygen or their baseline\namount of oxygen (74). The higher amount\nAMERICAN THORACIC SOCIETY DOCUMENTS\ne12 American Journal of Respiratory and Critical Care Medicine Volume 199 Number 3 | February 1 2019\nof oxygen was associated with increased\ntotal sleep duration, increased REM sleep\nduration, and decreased REM arousals,\nalthough the values of each were not\nreported.\nThe panel had very low con\ufb01dence that\nthe estimated effects described above are\nthe same for HOT in patients with BPD\ncomplicated by chronic hypoxemia. The\ndirect evidence was derived from a single,\nsmall observational study. The indirect\nevidence derived estimates from small\nobservational studies that used short-term\noxygen or nocturnal HOT rather than\nHOT.\nBene\ufb01ts. In patients with BPD who\nhave chronic hypoxemia, HOT increased\nthe growth rate, short-term oxygen use\ndecreased the mean pulmonary artery\npressure, and nocturnal oxygen administration\nimproved sleep duration and decreased\narousals.\nHarms. No harms were reported in any\nof the studies.\nConclusions. The panel emphasized\nthat patients with chronic hypoxemia\ndue to BPD generally reach a phase in\ntheir medical care when they face two\nalternatives: receive long-term oxygen in\nthe hospital or at home. This occurs when\nother medical issues have stabilized but\naltered oxygenation levels are only slowly\nimproving. The panel was certain, despite\nits very low con\ufb01dence in the estimated\neffects, that the bene\ufb01ts of HOT exceed the\nharms, burdens, and cost. In addition to\nimproved growth, lower pulmonary artery\npressure, improved sleep duration, and\nfewer arousals from sleep, it enables the\npatient and family to be at home and\ndiminishes the likelihood of harm by\npreventing the nosocomial and iatrogenic\nconsequences of hospitalization. The\nstrength of the panel\u2019s recommendation is\nstrong because its primary intention is to\nprevent the harmful effects of prolonged\nhospitalization.\nWhat others are saying. The BTS\nclinical practice guidelines recommended\nHOT for infants with chronic neonatal\nlung disease, including BPD, because BTS\nsimilarly concluded that HOT improves\nmultiple clinical outcomes, is preferable to a\nprolonged hospital stay for quality of life and\npsychological impact, and enables earlier\ndischarge from the hospital (121). In the more\nrecent guidelines for pediatric PH published\nas a combined effort by the ATS with\nthe American Heart Association (AHA),\nsupplemental oxygen therapy was graded as\nreasonable to avoid episodic or sustained\nhypoxemia with a suggested goal of\nmaintaining SpO2\nbetween 92% and 95% in\nchildren with established BPD and\nPH (123).\nATS recommendation.\nd For patients with BPD complicated by\nchronic hypoxemia, we recommend\nthat HOT be prescribed (strong\nrecommendation, very low-quality\nevidence). Chronic hypoxemia is de\ufb01ned\nas either 1) greater than or equal to 5% of\nrecording time spent with an SpO2\nless\nthan or equal to 93% if measurements\nare obtained by continuous recording\nor 2) at least three separate \ufb01ndings\nof an SpO2\nless than or equal to 93%\nif measurements are obtained\nintermittently.\nQuestion 3: Should Children with\nSleep-disordered Breathing\nComplicated by Chronic Hypoxemia\nBe Treated with HOT?\nEvidence base. We identi\ufb01ed two studies\nthat compared nocturnal oxygen with no\noxygen therapy in children with SDB\ncomplicated by nocturnal hypoxemia\n(124, 125). One study was a randomized\ncrossover trial that enrolled children (mean\nage, 5 yr) who had suspected OSA plus\ndesaturation during sleep to less than 92%\n(124); the other study was an observational\nstudy that enrolled children (mean age,\n4.3 yr) who had tonsillar hypertrophy\nand desaturations during sleep to less\nthan 90% (125). Both studies compared\nthe effects of supplemental oxygen\nwith room air during sleep; one study\nprovided oxygen at a rate of 1 L\/min\n(124), and the other provided oxygen at a\nrate needed to keep the patient\u2019s SpO2\nabove\n95% (125).\nThe apnea index was the only outcome\nmeasured by both studies; when pooled by\nmeta-analysis, oxygen use during sleep was\nassociated with no change in the apnea\nindex (MD, 23 events\/h; 95% CI, 212.92\nto 16.68 events\/h). In single studies,\noxygen use during sleep was associated with\na higher mean SpO2\n(MD, 18.2%; 95% CI,\n15.58% to 110.82%), nadir SpO2\n(MD,\n120.7%; 95% CI, 111.29% to 130.11%),\nand nadir SpO2\nduring REM sleep (MD,\n19%; 95% CI, 11.57% to 116.43%). It was\nalso associated with trends toward a higher\nmean SpO2\nduring REM sleep (MD, 14%;\n95% CI, 20.16% to 18.16%), mean SpO2\nduring NREM sleep (MD, 13%; 95% CI,\n20.39% to 16.39%), and nadir SpO2\nduring\nNREM sleep (MD, 14%; 95% CI, 20.47%\nto 18.47%). There was no difference in the\nhypopnea index (MD, 23.8 events\/h; 95%\nCI, 219.32 to 111.72 events\/h) or changes\nin overall end-tidal PCO2 levels, although\nPCO2 increased signi\ufb01cantly in a few patients.\nThe panel\u2019s con\ufb01dence in the accuracy\nof these estimated effects in the patient\npopulation of interest to them was very low.\nThere was indirectness of the intervention\nbecause the question is about HOT\nprovided chronically at night, but the\nstudies used oxygen provided during a\nsingle night. There was also indirectness of\noutcomes because those assessed were all\nshort-term physiologic measures rather\nthan the long-term clinical outcomes that\nthe panel would have preferred. In addition,\nthe studies were small, and there was a risk\nof bias, because neither study reported\nenrolling consecutive patients and one\nstudy was not blinded.\nBene\ufb01ts. In patients with SDB with\nnocturnal desaturation, HOT during sleep\nincreased both the mean and nadir SpO2\nduring sleep.\nHarms. No harms were reported in any\nof the studies.\nConclusions. The panel concluded that\nthe bene\ufb01ts of HOT likely exceed the harms,\nburdens, and cost for the majority of\npatients with severe nocturnal hypoxemia\ndue to SDB who either cannot tolerate\npositive airway pressure therapy or are\nawaiting surgical treatment of their SDB.\nAlthough the studies above merely show\nthat giving oxygen increases oxygenation,\nthere is abundant evidence that improving\nnocturnal oxygenation by other means,\nsuch as positive airway pressure, mitigates\nadverse cardiopulmonary consequences of\nnocturnal hypoxemia in children. The panel\nhad no reason to suspect that relief of\nnocturnal hypoxemia by oxygen or positive\nairway pressure will lead to different\nconsequences.\nWhat others are saying. The BTS\nclinical practice guidelines emphasized\nthat positive airway pressure is the\ntherapy of choice for children with OSA;\nhowever, for children in whom application\nof positive airway pressure is not\npossible, the BTS recommended HOT\nbut urged monitoring of CO2 levels\nduring the initiation of oxygen therapy\n(121).\nAMERICAN THORACIC SOCIETY DOCUMENTS\nAmerican Thoracic Society Documents e13\nATS recommendation.\nd For patients with SDB complicated\nby severe nocturnal hypoxemia who\ncannot tolerate positive airway pressure\ntherapy or are awaiting surgical\ntreatment of SDB, we suggest that\nHOT be prescribed (conditional\nrecommendation, very low-quality\nevidence). Severe nocturnal hypoxemia is\nde\ufb01ned as greater than or equal to 5% of\nrecording time spent with a SpO2\nless\nthan 90% during sleep.\nQuestion 4: Should Children with\nSickle Cell Disease Complicated by\nChronic Hypoxemia Be Treated with\nHOT?\nEvidence base. Many studies reported\nassociations between hypoxemia and\noutcomes such as stroke and pain crises, but\nthey were excluded because they did not\ncompare use of oxygen with no oxygen\ntherapy. We identi\ufb01ed two observational\nstudies that evaluated patients before,\nduring, and after receiving supplemental\noxygen (126, 127). Both studies enrolled\npatients with SCD, but neither reported the\nages of the patients or the degree of\nchronic hypoxemia. One study of three\npatients administered oxygen at 5 L\/min\nby nasal prongs (126), and the other\nstudy of four patients administered\n70\u2013100% oxygen continuously for 8 to 20\ndays (127).\nMeasures of oxygenation increased\nduring oxygen therapy. In one study, the\nPaO2\nranged from 72 to 83 mm Hg (9.60 to\n11.07 kPa) before receiving supplemental\noxygen and from 146 to 175 mm Hg (19.47\nto 23.33 kPa) while receiving oxygen (126).\nIn the other study, which reported a single\nrepresentative patient only, the SpO2\nwas\n89% before the initiation of oxygen, 100%\nduring administration, and 83% after\ndiscontinuation (127). In both studies, the\nnumber and percentage of sickle cells\ndecreased during oxygen administration,\nalthough this was not accompanied by\nless hemolysis. The amount of sickle cells\nrebounded when the oxygen was discontinued,\nwith six of seven patients rebounding to\nhigher-than-baseline levels and the remaining\npatient rebounding to baseline levels (126,\n127). One study was terminated early because\ntwo of three patients developed pain crises\nafter discontinuation of the supplemental\noxygen, although none of the four patients in\nthe other study experienced a pain crisis (126).\nThe panel\u2019s con\ufb01dence in the accuracy\nof these estimated effects in the patient\npopulation of interest to them was very low.\nThere was indirectness of the intervention\nbecause the oxygen was provided at much\nhigher levels than current norms. In\naddition, there was a risk of bias for\nmultiple reasons: The studies were not\nblinded, did not report enrolling consecutive\npatients, and did not report all of the data\nthat were collected.\nBene\ufb01ts. Oxygen therapy increased\noxygenation and decreased the amount of\nsickle cells.\nHarms. After discontinuation of\ncontinuous oxygen, the amount of sickle\ncells rebounded to higher-than-baseline\nlevels, and some patients developed a pain\ncrisis.\nConclusions. The panel acknowledged\nthat the studies described above raise serious\nconcerns about the potential for harm if\noxygen is discontinued in patients with\nSCD. However, the panel had very low\ncon\ufb01dence in the \ufb01ndings owing to the\nstudies\u2019 small size (only seven patients\ntotal) and publication age (cointerventions\nwere different in 1944 and 1984).\nMoreover, the panel has collectively used\noxygen in hundreds of patients with SCD\nfor a variety of reasons without increases\nin sickle cell crises or acute chest\nsyndrome upon discontinuation, and it was\nconcerned about the untoward effects of\nallowing severe chronic hypoxemia to go\nunabated.\nWhat others are saying. The BTS\nclinical practice guidelines recommended\nHOT for children with SCD and persistent\nnocturnal hypoxemia to reduce stroke and\npain crises (121). Although the National\nHealth Service guidelines on SCD and\nthalassemia do not speci\ufb01cally make\nrecommendations related to supplemental\noxygen use, the need for guidance in the\ndelivery of oxygen therapy was suggested\n(128). In an evidence-based summary\nof the management of SCD, long-term\noxygen therapy was not addressed,\nbut maintenance of SpO2\nabove 95%\nwas strongly recommended during\nacute chest syndrome, and exchange\ntransfusion was recommended when\nthe SpO2\ndropped below 90% (129). In\npatients with SCD with concomitant\nPH, the pediatric PH guidelines\nsuggested optimization of therapies\nwith no speci\ufb01cs about oxygen therapy\n(123).\nATS recommendation.\nd For patients with SCD complicated by\nsevere chronic hypoxemia, we suggest\nthat HOT be prescribed (conditional\nrecommendation, very low-quality\nevidence). Severe chronic hypoxemia is\nde\ufb01ned as either 1) greater than or equal\nto 5% of recording time spent with an\nSpO2\nless than 90% if measurements are\nobtained by continuous recording or 2)\nat least three separate \ufb01ndings of an SpO2\nless than 90% if measurements are\nobtained intermittently.\nQuestion 5: Should Children with\nPulmonary Hypertension without\nCongenital Heart Disease Be Treated\nwith HOT?\nEvidence base. We identi\ufb01ed no studies\nthat compared the effects of HOT with\nno oxygen therapy in children with PH\ncomplicated by chronic hypoxemia. The\npanel discussed whether to review indirect\nevidence from adults but judged adults\nwith PH to be too indirect a population\nto inform recommendations in children.\nInstead, the panel decided to inform its\nrecommendations with their collective\nnonsystematic clinical observations derived\nfrom caring for many such patients over\nseveral decades. Nonsystematic clinical\nobservations give very low con\ufb01dence in the\nestimated effects.\nConclusions. The panel emphasized\nthat empirical evidence comparing HOT\nwith no oxygen therapy will never be\nforthcoming, because withholding HOT\nin such patients is ethically questionable.\nThe panel\u2019s collective clinical experience\nsuggests that children with chronic\nhypoxemia due to PH are less dyspneic\nand more active when receiving HOT.\nAlthough harmful consequences of HOT\nare infrequent, there can be effects on\nquality of life. Most important, the panel\nwas particularly certain about the\npotential of HOT to bene\ufb01t patients by\nmitigating the undesirable consequences\nof chronic hypoxemia because it directly\ninterrupts the vicious cycle of PH causing\nhypoxemia, which in turn worsens\nthe PH.\nWhat others are saying. The BTS\nclinical practice guidelines recommended\nHOT for children with idiopathic PH\ncomplicated by sleep-associated desaturations,\nfor children with idiopathic PH who have\nsevere hypoxemia, and for PH secondary to\nAMERICAN THORACIC SOCIETY DOCUMENTS\ne14 American Journal of Respiratory and Critical Care Medicine Volume 199 Number 3 | February 1 2019\npulmonary disease. They recommended\nagainst HOT for PH associated with cardiac\neffects, owing to lack of good evidence (121).\nIn comparison, the combined ATS and\nAHA guidelines on pediatric PH reported\nthat treatment of hypoxemia with oxygen\ntherapy was reasonable in children with\nPH who had an SpO2\nless than 92%, especially\nif associated with any concomitant lung\ndisease (123).\nATS recommendation.\nd For patients with PH without CHD\ncomplicated by chronic hypoxemia, we\nrecommend that HOT be prescribed\n(strong recommendation, very low-quality\nevidence). Chronic hypoxemia is de\ufb01ned\nas either 1) greater than or equal to 5% of\nrecording time spent with an SpO2\nless\nthan or equal to 93% if measurements are\nobtained by continuous recording or 2) at\nleast three separate \ufb01ndings of an SpO2\nless than or equal to 93% if measurements\nare obtained intermittently.\nQuestion 6: Should Children with\nPulmonary Hypertension with\nCongenital Heart Disease Be Treated\nwith HOT?\nEvidence base. We identi\ufb01ed no studies\nthat compared the effects of HOT with\nno oxygen therapy exclusively in children\nwith CHD. The only relevant study was\na nonrandomized trial of supplemental\noxygen for patients with PH in which 13\nof the 15 patients had CHD (130). Nine\npatients were assigned to receive HOT for\nat least 12 hours per day, and six patients\nwere assigned no HOT. The patients were\nfollowed for up to 5 years. Baseline values\nrevealed a trend toward higher SpO2\nin the\nHOT group (15%; 24.43% to 114.43%), a\ntrend toward lower pulmonary vascular\nresistance in the HOT group (27 mm\nHg\/min\/m2\n\/L; 95% CI, 13.67 to 217.67 mm\nHg\/min\/m2\n\/L), and no difference in the\npulmonary artery pressure. Mortality was\nlower among children who received HOT\n(0% vs. 83%; relative risk not estimable).\nExercise capacity and symptoms were\nreportedly measured by questionnaire, but\nthe results were not described. The study\nprovided very low con\ufb01dence in its estimated\neffects.\nBene\ufb01ts. HOT was associated with\nlower mortality and trends toward\ndecreased pulmonary vascular resistance\nand increased pulmonary blood \ufb02ow.\nHarms. No harms were reported in the\nstudy.\nConclusions. The panel acknowledged\nthat the evidence favored HOT but had very\nlow con\ufb01dence in the estimated effects,\nowing to the study design, potential bias,\nand imprecision. They also expressed\nconcern that in some patients with\nunrepaired CHD and signi\ufb01cant left-to-\nright shunt, increased pulmonary blood \ufb02ow\ncan be harmful rather than bene\ufb01cial.\nGenerally speaking, they strongly believed\nthat the \ufb01ne balance between the potential\nfor either bene\ufb01cial or harmful effects\ndictates that such patients be evaluated and\ntreated by clinicians with experience in\nmanaging such complicated patients. In\nchildren with surgically repaired CHD,\nhowever, concerns of high pulmonary blood\n\ufb02ow would not persist, and the effects\nof oxygen therapy to avoid hypoxemia,\nespecially in the setting of PH, are likely\ngreater than potential adverse effects.\nWhat others are saying. The BTS\nclinical practice guidelines recommended\nagainst HOT for cyanotic CHD unless\naccompanied by other respiratory problems.\nThey similarly recommended against HOT\nfor acyanotic CHD (121). The combined\nATS and AHA guidelines on pediatric PH\ndid not address oxygen therapy in children\nwith CHD and chronic hypoxemia (123).\nATS recommendation.\nd For patients with PH with CHD\ncomplicated by chronic hypoxemia,\nsupplemental oxygen will impact\nhemodynamics and physiology; we\nrecommend that HOT NOT be\ninitiated in these children, regardless\nof previous reparative or palliative\ncongenital heart surgery, until there\nhas been consultation with a pediatric\npulmonologist or cardiologist who\nhas expertise in the management\nof PH in this clinical setting (strong\nrecommendation, very low-quality\nevidence).\nQuestion 7: Should Children with\nInterstitial Lung Disease Complicated\nby Chronic Hypoxemia Be Treated\nwith HOT?\nEvidence base. We identi\ufb01ed no studies that\ncompared the effects of HOT with no oxygen\ntherapy in children with ILD complicated\nby chronic hypoxemia. The panel discussed\nwhether to review indirect evidence from adults\nbut judged adults with ILD to be too indirect\na population to inform recommendations in\nchildren. Instead, the panel decided to inform\nits recommendations with their collective\nnonsystematic clinical observations.\nNonsystematic clinical observations give\nvery low con\ufb01dence in the estimated effects.\nConclusions. The panel again\nemphasized that empirical evidence\ncomparing oxygen use with no oxygen\ntherapy will never be forthcoming, because\nwithholding HOT in such patients is ethically\nquestionable. The panel was certain that the\nbene\ufb01ts of HOT exceed the harms, burdens,\nand cost in patients with ILD with severe\nchronic hypoxemia (SpO2\n, ,90%). This was\nbased on the large number of bene\ufb01cial\noutcomes that they have observed in\ntheir clinical practices and the absence of\nharmful outcomes, decades of clinical\nexperience in managing many such patients,\nand recognition that prolonged chronic\nhypoxemia can contribute to serious health\nconsequences such as PH and cor pulmonale.\nThe panel also concluded that the bene\ufb01ts of\nHOT likely exceed the harms, burden, and\ncost in patients with ILD who have mild\nhypoxemia (SpO2\n90\u201393%) that is chronic,\naccompanied by sequelae of hypoxemia\n(e.g., dyspnea on exertion), or associated with\ndesaturation during sleep or exertion.\nWhat others are saying. The BTS\nclinical practice guidelines recommended\nHOT for children with ILD complicated\nby chronic hypoxemia who are otherwise\nready for hospital discharge (121). Although\nspeci\ufb01c recommendations for oxygen therapy\nwere not addressed, the recent guideline\non ILD in children recommended routine\nmeasurement of SpO2\nfor pediatric patients by\npulse oximetry, with supplemental oxygen\npotentially indicated during the day, during\nthe night, and with exercise for all children as\nwell as during feeding for infants (104).\nATS recommendations.\nd For patients with ILD complicated\nby severe chronic hypoxemia, we\nrecommend that HOT be prescribed\n(strong recommendation, very low-quality\nevidence). Severe chronic hypoxemia is\nde\ufb01ned as either 1) greater than or equal\nto 5% of recording time spent with an\nSpO2\nless than 90% if measurements are\nobtained by continuous recording or 2)\nat least three separate \ufb01ndings of an SpO2\nless than 90% if measurements are obtained\nintermittently.\nd For patients with ILD who have both\nmild chronic hypoxemia and either\ndyspnea on exertion or desaturation\nAMERICAN THORACIC SOCIETY DOCUMENTS\nAmerican Thoracic Society Documents e15\nduring sleep or exertion, we suggest\nthat HOT be prescribed (conditional\nrecommendation, very low-quality\nevidence). Mild chronic hypoxemia is\nde\ufb01ned as either 1) greater than or equal\nto 5% of recording time spent with\nan SpO2\n90\u201393% if measurements are\nobtained by continuous recording or 2)\nat least three separate \ufb01ndings of an SpO2\n90\u201393% if measurements are obtained\nintermittently.\nProviding HOT\nEvidence-based data that address the\noptimal modalities of home oxygen\ndelivery and monitoring in the pediatric\npopulation are limited. Although an in-\ndepth discussion of speci\ufb01c delivery and\nmonitoring methods is beyond the scope of\nthis guideline, panel members identi\ufb01ed\nimportant considerations for equipment\nchoice, including the patient\u2019s age, size,\nand developmental stage, as well as the\nrequired \ufb02ow rate. Furthermore, equipment\nchoices should remain under appropriate\nsupervision.\nEquipment\nd All children require access to age-\nappropriate equipment and supplies\nthat will meet their supplemental\noxygen needs. These items should be\nreimbursed by insurers to ensure safe\nand effective delivery of oxygen in the\nhome. The prescriber should recognize\nthat there is currently signi\ufb01cant geographic\nvariability in access to and reimbursement\nfor pediatric patient\u2013speci\ufb01c equipment.\nd Oxygen concentrators are one of the\nmost commonly used delivery systems\nin the home and may be stationary or\nportable, whereas tanks may be more\nreadily available according to local\npreferences. The stationary devices are\nlarge and require reliable sources of\nelectricity. In areas where power outages\nare common, backup generators or\nalternative sources of oxygen are\nrequired. There are various types of\nconcentrators available, with \ufb02ows most\ncommonly ranging from 1 to 5 L\/min,\nproviding up to FIO2\n0.95 (131).\nd Children require access to low-\ufb02ow\ndelivery systems. Low-\ufb02ow meters\nshould be used to deliver \ufb02ows ranging\nfrom 0.1 to 1 L\/min for infants and\nyoung children (121). Some equipment\ncompanies have low-\ufb02ow concentrators\navailable to provide oxygen at 0.1 L\/min\nwithout the use of a \ufb02owmeter.\nd Size-adequate oxygen cylinders can be\nused in infants and small children as\nthe primary source of home oxygen if\n\ufb02ow rates are low (,0.3 L\/min) and\nif the duration of oxygen therapy is\nexpected to be limited to a few months\n(121).\nd Portability of equipment is an important\nconcern for pediatric patients. Continuous\n\ufb02ow portable concentrators are small\nand may be battery operated to allow\nfor increased mobility. Adaptation for\nstrollers and\/or wheelchairs should be\nconsidered (132). Lightweight cylinders\nallow for easier mobility, though\nthey do not last as long as standard\ncylinders outside the home. If using\na stationary oxygen system (e.g.,\nconcentrator, tanks) at home, a\nportable system is necessary to allow\nfor travel to school, medical visits, and\nso forth.\nd Pulse oxygen delivery systems (also\ncalled \u201coxygen conserver devices\u201d)\nare used in adult patients to restrict\noxygen administration to the period of\ninspiration, thereby avoiding the waste of\noxygen delivery during exhalation and\nassuring a consistent dose of oxygen per\nbreath, regardless of respiratory rate.\nVarying by device, this technology relies\non pressure, volume, or time to trigger\noxygen release (131). Because of higher\nrespiratory rates and low inspiratory\nvolumes in children, pulse oxygen\ndelivery systems should not be used\nin infants or young children, although\nthey can be considered for use in\nadolescents (121).\nd Humidi\ufb01cation of the oxygen circuit\nshould be provided for \ufb02ow rates above\n1 L\/min and can be achieved through\ncold bubble or heated humidi\ufb01cation\ndevices (121). A bene\ufb01t to humidi\ufb01cation\nof low-\ufb02ow oxygen therapy (,1 L\/min)\nhas not been clearly established (133).\nd The addition of humidi\ufb01cation (or\nother modi\ufb01cations to the original\ncircuit) may alter \ufb02ow delivery.\nAppropriate equipment (such as a gas\n\ufb02owmeter device) should be available\nfor families to monitor \ufb02ow delivery.\nd Home oxygen is typically delivered\nvia nasal cannula in the pediatric\npopulation. The delivered FIO2\nis\ndependent on the \ufb02ow through the\nprongs, the level of entrainment, and\nthe child\u2019s tidal volume, with the delivered\nFIO2\nranging from 0.22 to 0.95 at a\nmaximum \ufb02ow of 2 L\/min (134, 135).\nCannulae should be appropriately secured\nto the face to prevent skin breakdown and\nshould be replaced as often as weekly if\nrequired. The prescribers should be\nproactive in delineating the appropriate\noxygen delivery interface to minimize the\nrisk of equipment-related complications,\nwith special attention to maintaining skin\nintegrity. Older patients or those not\ntolerating nasal cannulas with a higher\noxygen \ufb02ow rates may opt for the use of\nan appropriate oxygen mask, although\nmore variability in FIO2\nbased on mask\npositioning and patient tidal volume may\nbe present (134).\nd Increased storage ef\ufb01ciency and\nportability have made liquid oxygen an\nattractive option for the adult population\n(131). Liquid oxygen cannot currently be\ndelivered using continuous \ufb02ows less\nthan 0.25 L\/min (121) and may not\nbe readily available. Storage of liquid\noxygen is not ef\ufb01cient for those needing\nintermittent supplemental oxygen.\nd The high-\ufb02ow nasal cannula has the\nability to deliver much higher \ufb02ow\nrates at varying oxygen concentrations.\nAlthough not routinely used in the\npediatric home setting, there are reports\nof successful cases using outpatient high-\n\ufb02ow nasal cannulas for hypoxemia\nsecondary to OSA (136) and tracheomalacia\n(137).\nMonitoring\nArterial blood gas measurements are not\nroutinely used to assess oxygenation in\nclinically stable children with chronic\ndiseases, owing to pain and discomfort\nfrom arterial puncture. Pulse oximetry\nis the primary method of monitoring\nSpO2\nin the pediatric population. The\noximeter measures red and infrared\nlight absorption of oxygenated and\ndeoxygenated hemoglobin to estimate the\nSpO2\n(138). Oximetric measurements have\ngenerally been shown to correlate at 2\u20133%\nabove measured arterial saturation, with\naccuracy worsening when SpO2\nmeasures\nbelow 90% (139). Some limitations to\naccurate SpO2\ndeterminations with pulse\noximeters include improper probe\nplacement, movement artifact, nail color,\nambient light, reduced distal extremity\nAMERICAN THORACIC SOCIETY DOCUMENTS\ne16 American Journal of Respiratory and Critical Care Medicine Volume 199 Number 3 | February 1 2019\nperfusion, hypothermia, skin pigmentation,\nand dysfunctional hemoglobin (134, 140).\nThe use of in-home pulse oximetry for\nlong-term monitoring of HOT in children\nis unanimously endorsed by the panel.\nSuch monitoring can alert caregivers to\ninterruptions in oxygen delivery that may\nsuggest clinical deterioration or the need\nfor clinical intervention such as airway\nsuctioning, patient repositioning, and so\nforth (141\u2013146). The panelists recognize the\nlimitations of the literature on in-home\npulse oximetry use in the care of children,\nso further research is recommended to\nidentify best practice of this valuable\nmedical equipment that has its own\ndrawbacks. During times of illness,\npulse oximetry can provide important\ninformation to the caregiver, potentially\ndecreasing the need for visits to the\nemergency department (147). The presence\nof a pulse oximeter can also identify\nreduced SpO2\nduring periods of exertion or\nduring infant feeding. However, concerns\nregarding home oximetry monitoring\ninclude the nuisance of frequent alarms,\nincreased caregiver anxiety, and the\npotential for overreliance by caregivers on\nnormal SpO2\nversus overall clinical status\n(121). Because SpO2\nis only one facet of a\npatient\u2019s clinical status, pediatric patients\nwith increased work of breathing and\npotential hypoventilation need to be\nassessed by a clinician, regardless of SpO2\n.\nWith the panel recommending the\nmonitoring of children on HOT with\npulse oximetry in the home, appropriate\ncaregiver training is required for its use and\napplication. Such training should include an\nunderstanding of when to apply the pulse\noximeter and how to interpret the\nmeasurements obtained. It is of great\nimportance that pediatric patient\u2013speci\ufb01c\nsensors be prescribed by healthcare providers.\nHome Safety\nAssurance of safety and support of all\nchildren and adolescents on HOT should be\na priority. Home caregiver education should\naddress appropriate management of the\nequipment and skills to interpret and\nrespond to abnormal SpO2\nmeasurements\nwhile applying these data to the clinical\nstatus of the child. Education regarding\nthe risks of smoking and open \ufb02ames in\nthe home, as well as the use of oil-based\nproducts or other fuels near the oxygen\nsource, should be provided (121, 134,\n140). The focus on the dangers of smoke\nexposure should include the \ufb02ammability\nof compressed oxygen and the known\nharms that inhaled smoke imparts to\ngrowing infants and children. The\npanel recommends documentation of\ncompetency in the delivery of HOT to\na child once all home caregivers have\ncompleted education. It is also imperative\nto ensure access to reliable electricity and a\ntelephone in case of emergencies (121).\nCommunication between the prescribing\nhealthcare provider, durable medical\nequipment agency, and other key parties is\nimportant to provide appropriate care to\nthese medically complex patients.\nFollow-up\nRegular follow-up with a healthcare\nprovider is required for children on\nHOT, because repeated assessment of\noxygen needs and changes in respiratory\nstatus should be performed. An outpatient\ncontinuous pulse oximetry study (nocturnal\nor daytime) can provide a more complete\nand objective assessment of SpO2\nthan what\ncan be obtained by parental report and\nevaluation in a clinic setting. In addition to\nSpO2\n, feeding patterns and growth, together\nwith activity tolerance, should be assessed.\nAny concern of hypoventilation\nshould be investigated with capillary\nblood gas analysis or serum bicarbonate\ndetermination, which are widely available,\nor with end-tidal or transcutaneous\nCO2 measurements, which are often\nimmediately available in hospital settings\nbut not readily available in an outpatient\nsetting or in the home. Although each of\nthese methods has its limitations (148),\nthey all have the potential for more\nwidespread use in the future. Depending\non the clinical scenario, a more de\ufb01nitive\nevaluation with polysomnography may be\nnecessary.\nDiscontinuation of HOT\nAlthough some conditions may warrant\ninde\ufb01nite HOT, improvements in\nrespiratory function that occur with age,\nmaturation, treatment, clinical course, and\nso forth can lead to an opportunity to wean\n(progressively decrease) or discontinue\n(stop altogether) HOT. Improvements in\nrespiratory status amenable to weaning\nof oxygen therapy are most applicable\nto infants with chronic lung disease of\nprematurity, but a standardized approach\nmay nonetheless be helpful in other\npopulations. Criteria for the justi\ufb01cation\nand initiation of HOT are outlined by CMS,\nbut weaning or discontinuation is not.\nAlthough many healthcare providers reduce\nor wean supplemental oxygen in the\noutpatient setting gradually and with the\nguidance of nocturnal oxygen assessments\n(121, 149\u2013152), there are no widely\naccepted, evidence-based guidelines, and\nfew report using a standardized protocol\n(149). The panel unanimously agrees\nthat a large, prospective trial comparing\nweaning strategies is needed. Nonetheless, we\ndescribe a consensus-based approach to\nidentifying patient readiness for weaning and\ndiscontinuation of HOT, the process for\ndoing so, and the monitoring necessary\nto determine its safety and tolerance. The\nuse, weaning, or discontinuation of other\ntherapies (e.g., diuretics in BPD) is outside the\nscope of this guideline, although providers are\ncautioned to avoid making multiple abrupt\nchanges in treatment at one time.\nAssessing Readiness\nAs previously mentioned, the measurement\nof arterial blood for PaO2\nis not practical\nfor routine outpatient monitoring of a\nchild\u2019s respiratory status; therefore, pulse\noximetry to monitor SpO2\nis standard for\nthe purposes of analyzing gas exchange. A\nchild may be considered appropriate for\nweaning of HOT if the following criteria\nare met, which are based on this panel\u2019s\nconsensus opinion and shaped by an earlier\nsurvey of pediatric pulmonologists (150):\nd Reassuring medical examination by a\nquali\ufb01ed healthcare provider that takes\ninto account the child\u2019s underlying\nmedical condition(s), gestational age,\ncondition-speci\ufb01c growth charts, home\naltitude, and so forth; ideally, the\nexamination should meet these criteria:\n\u2218 Period of relatively stable health (no\ncurrent or recent acute illness)\n\u2218 Age- and condition-appropriate\ngrowth, including positive trends in\nweight gain, linear growth, and head\ncircumference\n\u2218 Meeting developmental milestones as\nexpected for clinical condition, where\nfactors that may in\ufb02uence development,\nsuch as prematurity, concurrent\nsyndrome, perinatal neurodevelopmental\ninsult, and so forth, must be considered\n\u2218 Acceptably low frequency and\/or severity\nof illnesses requiring hospitalization\nAMERICAN THORACIC SOCIETY DOCUMENTS\nAmerican Thoracic Society Documents e17\n\u2218 Physical examination not suggestive of\nimpaired respiratory function (breathing\neffort, respiratory rate, and so forth are\nas expected for clinical course)\nd Reassuring objective measurement of\noxygenation, in which the following\nshould be considered:\n\u2218 Oxygen saturation measured at steady\nstate (not \u201cspot checked\u201d) by continuous\npulse oximetry in room air meets\npatient-speci\ufb01c goal.\n\u2218 Unfortunately, wakeful pulse oximetry\ndid not correlate with nocturnal\noxygenation in a population of premature\ninfants with BPD (121). Brief pulse\noximetry during wakefulness alone may\nbe appropriate for some patients, whereas\nothers may require monitoring during\nfeeding and\/or while asleep with an\novernight, in-home pulse oximetry study.\n\u2218 In general, the same oxygenation goals\nthat prompted initiation of HOT should\nbe used.\nd Depending on the underlying process,\nconsider an echocardiogram to demonstrate\nabsence of or improvement in \ufb01ndings\nsuggestive of PH or right heart strain (e.g.,\nnormal or improving estimation of right\nventricular pressure, lack of ventricular\nseptal \ufb02attening)\nWeaning of HOT\nOnce readiness for weaning of HOT is\ndetermined, it is suggested either to decrease\noxygen \ufb02ow rate gradually or to withdraw its\nuse during certain periods of the day. Some\nchildren may tolerate a reduction from\naround-the-clock home oxygen to nocturnal\nuse only, whereas infants and other children\nwith special circumstances may need to\ncontinue HOT with certain daytime activities\n(e.g., car rides, naps, during feeding).\nWhen gradually decreasing the oxygen\n\ufb02ow rate, it is practical to wean by halving\nbecause conventional home oxygen delivery\ndevices easily allow for this (1 L\/min to\n0.5 L\/min then 0.25 L\/min, and so forth)\nbefore room air challenges. We suggest\nweaning the \ufb02ow rate gradually over the\ncourse of weeks while frequently monitoring\nfor adverse effects. This should include\nregular (weekly to monthly) visits with a\nquali\ufb01ed healthcare provider to assess the\nchild as outlined above.\nSuccessful Discontinuation of HOT\nOnce the child has tolerated weaning\nHOT to a suf\ufb01ciently low \ufb02ow rate, then\ndiscontinuation can be considered. Preterm\nneonates with BPD had more successful\nroom air challenges and clinical stability at\n6 months postdischarge if previously stable\nreceiving less than or equal to 20 ml\/kg\/min\nof oxygen (153). By consensus, the panel\nrecommended that room air challenges be\nconsidered for clinically stable children\nunder 1 year of age receiving less than\n0.1 L\/min and children up to preschool age\nreceiving 0.1\u20130.25 L\/min. By extrapolation,\na \ufb02ow rate less than 0.25\u20130.5 L\/min could\nbe considered for school-age and older\nchildren. With HOT occurring in terms\nof \ufb02ow rate, it is not pertinent to wean or\ndiscontinue oxygen use on the basis of FIO2\n.\nOnce a patient is considered ready\nfor discontinuation of nighttime HOT\naltogether, then an in-home, room air,\nnocturnal pulse oximetry study should be\nperformed using appropriate pediatric\nequipment and reference ranges as outlined\nin this document. Healthcare providers\nshould encourage families to maintain\naccessibility to HOT for several months after\ndiscontinuation, particularly through the\nwinter season, when viral illnesses are\nprevalent. This allows for ample opportunity\nto determine whether the withdrawal of\nHOT was well timed, in addition to how well\nrespiratory illnesses are tolerated without\nsupplemental oxygen.\nAs suggested when assessing for\npatient readiness to wean HOT, it is\nnecessary to monitor responses to each\nchange repeatedly. Given the chronicity of\nthese respiratory conditions, changes should\nbe made on a weeks to months basis,\nas opposed to more quickly, so that\nsubtle deterioration is not missed and\nsuboptimal therapy is promptly reversed.\nThe factors to monitor re\ufb02ect those assessed\nwhen considering patient readiness and\ninclude patient growth, development,\ncardiorespiratory status, and stability of\nhealth (e.g., handling of respiratory illnesses,\ntravel to altitude).\nHOT and its necessary equipment are\noften burdensome and costly. However,\nhome caregivers and healthcare providers\nare reminded that the processes treated\nby HOT are chronic in nature, its use is\nlow risk, and patience is often rewarded.\nConversely, weaning HOT too soon or too\nabruptly can lead to patient and home\ncaregiver stress.\nConclusions\nDespite widespread use of HOT in children\nfor various lung and pulmonary vascular\ndiseases, there is a striking paucity of data\nregarding its implementation, ef\ufb01cacy,\nmonitoring, and discontinuation. With\nlimited evidence, the panel provides\nrecommendations based on expert opinion\nand experiences associated with patient-\nimportant outcomes that will aid clinicians\nin the management of complex pediatric\npatients requiring HOT. Future research\nshould address important areas including\nSpO2\nlevels associated with optimal growth\nand development and the identi\ufb01cation of\nbest practice for weaning and discontinuing\nHOT in children. n\nThis official clinical practice guideline was prepared by an ad hoc subcommittee of the ATS Assembly on Pediatrics.\nMembers of the subcommittee are as\nfollows:\nDON HAYES, JR., M.D., M.S., M.ED.1\n(Co-Chair)\nROBIN R. DETERDING, M.D.2\n(Co-Chair)\nSTEVEN H. ABMAN, M.D.2\n*\u2021\nJOYCE BAKER, M.B.A., R.R.T.-N.P.S.,\nA.E.-C.2x\nIAN M. BALFOUR-LYNN, M.D.3jj\nCHRISTOPHER L. CARROLL, M.D.4{\nMARY E. CATALETTO, M.D.5\n**\nANN GETTYS\n\u2021\u2021\nDAVID GOZAL, M.D., M.B.A.6\n*xx\nSTEPHEN M. M. HAWKINS, M.D.2jjjj\nTIMOTHY M. HOFFMAN, M.D.7{{\nDEBORAH KALEY, R.N., M.S.N., A.E.-C.8\n***\nKATELYN KRIVCHENIA, M.D.1\u2021\u2021\u2021\nGEOFFREY KURLAND, M.D.9\n*\nRICHARD J. MARTIN, M.D.10xxx\nEYAL OREN, PH.D., M.S.11\n**\nHOWARD B. PANITCH, M.D.12\n*\nGREGORY R. PORTA\n13\u2021\u2021\nLAWRENCE M. RHEIN, M.D., M.P.H.14\n*xxx\nMARK L. SPLAINGARD, M.D.1\n*xx\nDMITRY TUMIN, PH.D.1jjjjjj\nKEVIN C. WILSON, M.D.15,16\n**{{{\nAMERICAN THORACIC SOCIETY DOCUMENTS\ne18 American Journal of Respiratory and Critical Care Medicine Volume 199 Number 3 | February 1 2019\n*Pediatric pulmonary representative.\n\u2021\nPulmonary hypertension representative.\nx\nRespiratory therapy representative.\njj\nInternational representative.\n{\nPediatric critical care representative.\n**Methodologist.\n\u2021\u2021\nPatient representative.\nxx\nSleep medicine representative.\njjjj\nPediatric sleep medicine fellow representative.\n{{\nPediatric cardiology representative.\n***Nursing representative.\n\u2021\u2021\u2021\nPediatric pulmonary fellow representative.\nxxx\nNeonatology representative.\njjjjjj\nSociology and population health\nrepresentative.\n{{{\nProject manager.\n1\nDepartment of Pediatrics, The Ohio State\nUniversity College of Medicine, Nationwide\nChildren\u2019s Hospital, Columbus, Ohio;\n2\nDepartment of Pediatrics, University of\nColorado School of Medicine, Children\u2019s\nHospital Colorado, Denver, Colorado;\n3\nPediatric Respiratory Medicine, Royal\nBrompton Hospital, London, United\nKingdom; 4\nDepartment of Pediatrics,\nConnecticut Children\u2019s Medical Center,\nHartford, Connecticut; 5\nDepartment of\nPediatrics, Stony Brook University School\nof Medicine, Stony Brook, New York;\n6\nDepartment of Child Health, University of\nMissouri School of Medicine, Columbia,\nMissouri; 7\nDepartment of Pediatrics, University\nof North Carolina School of Medicine, Chapel\nHill, North Carolina; 8\nLucile Packard Children\u2019s\nHospital at Stanford, Palo Alto, California;\n9\nDepartment of Pediatrics, University of\nPittsburgh School of Medicine, Children\u2019s\nHospital of Pittsburgh, Pittsburgh,\nPennsylvania; 10\nDepartment of Pediatrics,\nCase Western Reserve University School of\nMedicine, Cleveland, Ohio; 11\nDivision of\nEpidemiology and Biostatistics, San Diego\nState University School of Public Health, San\nDiego, California; 12\nDepartment of Pediatrics,\nUniversity of Pennsylvania Perelman School of\nMedicine, Children\u2019s Hospital of Philadelphia,\nPhiladelphia, Pennsylvania; 13\nChildren\u2019s\nInterstitial Lung Disease Foundation Inc.,\nCincinnati, Ohio; 14\nDepartment of Pediatrics,\nUniversity of Massachusetts Medical School,\nWorcester, Massachusetts; 15\nDepartment\nof Medicine, Boston University School of\nMedicine, Boston, Massachusetts; and\n16\nAmerican Thoracic Society, New York,\nNew York\nAuthor Disclosures: R.R.D. served on an\nadvisory committee for Boehringer Ingelheim\nand ListenMD; served as a speaker for\nNovartis; received royalties from Elsevier\nPublishing; held a patent for a Personalized\nHealth Care Wearable Sensor System; had\npatents pending for Systems and Methods for\nDetermining Vital Information with a Computing\nDevice, for a Pediatric Nasal Endoscope, for a\nRespiration Rate Measurement System, and\nfor a Tongue Localization, Teeth Interaction,\nand Detection System; served as consultant\nfor, and had ownership or investment interests\nand other intellectual property with,\nTripleEndoscopy Inc.; and had ownership or\ninvestment interests and royalties, licensing\nfees, or other sales proceeds with Now\nVitals Inc. S.H.A. received research support\nfrom Shire Pharmaceuticals and United\nTherapeutics; and served on an advisory\ncommittee for Shire Pharmaceuticals. M.E.C.\nserved as editor-in-chief for and received\nan honorarium from Pediatric Allergy,\nImmunology, and Pulmonology; served as an\nassociate editor for the American Academy of\nPediatrics, Pediatric Pulmonology: A Manual\nfor Primary Care; and served as an editor for\nStatPearls. R.J.M. served on a data safety\nmonitoring board for CareFusion and Windtree\nTherapeutics. H.B.P. served on an advisory\ncommittee for Philips Respironics; and\nreceived royalties from UpToDate. K.C.W.\nreported employment by the American\nThoracic Society as Chief of Documents and\nPatient Education and Documents Editor and\nderived salary support from these roles, and\nas such he has a personal financial interest\nin the quality of all ATS clinical practice\nguidelines. D.H., J.B., I.M.B.-L., C.L.C., A.G.,\nD.G., S.M.M.H., T.M.H., D.K., K.K., G.K., E.O.,\nG.R.P., L.M.R., M.L.S., and D.T. reported\nno relationships with relevant commercial\ninterests.\nAcknowledgment: This official document\nwas prepared by a subcommittee of the\nAssembly on Pediatrics. The members of the\nclinical practice guideline panel on home oxygen\ntherapy for children thank Kimberly Lawrence\nfor the excellent and thoughtful job she did in\norganizing this panel, which was invaluable for the\ngeneration of this document.\nReferences\n1. Centers for Medicare & Medicaid Services. National coverage\ndetermination (NCD) for home use of oxygen [accessed 2018\nMay 8]. Available from: https:\/\/www.cms.gov\/medicare-coverage-\ndatabase\/details\/ncd-details.aspx?NCDId=169&ncdver=\n1&DocID=240.2&SearchType=Advanced&bc=IAAAABAAAAAA&.\n2. Nocturnal Oxygen Therapy Trial Group. 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Malnutrition and growth failure in cyanotic\nand acyanotic congenital heart disease with and without pulmonary\nhypertension. Arch Dis Child 1999;81:49\u201352.\n113. Nevel RJ, Garnett ET, Schaudies DA, Young LR. Growth trajectories\nand oxygen use in neuroendocrine cell hyperplasia of infancy.\nPediatr Pulmonol 2018;53:656\u2013663.\n114. Hayes D Jr, Splaingard ML, Cardamone S, Rohrbach R, Klima J,\nTobias JD, et al. Duration of home oxygen therapy in young children\nenrolled in an accountable care organization. Ann Am Thorac Soc\n2018;15:891\u2013893.\n115. Falk B, Nini A, Zigel L, Yahav Y, Aviram M, Rivlin J, et al. Effect of low\naltitude at the Dead Sea on exercise capacity and cardiopulmonary\nresponse to exercise in cystic \ufb01brosis patients with moderate to\nsevere lung disease. Pediatr Pulmonol 2006;41:234\u2013241.\n116. Gozal D. Nocturnal ventilatory support in patients with cystic \ufb01brosis:\ncomparison with supplemental oxygen. Eur Respir J 1997;10:\n1999\u20132003.\n117. Marcus CL, Bader D, Stabile MW, Wang C-I, Osher AB, Keens TG.\nSupplemental oxygen and exercise performance in patients with\ncystic \ufb01brosis with severe pulmonary disease. Chest 1992;101:52\u201357.\n118. McKone EF, Barry SC, FitzGerald MX, Gallagher CG. The role of\nsupplemental oxygen during submaximal exercise in patients with\ncystic \ufb01brosis. Eur Respir J 2002;20:134\u2013142.\n119. Milross MA, Piper AJ, Norman M, Becker HF, Willson GN, Grunstein\nRR, et al. Low-\ufb02ow oxygen and bilevel ventilatory support: effects\non ventilation during sleep in cystic \ufb01brosis. Am J Respir Crit Care\nMed 2001;163:129\u2013134.\n120. Nixon PA, Orenstein DM, Curtis SE, Ross EA. Oxygen supplementation\nduring exercise in cystic \ufb01brosis. Am Rev Respir Dis 1990;142:\n807\u2013811.\n121. Balfour-Lynn IM, Field DJ, Gringras P, Hicks B, Jardine E, Jones RC,\net al.; Paediatric Section of the Home Oxygen Guideline\nDevelopment Group of the BTS Standards of Care Committee. BTS\nguidelines for home oxygen in children. Thorax 2009;64(Suppl 2):\nii1\u2013ii26.\n122. Mourani PM, Ivy DD, Gao D, Abman SH. Pulmonary vascular effects\nof inhaled nitric oxide and oxygen tension in bronchopulmonary\ndysplasia. Am J Respir Crit Care Med 2004;170:1006\u20131013.\n123. Abman SH, Hansmann G, Archer SL, Ivy DD, Adatia I, Chung WK,\net al.; American Heart Association Council on Cardiopulmonary,\nCritical Care, Perioperative and Resuscitation; Council on Clinical\nCardiology; Council on Cardiovascular Disease in the Young;\nCouncil on Cardiovascular Radiology and Intervention; Council on\nCardiovascular Surgery and Anesthesia; and the American Thoracic\nSociety. Pediatric pulmonary hypertension: guidelines from the\nAmerican Heart Association and American Thoracic Society.\nCirculation 2015;132:2037\u20132099. [Published erratum appears in\nCirculation 2016;133:e368.]\n124. Marcus CL, Carroll JL, Bamford O, Pyzik P, Loughlin GM.\nSupplemental oxygen during sleep in children with sleep-\ndisordered breathing. Am J Respir Crit Care Med 1995;152:\n1297\u20131301.\n125. Aljadeff G, Gozal D, Bailey-Wahl SL, Burrell B, Keens TG, Ward SL.\nEffects of overnight supplemental oxygen in obstructive\nsleep apnea in children. Am J Respir Crit Care Med 1996;153:\n51\u201355.\n126. Embury SH, Garcia JF, Mohandas N, Pennathur-Das R, Clark MR.\nEffects of oxygen inhalation on endogenous erythropoietin kinetics,\nerythropoiesis, and properties of blood cells in sickle-cell anemia.\nN Engl J Med 1984;311:291\u2013295.\n127. Reinhard EH, Moore CV, Dubach R, Wade LJ. Depressant effects\nof high concentrations of inspired oxygen on erythrocytogenesis:\nobservations on patients with sickle cell anemia with a description\nof the observed toxic manifestations of oxygen. J Clin Invest 1944;\n23:682\u2013698.\n128. National Health Service (NHS). Sickle cell disease in childhood:\nstandards and guidelines for clinical care. 2nd ed. London: NHS\nSickle Cell and Thalassaemia Screening Programme and Sickle\nCell Society; Oct 2010 [accessed 2018 Jun 13]. Available from:\nhttps:\/\/assets.publishing.service.gov.uk\/government\/uploads\/system\/\nuploads\/attachment_data\/\ufb01le\/408961\/1332-SC-Clinical-Standards-\nWEB.pdf.\n129. Yawn BP, Buchanan GR, Afenyi-Annan AN, Ballas SK, Hassell KL,\nJames AH, et al. Management of sickle cell disease: summary of\nthe 2014 evidence-based report by expert panel members. JAMA\n2014;312:1033\u20131048.\n130. Bowyer JJ, Busst CM, Denison DM, Shinebourne EA. Effect of long\nterm oxygen treatment at home in children with pulmonary vascular\ndisease. Br Heart J 1986;55:385\u2013390.\n131. McCoy RW. Options for home oxygen therapy equipment: storage\nand metering of oxygen in the home. Respir Care 2013;58:\n65\u201385.\n132. Balfour-Lynn IM, Primhak RA, Shaw BN. Home oxygen for children:\nwho, how and when? Thorax 2005;60:76\u201381.\n133. Wen Z, Wang W, Zhang H, Wu C, Ding J, Shen M. Is humidi\ufb01ed better\nthan non-humidi\ufb01ed low-\ufb02ow oxygen therapy? A systematic review\nand meta-analysis. J Adv Nurs 2017;73:2522\u20132533.\n134. Walsh BK, Smallwood CD. Pediatric oxygen therapy: a review and\nupdate. Respir Care 2017;62:645\u2013661.\n135. Ortega Ruiz F, D\u0131\u0301az Lobato S, Galdiz Iturri JB, Garc\u0131\u0301a Rio F, Gu\u0308ell\nRous R, Morante Velez F, et al.; SEPAR. Continuous home oxygen\ntherapy. Arch Bronconeumol 2014;50:185\u2013200.\n136. Hawkins S, Huston S, Campbell K, Halbower A. High-\ufb02ow,\nheated, humidi\ufb01ed air via nasal cannula treats CPAP-intolerant\nchildren with obstructive sleep apnea. J Clin Sleep Med 2017;13:\n981\u2013989.\n137. Ve\u0301zina K, Laberge S, Nguyen TTD. Home high-\ufb02ow nasal cannula\nas a treatment for severe tracheomalacia: a pediatric case report.\nPediatr Pulmonol 2017;52:E43\u2013E45.\n138. Langley R, Cunningham S. How should oxygen supplementation be\nguided by pulse oximetry in children: do we know the level? Front\nPediatr 2017;4:138.\n139. Webb RK, Ralston AC, Runciman WB. Potential errors in pulse\noximetry. II. Effects of changes in saturation and signal quality.\nAnaesthesia 1991;46:207\u2013212.\n140. Adde FV, Alvarez AE, Barbisan BN, Guimar\u00e3es BR. Recommendations\nfor long-term home oxygen therapy in children and adolescents. J\nPediatr (Rio J) 2013;89:6\u201317.\n141. Montgomery M, Wiebicke W, Bibi H, Pagtakhan RD, Pasterkamp H.\nHome measurement of oxygen saturation during sleep in patients\nwith cystic \ufb01brosis. Pediatr Pulmonol 1989;7:29\u201334.\n142. Uyan ZS, Ozdemir N, Ersu R, Akpinar I, Keskin S, Cakir E, et al.\nFactors that correlate with sleep oxygenation in children with cystic\n\ufb01brosis. Pediatr Pulmonol 2007;42:716\u2013722.\n143. Ge\u0301linas JF, Davis GM, Arlegui C, Co\u0302te\u0301 A. Prolonged, documented\nhome-monitoring of oxygenation in infants and children. Pediatr\nPulmonol 2008;43:288\u2013296.\nAMERICAN THORACIC SOCIETY DOCUMENTS\ne22 American Journal of Respiratory and Critical Care Medicine Volume 199 Number 3 | February 1 2019\n144. O\u0308hman A, Stro\u0308mvall-Larsson E, Nilsson B, Mellander M. Pulse\noximetry home monitoring in infants with single-ventricle physiology\nand a surgical shunt as the only source of pulmonary blood \ufb02ow.\nCardiol Young 2013;23:75\u201381.\n145. Needleman JP, Franco ME, Varlotta L, Reber-Brodecki D, Bauer N,\nDampier C, et al. Mechanisms of nocturnal oxyhemoglobin\ndesaturation in children and adolescents with sickle cell disease.\nPediatr Pulmonol 1999;28:418\u2013422.\n146. Barratt CW, Vyas H, Hayes-Gill BR, Crowe JA, Flatman D. Detection\nof previously unrecognized daytime desaturation in children with\nchronic lung disease. J Med Eng Technol 2007;31:101\u2013108.\n147. Allen J, Zwerdling R, Ehrenkranz R, Gaultier C, Geggel R, Greenough\nA, et al.; American Thoracic Society. Statement on the care of the\nchild with chronic lung disease of infancy and childhood. Am J\nRespir Crit Care Med 2003;168:356\u2013396.\n148. Smallwood CD, Walsh BK. Noninvasive monitoring of oxygen and\nventilation. Respir Care 2017;62:751\u2013764.\n149. Fitzgerald DA, Massie RJ, Nixon GM, Jaffe A, Wilson A, Landau LI,\net al.; Thoracic Society of Australia and New Zealand. Infants with\nchronic neonatal lung disease: recommendations for the use of\nhome oxygen therapy. Med J Aust 2008;189:578\u2013582.\n150. Palm K, Simoneau T, Sawicki G, Rhein L. Assessment of current\nstrategies for weaning premature infants from supplemental\noxygen in the outpatient setting. Adv Neonatal Care 2011;11:\n349\u2013356.\n151. Silva DT, Hagan R, Sly PD. Home oxygen management of neonatal\nchronic lung disease in Western Australia. J Paediatr Child Health\n1995;31:185\u2013188.\n152. Yeh J, McGrath-Morrow SA, Collaco JM. Oxygen weaning after\nhospital discharge in children with bronchopulmonary dysplasia.\nPediatr Pulmonol 2016;51:1206\u20131211.\n153. Simoes EA, Rosenberg AA, King SJ, Groothuis JR. Room air challenge:\nprediction for successful weaning of oxygen-dependent infants.\nJ Perinatol 1997;17:125\u2013129.\nAMERICAN THORACIC SOCIETY DOCUMENTS\nAmerican Thoracic Society Documents e23","is_draft":"0","editor_type":"4","file_path":"\/docker_production\/zgvd51\/article\/Tl4sV95l\/article_file\/2019 ATS\u4e34\u5e8a\u5b9e\u8df5\u6307\u5357 \u513f\u7ae5\u5bb6\u5ead\u6c27\u7597.pdf","add_time":"1757143012","update_time":"1757143078"},"pure_content":"AMERICAN THORACIC SOCIETY\nDOCUMENTS\nHome Oxygen Therapy for Children\nAn Of\ufb01cial American Thoracic Society Clinical Practice Guideline\nDon Hayes, Jr., Kevin C. Wilson, Katelyn Krivchenia, Stephen M. M."},{"id":"610662","string_id":"lnHaHaAn","status":"1","parent_id":"610654","slug":"2020-ATS-lin-chuang-shi-jian-zhi-nan-cheng-ren-man-xing-fei-bing-jia-ting-yang-liao","order":"0","name":"2020 ATS\u4e34\u5e8a\u5b9e\u8df5\u6307\u5357 \u6210\u4eba\u6162\u6027\u80ba\u75c5\u5bb6\u5ead\u6c27\u7597","type":"2","cover":"","cover_alt":"","desc":null,"website":"","contact":"","seo_title":"","seo_keyword":"","seo_desc":"","share_switch":"0","share_code":"","author":"","published_time":"1757143079","add_time":"1757143012","update_time":"1757143079","corp_auth_id":"0","verify_code_auth_id":"0","editor_type":"4","file_type":"pdf","auth_id":"[\"610662\", \"610654\"]","content":{"content_id":"610662","content":"AMERICAN THORACIC SOCIETY\nDOCUMENTS\nHome Oxygen Therapy for Adults with Chronic Lung Disease\nAn Of\ufb01cial American Thoracic Society Clinical Practice Guideline\nSusan S. Jacobs, Jerry A. Krishnan, David J. Lederer, Marya Ghazipura, Tanzib Hossain, Ai-Yui M. Tan, Brian Carlin,\nM. Bradley Drummond, Magnus Ekstro\u0308m, Chris Garvey, Bridget A. Graney, Beverly Jackson, Thomas Kallstrom,\nShandra L. Knight, Kathleen Lindell, Valentin Prieto-Centurion, Elisabetta A. Renzoni, Christopher J. Ryerson,\nAnn Schneidman, Jeffrey Swigris, Dona Upson, and Anne E. Holland; on behalf of the American Thoracic Society\nAssembly on Nursing\nTHIS OFFICIAL CLINICAL PRACTICE GUIDELINE OF THE AMERICAN THORACIC SOCIETY WAS APPROVED SEPTEMBER 2020\nBackground: Evidence-based guidelines are needed for effective\ndelivery of home oxygen therapy to appropriate patients with chronic\nobstructive pulmonary disease (COPD) and interstitial lung disease\n(ILD).\nMethods: The multidisciplinary panel created six research questions\nusing a modi\ufb01ed Delphi approach. A systematic review of the\nliterature was completed, and the Grading of Recommendations\nAssessment, Development and Evaluation approach was used to\nformulate clinical recommendations.\nRecommendations: The panel found varying quality and\navailability of evidence and made the following judgments: 1) strong\nrecommendations for long-term oxygen use in patients with COPD\n(moderate-quality evidence) or ILD (low-quality evidence) with\nsevere chronic resting hypoxemia, 2) a conditional recommendation\nagainst long-term oxygen use in patients with COPD with moderate\nchronic resting hypoxemia, 3) conditional recommendations for\nambulatory oxygen use in patients with COPD (moderate-quality\nevidence) or ILD (low-quality evidence) with severe exertional\nhypoxemia, 4) a conditional recommendation for ambulatory liquid-\noxygen use in patients who are mobile outside the home and require\n.3 L\/min of continuous-\ufb02ow oxygen during exertion (very-low-\nquality evidence), and 5) a recommendation that patients and their\ncaregivers receive education on oxygen equipment and safety (best-\npractice statement).\nConclusions: These guidelines provide the basis for evidence-based\nuse of home oxygen therapy in adults with COPD or ILD but\nalso highlight the need for additional research to guide clinical\npractice.\nKeywords: mobility; hypoxemia; quality of life; chronic\nobstructive pulmonary disease; interstitial lung disease\nContents\nSummary of Recommendations\nChronic Obstructive Pulmonary\nDisease\nInterstitial Lung Disease\nLiquid Oxygen\nEducation and Safety\nIntroduction\nMethods\nResults\nQuestion 1: Should long-term\noxygen be prescribed for adults\nwith COPD who have severe\nchronic resting room air\nhypoxemia?\nQuestion 2: Should long-term\noxygen be prescribed for adults\nwith COPD who have moderate\nchronic resting room air\nhypoxemia?\nQuestion 3: Should ambulatory\noxygen be prescribed for adults\nwith COPD who have severe\nexertional room air hypoxemia?\nQuestion 4: Should long-term\noxygen be prescribed for adults\nwith ILD who have severe\nchronic resting room air\nhypoxemia?\nQuestion 5: Should ambulatory\noxygen be prescribed to adults\nwith ILD who have severe\nexertional room air hypoxemia?\nQuestion 6: Should portable LOX be\nprovided for adults with chronic\nlung disease who are prescribed\ncontinuous oxygen \ufb02ow rates of\n>3 L\/min during exertion?\nEducation and Safety Considerations\nPanel Discussion\nATS Recommendation\nConclusions\nORCID IDs: 0000-0002-8808-0038 (S.S.J.); 0000-0001-5525-4778 (J.A.K.); 0000-0001-5258-0228 (D.J.L.); 0000-0003-4328-6822 (M.G.);\n0000-0002-1995-7828 (T.H.); 0000-0003-1271-8792 (A.-Y.M.T.); 0000-0002-6968-4610 (M.B.D.); 0000-0002-7227-5113 (M.E.);\n0000-0002-8239-9427 (B.A.G.); 0000-0002-4404-3833 (S.L.K.); 0000-0002-3964-5063 (K.L.); 0000-0002-1118-797X (E.A.R.);\n0000-0003-1049-393X (C.J.R.); 0000-0002-2643-8110 (J.S.); 0000-0002-6310-3520 (D.U.); 0000-0003-2061-845X (A.E.H.).\nAm J Respir Crit Care Med Vol 202, Iss 10, pp e121\u2013e141, Nov 15, 2020\nCopyright \u00a9 2020 by the American Thoracic Society\nDOI: 10.1164\/rccm.202009-3608ST\nInternet address: www.atsjournals.org\nAmerican Thoracic Society Documents e121\nSummary of\nRecommendations\nChronic Obstructive Pulmonary\nDisease\nd In adults with chronic obstructive\npulmonary disease (COPD) who have\nsevere chronic resting room air\nhypoxemia,* we recommend\nprescribing long-term oxygen therapy\n(LTOT) for at least 15 h\/d (strong\nrecommendation, moderate-quality\nevidence).\n*Severe hypoxemia is de\ufb01ned as\nmeeting either of the following criteria:\n1) PaO2\n< 55 mm Hg (7.3 kPa) or\noxygen saturation as measured by pulse\noximetry (SpO2\n) < 88%; 2) PaO2\n= 56\u201359\nmm Hg (7.5\u20137.9 kPa) or SpO2\n= 89%\nplus one of the following: edema,\nhematocrit > 55%, or P pulmonale on\nan ECG.\nd In adults with COPD who have\nmoderate chronic resting room air\nhypoxemia,* we suggest not prescribing\nLTOT (conditional recommendation,\nlow-quality evidence).\n*Moderate hypoxemia is de\ufb01ned as an\nSpO2\nof 89\u201393%.\nd In adults with COPD who have severe\nexertional room air hypoxemia, we\nsuggest prescribing ambulatory oxygen\n(conditional recommendation, moderate-\nquality evidence).\nInterstitial Lung Disease\nd For adults with interstitial lung disease\n(ILD) who have severe chronic resting room\nair hypoxemia, we recommend prescribing\nLTOT for at least 15 h\/d (strong\nrecommendation, very-low-quality evidence).\nd For adults with ILD who have severe\nexertional room air hypoxemia, we\nsuggest prescribing ambulatory oxygen\n(conditional recommendation, low-\nquality evidence).\nLiquid Oxygen\nd In patients with chronic lung disease\nwho are mobile outside of the home and\nrequire continuous oxygen \ufb02ow rates of\n>3 L\/min during exertion, we suggest\nprescribing portable liquid oxygen\n(LOX) (conditional recommendation,\nvery-low-quality evidence).\nEducation and Safety\nd For patients prescribed home oxygen\ntherapy, we recommend that the\npatient and their caregivers receive\ninstruction and training on the use and\nmaintenance of all oxygen equipment\nand education on oxygen safety,\nincluding smoking cessation, \ufb01re\nprevention, and tripping hazards (best-\npractice statement).\nIntroduction\nFive million adults live with chronic lung\ndisease in the United States, with more than\none million prescribed LTOT (1, 2), de\ufb01ned\nas oxygen prescribed for at least 15 h\/d. The\nrationale for the provision of LTOT in\nadults is based on the survival bene\ufb01t\nreported by two randomized clinical trials\n(RCTs) published over three decades ago in\npatients with COPD and severe, chronic\nhypoxemia (3, 4). Since then, an additional\nclinical trial has examined the role of home\noxygen therapy in patients with COPD and\nmoderate resting hypoxemia or exertion-\nonly hypoxemia (LOTT [Long-Term\nOxygen Therapy Trial]) (5).\nAlthough several professional societies\nand groups have published clinical practice\nguidelines for home oxygen therapy (6\u201312),\nmost have not incorporated the recent\nLOTT results (5). Recent data highlight\nsigni\ufb01cant differences in home oxygen\nneeds and experiences across patients with\ndifferent lung diseases, lifestyles, and\noxygen supply requirements (13\u201316). For\nexample, the physiologic mechanisms of\nhypoxemia differ between obstructive and\nrestrictive lung diseases. The rapid and\nsteep rate of exertional desaturation for\npatients with ILD differs from that of those\nwith COPD (17, 18). These considerations\nhighlight the need for guidelines speci\ufb01c to\nindividuals with COPD and ILD, the two\nmajor diagnosis entities for which oxygen\ntherapy is prescribed (19).\nThe 2017 American Thoracic Society\n(ATS) workshop on optimizing home oxygen\ntherapy identi\ufb01ed the lack of evidence-based\nclinical practice guidelines for appropriate\nuse of home oxygen as a critical gap in the\ncare of patients (20). Workshop proceedings\nsuggested a need for additional research on\nportable oxygen technology, advocacy for\nimproved \ufb01nancing of oxygen therapy, and\nupdated guidelines to guide policy, advocacy,\nand practice, as none currently exist in the\nUnited States.\nOur aim was to conduct a rigorous and\nsystematic review and develop clinical\nguidelines targeting healthcare providers\nwho care for adults living with chronic lung\ndisease who need oxygen in the community\noutside of inpatient and emergency settings.\nIn applying these guidelines, clinicians\nshould use an interactive, shared decision-\nmaking approach to ensure oxygen\nprescriptions meet the needs of individual\npatients by considering physiology, lifestyle,\nand treatment preferences. The systematic\nreview underpinning this guideline did not\nspeci\ufb01cally address supplemental oxygen\nuse for patients with acute hypoxemia or for\npatients with signs of cor pulmonale,\npulmonary hypertension (PH), or\npolycythemia. However, the panel agreed\nthat clinical guidance related to hypoxemia\nand PH should be included when pertinent\nto each question.\nMethods\nThis clinical guideline was developed in\naccordance with policies and procedures of\nthe ATS. The guideline panel included 4 co-\nchairs and 18 voting members: 11\npulmonary and\/or critical care physicians, 4\nnurses, 1 registered respiratory therapist,\nand 1 physiotherapist. To capture the\ncritical input of an oxygen user, the panel\nincluded a patient representative (Box 1).\nWe used the Grading of Recommendations\nAssessment, Development and Evaluation\n(GRADE) approach to appraise the quality\nAn Executive Summary of this document is available at http:\/\/www.atsjournals.org\/doi\/suppl\/10.1164\/rccm.202009-3608ST.\nYou may print one copy of this document at no charge. However, if you require more than one copy, you must place a reprint order. Domestic reprint orders:\namy.schriver@sheridan.com; international reprint orders: louisa.mott@springer.com.\nCorrespondence and requests for reprints should be addressed to Susan S. Jacobs, M.S., R.N., Division of Pulmonary, Allergy and Critical Care, Department of\nMedicine, Stanford University, 300 Pasteur Drive, Stanford, CA 94035. E-mail: ssjpulm@stanford.edu.\nThis document has an online supplement, which is accessible from this issue\u2019s table of contents at www.atsjournals.org.\nAMERICAN THORACIC SOCIETY DOCUMENTS\ne122 American Journal of Respiratory and Critical Care Medicine Volume 202 Number 10 | November 15 2020\nof evidence and to formulate and grade\nrecommendations (Tables 1 and 2) (21). We\nadopted a published terminology for home\noxygen therapy (Table 3) (22). For the\nsystematic review to June 2019, we de\ufb01ned\nsevere hypoxemia as having an SpO2\n< 88%\nas assessed by pulse oximetry or having an\nPaO2\n< 55 mm Hg (7.3 kPa) as assessed by\nblood-gas sampling, and we de\ufb01ned\nmoderate hypoxemia as having an SpO2\n88\u201393% or PaO2\n56\u201360 mm Hg (7.5\u20137.8\nkPa). We de\ufb01ned severe exertional\nhypoxemia as having SpO2\n< 88% on\nexertion. However, we found substantial\nvariability in de\ufb01nitions for severe\nhypoxemia across studies, and the data were\nnot reported in a way that would allow\nreanalysis of outcomes at different\nthresholds. Thus, we also considered studies\nusing different thresholds and reported the\nde\ufb01nitions of severe and moderate\nhypoxemia used by study authors. We have\nprovided suggested thresholds for\nhypoxemia in the implementation-\nconsideration sections. Potential con\ufb02icts\nof interest were disclosed and managed in\naccordance with the policies and\nprocedures of the ATS (see Table E1 in\nthe online supplement). The online\nsupplement provides a detailed\ndescription of the methods.\nResults\nAfter a systematic literature review, the\nguideline panel created \ufb01nal\nrecommendations on the basis of the\navailable evidence. Table 4 summarizes these\n\ufb01ndings for questions related to patients\nwith COPD and ILD as well as for questions\nrelated to the use of LOX. A best-practice\nstatement was included to address education\nand safety needs for all home oxygen users.\nQuestion 1: Should long-term oxygen\nbe prescribed for adults with COPD\nwho have severe chronic resting\nroom air hypoxemia?\nBackground. Hypoxemia is common in\npeople with COPD, particularly those with\nmore advanced disease, because of\nworsening _\nV= _\nQ mismatch and decreased\ndiffusion capacity. In some patients,\nhypoxemia can be suf\ufb01ciently severe to\noccur at rest and is associated with dyspnea,\nworsening neurocognitive function, PH,\nand mortality (22, 23).\nIn 1917, Haldane described the\ntherapeutic potential of providing\nsupplemental oxygen (24). Since then,\nseveral studies have examined the role\nof oxygen therapy in patients with\nCOPD. \u201cLTOT\u201d refers to supplemental\noxygen for a period of years, and in\nmost cases for the remainder of the patient\u2019s\nlife (Table 3). LTOT can be delivered\nthrough a combination of stationary\nequipment (e.g., stationary oxygen\nconcentrator and liquid reservoirs) and\nambulatory oxygen equipment\n(e.g., compressed-oxygen cylinders, portable\noxygen concentrators [POCs], and LOX\ncanisters) (Figure 1). In this section, we\ndiscuss the role of LTOT for adults with\nCOPD and severe resting hypoxemia. The\ncritical outcome for this question was\nmortality, and important outcomes included\ndyspnea, healthcare resource use, exercise\ncapacity, fatigue, health-related quality of life\n(HRQL), physical activity, and safety.\nDescription of the evidence and its\nquality. We included \ufb01ve studies (two RCTs\n[3, 4]), one pre- versus postintervention\nstudy (25), and two observational studies (26,\n27) (see the SUMMARY OF STUDIES and Table\nE2 in the online supplement). Severe resting\nhypoxemia was de\ufb01ned as a PaO2\n< 55 mm\nHg (7.3 kPa) or a PaO2\n< 59 mm Hg (7.9\nkPa) plus one of the following: edema,\nhematocrit> 55%, or P pulmonale on ECG\nin the NOTT (Nocturnal Oxygen Therapy\nTrial) (3); or was de\ufb01ned as a PaO2\nof\n40\u201360 mm Hg (5.3\u20138.0 kPa) in patients with\nat least one prior episode of ankle edema in\nthe MRC (Medical Research Council) study\n(4). In the pre- versus postintervention\nstudy, eligibility criteria were not reported;\nparticipants (n = 6) had a PaO2\nof\n41.5\u201346.5 mm Hg (5.5\u20136.2 kPa) (25). The\nobservational studies enrolled individuals\nwith a PaO2\n< 55 mm Hg (7.3 kPa) (26, 27).\nTable 1. Certainty of Evidence\nEvidence Quality De\ufb01nition\nHigh High con\ufb01dence that the estimated effect is close to\nthe true effect.\nModerate Moderate con\ufb01dence that the estimated effect is\nclose to the true effect, but with a chance that the\ntrue effect is considerably different.\nLow Low con\ufb01dence in the estimated effect. Higher\nlikelihood that the true effect is considerably\ndifferent from the estimated effect.\nVery low Very low con\ufb01dence in the estimated effect. High\nlikelihood that the true effect is considerably\ndifferent from the estimated effect.\nBox 1\n\u201cThe ability to get out of the house and continue my activities is top of the chart\nin importance! There is no way I want to become a couch potato . . . All the\noxygen equipment was \u2018dumped\u2019 on me. I knew nothing and was in a daze. I am sure\nthat the delivery guy gave me some instructions when it was delivered but I retained\nnothing. . . . My \ufb01rst concern was to \ufb01nd a better solution than the shoulder carry bag\nthat the oxygen company provided. I needed to be hands free to play tennis. . . . I spent\na couple of years perfecting my system of how to carry enough tanks to a tennis match\n(requires 6\u20138 tanks). I did a lot of Internet research to \ufb01nd carts or carrying cases for\ntanks. I have settled on a rolling cart that was designed to carry wine bottles to tasting\nparties. Perfect size for 6 tanks . . . It is a pain to have to plan out a day of activities with\noxygen. What is the elevation, how far will I have to walk, how many tanks do I need,\nwhere can I recharge my POC [portable oxygen concentrator]? There may come a day\nwhen you can\u2019t do these things so enjoy every minute you have. When I don\u2019t get\nenough tanks it makes me mad as hell . . . I still do not let down my guard down around\nthe supplier. I never know when their business decisions will again affect my life.\u201d\n\u2014Supplemental home oxygen user\nAMERICAN THORACIC SOCIETY DOCUMENTS\nAmerican Thoracic Society Documents e123\nThere was moderate-quality evidence\non the effects of LTOT on mortality in adults\nwith COPD who have severe, chronic\nresting room air hypoxemia. The RCTs did\nnot employ masking (blinding), but the\nguideline panel did not judge this to be a\nserious risk of bias because the critical\noutcome (mortality) was objective.\nHowever, there was substantial imprecision\nin estimating the treatment effects (Table\nE2). The NOTT (3) study of 203\nparticipants indicates a 2-year mortality-\nrisk reduction of 55% in those prescribed\nLTOT (24 h\/d) compared with control\nsubjects prescribed only nocturnal oxygen\n(relative risk [RR], 0.45; 95% con\ufb01dence\ninterval [CI], 0.25\u20130.81). Similarly, the\nMRC study (4) in 87 participants indicates\na 5-year mortality-risk reduction of 59% in\nthose with LTOT versus no oxygen (RR,\n0.41; 95% CI, 0.17\u20130.98). Data from the\nNOTT and MRC studies were not pooled,\nas they employed different thresholds to\nde\ufb01ne severe hypoxemia, examined\ndifferent durations of home oxygen therapy\n(prescribed 24 h\/d vs. at least 15 h\/d),\nemployed different comparators (nocturnal\noxygen in NOTT; no oxygen in MRC), and\nreported mortality at different time points\n(1- and 2-yr risk [3] and 5-yr risk [4],\nrespectively).\nIn the NOTT study (3), subgroup\nanalysis suggested that LTOT improved\nsurvival compared with nocturnal oxygen in\npatients with a higher PaCO2\n(PaCO2\n> 43 mm\nHg [5.7 kPa]: 21.7% vs. 41.5%; P = 0.002),\nlower arterial pH (pH , 7.40: 16.0% vs.\n42.2%; P = 0.004), lower FVC (FVC , 1.89\nL: 20.8% vs. 43.5%; P = 0.01), more severe\nnocturnal hypoxemia (mean room air\nSaO2\n, 85%: 24.4% vs. 50.0%; P = 0.02),\nlower hematocrit (hematocrit , 47.4%:\n21.7% vs. 41.5%; P = 0.03), lower mean\npulmonary arterial pressure (PAP; mean\nPAP , 27 mm Hg: 17.5% vs. 37.0%,\nP = 0.03), and lower pulmonary vascular\nresistance (PVR; PVR , 279 dyn $ s\/cm5\n:\n12.8% vs. 33.3%; P = 0.03). The NOTT\nauthors were surprised to \ufb01nd smaller\ndifferences in mortality, only bordering\non statistical signi\ufb01cance, between\ncontinuous versus nocturnal oxygen in\nthose with higher baseline hematocrit\n(hematocrit > 47.4%: 24.5% vs. 38.8%;\nP = 0.20), higher PAP (mean\nPAP > 27 mm Hg: 24.0% vs. 39.6%;\nP = 0.14), and higher PVR (PVR > 279\ndyn $ s\/cm5\n: 38.6% vs. 45.2%; P = 0.11). Of\nnote however, the direction in the trend\ntoward improved mortality in these\nindividuals was similar to the trend in those\nwith less impaired hemodynamics, and the\nmean PAP threshold used to separate\nsubgroups (overall group median,\n27 mm Hg) was higher than the one used in\nthe currently accepted de\ufb01nition of PH. In\nthe NOTT study, continuous oxygen\ntherapy was associated with a reduction in\nPVR levels compared with nocturnal\noxygen, but a relationship between greater\nPVR decreases and reduced mortality was\nnot seen, while subgroup numbers were\nsmall. The MRC study did not report\nmortality bene\ufb01ts according to baseline\npulmonary hemodynamic characteristics\n(4) and was presumably enriched for\npatients with PH (at least one previous\nepisode of ankle edema in the inclusion\ncriteria), but a higher PaCO2 and red-cell\nmass were associated with greater mortality.\nThe MRC report (4) also incorrectly stated\n(p. 685) that participants in the NOTT\nstudy with higher baseline hematocrit or\nPAP derived the most bene\ufb01t from LTOT\nversus nocturnal oxygen. In light of the\ncaveats listed above, it is not possible to\ndraw \ufb01rm conclusions on the differential\neffects of LTOT in patients with\nconcomitant PH. A particular unanswered\nquestion is whether a lower threshold for\nstarting LTOT could be of bene\ufb01t for\npatients with early pulmonary\nhemodynamic impairment, an area in need\nof further research.\nThere was very-low-quality evidence on\nthe effects of LTOT on healthcare use. One\nretrospective study (26) found fewer\nhospitalizations over 3 years for participants\nusing LTOT compared with conventional\ntherapy (mean difference [MD], 21.17; 95%\nCI, 21.73 to 20.59). An observational study\n(27) did not \ufb01nd a reduction in admission\nrisk once patients began receiving LTOT\n(RR, 0.70; 95% CI, 0.15 to 3.30). There was a\n35% reduction in hospital-bed days per\npatient year of follow-up in patients\nreceiving LTOT, but this was not statistically\nsigni\ufb01cant (RR, 0.65; 95% CI, 0.40 to 1.05).\nTable 2. Implications of Clinical Guideline Recommendations by Stakeholder\nStakeholder Strong Recommendation Conditional Recommendation\nPatient The majority of patients would want the\nrecommended course of action in this situation,\nand only a small number would not.\nMany patients in this situation would prefer the\nrecommendation, but a substantial number may\nnot. This is an opportunity for shared\ndecision-making between the clinician and patient.\nClinician Most individuals should receive the course of\naction that is recommended. There is a low\nchance that additional formal decision aids are\nneeded to help individuals make decisions\nconsistent with their values and preferences, and\nadherence to this recommendation could be\nused as a performance indicator or quality\ncriterion.\nDifferent choices will be applicable to different\npatients, and additional factors will need to be\nconsidered in addition to the recommendation in\norder for a patient to make a decision according to\ntheir values and preferences. Decision aids may be\nneeded to assist individuals in making their best\nchoice. This is an opportunity for shared\ndecision-making between the clinician and patient.\nPolicy-maker The recommendation can be widely adapted as\npolicy and can be used for performance\nindicators.\nPolicy-making will require substantial additional\ndebate and involvement of many and\/or additional\nstakeholders. The likelihood of regional variance is\nalso higher, and performance indicators would\nneed to take into consideration any additional\ndeliberation that has occurred.\nAMERICAN THORACIC SOCIETY DOCUMENTS\ne124 American Journal of Respiratory and Critical Care Medicine Volume 202 Number 10 | November 15 2020\nFor the outcome of safety, the\nsystematic review identi\ufb01ed cases of \ufb01res,\nburns from smoking around oxygen\nequipment, nosebleeds, and tripping over\nthe equipment (28). For all COPD Medicare\nbene\ufb01ciaries who used home oxygen\n(LTOT, exertion only or sleep only), those\nwho had an emergency room visit for a\nburn injury were twice (odds ratio [OR],\n2.43; 95% CI, 1.57\u20133.78) as likely to be\nprescribed oxygen in the preceding 90 days\ncompared with those without burn injury\n(29). The LOTT trial found that for every\n100 person-years the rate of \ufb01res was 0.08,\nthe rate of burns from smoking around\noxygen equipment was 0.12, the rate of\nburns from oxygen around an open \ufb02ame\nwas 0.04, the rate of burns from LOX frost\nwas 0.16, the rate of nosebleeds was 0.35,\nand the rate of tripping or falling over\noxygen equipment was 0.90 (5). These\nsafety data from LOTT were for\nparticipants with moderate hypoxemia who\nwere prescribed continuous oxygen or\noxygen during both exertion and sleep.\nPanel judgments. DESIRABLE\nCONSEQUENCES AND THEIR MAGNITUDES\n(BENEFITS). The panel concluded that the size\nof the desirable anticipated effects on\nmortality is large. LTOT was associated with\ndecreased 2-year and 5-year mortality\n(critical outcome). There was insuf\ufb01cient\nevidence to evaluate the effects of LTOT on\nhealthcare use or other important outcomes.\nUNDESIRABLE CONSEQUENCES AND THEIR\nMAGNITUDES (HARMS). The panel concluded\nthat there is a moderate level of undesirable\nanticipated effects of LTOT. Patients report a\nphysical and mental burden of using oxygen\nequipment with reduced ability to travel\noutside of the home, dif\ufb01culty obtaining\ninformation about appropriate access to\noxygen equipment during travel, and\nequipment noise from the use of stationary\noxygen equipment, affecting sleep (10, 30).\nRationale for the recommendation. The\npanel concluded that the balance of\ndesirable and undesirable effects supported\nthe use of LTOT in patients with COPD\nassociated with severe resting hypoxemia.\nThe NOTT trial (3) reported that patients\nwith severe hypoxemia associated with\nventilatory compromise (on the basis of\nPaCO2, arterial pH, and FVC) and milder\ndisturbances in pulmonary hemodynamics\n(on the basis of PVR and PAP) may be\nmore likely to bene\ufb01t from LTOT.\nHowever, these were subgroup analyses,\nand similar analyses were not performed in\nthe MRC study (4), so the panel concluded\nthat there is insuf\ufb01cient evidence to\nrecommend preferentially prescribing\nLTOT to speci\ufb01c subgroups of patients with\nCOPD and severe hypoxemia.\nGiven the variability in reimbursement\nrates for medical expenses in the United\nStates, it is dif\ufb01cult to project the true cost\nper person for LTOT. In the United States,\nMedicare typically covers 80% of the\nMedicare-approved amount (31). However,\ncosts may vary depending on the payor.\nThe incremental cost-effectiveness ratio for\nLTOT was $16,124 per quality-adjusted life\nyear in the United States, which is within\nthe bounds considered to be cost-effective\n(32). Cost variables were based on the\nMedicare reimbursement rate for the 2009\npublished study and on appropriate sources\n(32). On the basis of these considerations,\nthe panel concluded that cost-effectiveness\nfavors the use of LTOT. Because COPD\ndisproportionately affects minority and\nlow-income populations, a standardized\napproach to prescribing LTOT will\nprobably increase health equity.\nLTOT is probably acceptable to most\npatients with COPD and severe chronic\nhypoxemia. LTOT is a widely recognized\nand recommended therapy for patients with\nTable 3. Terminology for Home Oxygen Therapy\nTerm De\ufb01nition\nAmbulatory oxygen Oxygen delivered during exercise or activities of daily\nliving.\nContinuous-\ufb02ow oxygen Oxygen delivered at a constant \ufb02ow rate, regardless\nof the respiratory rate, in contrast to pulse-dose\noxygen (see below).\nContinuous oxygen Oxygen prescribed 24 h\/d.\nHome oxygen Oxygen delivered in a home, also known as\ndomiciliary oxygen. It includes not only long-term\noxygen but also short-term, nocturnal, palliative,\nambulatory, and short-burst oxygen. It excludes\noxygen use in healthcare and emergency settings.\nLong-term oxygen Oxygen that is delivered to patients with chronic\nhypoxemia, in most cases for the remainder of the\npatient\u2019s life. Long-term oxygen therapy is\nprescribed for at least 15 h\/d.\nNocturnal oxygen Oxygen delivered during sleep time only.\nPalliative oxygen Oxygen to relieve dyspnea. Palliative oxygen may be\nprovided continuously, nocturnally, or during\nambulation. Short-burst oxygen therapy falls into\nthis category.\nPortable oxygen Oxygen delivered through systems that are\nsuf\ufb01ciently lightweight so that they can be carried\nor pulled by patients and allow them to leave their\nhome (e.g., oxygen cylinders or canisters carried or\npulled in trolleys or portable oxygen\nconcentrators).\nPulse-dose oxygen Oxygen delivered during inspiration only in such a\nway that the quantity of oxygen administered is\nin\ufb02uenced by the respiratory rate. The delivery\nsystem is at rest while the patient is exhaling.\nShort-burst oxygen Brief and intermittent oxygen administration before\nand\/or after exercise, generally used as needed, in\nthe absence of known hypoxemia.\nShort-term oxygen therapy Oxygen provided temporarily, during a period of\nsevere hypoxemia (e.g., during the course of and\nshortly after an exacerbation of COPD).\nDefinition of abbreviation: COPD = chronic obstructive pulmonary disease.\nThere are several types of home oxygen therapy. This table is provided to assist in standardizing the\nterminology and is adapted by permission from Reference 22.\nAMERICAN THORACIC SOCIETY DOCUMENTS\nAmerican Thoracic Society Documents e125\nCOPD and severe resting hypoxemia (7, 11,\n12). Although oxygen is generally available,\nthe main barrier in the United States is cost.\nThis varies internationally, with some\ncountries reporting higher direct costs of\noxygen for COPD care than others (33). In\naddition, reimbursement can vary by region,\nparticularly because of the requirements that\nmust be met for funding (34, 35).\nThe NOTT and MRC studies tested two\ndifferent durations of LTOT and two\ndifferent comparators for LTOT (NOTT:\nLTOT prescribed for a duration of 24 h\/d vs.\nLTOT prescribed for a duration 12 h\/d;\nMRC: LTOT prescribed for a duration of at\nleast 15 h\/d vs. no oxygen prescribed) in\npatients with COPD and severe resting\nhypoxemia. From these two studies, we\nknow that prescribing LTOT for at least\n15 h\/d is superior to prescribing no oxygen\nand that prescribing LTOT for 24 h\/d is\nlikely superior to prescribing the therapy for\n12 h\/d, as assessed by mortality. We do not\nknow if prescribing LTOT for at least 15 h\/d\nis superior to prescribing it for 12 h\/d (no\nstudies compared these two interventions\ndirectly) on the basis of mortality. On the\nbasis of these considerations and the\npotential for a longer duration of LTOT use\nper day to be a patient burden, the panel\nbelieves that prescribing LTOT for at least\n15 h\/d is justi\ufb01ed in patients with COPD\nand severe resting hypoxemia.\nATS recommendation. In adults with\nCOPD who have severe chronic resting room\nair hypoxemia, we recommend prescribing\nTable 4. Summary of ATS Recommendations\nQuestion ATS Recommendation\nStrength of Recommendation and Level\nof Evidence\nCOPD\nQuestion 1: Should long-term oxygen be\nprescribed for adults with COPD who\nhave severe* chronic resting room air\nhypoxemia?\nIn adults with COPD who have severe\nchronic resting room air hypoxemia, we\nrecommend prescribing LTOT for at least\n15 h\/d.\nStrong recommendation, moderate-quality\nevidence\nQuestion 2: Should long-term oxygen be\nprescribed for adults with COPD who\nhave moderate\u2020\nchronic resting room air\nhypoxemia?\nIn adults with COPD who have moderate\nchronic resting room air hypoxemia, we\nsuggest not prescribing LTOT.\nConditional recommendation, low-quality\nevidence\nQuestion 3: Should ambulatory oxygen be\nprescribed for adults with COPD who\nhave severe exertional room air\nhypoxemia?\nIn adults with COPD who have severe\nexertional room air hypoxemia, we\nsuggest prescribing ambulatory oxygen.\nConditional recommendation,\nmoderate-quality evidence\nILD\nQuestion 4: Should long-term oxygen be\nprescribed for adults with ILD who have\nsevere chronic resting room air\nhypoxemia?\nFor adults with ILD who have severe\nchronic resting room air hypoxemia, we\nrecommend prescribing LTOT for at least\n15 h\/d.\nStrong recommendation, very-low-quality\nevidence\nQuestion 5: Should ambulatory oxygen be\nprescribed for adults with ILD who have\nsevere exertional room air hypoxemia?\nFor adults with ILD who have severe\nexertional room air hypoxemia, we\nsuggest prescribing ambulatory oxygen.\nConditional recommendation, low-quality\nevidence\nLiquid oxygen\nQuestion 6: Should portable liquid oxygen\nbe provided for adults with chronic lung\ndisease who are prescribed continuous\noxygen \ufb02ow rates of .3 L\/min during\nexertion?\nIn patients with chronic lung disease who\nare mobile outside of the home and\nrequire continuous oxygen \ufb02ow rates of\n.3 L\/min during exertion, we suggest\nprescribing portable liquid oxygen.\nConditional recommendation,\nvery-low-quality evidence\nEducation\nEducation and safety for patients and\ncaregivers\nFor all patients prescribed home oxygen\ntherapy, we recommend that the patient\nand their caregivers receive instruction\nand training on the use and maintenance\nof all oxygen equipment and education on\noxygen safety, including smoking\ncessation, \ufb01re prevention, and tripping\nhazards.\nBest-practice statement\nDefinition of abbreviations: ATS = American Thoracic Society; COPD = chronic obstructive pulmonary disease; ILD = interstitial lung disease;\nLTOT = long-term oxygen therapy.\n*On the basis of two clinical trials (3, 4), severe hypoxemia is defined as meeting either of the following criteria: 1) PaO2\n< 55 mm Hg (7.3 kPa) or oxygen\nsaturation as measured by pulse oximetry (SpO2\n) < 88% or 2) PaO2\n= 56\u201359 mm Hg (7.5\u20137.9 kPa) or SpO2\n= 89% plus one of the following: edema,\nhematocrit > 55%, or P pulmonale on an ECG.\n\u2020\nOn the basis of a single clinical trial (5), moderate hypoxemia is defined as an SpO2\nof 89\u201393%. The corresponding PaO2\nwas not reported in that study.\nAMERICAN THORACIC SOCIETY DOCUMENTS\ne126 American Journal of Respiratory and Critical Care Medicine Volume 202 Number 10 | November 15 2020\nLTOT for at least 15 h\/d (strong\nrecommendation, moderate-quality evidence).\nWhat others are saying. A 2015 British\nThoracic Society (BTS) guideline recommends\nthat patients with stable COPD and severe\nresting hypoxemia (PaO2\n< 55 mm Hg [7.3\nkPa]), or with a resting PaO2\n< 60 mm Hg\n(8.0 kPa) with evidence of peripheral edema,\nhematocrit> 55, or PH, should be considered\nfor LTOT because of its survival bene\ufb01ts\nand potential to improve pulmonary\nhemodynamics (36). They recommend\nLTOT be used for 15\u201324 h\/d (36). The\nThoracic Society of Australia and New\nZealand (TSANZ) recommends titrating\noxygen to maintain a PaO2\n. 60 mm Hg\n(8.0 kPa) or an SpO2\n. 90% during waking at\nrest (9, 37). The Global Initiative for Chronic\nLung Disease (GOLD) report recommends\nLTOT if SpO2\nis <88% and recommends\noxygen titration to maintain a saturation of\n>90% in patients with COPD (12).\nImplementation considerations. Severe\nhypoxemia was de\ufb01ned using different\nthresholds in the two RCTs that reported our\ncritical outcome of survival (PaO2\n< 55 mm\nHg [7.3 kPa] or PaO2\n< 59 mm Hg [7.9 kPa]\nplus one of the following: edema,\nhematocrit > 55%, or P pulmonale on ECG\n[3]; vs. PaO2\n40\u201360 mm Hg [5.3\u20138.0 kPa]\n[4]). Because a mortality bene\ufb01t was\ndemonstrated in both studies, the panel\nconcluded that either de\ufb01nition of severe\nhypoxemia is clinically justi\ufb01ed.\nNeither clinical trial reported SpO2\n-based\nthresholds for severe hypoxemia. We\nrecognize that the relationship between SpO2\nand PaO2\ncan vary because of an individual\u2019s\npH, 2,3-diphosphoglycerate concentration,\nPaCO2\n, and temperature. However, the\nguideline panel concluded that providing\napproximate thresholds for SpO2\nthat\ncorrespond to the PaO2\nthresholds used in the\nNOTT and MRC studies would improve\nthe usability of the guideline report in\ncircumstances in which arterial blood gas\nmeasurements were not available. The panel\nsuggests titrating the level of LTOT to achieve\na target saturation of 90%, as opposed to 88%\nin some guidelines, to avoid prolonged\nepisodes of desaturation with minimal activity.\nIn addition, the NOTT and MRC trials\nused slightly different de\ufb01nitions of \u201cchronic.\u201d\nIn the NOTT study (3), chronic was de\ufb01ned\nas meeting the de\ufb01nition of severe\nhypoxemia on \u201cat least two occasions more\nthan 1 week apart over a 3-week observation\nperiod\u201d while the patient was free of\nexacerbations. In the MRC study (4), chronic\nwas de\ufb01ned as meeting the PaO2\n-based\ncriteria for hypoxemia on \u201ctwo repeated\nmeasurements at least 3 weeks apart.\u201d\nFor implementation purposes, we\nde\ufb01ne chronic resting hypoxemia as resting\nhypoxemia in the absence of a reversible\ncause. Although the NOTT and MRC trials\nused de\ufb01nitions that required repeated\nmeasures 3 weeks apart, this may not be\npossible or necessary in clinical practice (for\ninstance, for a patient with idiopathic\npulmonary \ufb01brosis [IPF] who has resting\nhypoxemia as a result of progressive lung\ndisease, without reversible cause). This\ndiffers from the patient who is discharged\nfrom the hospital after a COPD\nexacerbation, in which case resolution of\nresting hypoxemia may occur over time and\nreassessment of oxygen needs is important\nto avoid unnecessary treatment with oxygen.\nReassessment of patients\u2019 oxygen needs\nafter an acute exacerbation is critical.\nRespiratory exacerbations (in some cases\naccompanied by pneumonia, pulmonary\nembolism, or heart failure) usually increase\noxygen requirements (e.g., require higher \ufb02ows\nto maintain an SpO2\nof at least 90%). In\naddition, the pace at which patients recover\npartially or fully from their respiratory\nexacerbations varies and can range from days\nto months, and their oxygen requirements\nmay therefore vary over time. Moreover, a\nsubstantial proportion (perhaps as many as\n50%) of patients who are initiated on home\noxygen at the time of a respiratory exacerbation\nmay recover suf\ufb01ciently to no longer have a\nclinical indication for home oxygen (38, 39).\nPatient education (e.g., how to use new\nequipment, how to titrate oxygen \ufb02ow to\nevolving requirements), oxygen prescriptions,\nand communication with other providers\n(e.g., primary care and home health agencies)\nwould need to match the requirements for\nhome oxygen after a respiratory exacerbation.\nProper reassessment of home oxygen needs\nis so important that it has been identi\ufb01ed as one\nof the top \ufb01ve areas for further improvement in\nadult respiratory medicine by the Choosing\nCompressed Gas Cylinders Liquid Oxygen\nPortable Oxygen Concentrators\nStationary Oxygen Concentrators\nPortable Cylinders\nA\n5\u22128 in\nC\n11 in\nE\n26 in\nD\n16 in\nB\n12 in\nH\n22\u201352 in\nHome Fill Unit\non Top\nReservoir plus\nPortable Canister\nPortable\nCanister\nPortable E\nPortable D\nFigure 1. Examples of stationary and portable oxygen devices in the United States. Illustration by\nPatricia Ferrer Beals.\nAMERICAN THORACIC SOCIETY DOCUMENTS\nAmerican Thoracic Society Documents e127\nWisely Campaign (40). According to the\nTSANZ guideline, patients who commence\nLTOT after a COPD exacerbation should be\nreassessed 4\u20138 weeks after hospital discharge to\nensure continued eligibility (9). In patients\nprescribed home oxygen for severe chronic\nresting room air hypoxemia, the 2020 GOLD\ninitiative recommends reassessing the need for\noxygen after 60\u201390 days; when home oxygen is\nstarted to treat severe hypoxemia after a COPD\nexacerbation, the GOLD initiative recommends\nreassessing the home oxygen requirement at\n1\u20134 weeks and again at 12\u201316 weeks to update\nthe oxygen prescription as clinically indicated\n(12). At the time of reassessments, SpO2\n(or\narterial blood gases) at rest and with exertion\nshould be considered. Ideally, reevaluation\nshould occur at home to capture context and\nbarriers to use. Expert opinion suggests that\npatients should be monitored, at minimum,\nevery 6 months to con\ufb01rm continued oxygen\nuse, a current oxygen prescription, and\nadequacy of the equipment used.\nValues and preferences. This\nrecommendation places a high value on\nreducing mortality and a lower value on cost\nand resource use.\nResearch needs. The practice of\ninitiating short-term oxygen therapy on\nhospital discharge in patients with severe\nhypoxemia is based on indirect evidence from\nthe NOTT and MRC clinical trial populations\nwith chronic hypoxemia. The harms and\nbene\ufb01ts of prescribing short-term oxygen\ntherapy on hospital discharge deserves further\nstudy. The panel recommends studies to\ndevelop and test the acceptability and\neffectiveness of easy-to-use ambulatory\noxygen equipment that can facilitate LTOT\nuse by patients, to identify strategies that\nimprove adherence to LTOT, and to develop\nand test strategies to discontinue home oxygen\nin patients who recover suf\ufb01ciently after an\nexacerbation or no longer have a clinical\nindication for its use. Studies to examine\nwhether some subgroups of patients with\nCOPD and severe hypoxemia (e.g., higher\nhematocrit, higher mean PAP, early\nhemodynamic impairment) are more or less\nlikely to bene\ufb01t from LTOT are also needed.\nQuestion 2: Should long-term oxygen\nbe prescribed for adults with COPD\nwho have moderate chronic resting\nroom air hypoxemia?\nBackground. Some patients with COPD\ndevelop moderate resting room air\nhypoxemia that may be asymptomatic or\nassociated with dyspnea. Moderate\nhypoxemia is rarely mentioned in clinical\nguidelines. In this section, we discuss the\nrole of LTOT for adults with COPD\nassociated with moderate resting\nhypoxemia. For this question, mortality was\nthe critical outcome, and important\noutcomes were dyspnea, COPD\nexacerbation, HRQL, fatigue, physical\nactivity, healthcare resource use, and\nsafety.\nDescription of the evidence and its\nquality. There was only one study, and the\nquality of evidence was considered low\nbecause of imprecision in the estimate of\ntreatment effects for the critical and\nimportant outcomes (see the SUMMARY OF\nSTUDIES and Table E3 in the online\nsupplement). The LOTT study included\nparticipants who had moderate hypoxemia\nat rest (de\ufb01ned as room air SpO2\nof 89\u201393%,\nno PaO2\nthreshold speci\ufb01ed) as well as those\nwith no hypoxemia at rest but desaturation\nonly on exertion (de\ufb01ned as an SpO2\n> 80%\nfor >5 min and ,90% for >10 s during a\n6-min-walk test [6MWT]). No information\nwas provided on the presence of PH. Study\nparticipants with moderate hypoxemia at\nrest were randomly allocated to continuous\nLTOT or no oxygen. Those with isolated\nexertional hypoxemia were randomly\nallocated to LTOT during both exertion\nand sleep or to no oxygen. Unlike the\nNOTT and MRC trials, chronicity\n(hypoxemia sustained over 3 wk in stable\ncondition) was not assessed. As with the\nNOTT and MRC trials, the intervention\nwas not masked (blinded).\nAt the request of the guideline panel, the\nLOTT group conducted additional analyses\ncomparing the risk of death with and without\nLTOT in the subgroup of participants who\nhad moderate resting hypoxemia (n = 419,\n57% of LOTT participants) (Table E3). The\nresults indicated no difference between\ngroups in time to death (hazard ratio [HR],\n0.95; 95% CI, 0.59\u20131.50). A previous smaller\nRCT of 135 patients with COPD by Go\u0301recka\nand colleagues (41) also reported no effect\non mortality with LTOT versus no oxygen in\npatients with PaO2\n56\u201365 mm Hg (7.5\u20138.7\nkPa); the relative hazard of survival was 0.92\n(95% CI, 0.57\u20131.47). This smaller study\nde\ufb01ned moderate hypoxemia on the basis of\nPaO2\nof 56\u201365 mm Hg (no SpO2\nthresholds\nspeci\ufb01ed) and study participants received\nmonthly home visits by a respiratory nurse.\nBecause moderate hypoxemia was de\ufb01ned\ndifferently in the LOTT and Go\u0301recka and\ncolleagues studies, and the study by Go\u0301recka\nand colleagues included intensive home-\nbased follow-up, inclusion in the evidence\ntables and a meta-analysis that included\nboth studies was not considered appropriate.\nThe panel concluded the quality of\nevidence for effects on HRQL was moderate.\nThe St. George\u2019s Respiratory Questionnaire\n(SGRQ) favored the use of LTOT at\n4-month follow-up in those with both\nmoderate resting and exertional\ndesaturation (MD, 23.30; 95% CI, 26.50 to\n20.10). However, no signi\ufb01cant differences\nwere found at 12-month follow-up or in\nthose with only resting desaturation. There\nwere no differences between groups in the\nQuality of Well-Being Scale (5).\nIn the LOTT study, the composite\nendpoint of time to death or \ufb01rst\nhospitalization was not signi\ufb01cantly different\nbetween those in the LTOT group compared\nwith those in the no-LTOT group in those\nwith moderate hypoxemia at rest only (HR,\n0.96; 95% CI, 0.79\u20131.12) or in those with\nmoderate hypoxemia at rest and\ndesaturation with ambulation (HR, 0.95;\n95% CI, 0.72\u20131.27). No study that met our\ninclusion criteria directly reported on the\neffects of LTOT on other outcomes\nconsidered \u201cimportant\u201d by the guideline\npanel (dyspnea, physical activity, fatigue, or\nhealthcare resource use) in participants with\nCOPD and moderate hypoxemia at rest.\nThe LOTT trial reported \ufb01res, burns,\nnosebleeds, and tripping or falling over\noxygen equipment in the study participants\nprescribed LTOT or oxygen during exertion\nand sleep (5); see description of results in\nquestion 1.\nPanel judgments. DESIRABLE\nCONSEQUENCES AND THEIR MAGNITUDES\n(BENEFITS). The panel concluded that the size\nof the desirable anticipated effects on\nmortality (critical outcome) was not\nclinically meaningful. Likewise, the effect on\nHRQL at 12 months was not clinically\nmeaningful. Data were insuf\ufb01cient to\nevaluate other important outcomes (5).\nUNDESIRABLE CONSEQUENCES AND THEIR\nMAGNITUDES (HARMS). In a judgment similar\nto that developed for question 1, the panel\nconcluded that there is a moderate level of\nundesirable anticipated effects of LTOT.\nRationale for the recommendation. The\npanel concluded that the certainty of evidence\nwas moderate and was based on a single clinical\ntrial that used SpO2\nof 89\u201393% to de\ufb01ne\nmoderate hypoxemia. Similar results were\nnoted in a trial by Go\u0301recka and colleagues (41),\nAMERICAN THORACIC SOCIETY DOCUMENTS\ne128 American Journal of Respiratory and Critical Care Medicine Volume 202 Number 10 | November 15 2020\nwhich compared LTOT plus monthly home\nvisits by a nurse versus monthly home visits by\na nurse alone in patients with moderate resting\nhypoxemia as de\ufb01ned by a PaO2\nof\n56\u201365 mm Hg. There was probably no\nimportant uncertainty or variability about how\nmuch people value mortality as the critical\noutcome. Some patients may not experience\nany value added on additional life years if they\nare very ill. However, this is less likely in\npatients with moderate hypoxemia, as they\ntend to have less severe COPD than those with\nsevere resting hypoxemia. The balance between\ndesirable and undesirable effects does not favor\nLTOT in those with moderate hypoxemia.\nATS recommendation. In adults with\nCOPD who have moderate chronic resting\nroom air hypoxemia, we suggest not\nprescribing LTOT (conditional\nrecommendation, low-quality evidence).\nWhat others are saying. Only one\nguideline was found that makes\nrecommendations regarding LTOT in\npatients with moderate resting hypoxemia.\nThe 2020 GOLD document states, \u201cIn\npatients with stable COPD and resting or\nexercise-induced moderate desaturation,\nlong-term oxygen treatment should not be\nprescribed routinely. However, individual\npatient factors must be considered when\nevaluating the patient\u2019s need for\nsupplemental oxygen\u201d (12).\nImplementation considerations. On the\nbasis of the LOTT study, we de\ufb01ned\nmoderate resting hypoxemia as an SpO2\nof\n89\u201393%. The corresponding PaO2\nwas not\nreported (5). The costs and burden of the\ntreatment outweigh the minimal bene\ufb01t of\nLTOT in adults with COPD who have\nmoderate resting room air hypoxemia.\nPatients likely would not choose LTOT on\nthe basis of the lack of bene\ufb01t; they may\ndecide to defer using oxygen at rest until\ntheir resting hypoxemia worsens. The\nLOTT study did not report any data on\npulmonary hemodynamics, and it is\ntherefore not possible to conclude whether\neffects of LTOT in this group of patients\ndiffers according to the presence of PH.\nWhen patients have moderate resting\nhypoxemia, it is an opportunity for shared\ndecision-making between the clinician and\npatient (see Table 2, which discusses the\nsituations that provide an opportunity for\nshared decision-making).\nValues and preferences. This\nrecommendation against LTOT in this\nsetting places a high value on the absence of\na mortality reduction and a lower value on\nshort-term improvement in HRQL (which\nwas observed at 4 mo but not at 12 mo).\nResearch needs. The panel\nrecommends studies on the use of shared\ndecision-making to personalize the use of\nhome oxygen in participants with moderate\nresting hypoxemia, as well as studies\nevaluating the discontinuation of\nsupplemental oxygen in patients who\npreviously had severe resting room air\nhypoxemia but now have moderate resting\nroom air hypoxemia. Con\ufb01rmatory\nevidence is needed to determine the effect of\nLTOT on dyspnea and other outcomes for\npatients with moderate resting hypoxemia.\nQuestion 3: Should ambulatory\noxygen be prescribed for adults with\nCOPD who have severe exertional\nroom air hypoxemia?\nBackground. Exertional hypoxemia occurs\nin up to 40% of people with moderate to\nsevere COPD who have normoxemia at\nrest (42). It is seen most frequently in those\nwith low lung function (FEV1 , 45%,\nDLCO , 50%), in those with low resting\nsaturation (,95%), and in women (42).\nThe imbalance between oxygen delivery and\ndemand is a major contributor (43).\nExertional hypoxemia is linked to more\nrapid decline in lung function, worse HRQL\n(44), and increased mortality. In 576 people\nwith severe COPD followed for at least 3\nyears, mortality in those with isolated\nexertional hypoxemia on a 6MWT was 2.63-\nfold higher than in those without exertional\nhypoxemia (95% CI, 1.53\u20134.51) (45).\n\u201cAmbulatory oxygen\u201d is de\ufb01ned as\noxygen delivered during exercise or activities\nof daily living when the individual is walking\nfreely (Table 3) (22). It is prescribed for\npeople with COPD to improve oxygen\ndelivery during exertion, reduce symptoms,\nand enhance physical capacity. It may be\nprescribed for individuals using LTOT who\nrequire a portable oxygen supply when\nleaving the house or for those with isolated\nexertional hypoxemia. Although the\nbene\ufb01cial effects of supplemental oxygen\nduring laboratory-based exercise tests have\nbeen reported in COPD (46\u201349), clinical\ntrials of ambulatory oxygen used during\ndaily life have had less consistent results\n(50\u201352). There is variation in prescribing\npractices and access to ambulatory oxygen\nacross jurisdictions (10, 51, 52).\nThe prespeci\ufb01ed critical outcome for\nthis question was HRQL; important\noutcomes included dyspnea, fatigue,\nexercise capacity, physical activity,\nmortality, healthcare resource use, and\nsafety.\nDescription of the evidence and its\nquality. Several studies assessed patients\nwith COPD who had severe exertional\ndesaturation (46, 47, 49\u201358), but cohorts\nvaried from those who were on or eligible\nfor LTOT (46, 49, 53\u201355) to those who had\nisolated exertional desaturation (47, 50\u201352,\n56\u201358) (Table E4). The quality of evidence\nwas low. Most studies reported the acute\neffects of oxygen during exercise testing,\nwith only four studies evaluating use of\noxygen during daily life (50\u201352, 55), of\nwhich two were crossover trials (50, 52).\nThere were only two parallel-group RCTs\nof ambulatory oxygen (51, 55), of which\nonly one included blinding to the\nintervention (51). Three additional RCTS\n(48, 59, 60) reported on the effects of\noxygen supplementation during exercise\ntraining, so these were not directly relevant\nto our question; however, two of them (48,\n59) reported baseline data for the acute\neffects of oxygen during an exercise test\nthat we were able to include in our analysis.\nThe LOTT study was not included in this\nreview, as the patients with exertion-only\ndesaturation were required to wear oxygen\nduring sleep as well as during exercise, thus\nnot meeting our de\ufb01nition of ambulatory\noxygen (5). One additional study was\nidenti\ufb01ed in which the degree of exertional\ndesaturation was not speci\ufb01ed, but the\nparticipants were users of LTOT (61). As it\nis likely that these participants would have\nmet our inclusion criteria, this study was\nincluded in the narrative review as indirect\nevidence.\nEvidence for patients with isolated\nexertional desaturation. Several different\ntools were used to measure HRQL. Meta-\nanalysis of three studies (50\u201352) found a\nsmall but signi\ufb01cant improvement in the\ndyspnea-related quality-of-life domain of\nthe Chronic Respiratory Disease\nQuestionnaire (CRQ) (standardized mean\ndifference, 0.42; 95% CI, 0.04\u20130.79;\nI2\n= 12%; n = 211) in favor of ambulatory\noxygen (62). However, the effect size was\nsmall, and the mean number of changes for\nthe CRQ dyspnea domain was generally less\nthan the minimal clinically important\ndifference (MCID) (63) and was of\nuncertain clinical signi\ufb01cance. The number\nof participants in whom changes exceeded\nthe MCID was not reported in any study.\nAMERICAN THORACIC SOCIETY DOCUMENTS\nAmerican Thoracic Society Documents e129\nImprovements with oxygen in individual\nparticipants could not be predicted by\nparticipant characteristics (degree of\nexertional desaturation, severity of air\ufb02ow\nobstruction or dyspnea, volume or exercise\nresponse to hyperoxia, and sex) (51). The\nemotion, fatigue, and mastery domains\nwere not different between the groups. A\nsensitivity analysis strati\ufb01ed by study design\n(crossover trial vs. parallel groups) found\nthat the results remained signi\ufb01cant for the\ndyspnea domain (Table E4 and Figures E1\nand E2).\nOne study assessed HRQL using the\nSGRQ (50). No differences for the\nadministration of supplemental oxygen\nversus compressed room air were\nobserved. However, using the 36-Item\nShort-Form Health Survey, Eaton and\ncolleagues (52) observed a signi\ufb01cant\ndifference in favor of ambulatory oxygen\nin the domains of physical role (MD, 16.8;\n95% CI, 6.02\u201327.58), general health (MD,\n6.1; 95% CI, 0.42\u201311.78), social\nfunctioning (MD, 10.5; 95% CI,\n0.31\u201320.69), and emotional role (MD,\n18.3; 95% CI, 3.21\u201333.39), which exceed\nthe reported MCID for all domains except\nsocial functioning (64).\nThe acute effects of oxygen on\nfunctional exercise capacity were assessed\nusing multiple tests. We meta-analyzed the\nresults from two studies (52, 56) using the\n6MWT, one of which used cylinder room\nair and the other of which used room air as\nthe comparator. An MD of 28.9 m (95% CI,\n16.1\u201341.9 m; I2\n= 0%) was found in favor of\nthe oxygen group. Oxygen acutely increased\nexercise endurance time on a cycle\nergometer by 5.8 minutes (95% CI,\n2.23\u20139.37 min) compared with room air\n(58). Peak workload on a stationary bike\nwas acutely improved with ambulatory\noxygen (MD, 17.9 W; 95% CI, 8.10\u201327.70\nW) (47). Ambulatory oxygen increased the\nnumber of steps walked in 5 minutes\ncompared with cylinder room air (MD,\n14.90; 95% CI, 0.85\u201328.94) (50). Meta-\nanalysis of three studies reporting on the\nBorg dyspnea score at the end of exercise\n(52, 56, 58) showed a reduction of 1.11 U\n(95% CI, 0.53\u20131.69 U; I2\n= 39%) in favor of\nambulatory oxygen. This remained\nsigni\ufb01cant when we did a sensitivity\nanalysis by study design (crossover trial vs.\nparallel groups; Table E4). No studies\nreported the long-term effects of\nambulatory oxygen on exercise capacity\nbeyond acute laboratory or \ufb01eld tests, and\nno studies reported effects on physical\nactivity in daily life.\nEvidence for patients with resting\nhypoxemia and severe exertional\ndesaturation. For the subgroup of studies in\nwhich patients had both resting and\nexertional hypoxemia, six RCTs (46, 48, 49,\n53\u201355) met our inclusion criteria;\nhowever, none included results for HRQL,\nour critical outcome. In one randomized\ncrossover study of LTOT users (n = 24) in\nwhich the degree of exertional\ndesaturation was not speci\ufb01ed, ambulatory\noxygen had no effect on the CRQ dyspnea\ndomain (mean change over the 3-month\ntreatment period, 0.0 U; 95% CI, 20.3 to\n0.2 U) (61). A single-blind RCT found that\nambulatory oxygen at 2 and 4 L\/min\nacutely increased the distance patients\nwalked in 12 minutes compared with room\nair if they were not using a walker or\nshopping trolley, as carrying those devices\neliminated any gains in exercise tolerance\n(49). Baseline data from an RCT of\npulmonary rehabilitation found that\nambulatory oxygen acutely improved the\ndistance walked compared with room air,\nmeasured with the incremental shuttle\nwalk test (MD, 27.3 m; 95% CI, 14.7 to\n39.8 m) (48). In a crossover study,\nambulatory oxygen acutely improved\nendurance time by 4.70 minutes compared\nwith room air (95% CI, 3.76 to 5.64 min)\n(46). We meta-analyzed the results from\nthree studies reporting on the Borg\ndyspnea score (46, 48, 54) and found a\nreduction of 0.59 U (95% CI, 0.18 to 0.99;\nI2\n= 25%) in favor of ambulatory oxygen;\nthe MCID is reported to be 1.0 U (65).\nNo studies in our review examined\nsafety in patients with COPD using only\nambulatory portable oxygen systems.\nPanel judgments. DESIRABLE\nCONSEQUENCES AND THEIR MAGNITUDES\n(BENEFITS). For people with COPD and\nsevere exertional hypoxemia, we did not \ufb01nd\nconsistent evidence that ambulatory oxygen\ndelivered clinically signi\ufb01cant\nimprovements in the critical outcome of\nHRQL, whereas effects generally favored\nambulatory oxygen (moderate GRADE\nevidence). Acute improvements in exercise\ncapacity were seen both in those with\nisolated exertional hypoxemia and in those\neligible for LTOT. The effects of ambulatory\noxygen on dyspnea during exercise testing\nwere inconsistent. Mortality risks were not\nreported. Fatigue and physical activity in\ndaily life were not reported.\nUNDESIRABLE CONSEQUENCES AND THEIR\nMAGNITUDES (HARMS). There is a substantial\nbody of evidence regarding the patient and\ncaregiver burden associated with the use of\nambulatory oxygen, including managing the\nweight and bulk of equipment,\nembarrassment and perceived stigma, fear\nof cylinders running out, reduced ability to\ntravel outside the home, equipment noise\nthat may affect social activities, dif\ufb01culty\nobtaining POCs, and poor access to\ninformation about effective use of oxygen\nequipment (14, 66, 67).\nRationale for the recommendation. There\nis some evidence supporting the use of\nambulatory oxygen in people with COPD,\nwhich is complicated by the potential burden of\nthis therapy. Effects on the critical outcome of\nHRQL, which may or may not be clinically\nsigni\ufb01cant, tended to favor ambulatory oxygen.\nAmbulatory oxygen acutely improves exercise\ncapacity and may reduce breathlessness during\nexercise testing. There is little evidence\nregarding the effects of ambulatory oxygen\nwhen used in daily life. Given this uncertainty,\ntogether with the known burden of ambulatory\noxygen, it is likely that some patients will\nchoose not to use ambulatory oxygen.\nATS recommendation. In adults with\nCOPD who have severe exertional room air\nhypoxemia, we suggest prescribing\nambulatory oxygen (conditional\nrecommendation, low-quality evidence).\nWhat others are saying. A 2015\nguideline by the BTS states that ambulatory\noxygen should not be routinely offered to\npatients with isolated exertional hypoxemia\nand should only be offered to those eligible\nfor LTOT if they are mobile outdoors (7).\nThe 2020 GOLD strategy makes no\nrecommendations regarding ambulatory\noxygen (12).\nImplementation considerations. We\nde\ufb01ned exertional hypoxemia as an\nSpO2\n< 88%. Ambulatory oxygen seems to\nhave similar effects in patients who are\neligible for LTOT and in those who have\nisolated exertional hypoxemia. In patients\nwho are eligible for LTOT, prescription of\nambulatory oxygen may be important to\nincrease the daily hours of oxygen usage\n(68). Individuals who experience a\nreduction in dyspnea or increased activity\nlevels with ambulatory oxygen may be more\nlikely to bene\ufb01t from, and adhere to, this\ntherapy. Standardization of the level of\nexertion is critical when assessing the\neffects of oxygen on dyspnea (69, 70).\nAmbulatory oxygen devices vary in terms\nAMERICAN THORACIC SOCIETY DOCUMENTS\ne130 American Journal of Respiratory and Critical Care Medicine Volume 202 Number 10 | November 15 2020\nof portability, volume, and \ufb02ow; shared\ndecision-making between the patient and\nprovider is necessary to ensure that the\ndevice prescription meets the patient\u2019s\nneeds and goals.\nValues and preferences. This\nrecommendation places a high value on\nincreasing HRQL and the potential for\nfacilitating physical activity outside the\nhome and places a lower value on cost,\ninconvenience, and resource use.\nResearch needs. Given the well-\ndocumented burden of ambulatory oxygen,\nthere is an urgent need for new ambulatory\noxygen devices that increase portability\n(improved battery life, weight, \ufb02ow rates,\nwireless connections, etc.). Although we\nfound several studies evaluating the effects\nof oxygen during laboratory testing, few\nstudies evaluated ambulatory oxygen during\ndaily life activities, the context for which it is\nprescribed. Future studies of ambulatory\noxygen should address patient-centered\noutcomes such as HRQL and physical\nactivity in daily life, together with outcomes\npertinent to cost-effectiveness, such as\nproductivity, days missed from work, and\nhospital readmissions. Future studies should\nalso capture costs of care for other health\nconditions that may occur because of\nphysical inactivity, which could be reduced\nwith ambulatory oxygen.\nQuestion 4: Should long-term oxygen\nbe prescribed for adults with ILD who\nhave severe chronic resting room air\nhypoxemia?\nBackground. Severe resting hypoxemia is\nhighly prevalent in adults living with ILD.\nThose with \ufb01brotic forms of ILD, such as\nIPF, often experience a progressive course\ncharacterized by breathlessness, cough,\nhypoxemia, episodes of acute respiratory\nworsening, and early death. When present,\nsevere resting hypoxemia often contributes\nto disabling and distressing breathlessness,\nwhich is common in ILD. With the\nexception of lung transplantation,\nsupplemental oxygen is the only treatment\nthat improves hypoxemia that persists\ndespite optimal medical management of the\nunderlying disease.\nThe critical outcome for this question\nwas mortality; important outcomes were\ndyspnea, fatigue, HRQL, physical activity in\ndaily life, healthcare resource use, exercise\ncapacity, and safety.\nDescription of the evidence and its\nquality. No studies were found that met our\ninclusion criteria. A 2001 Cochrane\nsystematic review (71) reported the results\nfrom one unpublished RCT in which severe\nresting room air hypoxemia was de\ufb01ned as\na PaO2\nof 45\u201360 mm Hg (6.0\u20138.0 kPa),\nslightly above our prespeci\ufb01ed cutoff of\nPaO2\n< 55 mm Hg (7.3 kPa) (Table E5).\nBecause no other study was found reporting\non our outcomes of interest, we elected to\nreport these results. The study included 62\nparticipants, 49 of whom had IPF. No\nsigni\ufb01cant difference in mortality between\nthe LTOT and room air groups was\nobserved after 1 year (OR, 0.50; 95% CI,\n0.15\u20131.61), 2 years (OR, 1.76; 95% CI,\n0.64\u20134.86), or 3 years (OR, 0.99; 95% CI,\n0.16\u20136.26). As this is an unpublished RCT,\nthere is a high risk of bias and a very low\nGRADE quality of evidence for this\noutcome (Table E5).\nNo studies reported on dyspnea,\nfatigue, HRQL, physical activity, or\nhealthcare resource use.\nBecause of the paucity of any direct\nevidence regarding patients with ILD, we\nchose to consider indirect evidence from our\n\ufb01rst population, intervention, comparison,\nand outcome question that considered\npatients with COPD and severe resting\nroom air hypoxemia (6, 72\u201374).\nSafety data speci\ufb01c to LTOT in\npatients with ILD were scarce. A\nqualitative study reported tripping as a\nhardship after being on oxygen for 9\u201312\nmonths (75). The panel agreed that the\nsafety data for COPD related to risks of\ntripping, burns, \ufb01res, nosebleeds, and\ntransporting oxygen cylinders would also\nbe potential safety concerns for patients\nwith ILD on LTOT.\nPanel judgments. DESIRABLE\nCONSEQUENCES AND THEIR MAGNITUDES\n(BENEFITS). Despite the absence of any\npublished randomized trial data, the panel\njudged the perceived bene\ufb01ts of LTOT to\ntreat severe resting hypoxemia to be\nsubstantial for most adults with ILD. As\nnoted above, LTOT for severe resting\nhypoxemia may confer a mortality bene\ufb01t in\nCOPD. LTOT may also prevent organ\ndysfunction due to severe sustained\nhypoxemia, including prevention of PH.\nOther bene\ufb01ts may include relief of\nbreathlessness (76) as well as improvements\nin disability and HRQL. These desirable\nconsequences were considered to be\nsubstantial.\nUNDESIRABLE CONSEQUENCES AND THEIR\nMAGNITUDES (HARMS). The primary\nundesirable consequences are listed in\nquestion 1, including patient burden and\ncost. Overall, the panel deemed the\nsubstantial desirable consequences of LTOT\nto outweigh the undesirable consequences of\nuntreated severe resting hypoxemia.\nNotably, despite the very-low-quality\nevidence available to the panel, ethical\nconcerns about withholding LTOT were\nstrong factors in our decision-making.\nRationale for the recommendation. The\nabsence of published studies examining\neffects of LTOT in ILD led the panel to\nincorporate evidence from COPD trials\ntogether with their clinical experience in the\ndevelopment of the recommendation.\nDespite the burden of therapy, the panel\nconcluded that LTOT is likely to confer\ndesirable bene\ufb01ts for many patients with\nsevere resting hypoxemia.\nATS recommendation. For adults with\nILD who have severe chronic resting room\nair hypoxemia, we recommend prescribing\nLTOT for at least 15 h\/d (strong\nrecommendation, very-low-quality\nevidence).\nWhat others are saying. Because of the\nlack of direct evidence, the majority of\nguidelines made their recommendations on\nthe basis of expert opinion or extrapolated\nfrom COPD literature. A 2011 multisociety\nguideline on IPF recommends the use of\nLTOT in patients with severe resting room\nhypoxemia (77). The panel made a strong\nrecommendation in favor of LTOT, as they\nplaced a high value on evidence from other\nchronic lung diseases and low value on cost\nand inconvenience to patients. A 2015 BTS\nguideline on home oxygen use suggests a\nhigher threshold of 60 mm Hg (8.0 kPa) for\nthose who have concomitant PH. They also\nrecommend LTOT in patients with ILD\nwith a PaO2\n< 55 mm Hg (7.3 kPa) but\nnoted that the evidence base is extrapolated\nfrom evidence in COPD (7).\nImplementation considerations. For\npatients with ILD, we have applied the same\nde\ufb01nition of severe resting hypoxemia as in\nthose with COPD (question 1), as our\nrecommendation was based on indirect\nevidence from COPD trials. The assessment\nof PH in patients with ILD should be\nconsidered, as it predicts worsening lung\nfunction and functional status, increased\noxygen needs, and risk of acute exacerbation\nin ILD and is a predictor of increased\nmortality in IPF (6, 72\u201374). Some patients\nAMERICAN THORACIC SOCIETY DOCUMENTS\nAmerican Thoracic Society Documents e131\nmay not experience dyspnea, despite severe\nhypoxemia at rest, or may have strong\npersonal preferences against the use of\nLTOT. The panel encourages healthcare\nproviders to educate patients about the\nharms of severe chronic hypoxemia and to\npartner with patients and their caregivers to\nselect the oxygen delivery system that best\nmeets their medical and lifestyle needs.\nValues and preferences. This\nrecommendation places a high value on\nindirect evidence of decreased mortality, the\nrelief and prevention of distressing\nsymptoms, and a perceived likelihood of\noverall improved health status by\nprevention of organ dysfunction.\nResearch needs. The panel\nacknowledges that RCTs of LTOT to treat\nsevere hypoxemia in ILD may face\nchallenges, including a lack of perceived\nequipoise. We encourage the research\ncommunity to consider innovative\napproaches to studying the bene\ufb01ts and\nharms of LTOT in ILD, including clinical\ntrials and quasiexperimental trial designs.\nSuch trials may minimize harms and be\nmore ethically acceptable to patients,\ncaregivers, healthcare providers, and\nresearchers. Trials of short duration may\nneed to be performed before longer-term\ntrials.\nQuestion 5: Should ambulatory\noxygen be prescribed to adults with\nILD who have severe exertional room\nair hypoxemia?\nBackground. Exertional hypoxemia is a\nhallmark of ILD, occurring in more than\nhalf of patients evaluated at a tertiary ILD\nservice and in over 80% of patients with an\nFVC , 50% of that predicted (78). The\nmagnitude of exertional hypoxemia is\ngenerally greater in people with ILD than in\npeople with COPD (18). People with ILD\nwho desaturate to an SpO2\n< 88% on a\n6MWT have a fourfold greater risk of death\nthan those who do not, after adjusting for\nage, sex, smoking, respiratory function, and\nresting saturation (79). Exertional\ndesaturation is an independent predictor of\nPH (80), which is itself a strong predictor of\nmortality (81). Greater exertional\ndesaturation is strongly associated with\nreduced physical activity (82). These data\nprovide a strong rationale for treatment of\nexertional hypoxemia in ILD to improve\ndaily functioning and long-term outcomes.\nThe prespeci\ufb01ed critical outcome for\nthis key question was HRQL; important\noutcomes were dyspnea, fatigue, exercise\ncapacity, physical activity, mortality,\nhealthcare resource use, and safety.\nDescription of the evidence and its\nquality for participants with exertional\ndesaturation. The AmbOx (Ambulatory\nOxygen in Fibrotic Lung Disease) trial (83)\nexamined the effects of ambulatory oxygen\nused during daily activities on HRQL in a\nrandomized 2-week crossover trial\nconducted in 84 patients with \ufb01brotic ILD\nand isolated exertional hypoxemia (de\ufb01ned\nas an SpO2\n< 88% during a 6MWT). The\ncontrol group did not use a sham device,\nand there was no blinding of assessment.\nFor the King\u2019s Brief ILD questionnaire,\nthere was a signi\ufb01cant improvement in\nfavor of ambulatory oxygen for the total\nscore (MD, 3.7; 95% CI, 1.8 to 5.6),\nbreathlessness and activities score (MD, 8.6;\n95% CI, 4.7 to 12.5), and the chest\nsymptoms score (MD, 7.6; 95% CI, 1.9 to\n13.2), whereas no signi\ufb01cant difference was\nobserved for the psychological symptoms\nscore. The MCID for the total King\u2019s Brief\nILD score has been recently estimated as 3.9\n(84, 85). The SGRQ demonstrated a\nsigni\ufb01cant improvement in the total score\n(MD, 23.6; 95% CI, 26.7 to 20.6) and\nactivity score (MD, 27.5; 95% CI, 212.4 to\n22.5), with no signi\ufb01cant difference in the\nimpact and symptoms scores. The MCID\nfor the SGRQ is 4 U (86). Dyspnea\nassociated with activities of daily living was\nassessed using the University of California,\nSan Diego, Shortness of Breath\nQuestionnaire, showing an improvement of\n8 U (95% CI, 3.6 to 12.4). The MCID is 5 U\n(87). Despite the clear challenges posed by\nambulatory oxygen, highlighted in the\nqualitative component of the trial, two-\nthirds of patients decided to continue with\nambulatory oxygen at the end of the study.\nImprovements with oxygen in individual\nparticipants could not be predicted by\nparticipant characteristics, but preference to\ncontinue on oxygen after the trial was\nin\ufb02uenced by the patient perception of\nbene\ufb01t for breathlessness or walking ability\n(83).\nA 2016 Cochrane systematic review\n(88) included three crossover RCTs\nevaluating the acute effects of oxygen\nduring exercise testing in patients with ILD.\nNo change was found in 6-minute-walk\ndistance with ambulatory oxygen compared\nwith cylinder room air (89) or in the\nendurance shuttle walk test distance with\noxygen compared with room air (90). There\nwas no change in dyspnea, measured with\nthe Borg dyspnea score (89). One study\nreported an acute improvement in\nendurance time by 118.7 seconds (95% CI,\n23.9\u2013213.5 s) (91) with ambulatory oxygen\ncompared with room air. Two other\nsystematic reviews assessing the ambulatory\noxygen in ILD were subsequently published\n(92, 93) but did not meet our inclusion\ncriteria.\nWe identi\ufb01ed additional studies\nthat met our inclusion criteria; all used\n6MWTs. Meta-analysis of three studies\n(83, 89, 94) showed that oxygen acutely\nimproved 6-minute-walk distance by\n18.57 m (95% CI, 11.14 to 25.99 m;\nI2\n= 0%) compared with room or cylinder\nair (Table E6 and Figure E5). We pooled\nthe results of three studies (83, 89, 94) that\nreported the Borg dyspnea score at the end\nof a 6MWT, one of which was not\nincluded in the Cochrane systematic\nreview (83); no signi\ufb01cant difference\nwas found (MD, 20.72; 95% CI, 21.70\nto 0.27; I2\n= 73.28%). Meta-analysis of\nthree studies (83, 89, 94) found a\nsigni\ufb01cant reduction in the Borg\nperceived-exertion score at the end of a\n6MWT in favor of ambulatory oxygen\n(0.37 U; 95% CI, 0.19 to 0.54 U; I2\n= 0%).\nWe meta-analyzed the results from two\nstudies (90, 95) and found that exercise\nduration on cardiopulmonary exercise\ntesting improved by 57.67 seconds using\noxygen compared with room air (95%\nCI, 0.22 to 115.12; I2\n= 0%). No signi\ufb01cant\nimprovement was observed in the maximal\nwork rate (MD, 10.34 W; 95% CI, 23.59 to\n24.26 W; I2\n= 0%).\nNo studies reported the effects of\nambulatory oxygen on fatigue, exercise\ncapacity in the long term, physical activity in\ndaily life, or mortality. The quality of\nevidence was low, with no parallel-group\nRCTs and only one study evaluating use of\nambulatory oxygen in daily life (83): a\ncrossover trial that did not include blinding\nof participants or researchers. See Table E6\nfor an evidence pro\ufb01le.\nSafety data speci\ufb01c to ambulatory\noxygen in ILD were rarely reported. A\nCochrane review of the effects of ambulatory\nor short-burst oxygen in ILD did not report\nany serious adverse events or side effects\n(88). However, the panel agreed that risks\nof transporting cylinders, burns, \ufb01res, and\ntripping would be potential safety concerns\nAMERICAN THORACIC SOCIETY DOCUMENTS\ne132 American Journal of Respiratory and Critical Care Medicine Volume 202 Number 10 | November 15 2020\nfor patients with ILD using ambulatory\noxygen.\nPanel judgments. DESIRABLE\nCONSEQUENCES AND THEIR MAGNITUDES\n(BENEFITS). For people with ILD and\nexertional hypoxemia, ambulatory\noxygen resulted in improvements in the\ncritical outcome of HRQL that may be\nclinically important. However, there was\nonly one crossover trial with a 2-week\ntreatment period, so the long-term impact\non HRQL is unknown. In laboratory studies,\nthe improvements in exercise capacity\ntended to favor ambulatory oxygen but\nwere generally small. Physical activity\nin daily life and mortality were not\nreported.\nUNDESIRABLE CONSEQUENCES AND THEIR\nMAGNITUDES (HARMS). Qualitative studies in\npatients with ILD report negative physical\nand psychosocial impacts of ambulatory\noxygen therapy, which persist despite\nacceptance that this treatment may be\ninevitable as disease progresses (96).\nPatients and caregivers report that the\nequipment is challenging to use, that there\nmay be unmet expectations for symptom\nrelief (particularly dyspnea), and that\nchallenges related to use of cumbersome or\ncomplicated equipment, embarrassment\nwhen using ambulatory oxygen in public,\nreduced independence for patients, and\nincreased caregiver burden mark an\nimportant trade-off between bene\ufb01ts and\ninconvenience (75, 96, 97).\nRationale for the recommendation. Weak\nevidence supports the use of ambulatory\noxygen in people with ILD, suggesting bene\ufb01ts\nin HRQL; certainty is low, as the medium- to\nlong-term effects are unknown. Ambulatory\noxygen may improve exercise capacity, but\neffects on physical activity in daily life have not\nbeen examined. There is uncertainty regarding\nsymptom bene\ufb01ts. Given this uncertainty,\ntogether with the known burden of\nambulatory oxygen, it is likely that some\npatients will choose not to use ambulatory\noxygen.\nATS recommendation. For adults with\nILD who have severe exertional room air\nhypoxemia, we suggest prescribing\nambulatory oxygen (conditional\nrecommendation, low-quality evidence).\nWhat others are saying. A \u201cgood\npractice point\u201d in the 2015 BTS guideline\nacknowledges that ambulatory oxygen\ntherapy may be useful in patients with ILD\nand disabling breathlessness, and it could\nbe prescribed if there is evidence of bene\ufb01t\nand ongoing adherence (7). Guidelines\nfrom TSANZ state that in the absence of\ntrial-based evidence, the bene\ufb01t of\nambulatory oxygen in individual patients\nshould be established by comparing\nexercise endurance, oxygen saturation, and\ndyspnea during a blinded exercise test on\noxygen versus air (9). Current\nATS\/European Respiratory\nSociety\/Japanese Respiratory\nSociety\/Asociacio\u0301n Latinoamericana de\nTo\u0301rax guidelines on management of IPF do\nnot mention ambulatory oxygen therapy\n(6).\nImplementation considerations. We\nde\ufb01ned exertional hypoxemia as an\nSpO2\n< 88%. In ILD, exertional hypoxemia\nfrequently worsens as the disease progresses\nand may be profound in those with severe\ndisease; ambulatory oxygen is likely to be\nparticularly important for these patients. It\nmay also be important for those with\nfunctional limitation and those being\nconsidered for lung transplantation. The\npanel noted that the need for high-\ufb02ow\nambulatory devices is greater in people with\nILD than in those with COPD because of\nthe magnitude of exertional hypoxemia. It\nis prudent to ensure that ambulatory\noxygen devices with appropriate \ufb02ow\ncapacity are prescribed to patients on the\nbasis of their needs. The panel noted that\nthe majority of evidence is related to\nlaboratory tests that may not be indicative\nof activities of daily living. Standardization\nof the level of exertion is necessary to assess\nthe effects of oxygen on dyspnea (69, 70),\nwhich may be particularly important when\ndetermining the eligibility for and likely\nbene\ufb01ts of ambulatory oxygen.\nValues and preferences. This\nrecommendation places a high value on\nincreasing HRQL and facilitating physical\nactivity outside of the home and places a\nlower value on cost and resource use.\nResearch needs. Randomized parallel-\ngroup trials that evaluate the impact of\nambulatory oxygen on patient-centered\noutcomes, daily life activities, disease\nprogression, and mortality are required.\nThese trials should address outcomes\npertinent to cost-effectiveness, such as\nproductivity, days missed from work, and\nhospital readmissions. Although we found\nseveral studies evaluating the effects of\noxygen during laboratory testing, there\nwas only one study that evaluated\nambulatory oxygen during daily life\nactivities, the context for which it is\nprescribed. There is an urgent need for\nambulatory oxygen devices that can better\nmeet the high \ufb02ow requirements of people\nwith ILD during exercise. Novel devices\nshould also increase portability through\nimprovements in weight, maneuverability,\nand battery life.\nQuestion 6: Should portable LOX\nbe provided for adults with chronic\nlung disease who are prescribed\ncontinuous oxygen \ufb02ow rates of\n>3 L\/min during exertion?\nBackground. Three modes of portable\noxygen delivery are available for patients\u2019\nuse outside of the home: metal cylinders of\ncompressed gaseous oxygen, POCs, and\nLOX canisters. Each varies in size, weight,\nlevels of pulse- or continuous-\ufb02ow\nsettings, oxygen delivery capacity, and\nduration of supply (Figure 1 and Tables 5\nand E11). In the past, LOX has been used\nfor those with higher \ufb02ow requirements to\nfacilitate mobility and increase time spent\noutside of the home, but relative ef\ufb01cacy is\nunclear.\nSince the implementation of\nthe Medicare National Competitive\nBidding Program by the Centers for\nMedicare and Medicaid Services (CMS)\nin the United States in 2011, Medicare\nbene\ufb01ciary claims for portable LOX\ndeclined from 966,846 in 2004 to 97,690\nin 2016 (98). This decrease re\ufb02ects lower\nCMS reimbursement to durable medical\nequipment (DME) companies with\nsubsequent elimination of LOX, and\nother cost-saving changes including\ntransitioning patients to \u201cnondelivery\u201d\nhome-\ufb01ll oxygen systems (99\u2013101) and\nheavier E cylinders.\nThe impact of this decline in the\navailability and adequacy of portable oxygen\ndevices in the United States has been\nprofound. Supplemental oxygen users\nreported numerous problems, with the\noverarching theme being restricted mobility\nand isolation due to inadequate portable\noptions (13, 14, 16, 20, 102). The panel\nagreed that portable LOX for individuals\nrequiring .3 L\/min of continuous-\ufb02ow\noxygen was an important problem because\nlimited mobility affects our critical outcome\nof HRQL. The symptoms associated with\nsevere exertional hypoxemia in patients\nwith high-\ufb02ow oxygen needs may be\nsubstantial, but these have not been\nassessed in clinical trials.\nAMERICAN THORACIC SOCIETY DOCUMENTS\nAmerican Thoracic Society Documents e133\nTable 5. Characteristics of Portable Oxygen Devices\nMetal Oxygen Cylinders POCs LOX\nSize and weight Available in multiple sizes from 2.5\nto 9 kg (E cylinder in United\nStates, which requires a trolley)*\nVary in weight (1.5\u201310 kg), noise,\nbattery life, oxygen purity\n(87\u201395%), maximum breath\nrates, and settings (pulse \ufb02ow,\ncontinuous \ufb02ow, or both)\u2020\u2021\nMedium to large canister ranges\nbetween 2.5 and 4 kg\nFilling Some stationary concentrators\nallow patients to \ufb01ll smaller\noxygen cylinders in their home,\n(home-\ufb01ll units), but these last\n,1 h on continuous-\ufb02ow rates\n.3 L\/min and therefore are\ninadequate for high-\ufb02ow\npatients\nNo \ufb01lling; POCs \u201cconcentrate\u201d\noxygen by extracting nitrogen\nfrom ambient air. They run off of\na battery and can be recharged\nPatients re\ufb01ll portable canisters\nfrom a larger home reservoir of\nLOX\nOne liter of LOX expands to 860 L\nof gaseous oxygen\nPulse setting or\ncontinuous-\ufb02ow capacityx\nOxygen-conserving devices using\npulse-\ufb02ow technology can be\nattached to metal cylinders to\nprolong the duration of supply\nby releasing oxygen only during\ninspiration\nAt a given pulse-\ufb02ow setting,\nPOCs differ as to the volume\nof oxygen (ml) per pulse,\ninspiratory time, and triggering\nsensitivity and may not\nconsistently sense patients\u2019\ninspiratory efforts to trigger the\ndevice*\nPortable LOX technology allows\ndelivery of continuous-\ufb02ow\noxygen up to 15 L\/min via a\nlighter and longer-duration device\nBecause of differences in an\nindividual patient\u2019s ability to\ntrigger a pulse dose of oxygen,\nand the volume delivered with\neach pulse at different\nrespiratory rates, they may be\ninsuf\ufb01cient for patients who\nrequire continuous oxygen with\nexertion at .3 L\/min, such as\nthose with interstitial lung\ndisease, lung transplantation\ncandidates, and others with\nsevere hypoxemia\nPulse settings are based on an\noxygen volume unique to each\ndevice, not a standardized\nL\/min methodology\nDuration of supply A single E tank with a stroller will\nlast approximately 1.9 h on 6\nL\/min. Multiple cylinders are\nneeded for high-\ufb02ow (.3 L\/min)\npatients to be out of the home\n.2\u20134 hk\nAll POCs depend on a battery\nsupply that depletes more\nrapidly with higher settings,\nhigher respiratory rates, and the\nuse of continuous-\ufb02ow settings\nA medium LOX canister will last 3 h\nat 6 L\/min of continuous \ufb02ow\nCost Metal oxygen cylinders range\nfrom US$50 to US$100;\nadditional costs for a regulator\nor oxygen-conserving device.\nCommonly supplied by U.S.\nDME companies\nIn the United States, many DME\ncompanies offer POCs as a\nportable option together with\na stationary concentrator;\nindividuals can also purchase\nthem for US$2,000\u20134,000\nCost estimates are approximately\nfour times higher per patient\ncompared with POCs or\nmetal-cylinder options because\nof the requirements for DME\ncompanies to access and store\nLOX, use specially out\ufb01tted\ndelivery trucks, and provide\nweekly re\ufb01ll servicing\u00b6\nTravel Metal cylinders not allowed for air\ntravel\nPOCs are the only carry-on\nportable oxygen device allowed\nby the Federal Aviation\nAdministration for air travel;\nsome airlines may provide\noxygen cylinders for emergency\nin-\ufb02ight use only**\nLiquid oxygen not allowed for air\ntravel\nDefinition of abbreviations: DME = durable medical equipment; LOX = liquid oxygen; POCs = portable oxygen concentrators.\n*The availability of different oxygen devices varies by geographic region, and some jurisdictions do not have smaller metal oxygen cylinders.\n\u2020\nPOCs vary in pulse technology, oxygen purity, and triggering sensitivity (100, 114\u2013118).\n\u2021\nThe few POCs that currently provide a maximum of 3 L\/min on a continuous-flow setting weigh over 9 kg and require a trolley.\nx\nFor all devices, if an oxygen-conserving device is used, the patient should be tested using that device during exertion, similar to what they would do in daily life, to ensure\nadequate oxygenation. A continuous-flow setting of 5 L\/min and a pulse-flow setting of \u201c5\u201d may not deliver equivalent volumes of oxygen, despite direct marketing claims.\nk\nPatients depend on their DME company to deliver an adequate number of cylinders per week or month.\n\u00b6\nLOX costs are higher than costs for POCs or metal cylinders (103).\n**The Federal Aviation Administration stipulates which POCs are allowed for use during air travel (119).\nAMERICAN THORACIC SOCIETY DOCUMENTS\ne134 American Journal of Respiratory and Critical Care Medicine Volume 202 Number 10 | November 15 2020\nThe prespeci\ufb01ed critical outcome for\nthis key question was HRQL; important\noutcomes were oxygen saturation during\nexertion, dyspnea, exercise capacity,\nphysical activity, adherence, and safety.\nDescription of evidence and its\nquality. The literature search did not yield\nany studies that met our inclusion criteria,\nwhich speci\ufb01ed that patients be prescribed\ncontinuous oxygen \ufb02ow rates of .3 L\/min\nduring exertion. Because of the absence of\nother forms of evidence, we considered\nindirect evidence and synthesized the\nliterature for six studies in patients with\nCOPD (54, 55, 103\u2013106) with lower or\nunreported \ufb02ow rates. Five of those\nstudies tested subjects on continuous-\n\ufb02ow LOX (54, 55, 103\u2013105), whereas\none study (106) used pulse-\ufb02ow LOX\n(Table E7).\nA multicenter RCT (103) compared the\nuse of stationary oxygen concentrators plus\nsmall oxygen cylinders or LOX (stationary\nand portable) in patients with COPD\n(n = 51). They reported HRQL measured\nwith the Sickness Impact Pro\ufb01le (SIP) and\nthe EuroQol instruments. There was no\ndifference between groups in EuroQol\nscores, but there were signi\ufb01cant differences\nin favor of LOX for the SIP domains of\nmobility (MD, 24.57; P = 0.043), body care\n(MD, 25.83; P = 0.011), ambulation (MD,\n28.46; P = 0.017), social interaction (MD,\n25.27; P = 0.023), and total SIP score (MD,\n23.38; P = 0.018) (103). The MCID for SIP\nis a change of 5 U (107).\nNo difference in oxygen saturation was\nobserved during the 6MWT (54, 106) and 2-\nminute-walk test (105) between LOX and\nconcentrators. The Borg dyspnea score did\nnot differ after the 6MWT (MD, 20.10;\n95% CI, 21.23 to 1.03) (54) or 2-minute-\nwalk test (MD, 20.40; 95% CI, 21.36 to\n0.56) (105).\nA retrospective study (n = 146)\ncompared adherence in users of stationary\nand portable LOX to a group that used a\nstationary oxygen concentrator plus small\nportable metal cylinders (105). The LOX\ngroup used stationary and portable oxygen\nfor 6.50 h\/d (95% CI, 4.43\u20138.57 h\/d) longer;\n92% of the concentrator group did not use\ntheir provided portable cylinders. However,\nthe majority of patients in the concentrator\ngroup were sicker (presence of\ntracheostomy or use of home ventilation)\ncompared with the LOX group and were\ntherefore less likely to use portable oxygen\noutside of the home. An RCT (55) (n = 159)\nfound that portable oxygen increased\npatients\u2019 daily duration of oxygen therapy\ncompared with those solely using stationary\ndevices (MD, 3.00 h; 95% CI, 1.97\u20134.03 h);\n24% more patients who used oxygen for\ngreater than 18 h\/d were LOX users than\ncylinder users. In a crossover RCT in which\nall participants were LTOT users (n = 15),\nparticipants who were allocated metal\ncylinders spent more time each week using\ntheir home stationary oxygen concentrator\nthan those using LOX spent (13.1 h longer;\n95% CI, 1.57\u201327.92 h longer) (104). LOX\nusers spent more time outside the home\nthan metal-cylinder users (MD, 4.0 h; 95%\nCI, 0.9\u20137.1 h) (104, 105) and were more\nlikely to leave the home (105).\nOur systematic review did not identify\nsafety data speci\ufb01c to LOX, with the\nexception of guidance provided by the\nmanufacturer (108).\nPanel judgments. DESIRABLE\nCONSEQUENCES AND THEIR MAGNITUDES\n(BENEFITS). Despite the absence of studies\nexamining continuous-\ufb02ow LOX at .3\nL\/min, the panel judged that the desirable\nconsequences and bene\ufb01ts outweighed the\nundesirable consequences and harms of\nportable LOX therapy. Indirect evidence\ndemonstrated improvements in some\ndomains of HRQL, improved adherence,\nand increased time spent outside the home.\nLOX provides opportunity to leave the\nhome for patients with severe hypoxemia\nwho would otherwise require multiple,\nheavy, metal oxygen cylinders to access the\ncommunity. Patients who are caregivers for\nothers, have paid employment or classroom\neducation needs outside the home, or are\nattending pulmonary rehabilitation sessions\nto prepare for lung transplantation would\nhave a means to engage in such activities\nby having a longer duration of oxygen\nsupply.\nUNDESIRABLE CONSEQUENCES AND THEIR\nMAGNITUDES (HARMS). The panel agreed that\nsome of the undesirable consequences of\nLOX were similar to those previously\ndescribed, including equipment\nmanagement, unmet expectations for\nsymptom relief, embarrassment, reduced\nindependence, and increased caregiver\nburden. However, LOX may have less\nimpact on mobility because of smaller,\nlonger-lasting, and more lightweight\ncanisters and the ability to provide\ncontinuous high-\ufb02ow oxygen. Use of LOX\nrequires manual ability to \ufb01ll portable\ncanisters from a large reservoir, which is not\nrequired with other portable oxygen\nsystems. There is also a risk of skin burns\nfrom frost leaks when \ufb01lling portable\ncanisters that is unique to LOX.\nRationale for the recommendation. The\npanel made a conditional recommendation\nbecause although LOX is relevant to a\nsubgroup of patients, there are limited data\nto guide patient selection. However, the\npanel considered that, on the basis of the\nlimited capacity of POCs and portable metal\ncylinders, the prescription of LOX is\ncritically important for patients who require\nhigh \ufb02ow rates and who need to spend\nextended periods of time outside the home.\nPatients who require continuous-\ufb02ow\noxygen at .3 L\/min cannot spend .2\nhours outside the home with a single E\ntank. LOX at 3\u20134 L\/min may allow patients\nto spend up to 5 hours away from home,\nwhich is reduced to 4 hours if using LOX at\n5 L\/min (Table E11).\nATS recommendation. In patients with\nchronic lung disease who are mobile outside\nof the home and require continuous \ufb02ow\nrates of .3 L\/min during exertion, we\nsuggest prescribing portable LOX\n(conditional recommendation, very-low-\nquality evidence).\nWhat others are saying. The National\nInstitute for Clinical Excellence guidelines for\nCOPD management (109) state that \u201csmall\nlightweight cylinders, oxygen-conserving\ndevices and portable liquid oxygen systems\nshould be available for the treatment of\npatients with COPD. A choice about the\nnature of equipment prescribed should take\ninto account the hours of ambulatory\noxygen use required by the patient and the\noxygen \ufb02ow rate required.\u201d They suggest\nthat compressed gas cylinders be used for no\nless than 90 minutes and that LOX be used\nfor .4 hours or .30 minutes, for \ufb02ow rates\nhigher than 2 L\/min (109).\nGuidelines by the U.S. Department of\nVeterans Affairs state that LOX should be\n\u201cprescribed for ambulatory patients who\nuse an extensive amount of oxygen from\nportable sources\u201d (110). They further state\nthat \u201cThe most ef\ufb01cient and medically\nappropriate system for providing oxygen\nwill be determined by the prescribing\nphysician based upon the \ufb02ow rate (per\nminute) desired, the daily period of usage,\nthe patient\u2019s physical condition and daily\nactivities\u201d (110).\nAlthough individual coverage varies\nacross insurance companies, one national\ninsurer\u2019s policy for portable oxygen,\nAMERICAN THORACIC SOCIETY DOCUMENTS\nAmerican Thoracic Society Documents e135\nincluding ambulatory LOX, says it is\n\u201cConsidered medically necessary for\nmembers who occasionally go beyond the\nlimits of a stationary oxygen delivery\nsystem with 50-ft. tubing for .2 hours per\nday for most days of the week (minimum 2\nhours\/week)\u201d (111).\nFinally, a health technology assessment\nin Quebec, Canada, assessing the evidence\nbehind portable LOX concluded that\n\u201cadvantages are likely to be most bene\ufb01cial\nto a select group of patients who are\nrelatively active and compliant with\ntherapy, while there are no agreed social or\nclinical indicators that would be reliable\npredictors of use or bene\ufb01t\u201d (112).\nImplementation considerations. Costs\nassociated with LOX are higher than for other\ndelivery systems. DME suppliers in the\nUnited States are reluctant to provide LOX\nunder current CMS funding, as it does not\nfully reimburse costs associated with a special\ndelivery truck, frequent deliveries, and related\nequipment. In other countries, provision of\nLOX varies in its costs, availability, and\npatient eligibility requirements. The\nfeasibility of implementing LOX will vary\nacross geographic areas and reimbursement\npolicies.\nValues and preferences. This\nrecommendation places a high value on\nHRQL related to mobility outside of the\nhome and places a lower value on costs and\nresource use.\nResearch needs. The lack of any studies\nmeeting our evidence criteria underscores\nthe need for future research on the bene\ufb01ts\nof LOX in those with ILD and in other\npatients who require high-\ufb02ow oxygen and\nare mobile outside the home. Outcomes\nsuch as change in mobility, depressive\nsymptoms, use of healthcare resources, and\nsurvival require further investigation.\nTechnologic and device-development\nresearch is needed to develop lighter-weight\nand longer-lasting portable oxygen devices.\nEducation and Safety\nConsiderations\nPanel Discussion\nThe panel agreed that for all patients\nreceiving home oxygen therapy, there was\nno acceptable alternative to providing\npatients and their caregivers appropriate\neducation related to adherence to their\noxygen prescription, proper use and\ntroubleshooting of oxygen equipment,\noxygen safety education, and education on\nself-management. These were recurring\ntopics of discussion for all population,\nintervention, comparison, and outcome\nquestions. The panel agreed that these\nrecommendations applied to patients using\nLTOT as well as to ambulatory oxygen users.\nA best-practice statement was included to\naddress these recommendations.\nSafety education should be provided to\npatients and caregivers to avoid tripping and\nfalls and to decrease \ufb01re risk by not smoking\nor allowing smoking inside the home, to\navoid the use of inline devices, to avoid\nactivities around an open \ufb02ame or spark,\nand to avoid the use of nonpetroleum nasal\nproducts (5, 28). For LOX users, patients\nshould be provided product information\nthat includes instructions on avoiding skin\nburns from contact with any of the frosted\nparts on LOX-device connectors (108). The\npanel agreed that patients also need\nguidance on transporting and traveling\nsafely with oxygen (14).\nAccess to oxygen for patients who\ncontinue to smoke varies globally. In some\nregions, smoking is an absolute\ncontraindication to home oxygen therapy\n(9); the BTS recommends advising the\npatient that oxygen provides limited clinical\nbene\ufb01t for those who continue to smoke\n(36). Smoking safety is now inclusive of\ne-cigarettes, or vaping, on the basis of\nreported burn accidents in e-cigarette\nsmokers receiving home oxygen therapy\n(113). Included in safety concerns is\nestablishment of back-up devices for\nemergencies or loss of power. Current\nsmokers or caregiver smokers should\nreceive education and support for treatment\nof tobacco dependence (referral to\nappropriate resources).\nEducational support is necessary for\npatients and caregivers and should be tailored to\npatients\u2019 health literacy and cultural contexts.\nCurrent practice does not consistently include\neffective evaluation and support of the oxygen-\nusing patient by healthcare providers or oxygen\ndelivery personnel to ensure adequate education\nand return demonstration of their ability to use\ntheir prescribed devices (teaching back) both in\nthe home and ambulatory settings (13). Other\nconsiderations include access to appropriate\nequipment based on patients\u2019 physical,\nphysiologic, and lifestyle and\/or mobility needs.\nClinical support for monitoring at home by\nnurses and respiratory therapists is rare in the\nUnited States but common in other regions\n(19). The panel agreed that patients should be\nadvised to bring their portable device to\nhealthcare visits to assess its effectiveness and to\nreinforce self-management.\nAll panelists agreed on the need\nfor ongoing reassessment of patients\u2019\nincreased or decreased oxygen needs and\nacknowledged that the frequency would\nvary by disease characteristics, rate of\nprogression, or posthospitalization status.\nThe high priority for posthospitalization\nreassessment of the ongoing need\nfor oxygen is in agreement with the\nATS\/American College of Chest\nPhysicians policy statement (40) and\nothers \ufb01ndings (39).\nATS Recommendation\nFor patients prescribed home oxygen\ntherapy, we recommend that the patient\nand their caregivers receive instruction\nand training on adherence to their oxygen\nprescription; the use, maintenance and\ntroubleshooting of all oxygen equipment;\nand education on oxygen safety,\nincluding smoking cessation, \ufb01re\nprevention, and tripping hazards (best-\npractice statement).\nConclusions\nOur systematic review reveals that the\nquality and quantity of clinical trial evidence\nis low, thereby leaving signi\ufb01cant gaps in\navailable data regarding prescription of\nsupplemental oxygen. The need for\nguidance is high; the prescription of\nsupplemental oxygen is common. The\nrecommendations in this document re\ufb02ect\nan integration of current evidence and\nclinical experience by a multidisciplinary\nexpert panel.\nFor patients with severe resting\nhypoxemia, the prescription of LTOT to\nimprove survival is supported by historical\ntrials in patients with COPD. The panel\nalso strongly recommends prescribing\noxygen for patients with ILD with\nsevere resting hypoxemia. Existing\nevidence and panel consensus suggest not\nprescribing LTOT for patients with COPD\nwith moderate resting hypoxemia. The\npractice of initiating short-term oxygen\ntherapy on hospital discharge in patients\nwith severe hypoxemia is based on indirect\nevidence from the NOTT and MRC clinical\ntrial populations with chronic hypoxemia.\nThe harms and bene\ufb01ts of prescribing\nshort-term oxygen therapy on hospital\nAMERICAN THORACIC SOCIETY DOCUMENTS\ne136 American Journal of Respiratory and Critical Care Medicine Volume 202 Number 10 | November 15 2020\ndischarge deserves further study. Further\nresearch is needed on the appropriate use of\nshared decision-making between patients\nand their clinicians for decisions regarding\nhome oxygen therapy and on approaches to\ndiscontinue home oxygen in patients\nwho no longer have severe resting\nhypoxemia.\nThis review con\ufb01rmed scarce and\ninconclusive data to support the\nprescription of oxygen in patients who have\nnormoxemia at rest but desaturate\n(sometimes markedly) with exertion.\nEmerging evidence suggests that\nambulatory oxygen may improve HRQL in\npatients with ILD in the short term, but\nlonger-term data are needed. This was\nidenti\ufb01ed as a critical research need. The\nurgency is underscored by the treatment\u2019s\ncumbersome nature, associated risks, and\ncomplex effects on the patients, families,\nand caregivers.\nNo studies met the panel\u2019s criteria for\nthe evaluation of LOX in patients who use\n.3 L\/min of continuous-\ufb02ow oxygen and\nspend regular and frequent time outside the\nhome. The panel concluded that although\nan E tank, or other large metal cylinder, can\nadequately provide oxygen at up to 5 or 6\nL\/min, the patient would be restricted by\nthe need to carry multiple E tanks to leave\nhome for anything more than a very short\ntime period. Thus, this population is\nunintentionally denied the necessary\nmobility to travel, work, socialize, or attend\npulmonary rehabilitation\u2014critical\ncontributors to HRQL. The panel\nunanimously agreed that LOX should be\noffered to active patients on high-\ufb02ow\noxygen and that policies to accommodate\nthis subgroup should be moved\nforward.\nFinally, the minimal standard of\ncare for all patients receiving home\noxygen therapy must include education\nand training related to their oxygen\nequipment, oxygen safety, and self-\nmanagement.\nWe urge the research community and\nfunding agencies to work together to develop\na stronger evidence base that will guide\nclinical practice for oxygen prescription. Of\ncritical importance is the involvement of\nengineers and those in related \ufb01elds who can\ncombine creativity with applied science to\ndevelop methods of raising arterial blood\noxygen content to normal levels, even during\nintense exercise, without the burdens\nassociated with current oxygen delivery\nsystems. n\nThis official clinical practice guideline was prepared by an ad hoc subcommittee of the ATS Assembly on Nursing.\nMembers of the subcommittee are as\nfollows:\nSUSAN S. JACOBS, R.N., M.S.1\n(Co-Chair)\nANNE E. HOLLAND, P.T., PH.D.2\n(Co-Chair)\nJERRY A. KRISHNAN, M.D., PH.D.3\n(Co-Chair)\nDAVID J. LEDERER, M.D.4,5\n(Co-Chair)\nBRIAN CARLIN, M.D.6\nM. BRADLEY DRUMMOND, M.D., M.H.S.7\nMAGNUS EKSTRO\u0308M, M.D., PH.D.8\nCHRIS GARVEY, F.N.P., M.S.N., M.P.A.9\nMARYA GHAZIPURA, PH.D., M.S.10\n*\nBRIDGET A. GRANEY, M.D.11\nTANZIB HOSSAIN, M.D., M.S.10\u2021\nBEVERLY JACKSON, M.S.12x\nTHOMAS KALLSTROM, M.B.A., R.R.T.13\nSHANDRA L. KNIGHT, M.S.14k\nKATHLEEN LINDELL, PH.D., R.N.15\nVALENTIN PRIETO-CENTURION, M.D.3\nELISABETTA A. RENZONI, M.D., PH.D.16\nCHRISTOPHER J. RYERSON, M.D., M.A.S.17\nANN SCHNEIDMAN, M.S., C.N.S., C.H.P.N.18\nJEFFREY SWIGRIS, D.O., M.S.14\nAI-YUI M. TAN, M.D.3\u2021\nDONA UPSON, M.D., M.A.19\n*Lead methodologist.\n\u2021\nMethodologist.\nx\nPatient representative.\nk\nMedical librarian.\n1\nStanford University, Stanford, California; 2\nAlfred\nHealth, Monash University, Melbourne, Victoria,\nAustralia; 3\nUniversity of Illinois at Chicago,\nChicago, Illinois; 4\nRegeneron Pharmaceuticals,\nInc., Tarrytown, New York; 5\nColumbia University,\nNew York, New York; 6\nSleep Medicine and Lung\nHealth Consultants, Sewickley, Pennsylvania;\n7\nUniversity of North Carolina at Chapel Hill,\nChapel Hill, North Carolina; 8\nLund University,\nLund, Sweden; 9\nUniversity of California, San\nFrancisco, San Francisco, California; 10\nNew\nYork University Langone Health, New York\nUniversity, New York, New York; 11\nAnschutz\nMedical Campus, University of Colorado,\nAurora, Colorado; 12\nLAM Foundation,\nCincinnati, Ohio; 13\nAmerican Association for\nRespiratory Care, Irving, Texas; 14\nNational\nJewish Health, Denver, Colorado; 15\nUniversity\nof Pittsburgh, Pittsburgh, Pennsylvania; 16\nRoyal\nBrompton Hospital, London, United Kingdom;\n17\nUniversity of British Columbia, Vancouver,\nBritish Columbia, Canada; 18\nHospice of the\nValley, Phoenix, Arizona; and 19\nNew Mexico\nVeterans Affairs Health Care System,\nAlbuquerque, New Mexico\nAuthor Disclosures: S.S.J. served on an\nadvisory committee for the Pulmonary Fibrosis\nFoundation. A.E.H. served as a speaker for\nAstraZeneca and received research support\nfrom Air Liquide and Linde Healthcare.\nJ.A.K. served on a data safety and monitoring\nboard for Sanofi and received research\nsupport from Inogen, Patient-Centered\nOutcomes Research Institute, and ResMed.\nD.J.L. served on an advisory committee for\nBoehringer Ingelheim, Fibrogen, Galapagos,\nGenentech\/Roche, and Veracyte; served as a\nconsultant for Fibrogen, Galapagos, Galecto,\nGenentech\/Roche, Patara, the Pulmonary\nFibrosis Foundation, Sanofi, and Veracyte;\nreceived research support from Boehringer\nIngelheim, Fibrogen, and Global Blood\nTherapeutics; and is an employee of and\nowns stock and stock options with Regeneron.\nB.C. served on an advisory committee for\nAstraZeneca, GlaxoSmithKline, Monaghan,\nand Sunovion; served as a consultant for\nGlaxoSmithKline and Monaghan; and served\nas a speaker for GlaxoSmithKline, Monaghan,\nand Sunovion. M.B.D. served on an advisory\ncommittee for AstraZeneca, Boehringer\nIngelheim, GlaxoSmithKline, and Mylan; served\nas a consultant for AstraZeneca, Enterprise\nTherapeutics, GlaxoSmithKline, NovaVax,\nParion, Philips Respironics, and Theravance;\nreceived research support from Boehringer\nIngelheim; and received author royalties from\nKarger Publishing. C.G. served on an advisory\ncommittee, as a consultant, and as a speaker\nfor Boehringer Ingelheim. V.P.-C. received\nresearch support from ResMed and is an\nemployee of Vertex. E.A.R. served on\nan advisory committee for Roche; served\nas a speaker for Boehringer Ingelheim,\nMundipharma, and Roche; and received\ntravel support from Boehringer Ingelheim.\nC.J.R. served on an advisory committee for\nBoehringer Ingelheim and received research\nsupport from and served as a speaker for\nBoehringer Ingelheim and Roche. J.S. served as\na consultant for Boehringer Ingelheim; served on\nan advisory committee, served as a speaker for,\nand received research support from Boehringer\nIngelheim and Genentech; and served on the\nboard of directors and has an intellectual\nproperty\/patent unsold for Live Fully, Inc. M.E.,\nM.G., B.A.G., T.H., B.J., T.K., S.L.K., K.L., A.S.,\nA.-Y.M.T., and D.U. reported no relationships\nwith relevant commercial interests.\nAcknowledgment: The guideline panel thanks\nthe ATS staff for their organization and support,\nwhich was critical to this project\u2019s completion\nand success. The authors also thank panel\nmember Ms. Beverly Jackson for her insightful\ncontributions as an oxygen user and as an\nadvocate for those using home oxygen. The\npanel thanks the LOTT authors\u2019 sharing of their\nimportant data on patients with exertion-only\nhypoxemia and thanks the authors of the Moore\nand colleagues 2011 study (51) for providing\nadditional study information.\nAMERICAN THORACIC SOCIETY DOCUMENTS\nAmerican Thoracic Society Documents e137\nReferences\n1. Doherty DE, Petty TL, Bailey W, Carlin B, Cassaburi R, Christopher K,\net al. Recommendations of the 6th long-term oxygen therapy\nconsensus conference. Respir Care 2006;51:519\u2013525.\n2. Croxton TL, Bailey WC. Long-term oxygen treatment in chronic\nobstructive pulmonary disease: recommendations for future research:\nan NHLBI workshop report. Am J Respir Crit Care Med 2006;174:\n373\u2013378.\n3. Nocturnal Oxygen Therapy Trial Group. Continuous or nocturnal oxygen\ntherapy in hypoxemic chronic obstructive lung disease: a clinical trial.\nAnn Intern Med 1980;93:391\u2013398.\n4. Stuart-Harris C. 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Available from:\nhttps:\/\/www.faa.gov\/about\/initiatives\/cabin_safety\/portable_\noxygen\/.\nAMERICAN THORACIC SOCIETY DOCUMENTS\nAmerican Thoracic Society Documents e141","pure_content":"AMERICAN THORACIC SOCIETY\nDOCUMENTS\nHome Oxygen Therapy for Adults with Chronic Lung Disease\nAn Of\ufb01cial American Thoracic Society Clinical Practice Guideline\nSusan S. Jacobs, Jerry A. Krishnan, David J. Lederer, Marya Ghazipura, Tanzib Hossain, Ai-Yui M. Tan, Brian Carlin,\nM. Bradley Drummond, Magnus Ekstro\u0308m, Chris Garvey, Bridget A. Graney, Beverly Jackson, Thomas Kallstrom,\nShandra L. Knight, Kathleen Lindell, Valentin Prieto-Centurion, Elisabetta A. Renzoni, Christopher J. Ryerson,\nAnn Schneidman, Jeffrey Swigris, Dona Upson, and Anne E. Holland; on behalf of the American Thoracic Society\nAssembly on Nursing\nTHIS OFFICIAL CLINICAL PRACTICE GUIDELINE OF THE AMERICAN THORACIC SOCIETY WAS APPROVED SEPTEMBER 2020\nBackground: Evidence-based guidelines are needed for effective\ndelivery of home oxygen therapy to appropriate patients with chronic\nobstructive pulmonary disease (COPD) and interstitial lung disease\n(ILD).\nMethods: The multidisciplinary panel created six research questions\nusing a modi\ufb01ed Delphi approach. A systematic review of the\nliterature was completed, and the Grading of Recommendations\nAssessment, Development and Evaluation approach was used to\nformulate clinical recommendations.\nRecommendations: The panel found varying quality and\navailability of evidence and made the following judgments: 1) strong\nrecommendations for long-term oxygen use in patients with COPD\n(moderate-quality evidence) or ILD (low-quality evidence) with\nsevere chronic resting hypoxemia, 2) a conditional recommendation\nagainst long-term oxygen use in patients with COPD with moderate\nchronic resting hypoxemia, 3) conditional recommendations for\nambulatory oxygen use in patients with COPD (moderate-quality\nevidence) or ILD (low-quality evidence) with severe exertional\nhypoxemia, 4) a conditional recommendation for ambulatory liquid-\noxygen use in patients who are mobile outside the home and require\n.3 L\/min of continuous-\ufb02ow oxygen during exertion (very-low-\nquality evidence), and 5) a recommendation that patients and their\ncaregivers receive education on oxygen equipment and safety (best-\npractice statement).\nConclusions: These guidelines provide the basis for evidence-based\nuse of home oxygen therapy in adults with COPD or ILD but\nalso highlight the need for additional research to guide clinical\npractice.\nKeywords: mobility; hypoxemia; quality of life; chronic\nobstructive pulmonary disease; interstitial lung disease\nContents\nSummary of Recommendations\nChronic Obstructive Pulmonary\nDisease\nInterstitial Lung Disease\nLiquid Oxygen\nEducation and Safety\nIntroduction\nMethods\nResults\nQuestion 1: Should long-term\noxygen be prescribed for adults\nwith COPD who have severe\nchronic resting room air\nhypoxemia?\nQuestion 2: Should long-term\noxygen be prescribed for adults\nwith COPD who have moderate\nchronic resting room air\nhypoxemia?\nQuestion 3: Should ambulatory\noxygen be prescribed for adults\nwith COPD who have severe\nexertional room air hypoxemia?\nQuestion 4: Should long-term\noxygen be prescribed for adults\nwith ILD who have severe\nchronic resting room air\nhypoxemia?\nQuestion 5: Should ambulatory\noxygen be prescribed to adults\nwith ILD who have severe\nexertional room air hypoxemia?\nQuestion 6: Should portable LOX be\nprovided for adults with chronic\nlung disease who are prescribed\ncontinuous oxygen \ufb02ow rates of\n>3 L\/min during exertion?\nEducation and Safety Considerations\nPanel Discussion\nATS Recommendation\nConclusions\nORCID IDs: 0000-0002-8808-0038 (S.S.J.); 0000-0001-5525-4778 (J.A.K.); 0000-0001-5258-0228 (D.J.L.); 0000-0003-4328-6822 (M.G.);\n0000-0002-1995-7828 (T.H.); 0000-0003-1271-8792 (A.-Y.M.T.); 0000-0002-6968-4610 (M.B.D.); 0000-0002-7227-5113 (M.E.);\n0000-0002-8239-9427 (B.A.G.); 0000-0002-4404-3833 (S.L.K.); 0000-0002-3964-5063 (K.L.); 0000-0002-1118-797X (E.A.R.);\n0000-0003-1049-393X (C.J.R.); 0000-0002-2643-8110 (J.S.); 0000-0002-6310-3520 (D.U.); 0000-0003-2061-845X (A.E.H.).\nAm J Respir Crit Care Med Vol 202, Iss 10, pp e121\u2013e141, Nov 15, 2020\nCopyright \u00a9 2020 by the American Thoracic Society\nDOI: 10.1164\/rccm.202009-3608ST\nInternet address: www.atsjournals.org\nAmerican Thoracic Society Documents e121\nSummary of\nRecommendations\nChronic Obstructive Pulmonary\nDisease\nd In adults with chronic obstructive\npulmonary disease (COPD) who have\nsevere chronic resting room air\nhypoxemia,* we recommend\nprescribing long-term oxygen therapy\n(LTOT) for at least 15 h\/d (strong\nrecommendation, moderate-quality\nevidence).\n*Severe hypoxemia is de\ufb01ned as\nmeeting either of the following criteria:\n1) PaO2\n< 55 mm Hg (7.3 kPa) or\noxygen saturation as measured by pulse\noximetry (SpO2\n) < 88%; 2) PaO2\n= 56\u201359\nmm Hg (7.5\u20137.9 kPa) or SpO2\n= 89%\nplus one of the following: edema,\nhematocrit > 55%, or P pulmonale on\nan ECG.\nd In adults with COPD who have\nmoderate chronic resting room air\nhypoxemia,* we suggest not prescribing\nLTOT (conditional recommendation,\nlow-quality evidence).\n*Moderate hypoxemia is de\ufb01ned as an\nSpO2\nof 89\u201393%.\nd In adults with COPD who have severe\nexertional room air hypoxemia, we\nsuggest prescribing ambulatory oxygen\n(conditional recommendation, moderate-\nquality evidence).\nInterstitial Lung Disease\nd For adults with interstitial lung disease\n(ILD) who have severe chronic resting room\nair hypoxemia, we recommend prescribing\nLTOT for at least 15 h\/d (strong\nrecommendation, very-low-quality evidence).\nd For adults with ILD who have severe\nexertional room air hypoxemia, we\nsuggest prescribing ambulatory oxygen\n(conditional recommendation, low-\nquality evidence).\nLiquid Oxygen\nd In patients with chronic lung disease\nwho are mobile outside of the home and\nrequire continuous oxygen \ufb02ow rates of\n>3 L\/min during exertion, we suggest\nprescribing portable liquid oxygen\n(LOX) (conditional recommendation,\nvery-low-quality evidence).\nEducation and Safety\nd For patients prescribed home oxygen\ntherapy, we recommend that the\npatient and their caregivers receive\ninstruction and training on the use and\nmaintenance of all oxygen equipment\nand education on oxygen safety,\nincluding smoking cessation, \ufb01re\nprevention, and tripping hazards (best-\npractice statement).\nIntroduction\nFive million adults live with chronic lung\ndisease in the United States, with more than\none million prescribed LTOT (1, 2), de\ufb01ned\nas oxygen prescribed for at least 15 h\/d. The\nrationale for the provision of LTOT in\nadults is based on the survival bene\ufb01t\nreported by two randomized clinical trials\n(RCTs) published over three decades ago in\npatients with COPD and severe, chronic\nhypoxemia (3, 4). Since then, an additional\nclinical trial has examined the role of home\noxygen therapy in patients with COPD and\nmoderate resting hypoxemia or exertion-\nonly hypoxemia (LOTT [Long-Term\nOxygen Therapy Trial]) (5).\nAlthough several professional societies\nand groups have published clinical practice\nguidelines for home oxygen therapy (6\u201312),\nmost have not incorporated the recent\nLOTT results (5). Recent data highlight\nsigni\ufb01cant differences in home oxygen\nneeds and experiences across patients with\ndifferent lung diseases, lifestyles, and\noxygen supply requirements (13\u201316). For\nexample, the physiologic mechanisms of\nhypoxemia differ between obstructive and\nrestrictive lung diseases. The rapid and\nsteep rate of exertional desaturation for\npatients with ILD differs from that of those\nwith COPD (17, 18). These considerations\nhighlight the need for guidelines speci\ufb01c to\nindividuals with COPD and ILD, the two\nmajor diagnosis entities for which oxygen\ntherapy is prescribed (19).\nThe 2017 American Thoracic Society\n(ATS) workshop on optimizing home oxygen\ntherapy identi\ufb01ed the lack of evidence-based\nclinical practice guidelines for appropriate\nuse of home oxygen as a critical gap in the\ncare of patients (20). Workshop proceedings\nsuggested a need for additional research on\nportable oxygen technology, advocacy for\nimproved \ufb01nancing of oxygen therapy, and\nupdated guidelines to guide policy, advocacy,\nand practice, as none currently exist in the\nUnited States.\nOur aim was to conduct a rigorous and\nsystematic review and develop clinical\nguidelines targeting healthcare providers\nwho care for adults living with chronic lung\ndisease who need oxygen in the community\noutside of inpatient and emergency settings.\nIn applying these guidelines, clinicians\nshould use an interactive, shared decision-\nmaking approach to ensure oxygen\nprescriptions meet the needs of individual\npatients by considering physiology, lifestyle,\nand treatment preferences. The systematic\nreview underpinning this guideline did not\nspeci\ufb01cally address supplemental oxygen\nuse for patients with acute hypoxemia or for\npatients with signs of cor pulmonale,\npulmonary hypertension (PH), or\npolycythemia. However, the panel agreed\nthat clinical guidance related to hypoxemia\nand PH should be included when pertinent\nto each question.\nMethods\nThis clinical guideline was developed in\naccordance with policies and procedures of\nthe ATS. The guideline panel included 4 co-\nchairs and 18 voting members: 11\npulmonary and\/or critical care physicians, 4\nnurses, 1 registered respiratory therapist,\nand 1 physiotherapist. To capture the\ncritical input of an oxygen user, the panel\nincluded a patient representative (Box 1).\nWe used the Grading of Recommendations\nAssessment, Development and Evaluation\n(GRADE) approach to appraise the quality\nAn Executive Summary of this document is available at http:\/\/www.atsjournals.org\/doi\/suppl\/10.1164\/rccm.202009-3608ST.\nYou may print one copy of this document at no charge. However, if you require more than one copy, you must place a reprint order. Domestic reprint orders:\namy.schriver@sheridan.com; international reprint orders: louisa.mott@springer.com.\nCorrespondence and requests for reprints should be addressed to Susan S. Jacobs, M.S., R.N., Division of Pulmonary, Allergy and Critical Care, Department of\nMedicine, Stanford University, 300 Pasteur Drive, Stanford, CA 94035. E-mail: ssjpulm@stanford.edu.\nThis document has an online supplement, which is accessible from this issue\u2019s table of contents at www.atsjournals.org.\nAMERICAN THORACIC SOCIETY DOCUMENTS\ne122 American Journal of Respiratory and Critical Care Medicine Volume 202 Number 10 | November 15 2020\nof evidence and to formulate and grade\nrecommendations (Tables 1 and 2) (21). We\nadopted a published terminology for home\noxygen therapy (Table 3) (22). For the\nsystematic review to June 2019, we de\ufb01ned\nsevere hypoxemia as having an SpO2\n< 88%\nas assessed by pulse oximetry or having an\nPaO2\n< 55 mm Hg (7.3 kPa) as assessed by\nblood-gas sampling, and we de\ufb01ned\nmoderate hypoxemia as having an SpO2\n88\u201393% or PaO2\n56\u201360 mm Hg (7.5\u20137.8\nkPa). We de\ufb01ned severe exertional\nhypoxemia as having SpO2\n< 88% on\nexertion. However, we found substantial\nvariability in de\ufb01nitions for severe\nhypoxemia across studies, and the data were\nnot reported in a way that would allow\nreanalysis of outcomes at different\nthresholds. Thus, we also considered studies\nusing different thresholds and reported the\nde\ufb01nitions of severe and moderate\nhypoxemia used by study authors. We have\nprovided suggested thresholds for\nhypoxemia in the implementation-\nconsideration sections. Potential con\ufb02icts\nof interest were disclosed and managed in\naccordance with the policies and\nprocedures of the ATS (see Table E1 in\nthe online supplement). The online\nsupplement provides a detailed\ndescription of the methods.\nResults\nAfter a systematic literature review, the\nguideline panel created \ufb01nal\nrecommendations on the basis of the\navailable evidence. Table 4 summarizes these\n\ufb01ndings for questions related to patients\nwith COPD and ILD as well as for questions\nrelated to the use of LOX. A best-practice\nstatement was included to address education\nand safety needs for all home oxygen users.\nQuestion 1: Should long-term oxygen\nbe prescribed for adults with COPD\nwho have severe chronic resting\nroom air hypoxemia?\nBackground. Hypoxemia is common in\npeople with COPD, particularly those with\nmore advanced disease, because of\nworsening _\nV= _\nQ mismatch and decreased\ndiffusion capacity. In some patients,\nhypoxemia can be suf\ufb01ciently severe to\noccur at rest and is associated with dyspnea,\nworsening neurocognitive function, PH,\nand mortality (22, 23).\nIn 1917, Haldane described the\ntherapeutic potential of providing\nsupplemental oxygen (24). Since then,\nseveral studies have examined the role\nof oxygen therapy in patients with\nCOPD. \u201cLTOT\u201d refers to supplemental\noxygen for a period of years, and in\nmost cases for the remainder of the patient\u2019s\nlife (Table 3). LTOT can be delivered\nthrough a combination of stationary\nequipment (e.g., stationary oxygen\nconcentrator and liquid reservoirs) and\nambulatory oxygen equipment\n(e.g., compressed-oxygen cylinders, portable\noxygen concentrators [POCs], and LOX\ncanisters) (Figure 1). In this section, we\ndiscuss the role of LTOT for adults with\nCOPD and severe resting hypoxemia. The\ncritical outcome for this question was\nmortality, and important outcomes included\ndyspnea, healthcare resource use, exercise\ncapacity, fatigue, health-related quality of life\n(HRQL), physical activity, and safety.\nDescription of the evidence and its\nquality. We included \ufb01ve studies (two RCTs\n[3, 4]), one pre- versus postintervention\nstudy (25), and two observational studies (26,\n27) (see the SUMMARY OF STUDIES and Table\nE2 in the online supplement). Severe resting\nhypoxemia was de\ufb01ned as a PaO2\n< 55 mm\nHg (7.3 kPa) or a PaO2\n< 59 mm Hg (7.9\nkPa) plus one of the following: edema,\nhematocrit> 55%, or P pulmonale on ECG\nin the NOTT (Nocturnal Oxygen Therapy\nTrial) (3); or was de\ufb01ned as a PaO2\nof\n40\u201360 mm Hg (5.3\u20138.0 kPa) in patients with\nat least one prior episode of ankle edema in\nthe MRC (Medical Research Council) study\n(4). In the pre- versus postintervention\nstudy, eligibility criteria were not reported;\nparticipants (n = 6) had a PaO2\nof\n41.5\u201346.5 mm Hg (5.5\u20136.2 kPa) (25). The\nobservational studies enrolled individuals\nwith a PaO2\n< 55 mm Hg (7.3 kPa) (26, 27).\nTable 1. Certainty of Evidence\nEvidence Quality De\ufb01nition\nHigh High con\ufb01dence that the estimated effect is close to\nthe true effect.\nModerate Moderate con\ufb01dence that the estimated effect is\nclose to the true effect, but with a chance that the\ntrue effect is considerably different.\nLow Low con\ufb01dence in the estimated effect. Higher\nlikelihood that the true effect is considerably\ndifferent from the estimated effect.\nVery low Very low con\ufb01dence in the estimated effect. High\nlikelihood that the true effect is considerably\ndifferent from the estimated effect.\nBox 1\n\u201cThe ability to get out of the house and continue my activities is top of the chart\nin importance! There is no way I want to become a couch potato . . . All the\noxygen equipment was \u2018dumped\u2019 on me. I knew nothing and was in a daze. I am sure\nthat the delivery guy gave me some instructions when it was delivered but I retained\nnothing. . . . My \ufb01rst concern was to \ufb01nd a better solution than the shoulder carry bag\nthat the oxygen company provided. I needed to be hands free to play tennis. . . . I spent\na couple of years perfecting my system of how to carry enough tanks to a tennis match\n(requires 6\u20138 tanks). I did a lot of Internet research to \ufb01nd carts or carrying cases for\ntanks. I have settled on a rolling cart that was designed to carry wine bottles to tasting\nparties. Perfect size for 6 tanks . . . It is a pain to have to plan out a day of activities with\noxygen. What is the elevation, how far will I have to walk, how many tanks do I need,\nwhere can I recharge my POC [portable oxygen concentrator]? There may come a day\nwhen you can\u2019t do these things so enjoy every minute you have. When I don\u2019t get\nenough tanks it makes me mad as hell . . . I still do not let down my guard down around\nthe supplier. I never know when their business decisions will again affect my life.\u201d\n\u2014Supplemental home oxygen user\nAMERICAN THORACIC SOCIETY DOCUMENTS\nAmerican Thoracic Society Documents e123\nThere was moderate-quality evidence\non the effects of LTOT on mortality in adults\nwith COPD who have severe, chronic\nresting room air hypoxemia. The RCTs did\nnot employ masking (blinding), but the\nguideline panel did not judge this to be a\nserious risk of bias because the critical\noutcome (mortality) was objective.\nHowever, there was substantial imprecision\nin estimating the treatment effects (Table\nE2). The NOTT (3) study of 203\nparticipants indicates a 2-year mortality-\nrisk reduction of 55% in those prescribed\nLTOT (24 h\/d) compared with control\nsubjects prescribed only nocturnal oxygen\n(relative risk [RR], 0.45; 95% con\ufb01dence\ninterval [CI], 0.25\u20130.81). Similarly, the\nMRC study (4) in 87 participants indicates\na 5-year mortality-risk reduction of 59% in\nthose with LTOT versus no oxygen (RR,\n0.41; 95% CI, 0.17\u20130.98). Data from the\nNOTT and MRC studies were not pooled,\nas they employed different thresholds to\nde\ufb01ne severe hypoxemia, examined\ndifferent durations of home oxygen therapy\n(prescribed 24 h\/d vs. at least 15 h\/d),\nemployed different comparators (nocturnal\noxygen in NOTT; no oxygen in MRC), and\nreported mortality at different time points\n(1- and 2-yr risk [3] and 5-yr risk [4],\nrespectively).\nIn the NOTT study (3), subgroup\nanalysis suggested that LTOT improved\nsurvival compared with nocturnal oxygen in\npatients with a higher PaCO2\n(PaCO2\n> 43 mm\nHg [5.7 kPa]: 21.7% vs. 41.5%; P = 0.002),\nlower arterial pH (pH , 7.40: 16.0% vs.\n42.2%; P = 0.004), lower FVC (FVC , 1.89\nL: 20.8% vs. 43.5%; P = 0.01), more severe\nnocturnal hypoxemia (mean room air\nSaO2\n, 85%: 24.4% vs. 50.0%; P = 0.02),\nlower hematocrit (hematocrit , 47.4%:\n21.7% vs. 41.5%; P = 0.03), lower mean\npulmonary arterial pressure (PAP; mean\nPAP , 27 mm Hg: 17.5% vs. 37.0%,\nP = 0.03), and lower pulmonary vascular\nresistance (PVR; PVR , 279 dyn $ s\/cm5\n:\n12.8% vs. 33.3%; P = 0.03). The NOTT\nauthors were surprised to \ufb01nd smaller\ndifferences in mortality, only bordering\non statistical signi\ufb01cance, between\ncontinuous versus nocturnal oxygen in\nthose with higher baseline hematocrit\n(hematocrit > 47.4%: 24.5% vs. 38.8%;\nP = 0.20), higher PAP (mean\nPAP > 27 mm Hg: 24.0% vs. 39.6%;\nP = 0.14), and higher PVR (PVR > 279\ndyn $ s\/cm5\n: 38.6% vs. 45.2%; P = 0.11). Of\nnote however, the direction in the trend\ntoward improved mortality in these\nindividuals was similar to the trend in those\nwith less impaired hemodynamics, and the\nmean PAP threshold used to separate\nsubgroups (overall group median,\n27 mm Hg) was higher than the one used in\nthe currently accepted de\ufb01nition of PH. In\nthe NOTT study, continuous oxygen\ntherapy was associated with a reduction in\nPVR levels compared with nocturnal\noxygen, but a relationship between greater\nPVR decreases and reduced mortality was\nnot seen, while subgroup numbers were\nsmall. The MRC study did not report\nmortality bene\ufb01ts according to baseline\npulmonary hemodynamic characteristics\n(4) and was presumably enriched for\npatients with PH (at least one previous\nepisode of ankle edema in the inclusion\ncriteria), but a higher PaCO2 and red-cell\nmass were associated with greater mortality.\nThe MRC report (4) also incorrectly stated\n(p. 685) that participants in the NOTT\nstudy with higher baseline hematocrit or\nPAP derived the most bene\ufb01t from LTOT\nversus nocturnal oxygen. In light of the\ncaveats listed above, it is not possible to\ndraw \ufb01rm conclusions on the differential\neffects of LTOT in patients with\nconcomitant PH. A particular unanswered\nquestion is whether a lower threshold for\nstarting LTOT could be of bene\ufb01t for\npatients with early pulmonary\nhemodynamic impairment, an area in need\nof further research.\nThere was very-low-quality evidence on\nthe effects of LTOT on healthcare use. One\nretrospective study (26) found fewer\nhospitalizations over 3 years for participants\nusing LTOT compared with conventional\ntherapy (mean difference [MD], 21.17; 95%\nCI, 21.73 to 20.59). An observational study\n(27) did not \ufb01nd a reduction in admission\nrisk once patients began receiving LTOT\n(RR, 0.70; 95% CI, 0.15 to 3.30). There was a\n35% reduction in hospital-bed days per\npatient year of follow-up in patients\nreceiving LTOT, but this was not statistically\nsigni\ufb01cant (RR, 0.65; 95% CI, 0.40 to 1.05).\nTable 2. Implications of Clinical Guideline Recommendations by Stakeholder\nStakeholder Strong Recommendation Conditional Recommendation\nPatient The majority of patients would want the\nrecommended course of action in this situation,\nand only a small number would not.\nMany patients in this situation would prefer the\nrecommendation, but a substantial number may\nnot. This is an opportunity for shared\ndecision-making between the clinician and patient.\nClinician Most individuals should receive the course of\naction that is recommended. There is a low\nchance that additional formal decision aids are\nneeded to help individuals make decisions\nconsistent with their values and preferences, and\nadherence to this recommendation could be\nused as a performance indicator or quality\ncriterion.\nDifferent choices will be applicable to different\npatients, and additional factors will need to be\nconsidered in addition to the recommendation in\norder for a patient to make a decision according to\ntheir values and preferences. Decision aids may be\nneeded to assist individuals in making their best\nchoice. This is an opportunity for shared\ndecision-making between the clinician and patient.\nPolicy-maker The recommendation can be widely adapted as\npolicy and can be used for performance\nindicators.\nPolicy-making will require substantial additional\ndebate and involvement of many and\/or additional\nstakeholders. The likelihood of regional variance is\nalso higher, and performance indicators would\nneed to take into consideration any additional\ndeliberation that has occurred.\nAMERICAN THORACIC SOCIETY DOCUMENTS\ne124 American Journal of Respiratory and Critical Care Medicine Volume 202 Number 10 | November 15 2020\nFor the outcome of safety, the\nsystematic review identi\ufb01ed cases of \ufb01res,\nburns from smoking around oxygen\nequipment, nosebleeds, and tripping over\nthe equipment (28). For all COPD Medicare\nbene\ufb01ciaries who used home oxygen\n(LTOT, exertion only or sleep only), those\nwho had an emergency room visit for a\nburn injury were twice (odds ratio [OR],\n2.43; 95% CI, 1.57\u20133.78) as likely to be\nprescribed oxygen in the preceding 90 days\ncompared with those without burn injury\n(29). The LOTT trial found that for every\n100 person-years the rate of \ufb01res was 0.08,\nthe rate of burns from smoking around\noxygen equipment was 0.12, the rate of\nburns from oxygen around an open \ufb02ame\nwas 0.04, the rate of burns from LOX frost\nwas 0.16, the rate of nosebleeds was 0.35,\nand the rate of tripping or falling over\noxygen equipment was 0.90 (5). These\nsafety data from LOTT were for\nparticipants with moderate hypoxemia who\nwere prescribed continuous oxygen or\noxygen during both exertion and sleep.\nPanel judgments. DESIRABLE\nCONSEQUENCES AND THEIR MAGNITUDES\n(BENEFITS). The panel concluded that the size\nof the desirable anticipated effects on\nmortality is large. LTOT was associated with\ndecreased 2-year and 5-year mortality\n(critical outcome). There was insuf\ufb01cient\nevidence to evaluate the effects of LTOT on\nhealthcare use or other important outcomes.\nUNDESIRABLE CONSEQUENCES AND THEIR\nMAGNITUDES (HARMS). The panel concluded\nthat there is a moderate level of undesirable\nanticipated effects of LTOT. Patients report a\nphysical and mental burden of using oxygen\nequipment with reduced ability to travel\noutside of the home, dif\ufb01culty obtaining\ninformation about appropriate access to\noxygen equipment during travel, and\nequipment noise from the use of stationary\noxygen equipment, affecting sleep (10, 30).\nRationale for the recommendation. The\npanel concluded that the balance of\ndesirable and undesirable effects supported\nthe use of LTOT in patients with COPD\nassociated with severe resting hypoxemia.\nThe NOTT trial (3) reported that patients\nwith severe hypoxemia associated with\nventilatory compromise (on the basis of\nPaCO2, arterial pH, and FVC) and milder\ndisturbances in pulmonary hemodynamics\n(on the basis of PVR and PAP) may be\nmore likely to bene\ufb01t from LTOT.\nHowever, these were subgroup analyses,\nand similar analyses were not performed in\nthe MRC study (4), so the panel concluded\nthat there is insuf\ufb01cient evidence to\nrecommend preferentially prescribing\nLTOT to speci\ufb01c subgroups of patients with\nCOPD and severe hypoxemia.\nGiven the variability in reimbursement\nrates for medical expenses in the United\nStates, it is dif\ufb01cult to project the true cost\nper person for LTOT. In the United States,\nMedicare typically covers 80% of the\nMedicare-approved amount (31). However,\ncosts may vary depending on the payor.\nThe incremental cost-effectiveness ratio for\nLTOT was $16,124 per quality-adjusted life\nyear in the United States, which is within\nthe bounds considered to be cost-effective\n(32). Cost variables were based on the\nMedicare reimbursement rate for the 2009\npublished study and on appropriate sources\n(32). On the basis of these considerations,\nthe panel concluded that cost-effectiveness\nfavors the use of LTOT. Because COPD\ndisproportionately affects minority and\nlow-income populations, a standardized\napproach to prescribing LTOT will\nprobably increase health equity.\nLTOT is probably acceptable to most\npatients with COPD and severe chronic\nhypoxemia. LTOT is a widely recognized\nand recommended therapy for patients with\nTable 3. Terminology for Home Oxygen Therapy\nTerm De\ufb01nition\nAmbulatory oxygen Oxygen delivered during exercise or activities of daily\nliving.\nContinuous-\ufb02ow oxygen Oxygen delivered at a constant \ufb02ow rate, regardless\nof the respiratory rate, in contrast to pulse-dose\noxygen (see below).\nContinuous oxygen Oxygen prescribed 24 h\/d.\nHome oxygen Oxygen delivered in a home, also known as\ndomiciliary oxygen. It includes not only long-term\noxygen but also short-term, nocturnal, palliative,\nambulatory, and short-burst oxygen. It excludes\noxygen use in healthcare and emergency settings.\nLong-term oxygen Oxygen that is delivered to patients with chronic\nhypoxemia, in most cases for the remainder of the\npatient\u2019s life. Long-term oxygen therapy is\nprescribed for at least 15 h\/d.\nNocturnal oxygen Oxygen delivered during sleep time only.\nPalliative oxygen Oxygen to relieve dyspnea. Palliative oxygen may be\nprovided continuously, nocturnally, or during\nambulation. Short-burst oxygen therapy falls into\nthis category.\nPortable oxygen Oxygen delivered through systems that are\nsuf\ufb01ciently lightweight so that they can be carried\nor pulled by patients and allow them to leave their\nhome (e.g., oxygen cylinders or canisters carried or\npulled in trolleys or portable oxygen\nconcentrators).\nPulse-dose oxygen Oxygen delivered during inspiration only in such a\nway that the quantity of oxygen administered is\nin\ufb02uenced by the respiratory rate. The delivery\nsystem is at rest while the patient is exhaling.\nShort-burst oxygen Brief and intermittent oxygen administration before\nand\/or after exercise, generally used as needed, in\nthe absence of known hypoxemia.\nShort-term oxygen therapy Oxygen provided temporarily, during a period of\nsevere hypoxemia (e.g., during the course of and\nshortly after an exacerbation of COPD).\nDefinition of abbreviation: COPD = chronic obstructive pulmonary disease.\nThere are several types of home oxygen therapy. This table is provided to assist in standardizing the\nterminology and is adapted by permission from Reference 22.\nAMERICAN THORACIC SOCIETY DOCUMENTS\nAmerican Thoracic Society Documents e125\nCOPD and severe resting hypoxemia (7, 11,\n12). Although oxygen is generally available,\nthe main barrier in the United States is cost.\nThis varies internationally, with some\ncountries reporting higher direct costs of\noxygen for COPD care than others (33). In\naddition, reimbursement can vary by region,\nparticularly because of the requirements that\nmust be met for funding (34, 35).\nThe NOTT and MRC studies tested two\ndifferent durations of LTOT and two\ndifferent comparators for LTOT (NOTT:\nLTOT prescribed for a duration of 24 h\/d vs.\nLTOT prescribed for a duration 12 h\/d;\nMRC: LTOT prescribed for a duration of at\nleast 15 h\/d vs. no oxygen prescribed) in\npatients with COPD and severe resting\nhypoxemia. From these two studies, we\nknow that prescribing LTOT for at least\n15 h\/d is superior to prescribing no oxygen\nand that prescribing LTOT for 24 h\/d is\nlikely superior to prescribing the therapy for\n12 h\/d, as assessed by mortality. We do not\nknow if prescribing LTOT for at least 15 h\/d\nis superior to prescribing it for 12 h\/d (no\nstudies compared these two interventions\ndirectly) on the basis of mortality. On the\nbasis of these considerations and the\npotential for a longer duration of LTOT use\nper day to be a patient burden, the panel\nbelieves that prescribing LTOT for at least\n15 h\/d is justi\ufb01ed in patients with COPD\nand severe resting hypoxemia.\nATS recommendation. In adults with\nCOPD who have severe chronic resting room\nair hypoxemia, we recommend prescribing\nTable 4. Summary of ATS Recommendations\nQuestion ATS Recommendation\nStrength of Recommendation and Level\nof Evidence\nCOPD\nQuestion 1: Should long-term oxygen be\nprescribed for adults with COPD who\nhave severe* chronic resting room air\nhypoxemia?\nIn adults with COPD who have severe\nchronic resting room air hypoxemia, we\nrecommend prescribing LTOT for at least\n15 h\/d.\nStrong recommendation, moderate-quality\nevidence\nQuestion 2: Should long-term oxygen be\nprescribed for adults with COPD who\nhave moderate\u2020\nchronic resting room air\nhypoxemia?\nIn adults with COPD who have moderate\nchronic resting room air hypoxemia, we\nsuggest not prescribing LTOT.\nConditional recommendation, low-quality\nevidence\nQuestion 3: Should ambulatory oxygen be\nprescribed for adults with COPD who\nhave severe exertional room air\nhypoxemia?\nIn adults with COPD who have severe\nexertional room air hypoxemia, we\nsuggest prescribing ambulatory oxygen.\nConditional recommendation,\nmoderate-quality evidence\nILD\nQuestion 4: Should long-term oxygen be\nprescribed for adults with ILD who have\nsevere chronic resting room air\nhypoxemia?\nFor adults with ILD who have severe\nchronic resting room air hypoxemia, we\nrecommend prescribing LTOT for at least\n15 h\/d.\nStrong recommendation, very-low-quality\nevidence\nQuestion 5: Should ambulatory oxygen be\nprescribed for adults with ILD who have\nsevere exertional room air hypoxemia?\nFor adults with ILD who have severe\nexertional room air hypoxemia, we\nsuggest prescribing ambulatory oxygen.\nConditional recommendation, low-quality\nevidence\nLiquid oxygen\nQuestion 6: Should portable liquid oxygen\nbe provided for adults with chronic lung\ndisease who are prescribed continuous\noxygen \ufb02ow rates of .3 L\/min during\nexertion?\nIn patients with chronic lung disease who\nare mobile outside of the home and\nrequire continuous oxygen \ufb02ow rates of\n.3 L\/min during exertion, we suggest\nprescribing portable liquid oxygen.\nConditional recommendation,\nvery-low-quality evidence\nEducation\nEducation and safety for patients and\ncaregivers\nFor all patients prescribed home oxygen\ntherapy, we recommend that the patient\nand their caregivers receive instruction\nand training on the use and maintenance\nof all oxygen equipment and education on\noxygen safety, including smoking\ncessation, \ufb01re prevention, and tripping\nhazards.\nBest-practice statement\nDefinition of abbreviations: ATS = American Thoracic Society; COPD = chronic obstructive pulmonary disease; ILD = interstitial lung disease;\nLTOT = long-term oxygen therapy.\n*On the basis of two clinical trials (3, 4), severe hypoxemia is defined as meeting either of the following criteria: 1) PaO2\n< 55 mm Hg (7.3 kPa) or oxygen\nsaturation as measured by pulse oximetry (SpO2\n) < 88% or 2) PaO2\n= 56\u201359 mm Hg (7.5\u20137.9 kPa) or SpO2\n= 89% plus one of the following: edema,\nhematocrit > 55%, or P pulmonale on an ECG.\n\u2020\nOn the basis of a single clinical trial (5), moderate hypoxemia is defined as an SpO2\nof 89\u201393%. The corresponding PaO2\nwas not reported in that study.\nAMERICAN THORACIC SOCIETY DOCUMENTS\ne126 American Journal of Respiratory and Critical Care Medicine Volume 202 Number 10 | November 15 2020\nLTOT for at least 15 h\/d (strong\nrecommendation, moderate-quality evidence).\nWhat others are saying. A 2015 British\nThoracic Society (BTS) guideline recommends\nthat patients with stable COPD and severe\nresting hypoxemia (PaO2\n< 55 mm Hg [7.3\nkPa]), or with a resting PaO2\n< 60 mm Hg\n(8.0 kPa) with evidence of peripheral edema,\nhematocrit> 55, or PH, should be considered\nfor LTOT because of its survival bene\ufb01ts\nand potential to improve pulmonary\nhemodynamics (36). They recommend\nLTOT be used for 15\u201324 h\/d (36). The\nThoracic Society of Australia and New\nZealand (TSANZ) recommends titrating\noxygen to maintain a PaO2\n. 60 mm Hg\n(8.0 kPa) or an SpO2\n. 90% during waking at\nrest (9, 37). The Global Initiative for Chronic\nLung Disease (GOLD) report recommends\nLTOT if SpO2\nis <88% and recommends\noxygen titration to maintain a saturation of\n>90% in patients with COPD (12).\nImplementation considerations. Severe\nhypoxemia was de\ufb01ned using different\nthresholds in the two RCTs that reported our\ncritical outcome of survival (PaO2\n< 55 mm\nHg [7.3 kPa] or PaO2\n< 59 mm Hg [7.9 kPa]\nplus one of the following: edema,\nhematocrit > 55%, or P pulmonale on ECG\n[3]; vs. PaO2\n40\u201360 mm Hg [5.3\u20138.0 kPa]\n[4]). Because a mortality bene\ufb01t was\ndemonstrated in both studies, the panel\nconcluded that either de\ufb01nition of severe\nhypoxemia is clinically justi\ufb01ed.\nNeither clinical trial reported SpO2\n-based\nthresholds for severe hypoxemia. We\nrecognize that the relationship between SpO2\nand PaO2\ncan vary because of an individual\u2019s\npH, 2,3-diphosphoglycerate concentration,\nPaCO2\n, and temperature. However, the\nguideline panel concluded that providing\napproximate thresholds for SpO2\nthat\ncorrespond to the PaO2\nthresholds used in the\nNOTT and MRC studies would improve\nthe usability of the guideline report in\ncircumstances in which arterial blood gas\nmeasurements were not available. The panel\nsuggests titrating the level of LTOT to achieve\na target saturation of 90%, as opposed to 88%\nin some guidelines, to avoid prolonged\nepisodes of desaturation with minimal activity.\nIn addition, the NOTT and MRC trials\nused slightly different de\ufb01nitions of \u201cchronic.\u201d\nIn the NOTT study (3), chronic was de\ufb01ned\nas meeting the de\ufb01nition of severe\nhypoxemia on \u201cat least two occasions more\nthan 1 week apart over a 3-week observation\nperiod\u201d while the patient was free of\nexacerbations. In the MRC study (4), chronic\nwas de\ufb01ned as meeting the PaO2\n-based\ncriteria for hypoxemia on \u201ctwo repeated\nmeasurements at least 3 weeks apart.\u201d\nFor implementation purposes, we\nde\ufb01ne chronic resting hypoxemia as resting\nhypoxemia in the absence of a reversible\ncause. Although the NOTT and MRC trials\nused de\ufb01nitions that required repeated\nmeasures 3 weeks apart, this may not be\npossible or necessary in clinical practice (for\ninstance, for a patient with idiopathic\npulmonary \ufb01brosis [IPF] who has resting\nhypoxemia as a result of progressive lung\ndisease, without reversible cause). This\ndiffers from the patient who is discharged\nfrom the hospital after a COPD\nexacerbation, in which case resolution of\nresting hypoxemia may occur over time and\nreassessment of oxygen needs is important\nto avoid unnecessary treatment with oxygen.\nReassessment of patients\u2019 oxygen needs\nafter an acute exacerbation is critical.\nRespiratory exacerbations (in some cases\naccompanied by pneumonia, pulmonary\nembolism, or heart failure) usually increase\noxygen requirements (e.g., require higher \ufb02ows\nto maintain an SpO2\nof at least 90%). In\naddition, the pace at which patients recover\npartially or fully from their respiratory\nexacerbations varies and can range from days\nto months, and their oxygen requirements\nmay therefore vary over time. Moreover, a\nsubstantial proportion (perhaps as many as\n50%) of patients who are initiated on home\noxygen at the time of a respiratory exacerbation\nmay recover suf\ufb01ciently to no longer have a\nclinical indication for home oxygen (38, 39).\nPatient education (e.g., how to use new\nequipment, how to titrate oxygen \ufb02ow to\nevolving requirements), oxygen prescriptions,\nand communication with other providers\n(e.g., primary care and home health agencies)\nwould need to match the requirements for\nhome oxygen after a respiratory exacerbation.\nProper reassessment of home oxygen needs\nis so important that it has been identi\ufb01ed as one\nof the top \ufb01ve areas for further improvement in\nadult respiratory medicine by the Choosing\nCompressed Gas Cylinders Liquid Oxygen\nPortable Oxygen Concentrators\nStationary Oxygen Concentrators\nPortable Cylinders\nA\n5\u22128 in\nC\n11 in\nE\n26 in\nD\n16 in\nB\n12 in\nH\n22\u201352 in\nHome Fill Unit\non Top\nReservoir plus\nPortable Canister\nPortable\nCanister\nPortable E\nPortable D\nFigure 1. Examples of stationary and portable oxygen devices in the United States. Illustration by\nPatricia Ferrer Beals.\nAMERICAN THORACIC SOCIETY DOCUMENTS\nAmerican Thoracic Society Documents e127\nWisely Campaign (40). According to the\nTSANZ guideline, patients who commence\nLTOT after a COPD exacerbation should be\nreassessed 4\u20138 weeks after hospital discharge to\nensure continued eligibility (9). In patients\nprescribed home oxygen for severe chronic\nresting room air hypoxemia, the 2020 GOLD\ninitiative recommends reassessing the need for\noxygen after 60\u201390 days; when home oxygen is\nstarted to treat severe hypoxemia after a COPD\nexacerbation, the GOLD initiative recommends\nreassessing the home oxygen requirement at\n1\u20134 weeks and again at 12\u201316 weeks to update\nthe oxygen prescription as clinically indicated\n(12). At the time of reassessments, SpO2\n(or\narterial blood gases) at rest and with exertion\nshould be considered. Ideally, reevaluation\nshould occur at home to capture context and\nbarriers to use. Expert opinion suggests that\npatients should be monitored, at minimum,\nevery 6 months to con\ufb01rm continued oxygen\nuse, a current oxygen prescription, and\nadequacy of the equipment used.\nValues and preferences. This\nrecommendation places a high value on\nreducing mortality and a lower value on cost\nand resource use.\nResearch needs. The practice of\ninitiating short-term oxygen therapy on\nhospital discharge in patients with severe\nhypoxemia is based on indirect evidence from\nthe NOTT and MRC clinical trial populations\nwith chronic hypoxemia. The harms and\nbene\ufb01ts of prescribing short-term oxygen\ntherapy on hospital discharge deserves further\nstudy. The panel recommends studies to\ndevelop and test the acceptability and\neffectiveness of easy-to-use ambulatory\noxygen equipment that can facilitate LTOT\nuse by patients, to identify strategies that\nimprove adherence to LTOT, and to develop\nand test strategies to discontinue home oxygen\nin patients who recover suf\ufb01ciently after an\nexacerbation or no longer have a clinical\nindication for its use. Studies to examine\nwhether some subgroups of patients with\nCOPD and severe hypoxemia (e.g., higher\nhematocrit, higher mean PAP, early\nhemodynamic impairment) are more or less\nlikely to bene\ufb01t from LTOT are also needed.\nQuestion 2: Should long-term oxygen\nbe prescribed for adults with COPD\nwho have moderate chronic resting\nroom air hypoxemia?\nBackground. Some patients with COPD\ndevelop moderate resting room air\nhypoxemia that may be asymptomatic or\nassociated with dyspnea. Moderate\nhypoxemia is rarely mentioned in clinical\nguidelines. In this section, we discuss the\nrole of LTOT for adults with COPD\nassociated with moderate resting\nhypoxemia. For this question, mortality was\nthe critical outcome, and important\noutcomes were dyspnea, COPD\nexacerbation, HRQL, fatigue, physical\nactivity, healthcare resource use, and\nsafety.\nDescription of the evidence and its\nquality. There was only one study, and the\nquality of evidence was considered low\nbecause of imprecision in the estimate of\ntreatment effects for the critical and\nimportant outcomes (see the SUMMARY OF\nSTUDIES and Table E3 in the online\nsupplement). The LOTT study included\nparticipants who had moderate hypoxemia\nat rest (de\ufb01ned as room air SpO2\nof 89\u201393%,\nno PaO2\nthreshold speci\ufb01ed) as well as those\nwith no hypoxemia at rest but desaturation\nonly on exertion (de\ufb01ned as an SpO2\n> 80%\nfor >5 min and ,90% for >10 s during a\n6-min-walk test [6MWT]). No information\nwas provided on the presence of PH. Study\nparticipants with moderate hypoxemia at\nrest were randomly allocated to continuous\nLTOT or no oxygen. Those with isolated\nexertional hypoxemia were randomly\nallocated to LTOT during both exertion\nand sleep or to no oxygen. Unlike the\nNOTT and MRC trials, chronicity\n(hypoxemia sustained over 3 wk in stable\ncondition) was not assessed. As with the\nNOTT and MRC trials, the intervention\nwas not masked (blinded).\nAt the request of the guideline panel, the\nLOTT group conducted additional analyses\ncomparing the risk of death with and without\nLTOT in the subgroup of participants who\nhad moderate resting hypoxemia (n = 419,\n57% of LOTT participants) (Table E3). The\nresults indicated no difference between\ngroups in time to death (hazard ratio [HR],\n0.95; 95% CI, 0.59\u20131.50). A previous smaller\nRCT of 135 patients with COPD by Go\u0301recka\nand colleagues (41) also reported no effect\non mortality with LTOT versus no oxygen in\npatients with PaO2\n56\u201365 mm Hg (7.5\u20138.7\nkPa); the relative hazard of survival was 0.92\n(95% CI, 0.57\u20131.47). This smaller study\nde\ufb01ned moderate hypoxemia on the basis of\nPaO2\nof 56\u201365 mm Hg (no SpO2\nthresholds\nspeci\ufb01ed) and study participants received\nmonthly home visits by a respiratory nurse.\nBecause moderate hypoxemia was de\ufb01ned\ndifferently in the LOTT and Go\u0301recka and\ncolleagues studies, and the study by Go\u0301recka\nand colleagues included intensive home-\nbased follow-up, inclusion in the evidence\ntables and a meta-analysis that included\nboth studies was not considered appropriate.\nThe panel concluded the quality of\nevidence for effects on HRQL was moderate.\nThe St. George\u2019s Respiratory Questionnaire\n(SGRQ) favored the use of LTOT at\n4-month follow-up in those with both\nmoderate resting and exertional\ndesaturation (MD, 23.30; 95% CI, 26.50 to\n20.10). However, no signi\ufb01cant differences\nwere found at 12-month follow-up or in\nthose with only resting desaturation. There\nwere no differences between groups in the\nQuality of Well-Being Scale (5).\nIn the LOTT study, the composite\nendpoint of time to death or \ufb01rst\nhospitalization was not signi\ufb01cantly different\nbetween those in the LTOT group compared\nwith those in the no-LTOT group in those\nwith moderate hypoxemia at rest only (HR,\n0.96; 95% CI, 0.79\u20131.12) or in those with\nmoderate hypoxemia at rest and\ndesaturation with ambulation (HR, 0.95;\n95% CI, 0.72\u20131.27). No study that met our\ninclusion criteria directly reported on the\neffects of LTOT on other outcomes\nconsidered \u201cimportant\u201d by the guideline\npanel (dyspnea, physical activity, fatigue, or\nhealthcare resource use) in participants with\nCOPD and moderate hypoxemia at rest.\nThe LOTT trial reported \ufb01res, burns,\nnosebleeds, and tripping or falling over\noxygen equipment in the study participants\nprescribed LTOT or oxygen during exertion\nand sleep (5); see description of results in\nquestion 1.\nPanel judgments. DESIRABLE\nCONSEQUENCES AND THEIR MAGNITUDES\n(BENEFITS). The panel concluded that the size\nof the desirable anticipated effects on\nmortality (critical outcome) was not\nclinically meaningful. Likewise, the effect on\nHRQL at 12 months was not clinically\nmeaningful. Data were insuf\ufb01cient to\nevaluate other important outcomes (5).\nUNDESIRABLE CONSEQUENCES AND THEIR\nMAGNITUDES (HARMS). In a judgment similar\nto that developed for question 1, the panel\nconcluded that there is a moderate level of\nundesirable anticipated effects of LTOT.\nRationale for the recommendation. The\npanel concluded that the certainty of evidence\nwas moderate and was based on a single clinical\ntrial that used SpO2\nof 89\u201393% to de\ufb01ne\nmoderate hypoxemia. Similar results were\nnoted in a trial by Go\u0301recka and colleagues (41),\nAMERICAN THORACIC SOCIETY DOCUMENTS\ne128 American Journal of Respiratory and Critical Care Medicine Volume 202 Number 10 | November 15 2020\nwhich compared LTOT plus monthly home\nvisits by a nurse versus monthly home visits by\na nurse alone in patients with moderate resting\nhypoxemia as de\ufb01ned by a PaO2\nof\n56\u201365 mm Hg. There was probably no\nimportant uncertainty or variability about how\nmuch people value mortality as the critical\noutcome. Some patients may not experience\nany value added on additional life years if they\nare very ill. However, this is less likely in\npatients with moderate hypoxemia, as they\ntend to have less severe COPD than those with\nsevere resting hypoxemia. The balance between\ndesirable and undesirable effects does not favor\nLTOT in those with moderate hypoxemia.\nATS recommendation. In adults with\nCOPD who have moderate chronic resting\nroom air hypoxemia, we suggest not\nprescribing LTOT (conditional\nrecommendation, low-quality evidence).\nWhat others are saying. Only one\nguideline was found that makes\nrecommendations regarding LTOT in\npatients with moderate resting hypoxemia.\nThe 2020 GOLD document states, \u201cIn\npatients with stable COPD and resting or\nexercise-induced moderate desaturation,\nlong-term oxygen treatment should not be\nprescribed routinely. However, individual\npatient factors must be considered when\nevaluating the patient\u2019s need for\nsupplemental oxygen\u201d (12).\nImplementation considerations. On the\nbasis of the LOTT study, we de\ufb01ned\nmoderate resting hypoxemia as an SpO2\nof\n89\u201393%. The corresponding PaO2\nwas not\nreported (5). The costs and burden of the\ntreatment outweigh the minimal bene\ufb01t of\nLTOT in adults with COPD who have\nmoderate resting room air hypoxemia.\nPatients likely would not choose LTOT on\nthe basis of the lack of bene\ufb01t; they may\ndecide to defer using oxygen at rest until\ntheir resting hypoxemia worsens. The\nLOTT study did not report any data on\npulmonary hemodynamics, and it is\ntherefore not possible to conclude whether\neffects of LTOT in this group of patients\ndiffers according to the presence of PH.\nWhen patients have moderate resting\nhypoxemia, it is an opportunity for shared\ndecision-making between the clinician and\npatient (see Table 2, which discusses the\nsituations that provide an opportunity for\nshared decision-making).\nValues and preferences. This\nrecommendation against LTOT in this\nsetting places a high value on the absence of\na mortality reduction and a lower value on\nshort-term improvement in HRQL (which\nwas observed at 4 mo but not at 12 mo).\nResearch needs. The panel\nrecommends studies on the use of shared\ndecision-making to personalize the use of\nhome oxygen in participants with moderate\nresting hypoxemia, as well as studies\nevaluating the discontinuation of\nsupplemental oxygen in patients who\npreviously had severe resting room air\nhypoxemia but now have moderate resting\nroom air hypoxemia. Con\ufb01rmatory\nevidence is needed to determine the effect of\nLTOT on dyspnea and other outcomes for\npatients with moderate resting hypoxemia.\nQuestion 3: Should ambulatory\noxygen be prescribed for adults with\nCOPD who have severe exertional\nroom air hypoxemia?\nBackground. Exertional hypoxemia occurs\nin up to 40% of people with moderate to\nsevere COPD who have normoxemia at\nrest (42). It is seen most frequently in those\nwith low lung function (FEV1 , 45%,\nDLCO , 50%), in those with low resting\nsaturation (,95%), and in women (42).\nThe imbalance between oxygen delivery and\ndemand is a major contributor (43).\nExertional hypoxemia is linked to more\nrapid decline in lung function, worse HRQL\n(44), and increased mortality. In 576 people\nwith severe COPD followed for at least 3\nyears, mortality in those with isolated\nexertional hypoxemia on a 6MWT was 2.63-\nfold higher than in those without exertional\nhypoxemia (95% CI, 1.53\u20134.51) (45).\n\u201cAmbulatory oxygen\u201d is de\ufb01ned as\noxygen delivered during exercise or activities\nof daily living when the individual is walking\nfreely (Table 3) (22). It is prescribed for\npeople with COPD to improve oxygen\ndelivery during exertion, reduce symptoms,\nand enhance physical capacity. It may be\nprescribed for individuals using LTOT who\nrequire a portable oxygen supply when\nleaving the house or for those with isolated\nexertional hypoxemia. Although the\nbene\ufb01cial effects of supplemental oxygen\nduring laboratory-based exercise tests have\nbeen reported in COPD (46\u201349), clinical\ntrials of ambulatory oxygen used during\ndaily life have had less consistent results\n(50\u201352). There is variation in prescribing\npractices and access to ambulatory oxygen\nacross jurisdictions (10, 51, 52).\nThe prespeci\ufb01ed critical outcome for\nthis question was HRQL; important\noutcomes included dyspnea, fatigue,\nexercise capacity, physical activity,\nmortality, healthcare resource use, and\nsafety.\nDescription of the evidence and its\nquality. Several studies assessed patients\nwith COPD who had severe exertional\ndesaturation (46, 47, 49\u201358), but cohorts\nvaried from those who were on or eligible\nfor LTOT (46, 49, 53\u201355) to those who had\nisolated exertional desaturation (47, 50\u201352,\n56\u201358) (Table E4). The quality of evidence\nwas low. Most studies reported the acute\neffects of oxygen during exercise testing,\nwith only four studies evaluating use of\noxygen during daily life (50\u201352, 55), of\nwhich two were crossover trials (50, 52).\nThere were only two parallel-group RCTs\nof ambulatory oxygen (51, 55), of which\nonly one included blinding to the\nintervention (51). Three additional RCTS\n(48, 59, 60) reported on the effects of\noxygen supplementation during exercise\ntraining, so these were not directly relevant\nto our question; however, two of them (48,\n59) reported baseline data for the acute\neffects of oxygen during an exercise test\nthat we were able to include in our analysis.\nThe LOTT study was not included in this\nreview, as the patients with exertion-only\ndesaturation were required to wear oxygen\nduring sleep as well as during exercise, thus\nnot meeting our de\ufb01nition of ambulatory\noxygen (5). One additional study was\nidenti\ufb01ed in which the degree of exertional\ndesaturation was not speci\ufb01ed, but the\nparticipants were users of LTOT (61). As it\nis likely that these participants would have\nmet our inclusion criteria, this study was\nincluded in the narrative review as indirect\nevidence.\nEvidence for patients with isolated\nexertional desaturation. Several different\ntools were used to measure HRQL. Meta-\nanalysis of three studies (50\u201352) found a\nsmall but signi\ufb01cant improvement in the\ndyspnea-related quality-of-life domain of\nthe Chronic Respiratory Disease\nQuestionnaire (CRQ) (standardized mean\ndifference, 0.42; 95% CI, 0.04\u20130.79;\nI2\n= 12%; n = 211) in favor of ambulatory\noxygen (62). However, the effect size was\nsmall, and the mean number of changes for\nthe CRQ dyspnea domain was generally less\nthan the minimal clinically important\ndifference (MCID) (63) and was of\nuncertain clinical signi\ufb01cance. The number\nof participants in whom changes exceeded\nthe MCID was not reported in any study.\nAMERICAN THORACIC SOCIETY DOCUMENTS\nAmerican Thoracic Society Documents e129\nImprovements with oxygen in individual\nparticipants could not be predicted by\nparticipant characteristics (degree of\nexertional desaturation, severity of air\ufb02ow\nobstruction or dyspnea, volume or exercise\nresponse to hyperoxia, and sex) (51). The\nemotion, fatigue, and mastery domains\nwere not different between the groups. A\nsensitivity analysis strati\ufb01ed by study design\n(crossover trial vs. parallel groups) found\nthat the results remained signi\ufb01cant for the\ndyspnea domain (Table E4 and Figures E1\nand E2).\nOne study assessed HRQL using the\nSGRQ (50). No differences for the\nadministration of supplemental oxygen\nversus compressed room air were\nobserved. However, using the 36-Item\nShort-Form Health Survey, Eaton and\ncolleagues (52) observed a signi\ufb01cant\ndifference in favor of ambulatory oxygen\nin the domains of physical role (MD, 16.8;\n95% CI, 6.02\u201327.58), general health (MD,\n6.1; 95% CI, 0.42\u201311.78), social\nfunctioning (MD, 10.5; 95% CI,\n0.31\u201320.69), and emotional role (MD,\n18.3; 95% CI, 3.21\u201333.39), which exceed\nthe reported MCID for all domains except\nsocial functioning (64).\nThe acute effects of oxygen on\nfunctional exercise capacity were assessed\nusing multiple tests. We meta-analyzed the\nresults from two studies (52, 56) using the\n6MWT, one of which used cylinder room\nair and the other of which used room air as\nthe comparator. An MD of 28.9 m (95% CI,\n16.1\u201341.9 m; I2\n= 0%) was found in favor of\nthe oxygen group. Oxygen acutely increased\nexercise endurance time on a cycle\nergometer by 5.8 minutes (95% CI,\n2.23\u20139.37 min) compared with room air\n(58). Peak workload on a stationary bike\nwas acutely improved with ambulatory\noxygen (MD, 17.9 W; 95% CI, 8.10\u201327.70\nW) (47). Ambulatory oxygen increased the\nnumber of steps walked in 5 minutes\ncompared with cylinder room air (MD,\n14.90; 95% CI, 0.85\u201328.94) (50). Meta-\nanalysis of three studies reporting on the\nBorg dyspnea score at the end of exercise\n(52, 56, 58) showed a reduction of 1.11 U\n(95% CI, 0.53\u20131.69 U; I2\n= 39%) in favor of\nambulatory oxygen. This remained\nsigni\ufb01cant when we did a sensitivity\nanalysis by study design (crossover trial vs.\nparallel groups; Table E4). No studies\nreported the long-term effects of\nambulatory oxygen on exercise capacity\nbeyond acute laboratory or \ufb01eld tests, and\nno studies reported effects on physical\nactivity in daily life.\nEvidence for patients with resting\nhypoxemia and severe exertional\ndesaturation. For the subgroup of studies in\nwhich patients had both resting and\nexertional hypoxemia, six RCTs (46, 48, 49,\n53\u201355) met our inclusion criteria;\nhowever, none included results for HRQL,\nour critical outcome. In one randomized\ncrossover study of LTOT users (n = 24) in\nwhich the degree of exertional\ndesaturation was not speci\ufb01ed, ambulatory\noxygen had no effect on the CRQ dyspnea\ndomain (mean change over the 3-month\ntreatment period, 0.0 U; 95% CI, 20.3 to\n0.2 U) (61). A single-blind RCT found that\nambulatory oxygen at 2 and 4 L\/min\nacutely increased the distance patients\nwalked in 12 minutes compared with room\nair if they were not using a walker or\nshopping trolley, as carrying those devices\neliminated any gains in exercise tolerance\n(49). Baseline data from an RCT of\npulmonary rehabilitation found that\nambulatory oxygen acutely improved the\ndistance walked compared with room air,\nmeasured with the incremental shuttle\nwalk test (MD, 27.3 m; 95% CI, 14.7 to\n39.8 m) (48). In a crossover study,\nambulatory oxygen acutely improved\nendurance time by 4.70 minutes compared\nwith room air (95% CI, 3.76 to 5.64 min)\n(46). We meta-analyzed the results from\nthree studies reporting on the Borg\ndyspnea score (46, 48, 54) and found a\nreduction of 0.59 U (95% CI, 0.18 to 0.99;\nI2\n= 25%) in favor of ambulatory oxygen;\nthe MCID is reported to be 1.0 U (65).\nNo studies in our review examined\nsafety in patients with COPD using only\nambulatory portable oxygen systems.\nPanel judgments. DESIRABLE\nCONSEQUENCES AND THEIR MAGNITUDES\n(BENEFITS). For people with COPD and\nsevere exertional hypoxemia, we did not \ufb01nd\nconsistent evidence that ambulatory oxygen\ndelivered clinically signi\ufb01cant\nimprovements in the critical outcome of\nHRQL, whereas effects generally favored\nambulatory oxygen (moderate GRADE\nevidence). Acute improvements in exercise\ncapacity were seen both in those with\nisolated exertional hypoxemia and in those\neligible for LTOT. The effects of ambulatory\noxygen on dyspnea during exercise testing\nwere inconsistent. Mortality risks were not\nreported. Fatigue and physical activity in\ndaily life were not reported.\nUNDESIRABLE CONSEQUENCES AND THEIR\nMAGNITUDES (HARMS). There is a substantial\nbody of evidence regarding the patient and\ncaregiver burden associated with the use of\nambulatory oxygen, including managing the\nweight and bulk of equipment,\nembarrassment and perceived stigma, fear\nof cylinders running out, reduced ability to\ntravel outside the home, equipment noise\nthat may affect social activities, dif\ufb01culty\nobtaining POCs, and poor access to\ninformation about effective use of oxygen\nequipment (14, 66, 67).\nRationale for the recommendation. There\nis some evidence supporting the use of\nambulatory oxygen in people with COPD,\nwhich is complicated by the potential burden of\nthis therapy. Effects on the critical outcome of\nHRQL, which may or may not be clinically\nsigni\ufb01cant, tended to favor ambulatory oxygen.\nAmbulatory oxygen acutely improves exercise\ncapacity and may reduce breathlessness during\nexercise testing. There is little evidence\nregarding the effects of ambulatory oxygen\nwhen used in daily life. Given this uncertainty,\ntogether with the known burden of ambulatory\noxygen, it is likely that some patients will\nchoose not to use ambulatory oxygen.\nATS recommendation. In adults with\nCOPD who have severe exertional room air\nhypoxemia, we suggest prescribing\nambulatory oxygen (conditional\nrecommendation, low-quality evidence).\nWhat others are saying. A 2015\nguideline by the BTS states that ambulatory\noxygen should not be routinely offered to\npatients with isolated exertional hypoxemia\nand should only be offered to those eligible\nfor LTOT if they are mobile outdoors (7).\nThe 2020 GOLD strategy makes no\nrecommendations regarding ambulatory\noxygen (12).\nImplementation considerations. We\nde\ufb01ned exertional hypoxemia as an\nSpO2\n< 88%. Ambulatory oxygen seems to\nhave similar effects in patients who are\neligible for LTOT and in those who have\nisolated exertional hypoxemia. In patients\nwho are eligible for LTOT, prescription of\nambulatory oxygen may be important to\nincrease the daily hours of oxygen usage\n(68). Individuals who experience a\nreduction in dyspnea or increased activity\nlevels with ambulatory oxygen may be more\nlikely to bene\ufb01t from, and adhere to, this\ntherapy. Standardization of the level of\nexertion is critical when assessing the\neffects of oxygen on dyspnea (69, 70).\nAmbulatory oxygen devices vary in terms\nAMERICAN THORACIC SOCIETY DOCUMENTS\ne130 American Journal of Respiratory and Critical Care Medicine Volume 202 Number 10 | November 15 2020\nof portability, volume, and \ufb02ow; shared\ndecision-making between the patient and\nprovider is necessary to ensure that the\ndevice prescription meets the patient\u2019s\nneeds and goals.\nValues and preferences. This\nrecommendation places a high value on\nincreasing HRQL and the potential for\nfacilitating physical activity outside the\nhome and places a lower value on cost,\ninconvenience, and resource use.\nResearch needs. Given the well-\ndocumented burden of ambulatory oxygen,\nthere is an urgent need for new ambulatory\noxygen devices that increase portability\n(improved battery life, weight, \ufb02ow rates,\nwireless connections, etc.). Although we\nfound several studies evaluating the effects\nof oxygen during laboratory testing, few\nstudies evaluated ambulatory oxygen during\ndaily life activities, the context for which it is\nprescribed. Future studies of ambulatory\noxygen should address patient-centered\noutcomes such as HRQL and physical\nactivity in daily life, together with outcomes\npertinent to cost-effectiveness, such as\nproductivity, days missed from work, and\nhospital readmissions. Future studies should\nalso capture costs of care for other health\nconditions that may occur because of\nphysical inactivity, which could be reduced\nwith ambulatory oxygen.\nQuestion 4: Should long-term oxygen\nbe prescribed for adults with ILD who\nhave severe chronic resting room air\nhypoxemia?\nBackground. Severe resting hypoxemia is\nhighly prevalent in adults living with ILD.\nThose with \ufb01brotic forms of ILD, such as\nIPF, often experience a progressive course\ncharacterized by breathlessness, cough,\nhypoxemia, episodes of acute respiratory\nworsening, and early death. When present,\nsevere resting hypoxemia often contributes\nto disabling and distressing breathlessness,\nwhich is common in ILD. With the\nexception of lung transplantation,\nsupplemental oxygen is the only treatment\nthat improves hypoxemia that persists\ndespite optimal medical management of the\nunderlying disease.\nThe critical outcome for this question\nwas mortality; important outcomes were\ndyspnea, fatigue, HRQL, physical activity in\ndaily life, healthcare resource use, exercise\ncapacity, and safety.\nDescription of the evidence and its\nquality. No studies were found that met our\ninclusion criteria. A 2001 Cochrane\nsystematic review (71) reported the results\nfrom one unpublished RCT in which severe\nresting room air hypoxemia was de\ufb01ned as\na PaO2\nof 45\u201360 mm Hg (6.0\u20138.0 kPa),\nslightly above our prespeci\ufb01ed cutoff of\nPaO2\n< 55 mm Hg (7.3 kPa) (Table E5).\nBecause no other study was found reporting\non our outcomes of interest, we elected to\nreport these results. The study included 62\nparticipants, 49 of whom had IPF. No\nsigni\ufb01cant difference in mortality between\nthe LTOT and room air groups was\nobserved after 1 year (OR, 0.50; 95% CI,\n0.15\u20131.61), 2 years (OR, 1.76; 95% CI,\n0.64\u20134.86), or 3 years (OR, 0.99; 95% CI,\n0.16\u20136.26). As this is an unpublished RCT,\nthere is a high risk of bias and a very low\nGRADE quality of evidence for this\noutcome (Table E5).\nNo studies reported on dyspnea,\nfatigue, HRQL, physical activity, or\nhealthcare resource use.\nBecause of the paucity of any direct\nevidence regarding patients with ILD, we\nchose to consider indirect evidence from our\n\ufb01rst population, intervention, comparison,\nand outcome question that considered\npatients with COPD and severe resting\nroom air hypoxemia (6, 72\u201374).\nSafety data speci\ufb01c to LTOT in\npatients with ILD were scarce. A\nqualitative study reported tripping as a\nhardship after being on oxygen for 9\u201312\nmonths (75). The panel agreed that the\nsafety data for COPD related to risks of\ntripping, burns, \ufb01res, nosebleeds, and\ntransporting oxygen cylinders would also\nbe potential safety concerns for patients\nwith ILD on LTOT.\nPanel judgments. DESIRABLE\nCONSEQUENCES AND THEIR MAGNITUDES\n(BENEFITS). Despite the absence of any\npublished randomized trial data, the panel\njudged the perceived bene\ufb01ts of LTOT to\ntreat severe resting hypoxemia to be\nsubstantial for most adults with ILD. As\nnoted above, LTOT for severe resting\nhypoxemia may confer a mortality bene\ufb01t in\nCOPD. LTOT may also prevent organ\ndysfunction due to severe sustained\nhypoxemia, including prevention of PH.\nOther bene\ufb01ts may include relief of\nbreathlessness (76) as well as improvements\nin disability and HRQL. These desirable\nconsequences were considered to be\nsubstantial.\nUNDESIRABLE CONSEQUENCES AND THEIR\nMAGNITUDES (HARMS). The primary\nundesirable consequences are listed in\nquestion 1, including patient burden and\ncost. Overall, the panel deemed the\nsubstantial desirable consequences of LTOT\nto outweigh the undesirable consequences of\nuntreated severe resting hypoxemia.\nNotably, despite the very-low-quality\nevidence available to the panel, ethical\nconcerns about withholding LTOT were\nstrong factors in our decision-making.\nRationale for the recommendation. The\nabsence of published studies examining\neffects of LTOT in ILD led the panel to\nincorporate evidence from COPD trials\ntogether with their clinical experience in the\ndevelopment of the recommendation.\nDespite the burden of therapy, the panel\nconcluded that LTOT is likely to confer\ndesirable bene\ufb01ts for many patients with\nsevere resting hypoxemia.\nATS recommendation. For adults with\nILD who have severe chronic resting room\nair hypoxemia, we recommend prescribing\nLTOT for at least 15 h\/d (strong\nrecommendation, very-low-quality\nevidence).\nWhat others are saying. Because of the\nlack of direct evidence, the majority of\nguidelines made their recommendations on\nthe basis of expert opinion or extrapolated\nfrom COPD literature. A 2011 multisociety\nguideline on IPF recommends the use of\nLTOT in patients with severe resting room\nhypoxemia (77). The panel made a strong\nrecommendation in favor of LTOT, as they\nplaced a high value on evidence from other\nchronic lung diseases and low value on cost\nand inconvenience to patients. A 2015 BTS\nguideline on home oxygen use suggests a\nhigher threshold of 60 mm Hg (8.0 kPa) for\nthose who have concomitant PH. They also\nrecommend LTOT in patients with ILD\nwith a PaO2\n< 55 mm Hg (7.3 kPa) but\nnoted that the evidence base is extrapolated\nfrom evidence in COPD (7).\nImplementation considerations. For\npatients with ILD, we have applied the same\nde\ufb01nition of severe resting hypoxemia as in\nthose with COPD (question 1), as our\nrecommendation was based on indirect\nevidence from COPD trials. The assessment\nof PH in patients with ILD should be\nconsidered, as it predicts worsening lung\nfunction and functional status, increased\noxygen needs, and risk of acute exacerbation\nin ILD and is a predictor of increased\nmortality in IPF (6, 72\u201374). Some patients\nAMERICAN THORACIC SOCIETY DOCUMENTS\nAmerican Thoracic Society Documents e131\nmay not experience dyspnea, despite severe\nhypoxemia at rest, or may have strong\npersonal preferences against the use of\nLTOT. The panel encourages healthcare\nproviders to educate patients about the\nharms of severe chronic hypoxemia and to\npartner with patients and their caregivers to\nselect the oxygen delivery system that best\nmeets their medical and lifestyle needs.\nValues and preferences. This\nrecommendation places a high value on\nindirect evidence of decreased mortality, the\nrelief and prevention of distressing\nsymptoms, and a perceived likelihood of\noverall improved health status by\nprevention of organ dysfunction.\nResearch needs. The panel\nacknowledges that RCTs of LTOT to treat\nsevere hypoxemia in ILD may face\nchallenges, including a lack of perceived\nequipoise. We encourage the research\ncommunity to consider innovative\napproaches to studying the bene\ufb01ts and\nharms of LTOT in ILD, including clinical\ntrials and quasiexperimental trial designs.\nSuch trials may minimize harms and be\nmore ethically acceptable to patients,\ncaregivers, healthcare providers, and\nresearchers. Trials of short duration may\nneed to be performed before longer-term\ntrials.\nQuestion 5: Should ambulatory\noxygen be prescribed to adults with\nILD who have severe exertional room\nair hypoxemia?\nBackground. Exertional hypoxemia is a\nhallmark of ILD, occurring in more than\nhalf of patients evaluated at a tertiary ILD\nservice and in over 80% of patients with an\nFVC , 50% of that predicted (78). The\nmagnitude of exertional hypoxemia is\ngenerally greater in people with ILD than in\npeople with COPD (18). People with ILD\nwho desaturate to an SpO2\n< 88% on a\n6MWT have a fourfold greater risk of death\nthan those who do not, after adjusting for\nage, sex, smoking, respiratory function, and\nresting saturation (79). Exertional\ndesaturation is an independent predictor of\nPH (80), which is itself a strong predictor of\nmortality (81). Greater exertional\ndesaturation is strongly associated with\nreduced physical activity (82). These data\nprovide a strong rationale for treatment of\nexertional hypoxemia in ILD to improve\ndaily functioning and long-term outcomes.\nThe prespeci\ufb01ed critical outcome for\nthis key question was HRQL; important\noutcomes were dyspnea, fatigue, exercise\ncapacity, physical activity, mortality,\nhealthcare resource use, and safety.\nDescription of the evidence and its\nquality for participants with exertional\ndesaturation. The AmbOx (Ambulatory\nOxygen in Fibrotic Lung Disease) trial (83)\nexamined the effects of ambulatory oxygen\nused during daily activities on HRQL in a\nrandomized 2-week crossover trial\nconducted in 84 patients with \ufb01brotic ILD\nand isolated exertional hypoxemia (de\ufb01ned\nas an SpO2\n< 88% during a 6MWT). The\ncontrol group did not use a sham device,\nand there was no blinding of assessment.\nFor the King\u2019s Brief ILD questionnaire,\nthere was a signi\ufb01cant improvement in\nfavor of ambulatory oxygen for the total\nscore (MD, 3.7; 95% CI, 1.8 to 5.6),\nbreathlessness and activities score (MD, 8.6;\n95% CI, 4.7 to 12.5), and the chest\nsymptoms score (MD, 7.6; 95% CI, 1.9 to\n13.2), whereas no signi\ufb01cant difference was\nobserved for the psychological symptoms\nscore. The MCID for the total King\u2019s Brief\nILD score has been recently estimated as 3.9\n(84, 85). The SGRQ demonstrated a\nsigni\ufb01cant improvement in the total score\n(MD, 23.6; 95% CI, 26.7 to 20.6) and\nactivity score (MD, 27.5; 95% CI, 212.4 to\n22.5), with no signi\ufb01cant difference in the\nimpact and symptoms scores. The MCID\nfor the SGRQ is 4 U (86). Dyspnea\nassociated with activities of daily living was\nassessed using the University of California,\nSan Diego, Shortness of Breath\nQuestionnaire, showing an improvement of\n8 U (95% CI, 3.6 to 12.4). The MCID is 5 U\n(87). Despite the clear challenges posed by\nambulatory oxygen, highlighted in the\nqualitative component of the trial, two-\nthirds of patients decided to continue with\nambulatory oxygen at the end of the study.\nImprovements with oxygen in individual\nparticipants could not be predicted by\nparticipant characteristics, but preference to\ncontinue on oxygen after the trial was\nin\ufb02uenced by the patient perception of\nbene\ufb01t for breathlessness or walking ability\n(83).\nA 2016 Cochrane systematic review\n(88) included three crossover RCTs\nevaluating the acute effects of oxygen\nduring exercise testing in patients with ILD.\nNo change was found in 6-minute-walk\ndistance with ambulatory oxygen compared\nwith cylinder room air (89) or in the\nendurance shuttle walk test distance with\noxygen compared with room air (90). There\nwas no change in dyspnea, measured with\nthe Borg dyspnea score (89). One study\nreported an acute improvement in\nendurance time by 118.7 seconds (95% CI,\n23.9\u2013213.5 s) (91) with ambulatory oxygen\ncompared with room air. Two other\nsystematic reviews assessing the ambulatory\noxygen in ILD were subsequently published\n(92, 93) but did not meet our inclusion\ncriteria.\nWe identi\ufb01ed additional studies\nthat met our inclusion criteria; all used\n6MWTs. Meta-analysis of three studies\n(83, 89, 94) showed that oxygen acutely\nimproved 6-minute-walk distance by\n18.57 m (95% CI, 11.14 to 25.99 m;\nI2\n= 0%) compared with room or cylinder\nair (Table E6 and Figure E5). We pooled\nthe results of three studies (83, 89, 94) that\nreported the Borg dyspnea score at the end\nof a 6MWT, one of which was not\nincluded in the Cochrane systematic\nreview (83); no signi\ufb01cant difference\nwas found (MD, 20.72; 95% CI, 21.70\nto 0.27; I2\n= 73.28%). Meta-analysis of\nthree studies (83, 89, 94) found a\nsigni\ufb01cant reduction in the Borg\nperceived-exertion score at the end of a\n6MWT in favor of ambulatory oxygen\n(0.37 U; 95% CI, 0.19 to 0.54 U; I2\n= 0%).\nWe meta-analyzed the results from two\nstudies (90, 95) and found that exercise\nduration on cardiopulmonary exercise\ntesting improved by 57.67 seconds using\noxygen compared with room air (95%\nCI, 0.22 to 115.12; I2\n= 0%). No signi\ufb01cant\nimprovement was observed in the maximal\nwork rate (MD, 10.34 W; 95% CI, 23.59 to\n24.26 W; I2\n= 0%).\nNo studies reported the effects of\nambulatory oxygen on fatigue, exercise\ncapacity in the long term, physical activity in\ndaily life, or mortality. The quality of\nevidence was low, with no parallel-group\nRCTs and only one study evaluating use of\nambulatory oxygen in daily life (83): a\ncrossover trial that did not include blinding\nof participants or researchers. See Table E6\nfor an evidence pro\ufb01le.\nSafety data speci\ufb01c to ambulatory\noxygen in ILD were rarely reported. A\nCochrane review of the effects of ambulatory\nor short-burst oxygen in ILD did not report\nany serious adverse events or side effects\n(88). However, the panel agreed that risks\nof transporting cylinders, burns, \ufb01res, and\ntripping would be potential safety concerns\nAMERICAN THORACIC SOCIETY DOCUMENTS\ne132 American Journal of Respiratory and Critical Care Medicine Volume 202 Number 10 | November 15 2020\nfor patients with ILD using ambulatory\noxygen.\nPanel judgments. DESIRABLE\nCONSEQUENCES AND THEIR MAGNITUDES\n(BENEFITS). For people with ILD and\nexertional hypoxemia, ambulatory\noxygen resulted in improvements in the\ncritical outcome of HRQL that may be\nclinically important. However, there was\nonly one crossover trial with a 2-week\ntreatment period, so the long-term impact\non HRQL is unknown. In laboratory studies,\nthe improvements in exercise capacity\ntended to favor ambulatory oxygen but\nwere generally small. Physical activity\nin daily life and mortality were not\nreported.\nUNDESIRABLE CONSEQUENCES AND THEIR\nMAGNITUDES (HARMS). Qualitative studies in\npatients with ILD report negative physical\nand psychosocial impacts of ambulatory\noxygen therapy, which persist despite\nacceptance that this treatment may be\ninevitable as disease progresses (96).\nPatients and caregivers report that the\nequipment is challenging to use, that there\nmay be unmet expectations for symptom\nrelief (particularly dyspnea), and that\nchallenges related to use of cumbersome or\ncomplicated equipment, embarrassment\nwhen using ambulatory oxygen in public,\nreduced independence for patients, and\nincreased caregiver burden mark an\nimportant trade-off between bene\ufb01ts and\ninconvenience (75, 96, 97).\nRationale for the recommendation. Weak\nevidence supports the use of ambulatory\noxygen in people with ILD, suggesting bene\ufb01ts\nin HRQL; certainty is low, as the medium- to\nlong-term effects are unknown. Ambulatory\noxygen may improve exercise capacity, but\neffects on physical activity in daily life have not\nbeen examined. There is uncertainty regarding\nsymptom bene\ufb01ts. Given this uncertainty,\ntogether with the known burden of\nambulatory oxygen, it is likely that some\npatients will choose not to use ambulatory\noxygen.\nATS recommendation. For adults with\nILD who have severe exertional room air\nhypoxemia, we suggest prescribing\nambulatory oxygen (conditional\nrecommendation, low-quality evidence).\nWhat others are saying. A \u201cgood\npractice point\u201d in the 2015 BTS guideline\nacknowledges that ambulatory oxygen\ntherapy may be useful in patients with ILD\nand disabling breathlessness, and it could\nbe prescribed if there is evidence of bene\ufb01t\nand ongoing adherence (7). Guidelines\nfrom TSANZ state that in the absence of\ntrial-based evidence, the bene\ufb01t of\nambulatory oxygen in individual patients\nshould be established by comparing\nexercise endurance, oxygen saturation, and\ndyspnea during a blinded exercise test on\noxygen versus air (9). Current\nATS\/European Respiratory\nSociety\/Japanese Respiratory\nSociety\/Asociacio\u0301n Latinoamericana de\nTo\u0301rax guidelines on management of IPF do\nnot mention ambulatory oxygen therapy\n(6).\nImplementation considerations. We\nde\ufb01ned exertional hypoxemia as an\nSpO2\n< 88%. In ILD, exertional hypoxemia\nfrequently worsens as the disease progresses\nand may be profound in those with severe\ndisease; ambulatory oxygen is likely to be\nparticularly important for these patients. It\nmay also be important for those with\nfunctional limitation and those being\nconsidered for lung transplantation. The\npanel noted that the need for high-\ufb02ow\nambulatory devices is greater in people with\nILD than in those with COPD because of\nthe magnitude of exertional hypoxemia. It\nis prudent to ensure that ambulatory\noxygen devices with appropriate \ufb02ow\ncapacity are prescribed to patients on the\nbasis of their needs. The panel noted that\nthe majority of evidence is related to\nlaboratory tests that may not be indicative\nof activities of daily living. Standardization\nof the level of exertion is necessary to assess\nthe effects of oxygen on dyspnea (69, 70),\nwhich may be particularly important when\ndetermining the eligibility for and likely\nbene\ufb01ts of ambulatory oxygen.\nValues and preferences. This\nrecommendation places a high value on\nincreasing HRQL and facilitating physical\nactivity outside of the home and places a\nlower value on cost and resource use.\nResearch needs. Randomized parallel-\ngroup trials that evaluate the impact of\nambulatory oxygen on patient-centered\noutcomes, daily life activities, disease\nprogression, and mortality are required.\nThese trials should address outcomes\npertinent to cost-effectiveness, such as\nproductivity, days missed from work, and\nhospital readmissions. Although we found\nseveral studies evaluating the effects of\noxygen during laboratory testing, there\nwas only one study that evaluated\nambulatory oxygen during daily life\nactivities, the context for which it is\nprescribed. There is an urgent need for\nambulatory oxygen devices that can better\nmeet the high \ufb02ow requirements of people\nwith ILD during exercise. Novel devices\nshould also increase portability through\nimprovements in weight, maneuverability,\nand battery life.\nQuestion 6: Should portable LOX\nbe provided for adults with chronic\nlung disease who are prescribed\ncontinuous oxygen \ufb02ow rates of\n>3 L\/min during exertion?\nBackground. Three modes of portable\noxygen delivery are available for patients\u2019\nuse outside of the home: metal cylinders of\ncompressed gaseous oxygen, POCs, and\nLOX canisters. Each varies in size, weight,\nlevels of pulse- or continuous-\ufb02ow\nsettings, oxygen delivery capacity, and\nduration of supply (Figure 1 and Tables 5\nand E11). In the past, LOX has been used\nfor those with higher \ufb02ow requirements to\nfacilitate mobility and increase time spent\noutside of the home, but relative ef\ufb01cacy is\nunclear.\nSince the implementation of\nthe Medicare National Competitive\nBidding Program by the Centers for\nMedicare and Medicaid Services (CMS)\nin the United States in 2011, Medicare\nbene\ufb01ciary claims for portable LOX\ndeclined from 966,846 in 2004 to 97,690\nin 2016 (98). This decrease re\ufb02ects lower\nCMS reimbursement to durable medical\nequipment (DME) companies with\nsubsequent elimination of LOX, and\nother cost-saving changes including\ntransitioning patients to \u201cnondelivery\u201d\nhome-\ufb01ll oxygen systems (99\u2013101) and\nheavier E cylinders.\nThe impact of this decline in the\navailability and adequacy of portable oxygen\ndevices in the United States has been\nprofound. Supplemental oxygen users\nreported numerous problems, with the\noverarching theme being restricted mobility\nand isolation due to inadequate portable\noptions (13, 14, 16, 20, 102). The panel\nagreed that portable LOX for individuals\nrequiring .3 L\/min of continuous-\ufb02ow\noxygen was an important problem because\nlimited mobility affects our critical outcome\nof HRQL. The symptoms associated with\nsevere exertional hypoxemia in patients\nwith high-\ufb02ow oxygen needs may be\nsubstantial, but these have not been\nassessed in clinical trials.\nAMERICAN THORACIC SOCIETY DOCUMENTS\nAmerican Thoracic Society Documents e133\nTable 5. Characteristics of Portable Oxygen Devices\nMetal Oxygen Cylinders POCs LOX\nSize and weight Available in multiple sizes from 2.5\nto 9 kg (E cylinder in United\nStates, which requires a trolley)*\nVary in weight (1.5\u201310 kg), noise,\nbattery life, oxygen purity\n(87\u201395%), maximum breath\nrates, and settings (pulse \ufb02ow,\ncontinuous \ufb02ow, or both)\u2020\u2021\nMedium to large canister ranges\nbetween 2.5 and 4 kg\nFilling Some stationary concentrators\nallow patients to \ufb01ll smaller\noxygen cylinders in their home,\n(home-\ufb01ll units), but these last\n,1 h on continuous-\ufb02ow rates\n.3 L\/min and therefore are\ninadequate for high-\ufb02ow\npatients\nNo \ufb01lling; POCs \u201cconcentrate\u201d\noxygen by extracting nitrogen\nfrom ambient air. They run off of\na battery and can be recharged\nPatients re\ufb01ll portable canisters\nfrom a larger home reservoir of\nLOX\nOne liter of LOX expands to 860 L\nof gaseous oxygen\nPulse setting or\ncontinuous-\ufb02ow capacityx\nOxygen-conserving devices using\npulse-\ufb02ow technology can be\nattached to metal cylinders to\nprolong the duration of supply\nby releasing oxygen only during\ninspiration\nAt a given pulse-\ufb02ow setting,\nPOCs differ as to the volume\nof oxygen (ml) per pulse,\ninspiratory time, and triggering\nsensitivity and may not\nconsistently sense patients\u2019\ninspiratory efforts to trigger the\ndevice*\nPortable LOX technology allows\ndelivery of continuous-\ufb02ow\noxygen up to 15 L\/min via a\nlighter and longer-duration device\nBecause of differences in an\nindividual patient\u2019s ability to\ntrigger a pulse dose of oxygen,\nand the volume delivered with\neach pulse at different\nrespiratory rates, they may be\ninsuf\ufb01cient for patients who\nrequire continuous oxygen with\nexertion at .3 L\/min, such as\nthose with interstitial lung\ndisease, lung transplantation\ncandidates, and others with\nsevere hypoxemia\nPulse settings are based on an\noxygen volume unique to each\ndevice, not a standardized\nL\/min methodology\nDuration of supply A single E tank with a stroller will\nlast approximately 1.9 h on 6\nL\/min. Multiple cylinders are\nneeded for high-\ufb02ow (.3 L\/min)\npatients to be out of the home\n.2\u20134 hk\nAll POCs depend on a battery\nsupply that depletes more\nrapidly with higher settings,\nhigher respiratory rates, and the\nuse of continuous-\ufb02ow settings\nA medium LOX canister will last 3 h\nat 6 L\/min of continuous \ufb02ow\nCost Metal oxygen cylinders range\nfrom US$50 to US$100;\nadditional costs for a regulator\nor oxygen-conserving device.\nCommonly supplied by U.S.\nDME companies\nIn the United States, many DME\ncompanies offer POCs as a\nportable option together with\na stationary concentrator;\nindividuals can also purchase\nthem for US$2,000\u20134,000\nCost estimates are approximately\nfour times higher per patient\ncompared with POCs or\nmetal-cylinder options because\nof the requirements for DME\ncompanies to access and store\nLOX, use specially out\ufb01tted\ndelivery trucks, and provide\nweekly re\ufb01ll servicing\u00b6\nTravel Metal cylinders not allowed for air\ntravel\nPOCs are the only carry-on\nportable oxygen device allowed\nby the Federal Aviation\nAdministration for air travel;\nsome airlines may provide\noxygen cylinders for emergency\nin-\ufb02ight use only**\nLiquid oxygen not allowed for air\ntravel\nDefinition of abbreviations: DME = durable medical equipment; LOX = liquid oxygen; POCs = portable oxygen concentrators.\n*The availability of different oxygen devices varies by geographic region, and some jurisdictions do not have smaller metal oxygen cylinders.\n\u2020\nPOCs vary in pulse technology, oxygen purity, and triggering sensitivity (100, 114\u2013118).\n\u2021\nThe few POCs that currently provide a maximum of 3 L\/min on a continuous-flow setting weigh over 9 kg and require a trolley.\nx\nFor all devices, if an oxygen-conserving device is used, the patient should be tested using that device during exertion, similar to what they would do in daily life, to ensure\nadequate oxygenation. A continuous-flow setting of 5 L\/min and a pulse-flow setting of \u201c5\u201d may not deliver equivalent volumes of oxygen, despite direct marketing claims.\nk\nPatients depend on their DME company to deliver an adequate number of cylinders per week or month.\n\u00b6\nLOX costs are higher than costs for POCs or metal cylinders (103).\n**The Federal Aviation Administration stipulates which POCs are allowed for use during air travel (119).\nAMERICAN THORACIC SOCIETY DOCUMENTS\ne134 American Journal of Respiratory and Critical Care Medicine Volume 202 Number 10 | November 15 2020\nThe prespeci\ufb01ed critical outcome for\nthis key question was HRQL; important\noutcomes were oxygen saturation during\nexertion, dyspnea, exercise capacity,\nphysical activity, adherence, and safety.\nDescription of evidence and its\nquality. The literature search did not yield\nany studies that met our inclusion criteria,\nwhich speci\ufb01ed that patients be prescribed\ncontinuous oxygen \ufb02ow rates of .3 L\/min\nduring exertion. Because of the absence of\nother forms of evidence, we considered\nindirect evidence and synthesized the\nliterature for six studies in patients with\nCOPD (54, 55, 103\u2013106) with lower or\nunreported \ufb02ow rates. Five of those\nstudies tested subjects on continuous-\n\ufb02ow LOX (54, 55, 103\u2013105), whereas\none study (106) used pulse-\ufb02ow LOX\n(Table E7).\nA multicenter RCT (103) compared the\nuse of stationary oxygen concentrators plus\nsmall oxygen cylinders or LOX (stationary\nand portable) in patients with COPD\n(n = 51). They reported HRQL measured\nwith the Sickness Impact Pro\ufb01le (SIP) and\nthe EuroQol instruments. There was no\ndifference between groups in EuroQol\nscores, but there were signi\ufb01cant differences\nin favor of LOX for the SIP domains of\nmobility (MD, 24.57; P = 0.043), body care\n(MD, 25.83; P = 0.011), ambulation (MD,\n28.46; P = 0.017), social interaction (MD,\n25.27; P = 0.023), and total SIP score (MD,\n23.38; P = 0.018) (103). The MCID for SIP\nis a change of 5 U (107).\nNo difference in oxygen saturation was\nobserved during the 6MWT (54, 106) and 2-\nminute-walk test (105) between LOX and\nconcentrators. The Borg dyspnea score did\nnot differ after the 6MWT (MD, 20.10;\n95% CI, 21.23 to 1.03) (54) or 2-minute-\nwalk test (MD, 20.40; 95% CI, 21.36 to\n0.56) (105).\nA retrospective study (n = 146)\ncompared adherence in users of stationary\nand portable LOX to a group that used a\nstationary oxygen concentrator plus small\nportable metal cylinders (105). The LOX\ngroup used stationary and portable oxygen\nfor 6.50 h\/d (95% CI, 4.43\u20138.57 h\/d) longer;\n92% of the concentrator group did not use\ntheir provided portable cylinders. However,\nthe majority of patients in the concentrator\ngroup were sicker (presence of\ntracheostomy or use of home ventilation)\ncompared with the LOX group and were\ntherefore less likely to use portable oxygen\noutside of the home. An RCT (55) (n = 159)\nfound that portable oxygen increased\npatients\u2019 daily duration of oxygen therapy\ncompared with those solely using stationary\ndevices (MD, 3.00 h; 95% CI, 1.97\u20134.03 h);\n24% more patients who used oxygen for\ngreater than 18 h\/d were LOX users than\ncylinder users. In a crossover RCT in which\nall participants were LTOT users (n = 15),\nparticipants who were allocated metal\ncylinders spent more time each week using\ntheir home stationary oxygen concentrator\nthan those using LOX spent (13.1 h longer;\n95% CI, 1.57\u201327.92 h longer) (104). LOX\nusers spent more time outside the home\nthan metal-cylinder users (MD, 4.0 h; 95%\nCI, 0.9\u20137.1 h) (104, 105) and were more\nlikely to leave the home (105).\nOur systematic review did not identify\nsafety data speci\ufb01c to LOX, with the\nexception of guidance provided by the\nmanufacturer (108).\nPanel judgments. DESIRABLE\nCONSEQUENCES AND THEIR MAGNITUDES\n(BENEFITS). Despite the absence of studies\nexamining continuous-\ufb02ow LOX at .3\nL\/min, the panel judged that the desirable\nconsequences and bene\ufb01ts outweighed the\nundesirable consequences and harms of\nportable LOX therapy. Indirect evidence\ndemonstrated improvements in some\ndomains of HRQL, improved adherence,\nand increased time spent outside the home.\nLOX provides opportunity to leave the\nhome for patients with severe hypoxemia\nwho would otherwise require multiple,\nheavy, metal oxygen cylinders to access the\ncommunity. Patients who are caregivers for\nothers, have paid employment or classroom\neducation needs outside the home, or are\nattending pulmonary rehabilitation sessions\nto prepare for lung transplantation would\nhave a means to engage in such activities\nby having a longer duration of oxygen\nsupply.\nUNDESIRABLE CONSEQUENCES AND THEIR\nMAGNITUDES (HARMS). The panel agreed that\nsome of the undesirable consequences of\nLOX were similar to those previously\ndescribed, including equipment\nmanagement, unmet expectations for\nsymptom relief, embarrassment, reduced\nindependence, and increased caregiver\nburden. However, LOX may have less\nimpact on mobility because of smaller,\nlonger-lasting, and more lightweight\ncanisters and the ability to provide\ncontinuous high-\ufb02ow oxygen. Use of LOX\nrequires manual ability to \ufb01ll portable\ncanisters from a large reservoir, which is not\nrequired with other portable oxygen\nsystems. There is also a risk of skin burns\nfrom frost leaks when \ufb01lling portable\ncanisters that is unique to LOX.\nRationale for the recommendation. The\npanel made a conditional recommendation\nbecause although LOX is relevant to a\nsubgroup of patients, there are limited data\nto guide patient selection. However, the\npanel considered that, on the basis of the\nlimited capacity of POCs and portable metal\ncylinders, the prescription of LOX is\ncritically important for patients who require\nhigh \ufb02ow rates and who need to spend\nextended periods of time outside the home.\nPatients who require continuous-\ufb02ow\noxygen at .3 L\/min cannot spend .2\nhours outside the home with a single E\ntank. LOX at 3\u20134 L\/min may allow patients\nto spend up to 5 hours away from home,\nwhich is reduced to 4 hours if using LOX at\n5 L\/min (Table E11).\nATS recommendation. In patients with\nchronic lung disease who are mobile outside\nof the home and require continuous \ufb02ow\nrates of .3 L\/min during exertion, we\nsuggest prescribing portable LOX\n(conditional recommendation, very-low-\nquality evidence).\nWhat others are saying. The National\nInstitute for Clinical Excellence guidelines for\nCOPD management (109) state that \u201csmall\nlightweight cylinders, oxygen-conserving\ndevices and portable liquid oxygen systems\nshould be available for the treatment of\npatients with COPD. A choice about the\nnature of equipment prescribed should take\ninto account the hours of ambulatory\noxygen use required by the patient and the\noxygen \ufb02ow rate required.\u201d They suggest\nthat compressed gas cylinders be used for no\nless than 90 minutes and that LOX be used\nfor .4 hours or .30 minutes, for \ufb02ow rates\nhigher than 2 L\/min (109).\nGuidelines by the U.S. Department of\nVeterans Affairs state that LOX should be\n\u201cprescribed for ambulatory patients who\nuse an extensive amount of oxygen from\nportable sources\u201d (110). They further state\nthat \u201cThe most ef\ufb01cient and medically\nappropriate system for providing oxygen\nwill be determined by the prescribing\nphysician based upon the \ufb02ow rate (per\nminute) desired, the daily period of usage,\nthe patient\u2019s physical condition and daily\nactivities\u201d (110).\nAlthough individual coverage varies\nacross insurance companies, one national\ninsurer\u2019s policy for portable oxygen,\nAMERICAN THORACIC SOCIETY DOCUMENTS\nAmerican Thoracic Society Documents e135\nincluding ambulatory LOX, says it is\n\u201cConsidered medically necessary for\nmembers who occasionally go beyond the\nlimits of a stationary oxygen delivery\nsystem with 50-ft. tubing for .2 hours per\nday for most days of the week (minimum 2\nhours\/week)\u201d (111).\nFinally, a health technology assessment\nin Quebec, Canada, assessing the evidence\nbehind portable LOX concluded that\n\u201cadvantages are likely to be most bene\ufb01cial\nto a select group of patients who are\nrelatively active and compliant with\ntherapy, while there are no agreed social or\nclinical indicators that would be reliable\npredictors of use or bene\ufb01t\u201d (112).\nImplementation considerations. Costs\nassociated with LOX are higher than for other\ndelivery systems. DME suppliers in the\nUnited States are reluctant to provide LOX\nunder current CMS funding, as it does not\nfully reimburse costs associated with a special\ndelivery truck, frequent deliveries, and related\nequipment. In other countries, provision of\nLOX varies in its costs, availability, and\npatient eligibility requirements. The\nfeasibility of implementing LOX will vary\nacross geographic areas and reimbursement\npolicies.\nValues and preferences. This\nrecommendation places a high value on\nHRQL related to mobility outside of the\nhome and places a lower value on costs and\nresource use.\nResearch needs. The lack of any studies\nmeeting our evidence criteria underscores\nthe need for future research on the bene\ufb01ts\nof LOX in those with ILD and in other\npatients who require high-\ufb02ow oxygen and\nare mobile outside the home. Outcomes\nsuch as change in mobility, depressive\nsymptoms, use of healthcare resources, and\nsurvival require further investigation.\nTechnologic and device-development\nresearch is needed to develop lighter-weight\nand longer-lasting portable oxygen devices.\nEducation and Safety\nConsiderations\nPanel Discussion\nThe panel agreed that for all patients\nreceiving home oxygen therapy, there was\nno acceptable alternative to providing\npatients and their caregivers appropriate\neducation related to adherence to their\noxygen prescription, proper use and\ntroubleshooting of oxygen equipment,\noxygen safety education, and education on\nself-management. These were recurring\ntopics of discussion for all population,\nintervention, comparison, and outcome\nquestions. The panel agreed that these\nrecommendations applied to patients using\nLTOT as well as to ambulatory oxygen users.\nA best-practice statement was included to\naddress these recommendations.\nSafety education should be provided to\npatients and caregivers to avoid tripping and\nfalls and to decrease \ufb01re risk by not smoking\nor allowing smoking inside the home, to\navoid the use of inline devices, to avoid\nactivities around an open \ufb02ame or spark,\nand to avoid the use of nonpetroleum nasal\nproducts (5, 28). For LOX users, patients\nshould be provided product information\nthat includes instructions on avoiding skin\nburns from contact with any of the frosted\nparts on LOX-device connectors (108). The\npanel agreed that patients also need\nguidance on transporting and traveling\nsafely with oxygen (14).\nAccess to oxygen for patients who\ncontinue to smoke varies globally. In some\nregions, smoking is an absolute\ncontraindication to home oxygen therapy\n(9); the BTS recommends advising the\npatient that oxygen provides limited clinical\nbene\ufb01t for those who continue to smoke\n(36). Smoking safety is now inclusive of\ne-cigarettes, or vaping, on the basis of\nreported burn accidents in e-cigarette\nsmokers receiving home oxygen therapy\n(113). Included in safety concerns is\nestablishment of back-up devices for\nemergencies or loss of power. Current\nsmokers or caregiver smokers should\nreceive education and support for treatment\nof tobacco dependence (referral to\nappropriate resources).\nEducational support is necessary for\npatients and caregivers and should be tailored to\npatients\u2019 health literacy and cultural contexts.\nCurrent practice does not consistently include\neffective evaluation and support of the oxygen-\nusing patient by healthcare providers or oxygen\ndelivery personnel to ensure adequate education\nand return demonstration of their ability to use\ntheir prescribed devices (teaching back) both in\nthe home and ambulatory settings (13). Other\nconsiderations include access to appropriate\nequipment based on patients\u2019 physical,\nphysiologic, and lifestyle and\/or mobility needs.\nClinical support for monitoring at home by\nnurses and respiratory therapists is rare in the\nUnited States but common in other regions\n(19). The panel agreed that patients should be\nadvised to bring their portable device to\nhealthcare visits to assess its effectiveness and to\nreinforce self-management.\nAll panelists agreed on the need\nfor ongoing reassessment of patients\u2019\nincreased or decreased oxygen needs and\nacknowledged that the frequency would\nvary by disease characteristics, rate of\nprogression, or posthospitalization status.\nThe high priority for posthospitalization\nreassessment of the ongoing need\nfor oxygen is in agreement with the\nATS\/American College of Chest\nPhysicians policy statement (40) and\nothers \ufb01ndings (39).\nATS Recommendation\nFor patients prescribed home oxygen\ntherapy, we recommend that the patient\nand their caregivers receive instruction\nand training on adherence to their oxygen\nprescription; the use, maintenance and\ntroubleshooting of all oxygen equipment;\nand education on oxygen safety,\nincluding smoking cessation, \ufb01re\nprevention, and tripping hazards (best-\npractice statement).\nConclusions\nOur systematic review reveals that the\nquality and quantity of clinical trial evidence\nis low, thereby leaving signi\ufb01cant gaps in\navailable data regarding prescription of\nsupplemental oxygen. The need for\nguidance is high; the prescription of\nsupplemental oxygen is common. The\nrecommendations in this document re\ufb02ect\nan integration of current evidence and\nclinical experience by a multidisciplinary\nexpert panel.\nFor patients with severe resting\nhypoxemia, the prescription of LTOT to\nimprove survival is supported by historical\ntrials in patients with COPD. The panel\nalso strongly recommends prescribing\noxygen for patients with ILD with\nsevere resting hypoxemia. Existing\nevidence and panel consensus suggest not\nprescribing LTOT for patients with COPD\nwith moderate resting hypoxemia. The\npractice of initiating short-term oxygen\ntherapy on hospital discharge in patients\nwith severe hypoxemia is based on indirect\nevidence from the NOTT and MRC clinical\ntrial populations with chronic hypoxemia.\nThe harms and bene\ufb01ts of prescribing\nshort-term oxygen therapy on hospital\nAMERICAN THORACIC SOCIETY DOCUMENTS\ne136 American Journal of Respiratory and Critical Care Medicine Volume 202 Number 10 | November 15 2020\ndischarge deserves further study. Further\nresearch is needed on the appropriate use of\nshared decision-making between patients\nand their clinicians for decisions regarding\nhome oxygen therapy and on approaches to\ndiscontinue home oxygen in patients\nwho no longer have severe resting\nhypoxemia.\nThis review con\ufb01rmed scarce and\ninconclusive data to support the\nprescription of oxygen in patients who have\nnormoxemia at rest but desaturate\n(sometimes markedly) with exertion.\nEmerging evidence suggests that\nambulatory oxygen may improve HRQL in\npatients with ILD in the short term, but\nlonger-term data are needed. This was\nidenti\ufb01ed as a critical research need. The\nurgency is underscored by the treatment\u2019s\ncumbersome nature, associated risks, and\ncomplex effects on the patients, families,\nand caregivers.\nNo studies met the panel\u2019s criteria for\nthe evaluation of LOX in patients who use\n.3 L\/min of continuous-\ufb02ow oxygen and\nspend regular and frequent time outside the\nhome. The panel concluded that although\nan E tank, or other large metal cylinder, can\nadequately provide oxygen at up to 5 or 6\nL\/min, the patient would be restricted by\nthe need to carry multiple E tanks to leave\nhome for anything more than a very short\ntime period. Thus, this population is\nunintentionally denied the necessary\nmobility to travel, work, socialize, or attend\npulmonary rehabilitation\u2014critical\ncontributors to HRQL. The panel\nunanimously agreed that LOX should be\noffered to active patients on high-\ufb02ow\noxygen and that policies to accommodate\nthis subgroup should be moved\nforward.\nFinally, the minimal standard of\ncare for all patients receiving home\noxygen therapy must include education\nand training related to their oxygen\nequipment, oxygen safety, and self-\nmanagement.\nWe urge the research community and\nfunding agencies to work together to develop\na stronger evidence base that will guide\nclinical practice for oxygen prescription. Of\ncritical importance is the involvement of\nengineers and those in related \ufb01elds who can\ncombine creativity with applied science to\ndevelop methods of raising arterial blood\noxygen content to normal levels, even during\nintense exercise, without the burdens\nassociated with current oxygen delivery\nsystems. n\nThis official clinical practice guideline was prepared by an ad hoc subcommittee of the ATS Assembly on Nursing.\nMembers of the subcommittee are as\nfollows:\nSUSAN S. JACOBS, R.N., M.S.1\n(Co-Chair)\nANNE E. HOLLAND, P.T., PH.D.2\n(Co-Chair)\nJERRY A. KRISHNAN, M.D., PH.D.3\n(Co-Chair)\nDAVID J. LEDERER, M.D.4,5\n(Co-Chair)\nBRIAN CARLIN, M.D.6\nM. BRADLEY DRUMMOND, M.D., M.H.S.7\nMAGNUS EKSTRO\u0308M, M.D., PH.D.8\nCHRIS GARVEY, F.N.P., M.S.N., M.P.A.9\nMARYA GHAZIPURA, PH.D., M.S.10\n*\nBRIDGET A. GRANEY, M.D.11\nTANZIB HOSSAIN, M.D., M.S.10\u2021\nBEVERLY JACKSON, M.S.12x\nTHOMAS KALLSTROM, M.B.A., R.R.T.13\nSHANDRA L. KNIGHT, M.S.14k\nKATHLEEN LINDELL, PH.D., R.N.15\nVALENTIN PRIETO-CENTURION, M.D.3\nELISABETTA A. RENZONI, M.D., PH.D.16\nCHRISTOPHER J. RYERSON, M.D., M.A.S.17\nANN SCHNEIDMAN, M.S., C.N.S., C.H.P.N.18\nJEFFREY SWIGRIS, D.O., M.S.14\nAI-YUI M. TAN, M.D.3\u2021\nDONA UPSON, M.D., M.A.19\n*Lead methodologist.\n\u2021\nMethodologist.\nx\nPatient representative.\nk\nMedical librarian.\n1\nStanford University, Stanford, California; 2\nAlfred\nHealth, Monash University, Melbourne, Victoria,\nAustralia; 3\nUniversity of Illinois at Chicago,\nChicago, Illinois; 4\nRegeneron Pharmaceuticals,\nInc., Tarrytown, New York; 5\nColumbia University,\nNew York, New York; 6\nSleep Medicine and Lung\nHealth Consultants, Sewickley, Pennsylvania;\n7\nUniversity of North Carolina at Chapel Hill,\nChapel Hill, North Carolina; 8\nLund University,\nLund, Sweden; 9\nUniversity of California, San\nFrancisco, San Francisco, California; 10\nNew\nYork University Langone Health, New York\nUniversity, New York, New York; 11\nAnschutz\nMedical Campus, University of Colorado,\nAurora, Colorado; 12\nLAM Foundation,\nCincinnati, Ohio; 13\nAmerican Association for\nRespiratory Care, Irving, Texas; 14\nNational\nJewish Health, Denver, Colorado; 15\nUniversity\nof Pittsburgh, Pittsburgh, Pennsylvania; 16\nRoyal\nBrompton Hospital, London, United Kingdom;\n17\nUniversity of British Columbia, Vancouver,\nBritish Columbia, Canada; 18\nHospice of the\nValley, Phoenix, Arizona; and 19\nNew Mexico\nVeterans Affairs Health Care System,\nAlbuquerque, New Mexico\nAuthor Disclosures: S.S.J. served on an\nadvisory committee for the Pulmonary Fibrosis\nFoundation. A.E.H. served as a speaker for\nAstraZeneca and received research support\nfrom Air Liquide and Linde Healthcare.\nJ.A.K. served on a data safety and monitoring\nboard for Sanofi and received research\nsupport from Inogen, Patient-Centered\nOutcomes Research Institute, and ResMed.\nD.J.L. served on an advisory committee for\nBoehringer Ingelheim, Fibrogen, Galapagos,\nGenentech\/Roche, and Veracyte; served as a\nconsultant for Fibrogen, Galapagos, Galecto,\nGenentech\/Roche, Patara, the Pulmonary\nFibrosis Foundation, Sanofi, and Veracyte;\nreceived research support from Boehringer\nIngelheim, Fibrogen, and Global Blood\nTherapeutics; and is an employee of and\nowns stock and stock options with Regeneron.\nB.C. served on an advisory committee for\nAstraZeneca, GlaxoSmithKline, Monaghan,\nand Sunovion; served as a consultant for\nGlaxoSmithKline and Monaghan; and served\nas a speaker for GlaxoSmithKline, Monaghan,\nand Sunovion. M.B.D. served on an advisory\ncommittee for AstraZeneca, Boehringer\nIngelheim, GlaxoSmithKline, and Mylan; served\nas a consultant for AstraZeneca, Enterprise\nTherapeutics, GlaxoSmithKline, NovaVax,\nParion, Philips Respironics, and Theravance;\nreceived research support from Boehringer\nIngelheim; and received author royalties from\nKarger Publishing. C.G. served on an advisory\ncommittee, as a consultant, and as a speaker\nfor Boehringer Ingelheim. V.P.-C. received\nresearch support from ResMed and is an\nemployee of Vertex. E.A.R. served on\nan advisory committee for Roche; served\nas a speaker for Boehringer Ingelheim,\nMundipharma, and Roche; and received\ntravel support from Boehringer Ingelheim.\nC.J.R. served on an advisory committee for\nBoehringer Ingelheim and received research\nsupport from and served as a speaker for\nBoehringer Ingelheim and Roche. J.S. served as\na consultant for Boehringer Ingelheim; served on\nan advisory committee, served as a speaker for,\nand received research support from Boehringer\nIngelheim and Genentech; and served on the\nboard of directors and has an intellectual\nproperty\/patent unsold for Live Fully, Inc. M.E.,\nM.G., B.A.G., T.H., B.J., T.K., S.L.K., K.L., A.S.,\nA.-Y.M.T., and D.U. reported no relationships\nwith relevant commercial interests.\nAcknowledgment: The guideline panel thanks\nthe ATS staff for their organization and support,\nwhich was critical to this project\u2019s completion\nand success. The authors also thank panel\nmember Ms. Beverly Jackson for her insightful\ncontributions as an oxygen user and as an\nadvocate for those using home oxygen. The\npanel thanks the LOTT authors\u2019 sharing of their\nimportant data on patients with exertion-only\nhypoxemia and thanks the authors of the Moore\nand colleagues 2011 study (51) for providing\nadditional study information.\nAMERICAN THORACIC SOCIETY DOCUMENTS\nAmerican Thoracic Society Documents e137\nReferences\n1. Doherty DE, Petty TL, Bailey W, Carlin B, Cassaburi R, Christopher K,\net al. Recommendations of the 6th long-term oxygen therapy\nconsensus conference. Respir Care 2006;51:519\u2013525.\n2. Croxton TL, Bailey WC. Long-term oxygen treatment in chronic\nobstructive pulmonary disease: recommendations for future research:\nan NHLBI workshop report. Am J Respir Crit Care Med 2006;174:\n373\u2013378.\n3. Nocturnal Oxygen Therapy Trial Group. Continuous or nocturnal oxygen\ntherapy in hypoxemic chronic obstructive lung disease: a clinical trial.\nAnn Intern Med 1980;93:391\u2013398.\n4. Stuart-Harris C. 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Available from:\nhttps:\/\/www.faa.gov\/about\/initiatives\/cabin_safety\/portable_\noxygen\/.\nAMERICAN THORACIC SOCIETY DOCUMENTS\nAmerican Thoracic Society Documents e141","is_draft":"0","editor_type":"4","file_path":"\/docker_production\/zgvd51\/article\/lnHaHaAn\/article_file\/2020 ATS\u4e34\u5e8a\u5b9e\u8df5\u6307\u5357 \u6210\u4eba\u6162\u6027\u80ba\u75c5\u5bb6\u5ead\u6c27\u7597.pdf","add_time":"1757143013","update_time":"1757143079"},"pure_content":"AMERICAN THORACIC SOCIETY\nDOCUMENTS\nHome Oxygen Therapy for Adults with Chronic Lung Disease\nAn Of\ufb01cial American Thoracic Society Clinical Practice Guideline\nSusan S. Jacobs, Jerry A. Krishnan, David"},{"id":"610663","string_id":"e13amDwk","status":"1","parent_id":"610654","slug":"2024-TSANZ-lin-chuang-shi-jian-zhi-nan-cheng-ren-jia-ting-yang-liao","order":"0","name":"2024 TSANZ\u4e34\u5e8a\u5b9e\u8df5\u6307\u5357\uff1a\u6210\u4eba\u5bb6\u5ead\u6c27\u7597","type":"2","cover":"","cover_alt":"","desc":null,"website":"","contact":"","seo_title":"","seo_keyword":"","seo_desc":"","share_switch":"0","share_code":"","author":"","published_time":"1757143080","add_time":"1757143013","update_time":"1757143080","corp_auth_id":"0","verify_code_auth_id":"0","editor_type":"4","file_type":"pdf","auth_id":"[\"610663\", \"610654\"]","content":{"content_id":"610663","content":"C L I N I C A L P R A C T I C E G U I D E L I N E\nThoracic Society of Australia and New Zealand clinical practice\nguideline on adult home oxygen therapy\nChristine F. McDonald1,2,3\n| John Serginson4,5\n| Saad AlShareef6\n|\nCatherine Buchan7,8\n| Huw Davies9\n| Belinda R. Miller8,10\n| Maitri Munsif1,2,3\n|\nNatasha Smallwood7,8\n| Lauren Troy11,12,13\n| Yet Hong Khor1,2,3,7\n1\nDepartment of Respiratory and Sleep Medicine, Austin Health, Heidelberg, Victoria, Australia\n2\nInstitute for Breathing and Sleep, Heidelberg, Victoria, Australia\n3\nFaculty of Medicine, University of Melbourne, Melbourne, Victoria, Australia\n4\nDepartment of Respiratory Medicine, Sunshine Coast Health, Birtinya, Queensland, Australia\n5\nSchool of Nursing, Midwifery & Social Work, University of Queensland, St Lucia, Queensland, Australia\n6\nDepartment of Medicine, College of Medicine, Imam Mohammad Ibn Saud Islamic University (IMSIU), Riyadh, Saudi Arabia\n7\nRespiratory Research@Alfred, Central Clinical School, Monash University, Melbourne, Victoria, Australia\n8\nDepartment of Respiratory Medicine, Alfred Health, Melbourne, Victoria, Australia\n9\nRespiratory and Sleep Services, Flinders Medical Centre, Southern Adelaide Local Health Network, South Australia, Australia\n10\nCentral Clinical School, Monash University, Melbourne, Victoria, Australia\n11\nDepartment of Respiratory and Sleep Medicine, Royal Prince Alfred Hospital, Camperdown, New South Wales, Australia\n12\nSydney Medical School, Faculty of Medicine and Health, University of Sydney, Sydney, New South Wales, Australia\n13\nInstitute for Academic Medicine, Royal Prince Alfred Hospital, Camperdown, New South Wales, Australia\nCorrespondence\nChristine F. McDonald\ncmcdo@unimelb.edu.au\nHandling Editors: Philip Bardin and Paul\nReynolds\nAbstract\nThis Thoracic Society of Australia and New Zealand Guideline on the provision of\nhome oxygen therapy in adults updates a previous Guideline from 2015. The\nGuideline is based upon a systematic review and meta-analysis of literature to\nSeptember 2022 and the strength of recommendations is based on GRADE meth-\nodology. Long-term oxygen therapy (LTOT) is recommended for its mortality ben-\nefit for patients with COPD and other chronic respiratory diseases who have\nconsistent evidence of significant hypoxaemia at rest (PaO2 \u2264 55 mm Hg or PaO2\n\u226459 mm Hg in the presence of hypoxaemic sequalae) while in a stable state. Evi-\ndence does not support the use of LTOT for patients with COPD who have moder-\nate hypoxaemia or isolated nocturnal hypoxaemia. In the absence of hypoxaemia,\nthere is no evidence that oxygen provides greater palliation of breathlessness than\nair. Evidence does not support the use of supplemental oxygen therapy during pul-\nmonary rehabilitation in those with COPD and exertional desaturation but normal\nresting arterial blood gases. Both positive and negative effects of LTOT have been\ndescribed, including on quality of life. Education about how and when to use oxy-\ngen therapy in order to maximize its benefits, including the use of different deliv-\nery devices, expectations and limitations of therapy and information about hazards\nand risks associated with its use are key when embarking upon this treatment.\nK E Y W O R D S\nclinical respiratory medicine, hypoxaemia, long-term oxygen therapy, oxygen guideline, oxygen therapy\nReceived: 5 December 2023 Accepted: 27 June 2024\nDOI: 10.1111\/resp.14793\nThis is an open access article under the terms of the Creative Commons Attribution-NonCommercial License, which permits use, distribution and reproduction in any medium,\nprovided the original work is properly cited and is not used for commercial purposes.\n\u00a9 2024 The Author(s). Respirology published by John Wiley & Sons Australia, Ltd on behalf of Asian Pacific Society of Respirology.\nRespirology. 2024;1\u201320. wileyonlinelibrary.com\/journal\/resp 1\nINTRODUCTION\nThis Thoracic Society of Australia and New Zealand\n(TSANZ) Clinical Practice Guideline updates previous\nevidence-based guidance published by the Society on the use\nof domiciliary oxygen therapy for adults in the community.1\nThe Guideline is intended for use by health care profes-\nsionals, as well as government agencies and other providers\nof domiciliary oxygen therapy.\nThe Guideline includes broad recommendations for the\nuse of domiciliary oxygen therapy, including: long-term con-\ntinuous oxygen therapy, nocturnal oxygen therapy, ambulatory\noxygen therapy, palliative oxygen therapy, short-term oxygen\ntherapy and oxygen for specific indications, including during\npulmonary rehabilitation, air travel, acute asthma and other.\nThe Guideline also reviews the evidence base for guid-\nance on different oxygen delivery devices, considerations of\nsafety and risks associated with using domiciliary oxygen\ntherapy, initial assessment and follow-up of domiciliary oxy-\ngen therapy and education provision.\nMETHODS\nWorking Party formation\nFollowing a call for expressions of interest, a multidisciplinary\nand geographically diverse group of TSANZ members was\nappointed to the Working Party including adult respiratory\nand sleep physicians, a respiratory and sleep nurse consultant,\na respiratory nurse practitioner and a methodologist, with con-\ntributions during the early phase of development from a phys-\niotherapist and an additional adult respiratory and sleep\nphysician (see Table S1 in the Supporting Information for\nmembership details).\nLiterature review\nKey topic areas were identified by the Working Party to define\nthe scope and priorities of the Guideline (Table S2 in the Sup-\nporting Information). A literature search was conducted using\nOvid MEDLINE, EMBASE, CINAHL, Cochrane Database of\nSystematic Reviews and Cochrane Central Register of Con-\ntrolled Trials, from inception. The initial search was conducted\nin February 2021 and updated in September 2022. For the full\nsearch strategies and results, see Table S3 and Figure S1 in the\nSupporting Information, respectively.\nInclusion and exclusion criteria for study selection are\nlisted in Table S4 in the Supporting Information. Briefly,\nonly original English language research articles were\nincluded. All working party members were involved in the\nliterature appraisal. Sequential review of titles and abstracts\nfollowed by full-text articles was performed by two members\nindependently to identify eligible citations. Data extraction\nwas performed by one member using a standardized data\nextraction form, which was verified by a second member.\nEvidence synthesis and appraisal\nExisting data from relevant guidelines and systematic\nreviews of long-term oxygen therapy (LTOT) and ambula-\ntory oxygen therapy were reviewed, checked and incorpo-\nrated into the evidence synthesis with additional studies\nidentified from the literature search. Meta-analyses using\nrandom-effects models were performed for nocturnal oxy-\ngen therapy using Review Manager (RevMan, version 5.4;\nthe Cochrane Collaboration), as this had not been per-\nformed in previous guidelines and systematic reviews. Nar-\nrative synthesis of identified literature was performed for the\nremaining sections.\nRisk-of-bias assessment of all included studies was\nevaluated independently by two members using risk\nassessment tools according to the Cochrane Handbook\nfor Systematic Reviews of Interventions for randomized\nand non-randomized intervention trials and the\nNewcastle-Ottawa scale for observational studies. Dis-\nagreements were resolved by a third member if required.\nFor grading of recommendations regarding different types\nof oxygen therapy the GRADE approach was adopted\nwith consideration of study design, imprecision, indirect-\nness, inconsistency, publication bias, risk of bias and\nother aspects (effect magnitude, dose\u2013response gradients\nand confounders biasing toward an opposite effect). The\nstrength of recommendations was graded as strong and\nweak based on consensus discussion, with the level of evi-\ndence being classified as high, moderate, low and very\nlow.2\nRecommendations concerning oxygen delivery\ndevices, safety considerations when using domiciliary\noxygen therapy, initial assessment, education provision\nand follow-up of patients receiving domiciliary oxygen\ntherapy were developed based on consensus discussion\nfollowing literature review.\nPeer review and dissemination\nThis Guideline underwent joint peer review by TSANZ and\nRespirology and will be reviewed by TSANZ for currency\nwithin 36\u201348 months. Once published, this Guideline is\nintended for dissemination through the TSANZ website and\neducational program.\nLONG-TERM CONTINUOUS OXYGEN\nTHERAPY\nChronic obstructive pulmonary disease\na. Severe resting hypoxaemia\nThere have not been any high-quality randomized con-\ntrolled trials (RCTs) of LTOT for severe resting hypoxaemia\nsince the landmark Nocturnal Oxygen Therapy Trial\n(NOTT) and Medical Research Council (MRC) trial were\n2 MCDONALD ET AL.\nreported in the 1980s (Table S5 in the Supporting Informa-\ntion). Criteria for entry to the NOTT were PaO2 \u226455 mm\nHg with or without hypercapnia or PaO2 \u226459 mm Hg in the\npresence of cor pulmonale, haematocrit \u226555% or electrocar-\ndiographic evidence of P pulmonale on two measurements\nover a 3-week exacerbation free period.3\nThe trial enrolled\n203 patients with stable hypoxaemia who were randomized\nto nocturnal or continuous oxygen therapy (concentrator\nplus portable oxygen) with follow-up for 3 years or until\ndeath. Overall mortality in the nocturnal group was signifi-\ncantly higher at 1.94 times that in the continuous oxygen\ntherapy group, with the latter averaging 18 h of\noxygen usage per 24 h. The MRC trial included 87 hypercap-\nnic patients with COPD and PaO2 40\u201360 mm Hg on two\nmeasurements over a 3-week exacerbation-free observation\nperiod.4\nIn this unblinded study, patients received oxygen\nvia concentrator for 15 h\/day (without portable oxygen) or\nno oxygen at all. Patients were followed for 5 years or until\ndeath. Nineteen of the 43 treated patients died during\nfollow-up compared with 30 out of 45 controls.4\nThere have\nbeen no head-to-head studies examining what the appropri-\nate duration of continuous oxygen therapy should be. In a\nprospective Swedish cohort study of 2249 patients with\nCOPD, no mortality difference was observed between\npatients who were prescribed oxygen for 24 h or 15 h\nper day.5\nFew studies have evaluated the impact of LTOT on hos-\npitalization. In an Egyptian observational study, LTOT fol-\nlowing hospital discharge after exacerbation of COPD\nreduced hospitalizations and improved health-related qual-\nity of life (HRQoL),6\nwhile in an Australian study, bed days\nper patient year of follow-up of a cohort of patients with\nchronic airflow limitation were reduced by 35% after the\nintroduction of LTOT.7\nIn a retrospective Swedish study\nthere was no difference in hospitalization between the two\ndurations of therapy\u201415 h versus 24 h.8\nEvidence regarding other treatment effects of LTOT in\npatients with COPD remains limited. Although modest\nand comparable improvements in neuropsychological tests\ncompared to baseline were demonstrated after 6 months\nof either continuous or nocturnal oxygen therapy in a sub-\nset of the NOTT, no appreciable changes were found in\nself-reported general emotional status or HRQoL.9\nSimi-\nlarly, no HRQoL effect of LTOT was found after 6 months\nof LTOT in a United Kingdom (UK) study.10\nIn a\nNew Zealand study of two groups of patients with COPD,\none fulfilling criteria for and started on LTOT (as per the\nNOTT study3\n) and the second not fulfilling criteria and\ncontinuing with usual care, HRQoL was worse at baseline\nin the LTOT group and showed significant improvements\nat 2 and 6 months, while the non-LTOT group showed a\nprogressive decline.11\nb. Moderate resting hypoxaemia\nBenefits of LTOT in patients with COPD and moderate\nresting hypoxaemia remain unproven, where varying\ndefinitions of \u2018moderate\u2019 are used in this context (Table S6\nin the Supporting Information). A Polish study of\n135 patients with COPD and resting PaO2 56\u201365 mm Hg,\nrandomly assigned to LTOT 17 h\/day versus no LTOT\nfound no difference in cumulative survival,12\nand no reduc-\ntion in hospitalizations was found in a Danish study com-\nparing pre- and post-oxygen hospitalizations after at least\n1 month of continuous oxygen therapy in patients with\nPaO2 55\u201371 mm Hg.13\nSimilar results to these two earlier\nstudies were found in the long-term oxygen treatment trial\n(LOTT) where 738 patients with COPD and resting SpO2\n89%\u201393% were randomized to continuous oxygen or no\noxygen.14\nInitial recruitment was slow and entry criteria\nwere expanded to also include patients who desaturated only\nduring exercise. Treatments included oxygen 24 h per day\n(via stationary and portable devices) for moderate resting\nhypoxaemia and nocturnal and exertional oxygen in the case\nof exercise desaturation only. No differences between groups\nwere found for the primary composite outcome of death or\nhospitalization for COPD or for any secondary outcome.\nOther chronic respiratory and cardiac diseases\nThere are limited published clinical trials evaluating treatment\neffects of LTOT beyond patients with COPD (Table S7 in the\nSupporting Information), which are summarized below.\na. Heart failure\nIn a UK RCT, 139 patients with heart failure and New York\nHeart Association (NYHA) class III\/IV symptoms were ran-\ndomized to receive 6 months of LTOT 15 h\/day versus no\ntreatment.15\nNo benefit was observed in any outcome mea-\nsure at 6 months, although the Minnesota Living with Heart\nFailure score was lower at 3 months in the LTOT group.\nb. Chronic thromboembolic pulmonary hypertension\n(CTEPH)\nIn a crossover study of 30 patients with CTEPH and exer-\ntional desaturation without resting hypoxaemia randomized\nto oxygen >16 h\/day via concentrator (mean usage 13.2 h\/\nday) or identical concentrator modified to provide 21% oxy-\ngen over 5 weeks, there was a statistically significant\nimprovement of 19 m in 6-min walk distance on room air\n(although this was less than the minimal important differ-\nence), compared with 1 m for the placebo air group.16\nThere were improvements in HRQoL with between-group\ndifference of 6 points for SF-36 physical functioning and\nNYHA functional class, compared with air.\nc. Kyphoscoliosis\nIn a prospective observational study of 244 patients with\nrespiratory failure due to kyphoscoliosis, LTOT was infe-\nrior to mechanical ventilation at home for survival.17\nTSANZ ADULT HOME OXYGEN GUIDELINE 3\nRecommendations for LTOT.\nUnchanged from previous Guideline.\n\u2022 Long-term continuous oxygen therapy aimed at\nimproving survival is recommended for suitable\npatients with awake resting PaO2 on room air\nconsistently \u226455 mm Hg, or PaO2 \u2264 59 mm Hg\nin the presence of cor pulmonale, haematocrit\n\u226555% or ECG evidence of P pulmonale during an\nexacerbation free period who have\n\u000e COPD, (Strength of recommendation: Strong;\nEvidence: Moderate)\n\u000e other conditions, including but not limited to\nchronic respiratory or cardiac diseases\n(Strength of recommendation: Strong; Evi-\ndence: Low)\n\u2022 Safety considerations should be included in\npatient-centric discussions of LTOT initiation,\nincluding both physical and psychological\nimpacts (Tables S5\u2013S7 in the Supporting Infor-\nmation and see \u2018Safety considerations\u2019 section)\nChanged from previous Guideline-new\nrecommendation.\n\u2022 Long-term continuous oxygen therapy is not\nrecommended for patients with COPD and mod-\nerate resting hypoxaemia (i.e., PaO2 56\u201359 mm\nHg in the absence of cor pulmonale, haematocrit\n\u226555% or ECG evidence of p pulmonale)\n(Strength of recommendation: Strong; Evidence:\nLow). Extrapolating from this, and in the absence\nof evidence, long-term continuous oxygen is not\nrecommended for patients with moderate hypox-\naemia due to other conditions\nNOCTURNAL OXYGEN THERAPY\nNocturnal hypoxaemia may occur in the absence of day-\ntime hypoxaemia in patients with chronic respiratory\nand cardiac diseases, with or without associated sleep\ndisordered breathing. Nocturnal hypoxaemia has been\nlinked with poorer prognosis, disease progression and\ndevelopment of pulmonary hypertension in patients\nwith COPD, interstitial lung disease (ILD) and cystic\nfibrosis (CF).18\u201321\nChronic obstructive pulmonary disease\nThree RCTs including a total of 183 patients with COPD\nand isolated nocturnal hypoxaemia investigated the impact\nof nocturnal oxygen therapy (NOT) on survival and\nprogression to LTOT,22\u201324\nincluding the International Noc-\nturnal Oxygen trial (INOX). Meta-analyses of these studies\nshowed no impact of nocturnal oxygen therapy on 3-year\nsurvival and\/or progression to LTOT (Figure S2 in the Sup-\nporting Information), with a similar absence of effects\nobserved for secondary endpoints in the INOX trial includ-\ning hospitalizations, acute exacerbation rates or HRQoL.22\nConflicting results were reported regarding the impact of\nNOT on invasively measured pulmonary haemodynamics in\nthe two smaller studies.23,24\nSeveral small crossover studies of NOT versus room air\nin patients with COPD and varying degrees of nocturnal\noxygen desaturation failed to demonstrate any benefit with\nrespect to sleep quality or daytime exercise performance\n(Table S8 in the Supporting Information). A small study\ncomparing nasal continuous positive airway pressure\n(CPAP) with entrained oxygen at 1.5 L\/min against CPAP\nand room air on three single overnight studies in 10 hypox-\naemic male patients with COPD-OSA overlap showed\nimproved oxygenation and abolition of obstructive events\nwith the combination intervention of CPAP and oxygen,\ncompared with CPAP and room air.25\nHeart failure\nMultiple short- and long-term studies have compared NOT\nwith different controls (medical air, room air, or no treat-\nment) in patients with heart failure and associated Cheyne\nStokes respiration (Table S9 in the Supporting Information).\nTwo RCTs of NOT versus air for 6\u201312 months in patients\nwith heart failure demonstrated consistent improvements in\nindices of sleep disordered breathing, but conflicting impacts\non HRQoL, functional status and left ventricular ejection\nfraction.26,27\nSimilar benefits in sleep indices were observed\nin a meta-analysis of two RCTs including a total of\n76 patients assigned to NOT or room air during sleep over\n12 weeks (Figure S3 in the Supporting Information).28,29\nA\nfollow-up survey sub-study of these Japanese studies\nreported economic benefits with NOT resulting in total\nmedical cost-reduction, which was primarily related to\nreduced hospital bed-days.30\nFindings from several small crossover, before-and-after\nand uncontrolled studies support the benefit of NOT over\nroom air for treating obstructive and central sleep apnoea,\nwith variable impact on HRQoL measures, cognition, car-\ndiac function and daytime exercise performance (Table S9\nin the Supporting Information). In-laboratory single-night\nstudies also consistently show an improvement in mean\nsleep oxygenation, overall apnoea-hypopnoea index (AHI)\nand central AHI with NOT (Table S9 in the Supporting\nInformation). Cardiac arrhythmias and heart rate variability\nwere not attenuated with NOT compared with room air in\nthese studies, however, heterogeneity in individual respon-\nsiveness has been observed.31\u201333\nNocturnal oxygen therapy has also been evaluated\nagainst CPAP and adaptive servoventilation (ASV) in two\n4 MCDONALD ET AL.\nstudies of patients with heart failure. With small sample\nsizes and limited intervention periods of 12 weeks, neither\nstudy demonstrated clear superiority for either interven-\ntion with respect to indirect measures of right ventricular\nstrain, pulmonary haemodynamics or exercise capacity,\nalthough there was a greater reduction in AHI with CPAP\nor ASV than with NOT.34,35\nObstructive sleep apnoea\nUncomplicated obstructive sleep apnoea (OSA) is typically\nmanaged with risk factor mitigation, and CPAP therapy. Alter-\nnative therapeutic strategies including NOT have been studied\n(Table S10 in the Supporting Information). One large RCT\nevaluated CPAP versus NOT at 2 L\/min versus education only\nin an OSA population with cardiovascular disease or multiple\ncardiac risk factors over 12 weeks.36,37\nThis study demonstrated\nreduced blood pressure and improvements in sleepiness, men-\ntal health, social functioning and depressive symptoms in the\nCPAP group, but no impact with lifestyle education alone or\nNOT.36,37\nPhysical function as assessed by the SF-36 question-\nnaire, however, was superior in the NOT group, compared\nwith the CPAP group. Short-term studies comparing NOT\nwith CPAP in patients with OSA have generally confirmed\nsuperiority of CPAP over NOT for sleep quality, neuropsycho-\nlogical and cardiovascular endpoints,38\u201340\nexcept for one\nreporting improved depression scores from baseline in subjects\nassigned to NOT but not in CPAP or sham CPAP groups.41\nOther chronic respiratory diseases\nThere are limited published clinical trials evaluating treat-\nment effects of NOT in patients with CF and ILD\n(Table S11 in the Supporting Information).\na. Cystic fibrosis\nSmall studies of single-night NOT in adults with CF and iso-\nlated nocturnal hypoxaemia suggested a modest improve-\nment in oxygenation compared with room air, however,\nwith consequent elevations in transcutaneous CO2\nlevels.42\u201344\nIn an Australian RCT of non-invasive ventilation\n(NIV) with or without entrained oxygen versus low-flow\nNOT alone over 12 months in patients with nocturnal\nhypoxaemia45\nthose receiving NIV with or without oxygen\nhad a greater event-free survival compared with the NOT\ngroup, with events defined as worsening hypercapnia, death\nor lung transplantation.\nb. Interstitial lung disease\nWhile a recent Delphi survey of international ILD\nexperts supported the use of NOT in patients with ILD\nwith isolated nocturnal hypoxaemia,46\nthere has only\nbeen one published paper evaluating this therapy.47\nIn\nthis case\u2013controlled study over two nights at 2240 m\naltitude, 19 patients who received oxygen during sleep\nhad improved mean SpO2 and reduced heart and respi-\nratory rates during sleep, compared to those on\nroom air.\nRecommendations for NOT.\nMajor changes from previous Guideline.\nThe previous Guideline recommended NOT for\na subgroup of patients with lung disease and associ-\nated sleep-related hypoxaemia (desaturating to\n\u226488% for more than a third of total sleep time) but\nwithout severe daytime hypoxaemia, in particular\nfor those with evidence of hypoxic sequelae such as\npulmonary hypertension and polycythaemia, based\non weak evidence.1\nThis recommendation has been\nupdated based on recent literature as follows:\n\u2022 Nocturnal oxygen therapy is not recommended\nfor nocturnal hypoxaemia in the absence of day-\ntime hypoxaemia and\/or sleep disordered breath-\ning in patients who have:\n\u000e COPD, (Strength of recommendation: Weak;\nEvidence: Low)\n\u000e other chronic respiratory conditions (Strength\nof recommendation: Weak; Evidence:\nVery low)\n\u2022 Nocturnal oxygen therapy is recommended as\nsecond-line treatment for patients with\nchronic heart failure and persistent Cheyne\nStokes respiration after medical optimisation\nand consideration of CPAP as a treatment\noption (Strength of recommendation: Strong;\nEvidence: Moderate)\n\u2022 Nocturnal oxygen therapy is not recommended\nas first-line treatment for patients with OSA\n(Strength of recommendation: Strong; Evidence:\nModerate) although it may be considered in those\nwho are intolerant of CPAP (Strength of recom-\nmendation: Weak; Evidence: Very low).\nAMBULATORY OXYGEN THERAPY\nAmbulatory oxygen therapy can be used as either a\ncomponent of LTOT for patients with resting hypoxae-\nmia or in isolation for patients with exertional hypoxae-\nmia without resting hypoxaemia where benefit in terms\nTSANZ ADULT HOME OXYGEN GUIDELINE 5\nof exercise capacity or dyspnoea is demonstrated.\nAcross cohorts of patients with isolated exertional\nhypoxaemia, however, evidence for preferred laboratory-\nbased testing modalities, thresholds for clinical response\nand evidence for long-term therapeutic benefit based\nupon in-laboratory assessments is limited.\nChronic obstructive pulmonary disease\nThere have been no RCTs evaluating ambulatory oxygen\ntherapy in patients with COPD since the last TSANZ\nGuideline (Tables S12 and S13 in the Supporting Infor-\nmation). For patients with resting hypoxaemia needing\nLTOT, provision of ambulatory oxygen therapy in addi-\ntion to a stationary oxygen concentrator may assist with\nachieving a longer duration of oxygen treatment in\norder to maximize the benefits of LTOT.3\nFor patients\nwith isolated exertional hypoxaemia or without evidence\nof resting or exertional hypoxaemia, while acute benefits\nincluding improved oxygenation, exercise capacity (fre-\nquently measured as 6-min walk distance) and dyspnoea\nhave been demonstrated in some studies of supplemen-\ntal oxygen during in-laboratory exercise tests, there is\nno evidence suggestive of short-term or long-term\neffects on symptoms, HRQoL, healthcare utilization or\nsurvival for ambulatory oxygen therapy. A recent retro-\nspective observational study of 174 patients with iso-\nlated exertional desaturation showed no difference in\nsurvival over a median of 55 months between patients\nwith or without improved 6-min walk distance using\nambulatory oxygen therapy.48\nInterstitial lung disease\nNo studies evaluated effects of LTOT or ambulatory\noxygen therapy in patients with ILD and chronic resting\nhypoxaemia. For patients with isolated exertional hypoxae-\nmia, an unblinded crossover study of 2 weeks of ambulatory\noxygen therapy in 84 patients showed improved HRQoL,\ncompared to no treatment.49\nAs in similar studies of\npatients with COPD, acute benefits of improved\nexercise capacity were observed with supplemental oxygen\nduring in-laboratory exercise tests, without consistent\nchanges in dyspnoea scores (Table S14 in the Supporting\nInformation).\nOther chronic respiratory and cardiac diseases\nThere are limited in-laboratory studies of supplemental oxy-\ngen during exercise tests in patients with other chronic\nrespiratory diseases and cardiac diseases, demonstrating\ninconsistent effects on symptoms and exercise capacity\n(Table S15 in the Supporting Information).\nRecommendations for ambulatory oxygen\ntherapy.\nUnchanged from previous Guideline.\n\u2022 Ambulatory oxygen therapy is recommended to\nmaximize the benefits of LTOT in those fulfilling\ncriteria for LTOT. (Strength of recommendation:\nStrong; Evidence: Low)\n\u2022 Ambulatory oxygen therapy may be recom-\nmended for suitable patients with lung diseases\nwithout severe resting hypoxaemia and during an\nexacerbation-free period, who have exertional\nhypoxaemia (desaturation to \u226488% during exer-\ncise tests such as the 6-min walk test [6MWT])\nwhere improvement is demonstrated in exercise\ncapacity or level of dyspnoea. (Strength of recom-\nmendation: Weak; Evidence: Low).\n\u2022 While the use of ambulatory oxygen therapy may\nallow outdoor access and encourage physical\nactivities, it is associated with physical challenges\ndue to equipment weight and non-ergonomic\ndesign, as well as psychosocial stresses (Table S16\nin the Supporting Information and see \u2018Safety\nconsiderations\u2019 section). Adequate education and\ndiscussion with patients and their caregivers are\nneeded to support treatment decision-making for\nthe prescription and use of ambulatory oxygen\ntherapy.\nPALLIATIVE OXYGEN THERAPY\nPalliative oxygen therapy refers to domiciliary oxygen ther-\napy prescribed for the relief of dyspnoea in patients with\nlife-limiting illness who may not have hypoxaemia.\nIn five of six studies, including one multicentre inter-\nnational RCT of 239 patients,50\npalliative oxygen therapy\nshowed no significant difference in reduction of dyspnoea\ncompared to either medical air or no control (Table S17\nin the Supporting Information).50\u201354\nThe studied popula-\ntions and settings included patients with and without\nhypoxaemia, and with malignant and non-malignant ill-\nnesses, who were evaluated for domiciliary or inpatient\nusage, as well as during in-laboratory assessments. In the\nlarge RCT of stable patients with life-limiting illness and\nsevere dyspnoea, no differences were found in HRQoL or\nsleep parameters between oxygen and air at 2 L\/min via\nstationary concentrators for at least 15 h per day for\n7 days.50\nA retrospective cohort study showed that domi-\nciliary oxygen therapy was not significantly associated\nwith survival in patients with advanced cancer and low\noxygen saturation.55\n6 MCDONALD ET AL.\nAlthough there is no high-quality evidence demonstrat-\ning that palliative oxygen therapy reduces dyspnoea, some\npatients do appear to derive benefit from oxygen therapy. In\none pre- and post-study of patients referred to palliative\ncare, which showed no significant difference in mean dys-\npnoea after 1\u20132 weeks of domiciliary oxygen therapy, a sub-\nset of 150 patients amongst 413 showed 20% or greater\nimprovements in dyspnoea score.54\nHowever, no underlying diagnostic or demographic fac-\ntors could be identified as predicting responders at 1 week.54\nCaregivers for people receiving domiciliary oxygen\ntherapy for refractory dyspnoea in a palliative setting\nreported conflicting feelings. Many felt extreme distress\nat witnessing refractory dyspnoea and felt oxygen ful-\nfilled critical and beneficial roles in this context, but\nalso reported burden in loss of patient autonomy and\ncost.56\nClinicians similarly report mixed opinions on the\nrole of palliative oxygen therapy to treat dyspnoea.57\u201359\nIn a randomized crossover laboratory study of\n51 patients with advanced cancer and dyspnoea, there\nwas no difference in patient preference for medical air\nor oxygen therapy.52\nRecommendations for palliative oxygen therapy.\nMinor changes from previous Guideline.\nPalliative oxygen therapy is not recommended to\ntreat patients with severe dyspnoea and a life-\nlimiting illness who do not have severe resting\nhypoxaemia. (Strength of recommendation: Strong;\nEvidence: Low).\nSHORT-TERM OXYGEN THERAPY\nThe provision of domiciliary oxygen to patients who remain\nsignificantly hypoxaemic, typically at rest, upon hospital dis-\ncharge, has been termed short-term oxygen therapy (STOT).\nThe rationale for STOT provision lies in the concern that\nongoing hypoxaemia may have adverse outcomes. There is a\npaucity of studies to support its use (Table S18 in the Sup-\nporting Information) and potential adverse effects include\nrisk of worsened underlying hypercapnia in the setting of\nunstable respiratory disease, patient safety and risk consider-\nations such as fire and burns (described later), as well as\nincreased healthcare costs. Nevertheless, hypoxaemia and\nthe requirement for domiciliary oxygen therapy at discharge\nhave been reported as independent predictors of long-term\nmortality in patients hospitalized for acute exacerbation of\nCOPD.60\nMore recently, STOT has been used to facilitate early\ndischarge and outpatient management of patients with\nCOVID-19 pneumonia at times of scarce hospital resources,\nwhich is not covered in this Guideline.61\nPrescribing eligibility and reassessment\nfor STOT\nEligibility criteria for STOT are not standardized and thus\nare likely to vary across health services. Reported criteria\nfor STOT provision are often derived directly from those\nused to assess eligibility for LTOT for severe resting\nhypoxaemia, using arterial blood gas measurements of\nPaO2 \u226455 mm Hg or 56\u201359 mm Hg with evidence of hyp-\noxic end-organ damage.62\u201366\nThere is no evidence of the\nbenefits or otherwise of prescription of STOT for ambula-\ntion alone.\nIt is well-recognized that hypoxaemia may resolve after\nan acute illness, and that unnecessary ongoing oxygen use\nincurs significant resource costs and potential patient\nadverse events. Previous studies reported that 40%\u201380% of\npatients on STOT did not meet criteria for LTOT at subse-\nquent assessment at a range of 30\u201390 days post hospital dis-\ncharge.62\u201364,66\u201368\nAdditionally, appropriate reassessment for\neligibility for LTOT occurred in only 43%\u201362% of patients\ndischarged on STOT.64,66,67\nDifferent societies and expert\ngroups consistently recommend reassessment of oxygena-\ntion status within 90 days of hospital discharge,69,70\npending\nfurther studies. Predictors of progression of patients to\nLTOT from STOT have not been well identified.64,65\nRecommendations for STOT.\nNew recommendations.\nThere is a paucity of evidence-based data to guide\ndecision-making with respect to STOT. However,\nongoing provision of STOT may be justified if the\nbenefits of alleviating hypoxaemia in an individual\npatient are deemed to outweigh the potential risks\nof domiciliary oxygen therapy.\n\u2022 Short-term oxygen therapy may be recommended\nfor patients with persistent severe resting hypox-\naemia at hospital discharge. The use of LTOT\nprescribing criteria in the assessment for STOT is\nrecommended as a pragmatic approach. (Strength\nof recommendation: Weak; Evidence: Very low)\n\u2022 Reassessment for oxygen requirement should be\nconducted between 30 and 90 days post discharge\nand when stable. (Strength of recommendation:\nStrong; Evidence: Very low)\n\u2022 Education regarding oxygen therapy should be\nprovided to patients and their caregivers prior to\ndischarge, including realistic expectations of its\neffects. In addition, patients and their caregivers\nshould be informed of the need for reassessment\nTSANZ ADULT HOME OXYGEN GUIDELINE 7\nof oxygenation status post discharge and the\npotential withdrawal of oxygen therapy if no lon-\nger indicated.\nSPECIFIC INDICATIONS: EXERCISE\nTRAINING, AIR TRAVEL, ACUTE ASTHMA,\nHEADACHE\nExercise training\nThe effects of supplemental oxygen during exercise\ntraining have been primarily studied in patients with COPD\n(Table S19 in the Supporting Information). Since the last\nTSANZ guideline, a multicentre RCT demonstrated\nimproved exercise endurance and HRQoL after 24 sessions of\nexercise training over 8 weeks with oxygen or air delivered at\n5 L\/min in 111 patients with COPD and exertional desatura-\ntion, with no between-group differences identified.71\nSimilar\nfindings were observed in a number of small RCTs with\nmoderate-to-high risk of bias in patients with COPD who had\nvarying oxygen requirements72\u201377\nwhile one small study that\nincluded patients with chronic respiratory failure from a range\nof causes on LTOT demonstrated greater improvement in\n6MWD following pulmonary rehabilitation with heated,\nhumidified nasal high flow oxygen (hNHF-O2) compared with\noxygen via standard nasal cannula at 6 L\/min.78\nOf note, there\nmay be benefits of exercise training with supplemental oxygen\nin a selected population of patients with COPD, exertional\ndesaturation and positive acute response to supplemental oxy-\ngen during exercise tests.79\nThis warrants further evaluation.\nRecommendations for exercise training.\nMajor changes from previous Guideline.\n\u2022 Supplemental oxygen is not recommended for\nexercise training in patients with COPD not ful-\nfilling LTOT criteria. (Strength of recommenda-\ntion: Strong; Evidence: Low).\n\u2022 There are insufficient data to make recom-\nmendations regarding the use of oxygen for\nexercise training in other chronic respiratory\nconditions\nAir travel\nCabin pressures of commercial passenger aircraft range\nup to 2500 m above sea level ambient pressures during\nstandard operating conditions, which is analogous to\nbreathing 15% oxygen at sea level.1\nA small number of\nstudies have explored the impact of oxygen therapy on\nPaO2 at high altitude in patients with chronic respira-\ntory disease.80\u201384\nMost were experimental studies simu-\nlating a commercial aircraft cabin altitude of 8000 ft\nand administered supplemental oxygen via different\ndelivery methods, including continuous flow via a nasal\ncannula, an oxygen-conserving device, portable oxygen\nconcentrator (POC), or Venturi mask (Table S20 in the\nSupporting Information). Oxygen administration signifi-\ncantly increased PaO2 at altitude in some80\u201382\nbut not\nall studies,83\nwith results appearing to be affected by the\noxygen delivery method. In a survey of patients using\nLTOT who had flown with supplemental oxygen,84\nthe\nmajority found it complicated their travel in terms of\naccessing required information and organization,\nalthough four-fifths stated they would fly again.\nAs a practical approach, individuals with resting oxy-\ngen saturation \u226595% are unlikely to require in-flight sup-\nplemental oxygen.85,86\nFor other individuals, in-flight\noxygen should be considered, particularly for those with\nprevious significant intolerance to air travel, such as the\nrequirement for mid-air emergency oxygen or diversion,\nor who are using LTOT. Of note, neither resting sea level\noxygen saturation nor lung function reliably predicts\nhypoxaemia or complications of air travel in patients with\nrespiratory disease.86\u201388\nA hypoxic challenge test, also\nknown as an altitude simulation test, can be performed to\nprovide a more accurate evaluation of altitude oxygena-\ntion and prescription of in-flight supplemental oxygen for\nmaintaining PaO2 >50 mm Hg or oxygen saturation\n>85%, particularly in those with existing hypercapnia or\nat risk thereof.85,89,90\nRecommendations for air travel.\nMinor changes from previous Guideline.\n\u2022 Consideration of supplemental oxygen during\nair travel is recommended, where a traveller\nfulfils criteria for requiring LTOT (without\nevidence of hypercapnia) or has a demon-\nstrated fall in PaO2 to <50 mm Hg or SpO2\nto <85% during a hypoxic challenge test.\n(Strength of recommendation: Strong; Evi-\ndence: Low).\nAcute asthma\nThere is one prospective observational study showing that\nthe availability of domiciliary oxygen for administration\nat the start of an asthma attack reduced the risk of death\nin individuals at high risk for recurrent life-threatening\n8 MCDONALD ET AL.\nasthmatic attacks (Table S20 in the Supporting\nInformation).91\nRecommendations for acute asthma.\nMinor changes from previous Guideline.\n\u2022 Domiciliary oxygen therapy for acute use while\nawaiting medical attention can be considered in\npatients with previous near-fatal asthmatic\nattacks, at high risk of a future fatal asthmatic\nattack, or in patients with episodic acute asthma\nliving in isolated areas. (Strength of recommenda-\ntion: Weak; Evidence: Very low)\nHeadache\nSupplemental oxygen therapy has been studied for treatment of\nacute episodes of chronic headache (Table S20 in the Supporting\nInformation). Inhaled oxygen at a flow rate of \u226510 L\/min was\nfound to be effective in treating acute attacks of cluster head-\nache92,93\nand acute migraine94\nin randomized crossover trials,\nbut not for medication overuse headache in a case series.95\nRecommendations for headache.\nMajor changes from previous Guideline.\n\u2022 Intermittent inhaled high-flow oxygen (100% at\n10\u201315 L\/min via a non-rebreather mask) can be\noffered to patients to treat acute cluster headache\nattacks and acute migraine. (Strength of recom-\nmendation: Strong; Evidence: Low).\nDOMICILIARY OXYGEN DELIVERY\nOxygen therapy sources and equipment for improving the effi-\nciency of oxygen use are key to domiciliary oxygen delivery. In\nrecent years, domiciliary use of humidified nasal high-flow oxy-\ngen (hNHF-O2) has been explored. While there has been inter-\nest in the development of novel devices for auto-titration,96\u2013100\nremote control,101\ncompliance monitoring,102\u2013104\nand alterna-\ntive sources of oxygen therapy,105\nthey remain yet to be avail-\nable for commercial use.\nSources of domiciliary oxygen delivery\nSources of domiciliary oxygen delivery can be divided into\nstationary and ambulatory (Table S21 in the Supporting\nInformation). While liquid oxygen systems are used in some\ncountries,106\u2013108\nthey are not available for domiciliary use in\nAustralia and New Zealand.\nStationary oxygen source\nStationary oxygen concentrators remain the major source for\nproviding LTOT within the home. They are floor-standing\ndevices powered by the domestic electricity supply and provide\nan oxygen concentration of 90%\u201395%.1\nThe maximum flow\ndelivery of stationary oxygen concentrators is typically 5 L\/min\nwith some being capable of delivering up to 10 L\/min, although\nthe percentage of oxygen falls with increasing flow rate.109,110\nWith the use of 9 m extension tubing, patients can move\naround the home, but it is important to note that increasing\ntubing length beyond 30 m can result in a fall in the concentra-\ntion of delivered oxygen,111,112\nin addition to the potential haz-\nard of tripping or falling. Performance of stationary oxygen\nconcentrators can be affected by their working duration, with\nlower oxygen concentration associated with longer working\nduration,110,113\nindicating the importance of regular device\nchecks and servicing.\nAmbulatory oxygen source\nIn Australia and New Zealand, there are two sources for\nambulatory oxygen, with compressed oxygen cylinders of\nvarying sizes being the most common and POCs of different\nmodels being increasingly used in recent years. Compressed\noxygen cylinders contain 100% pure oxygen delivered at\nflow rates ranging between 1 and 6 L\/min, whereas POCs\nare rechargeable lightweight devices that generally deliver\noxygen concentrations of \u226590% in pulsed doses and\/or con-\ntinuous flow. Of note, POCs offer a range of numbered flow\nsettings that vary across models. These are not equivalent to\nthe numbered flow rate for compressed oxygen cylinders\n(e.g., setting of 1 for POC is not equivalent to flow rate of\n1 L\/min for compressed oxygen cylinder). Different POC\nmodels vary in their weight and size, oxygen pulse delivery,\nbattery life and performance at altitude (Table S21 in the\nSupporting Information).114\u2013117\nStudies comparing the performance of compressed oxy-\ngen cylinders and various POCs during in-laboratory assess-\nments and short-term domiciliary use in patients with\ndifferent respiratory diseases generally revealed similar dys-\npnoea scores, HRQoL, oxygenation capacity and 6-min walk\ndistances between cylinders and POCs, although there were\nsome between-study variations (Table S21 in the Supporting\nInformation).118\u2013128\nPOCs are preferred over compressed\noxygen cylinders for their portability and ease of use,\nalthough these factors may be of less concern for younger\npatients.123,125,127,128\nOf note, POCs have potential limita-\ntions with regard to battery life and oxygenation capacity,\nparticularly for patients requiring high flow settings,\ngiven their lower oxygen concentration delivery. The trans-\nportability of the ambulatory oxygen source may affect\nTSANZ ADULT HOME OXYGEN GUIDELINE 9\npatients\u2019 exercise capacity and dyspnoea level, noting that\ncarrying the device in a backpack may be favoured over\nusing a trolley or shoulder strap.129\u2013131\nEfficient use of oxygen\nEfficient oxygen use can be achieved by using oxygen con-\nserving devices (OCDs), including demand oxygen delivery\nsystems and specialized oxygen-conserving nasal cannulae.\nThese devices allow breath-triggered oxygen pulse delivery\nearly in inspiration to reduce gas wastage during expiration\ncompared to continuous flow. The efficiency of maintaining\nadequate oxygenation at lower oxygen usage yields practical\nbenefits, including extended cylinder range or the same\nrange with smaller and lighter cylinders, resulting in reduced\ncumulative refilling costs. There have been few advances in\nthis area since the last TSANZ Guideline (Table S22 in the\nSupporting Information).\nThe volume, delivery waveform and frequency vary\nacross different OCD models, which are given as either a\npre-set pulse volume (some or all breaths) or a pre-set\nminute volume averaged by respiratory rate that can affect\noxygen delivery during exertion.132\nThe specialized nasal\ncannula with a pendant-shaped reservoir allows its filling\nwith oxygen during exhalation and delivers a bolus\nentrained from the reservoir early in the subsequent inspira-\ntion. Compared to conventional nasal cannulae, it has been\nshown to enable adequate oxygenation at reduced mean\noxygen flow rates at 33%\u201350%133\u2013135\nand improved exercise\ntolerance for the same oxygen usage.136,137\nOf note, the\nadjustment in the oxygen flow rate for OCDs or oxygen-\nconserving nasal cannulae cannot be predicted based on the\nprescribed or current continuous flow rate, nor are these\nconsistent between different OCD models.132,136,138\u2013142\nHumidified nasal high-flow devices\nHumidified nasal high-flow devices deliver heated, humidi-\nfied oxygen (hNHF-O2) via wide-bore nasal cannulae (high\nflow nasal cannulae [HFNC]), with delivered concentrations\nof up to 100% and flow rates of up to 70 L\/min. These\ndevices have primarily been used in hospitals, including for\ndelivery of warm humidified air. The focus here is on their\nuse in the home (Table S23 in the Supporting Information).\nOne RCT of 200 patients with COPD and chronic\nhypoxaemic respiratory failure showed a reduction in exac-\nerbations in those using hNHF-O2 at 20 L\/min for an aver-\nage of 6 h\/day in addition to LTOT compared to those\nreceiving LTOT alone at 12 months, with no difference in\nmortality between the groups.143\nAnother study using at\nleast overnight HFNC with daytime LTOT versus LTOT\nalone showed a reduction in the rate of and increased\ntime to moderate-to-severe exacerbation in those with\nmoderate-to-severe disease and daytime hypercapnia over\n12 months.144\nPost-hoc analyses from a previous RCT sug-\ngested potential benefits of hNHF-O2 in selected patients\nwith severe COPD and chronic hypoxaemic respiratory fail-\nure with recurrent exacerbations.145\nCompared to LTOT,\nhNHF-O2 was found to improve HRQoL in patients with\nCOPD in two RCTs over 12 months, and in a randomized\ncrossover trial after 6 weeks of therapy.143,144,146\nHowever,\nvarying effects of hNHF-O2 on dyspnoea were reported\nin studies of different trial designs and patient\npopulations.143,146\u2013148\nIn terms of physiological effects on\ngas exchange and respiratory rates, hNHF-O2 was found to\nachieve at least comparable oxygenation levels in compari-\nson to LTOT,146,147,149\nreduced arterial partial pressure or\ntranscutaneous carbon dioxide levels at rest, during exercise\nand overnight,143,146,147,149\u2013152\nand reduced respiratory\nrate.147,152\nSerious adverse events have not been reported with the\ndomiciliary use of hNHF-O2.144,146\nNoise generated by hNHF-O2 devices is a common com-\nplaint which may be addressed through the use of filters\ndesigned for noise reduction.153\nFactors reported by patients\naffecting adherence with domiciliary hNHF-O2 in a RCT\nincluded perceived symptom and functional improvement,\nas well as perceived safety and familiarity with the device.154\nNevertheless, some patients reported preference for\nLTOT over hNHF-O2 with respect to dyspnoea and device\ninterface comfort.152\nCost evaluations in a New Zealand\nhealthcare setting showed cost-effectiveness and savings of\nup to $5535 NZD per patient-year associated with domicili-\nary hNHF-O2 compared to usual care (including LTOT) in\npatients with severe COPD,155\nwith similar cost-effectiveness\nreported in a European study.156\nRecommendations for sources of domiciliary oxy-\ngen delivery.\nNew recommendations.\n\u2022 Stationary concentrators are the recommended\nmeans of delivering oxygen in the home\n\u2022 Portable oxygen concentrators can be used as\nsources of ambulatory oxygen therapy, with titra-\ntion required to determine adequate oxygenation\nfor the specific prescribed device\n\u2022 Oxygen conserving devices (OCDs), including\ndemand oxygen delivery systems and specialized\noxygen-conserving nasal cannulae, can be used to\nachieve efficient oxygen use. Oxygen titration is\nneeded to determine the appropriate settings for\nthe individual with the specific OCD model\n\u2022 Routine use of domiciliary hNHF-O2 is not\nrecommended, although it may be considered on\na case-by-case basis, particularly in patients with\nCOPD and frequent exacerbations.\n10 MCDONALD ET AL.\nSAFETY CONSIDERATIONS\nThere are potential safety concerns and risks associated with\nthe use of domiciliary oxygen therapy. These include burns,\nfires, falls and other health consequences including the\ndevelopment of hypercapnia, as well as physical and psycho-\nlogical impacts on patients and caregivers (Tables S24 and\nS25 in the Supporting Information).\nFires and burns\nThere are limited published prospective safety studies on the\nrisks of burns in patients using domiciliary oxygen ther-\napy,157,158\nwith the majority being reported in retrospective\nstudies including case series and observational studies\n(Table S24 in the Supporting Information). Smoking by the\npatient or by others, is a major cause of burns and fires\nattributed to the use of domiciliary oxygen therapy, with\nother sources of ignition related to open flames such as dur-\ning cooking.159\u2013161\nBurns may be facial or to other external parts of the\nbody, but also include inhalation injuries in up to 39% of\npatients intubated for burns arising from domiciliary oxygen\ntherapy.162\u2013165\nDeaths as a result of fires and burns in the setting of\ndomiciliary oxygen therapy use have been reported, with a\nmean average hospital stay of 3.6 days in those with minor\nburns.157,159\u2013161,163,165\u2013167\nFalls\nThere is little data regarding the risk of falls associated\nwith using domiciliary oxygen therapy (Table S25 in the\nSupporting Information), although it is likely significant\ngiven the patient populations have high levels of frailty\nand multimorbidities.168\u2013170\nThis risk is of particular con-\ncern for patients who are cognitively, physically and\/or\nvisually impaired. An Australian observational study\nreported three cases of hospitalizations for falls associated\nwith domiciliary oxygen tubing over 4 years of follow-up\nin 291 patients on LTOT, with one complicated by\nfracture.171\nHypercapnia\nWhile worsening hypercapnia is a potential risk associated\nwith domiciliary supplemental oxygen therapy, this does not\nappear to be of significant concern in most patients. Specific\npopulations at risk of hypercapnic respiratory failure\n(including, but not limited to those with advanced suppura-\ntive lung diseases, chest wall deformities, severe obesity and\noverlapping sleep-disordered breathing), may require closer\nsurveillance and consideration of specialized respiratory fail-\nure support.\nOther health consequences\nA single case\u2013control study reported no differences in smell\nand taste for patients with COPD who were treated and not\ntreated with domiciliary oxygen therapy.172\nThree experimental\ncase\u2013control studies explored the impact of supplemental oxy-\ngen on systemic redox balance in patients with COPD.173\u2013175\nTwo studies reported significant increases in proinflamma-\ntory or oxidative stress biomarkers using supplemental\noxygen,173,174\nwith administration of the antioxidant N-\nacetylcysteine in one study reversing erythrocyte protein\noxidation.174\nThe third study did not detect any difference\nin the oxidative stress biomarker isofuran between patients\nreceiving and not receiving supplemental oxygen therapy.175\nPhysical and psychological impacts on patients\nand caregivers\nQualitative studies and surveys have explored the impact of\nusing domiciliary oxygen therapy on patients and caregivers\n(Tables S5\u2013S7, S16 and S25 in the Supporting Information).\nStigma associated with domiciliary oxygen therapy is com-\nmonly reported by patients.176\u2013178\nSome patients, who had\nused LTOT for more than 12 months, described poor self-\nimage and sadness,179\nwhile other patients and caregivers\nreported increased social activity and perceived improve-\nments in health status and capacity to participate in daily\nactivities as a result of LTOT.180\nThe use of domiciliary oxy-\ngen therapy also fails to meet patients\u2019 treatment\nexpectations.176,181,182\nAdverse impacts during daily living, as well as psycho-\nlogical and physical challenges, associated with using domi-\nciliary oxygen therapy affect both patients and their\ncaregivers.181\u2013185\nRecommendations regarding safety and risk\nconsiderations.\nSafety factors are essential considerations in the\nprescription of domiciliary oxygen therapy. Educa-\ntion and verbal and written information should be\nprovided to all patients, caregivers and any co-\ninhabitants.\nUnchanged from previous Guideline.\n\u2022 Oxygen should not be prescribed in patients who\ncontinue to smoke\nNew recommendations.\n\u2022 Oxygen should not be used in close proximity to\nnaked flames and other potential ignition sources\nincluding e-cigarettes\n\u2022 Caregivers and others should be advised not to\nsmoke in proximity to people using domiciliary\noxygen therapy\nTSANZ ADULT HOME OXYGEN GUIDELINE 11\n\u2022 Adherence with smoking abstinence can be mon-\nitored with urinary cotinine, and\/or carboxyhae-\nmoglobin and carbon monoxide measurements\n\u2022 Consideration should be given to withdrawing\ndomiciliary oxygen therapy if the user continues\nto smoke, or if there are other concerns regarding\nfire risk\n\u2022 Home visits by healthcare personnel may be an\nopportunity to provide additional information\nregarding fire and falls risks\n\u2022 Potential psychosocial impact of domiciliary oxy-\ngen therapy should be considered and discussed\nwith patients and caregivers as indicated\n\u2022 Potential risk of hypercapnia should be consid-\nered on a case-by-case basis\nASSESSMENT AND SUPPORT FOR\nDOMICILIARY OXYGEN THERAPY\nAssessment and support are key components for prescribing\ndomiciliary oxygen therapy (Table S26 in the Supporting\nInformation). In Australia and New Zealand, government-\nfunded domiciliary oxygen therapy is generally prescribed\nby a respiratory physician, general physician, cardiologist or\npaediatrician, with additional approval from a specified\nrespiratory physician required in some jurisdictions.1\nIn\nselected states of Australia and in New Zealand, oncologists,\ngeriatricians, palliative care specialists and nurse practi-\ntioners (respiratory) are listed as approved prescribers for\ndomiciliary oxygen therapy.1\nFor patients who reside in aged\ncare facilities, domiciliary oxygen may be ordered by any\nregistered medical officer.1\nThe availability of a domiciliary\noxygen therapy clinic, which may assist with appropriate\nassessment, prescription, support and follow-up of patients\nconsidered for domiciliary oxygen therapy varies across\nregions.68,186\u2013189\nOxygenation status assessment\na. Resting hypoxaemia\nRoom air arterial blood gas (ABG) analysis at rest is\nrequired to ascertain the presence of severe resting hypoxae-\nmia. After the patient is rested for 5\u201310 min breathing room\nair and an Allen\u2019s test is performed, an arterial sample using\na small 25-gauge needle without anaesthetic should be\nobtained by a trained operator experienced in the technique.\nThis approach will minimize pain and associated trauma,\nalthough patient preference should be considered.1\nOf note,\nusing a topical anaesthetic has not been demonstrated to\nreduce pain associated with radial artery sampling.190,191\nWhile pulse oximeters are non-invasive and easily available,\nmeasurements of oxygen saturation do not provide an accu-\nrate estimation of PaO2, and should only be used for screen-\ning purposes.192\u2013195\nIn order to determine the optimal\noxygen prescription to achieve SpO2 >90% or PaO2\n>60 mm Hg, assessment with pulse oximetry or repeat ABG\non supplemental oxygen may be performed. In patients with\na background or at risk of hypercapnia, assessments using\nABG on supplemental oxygen are required. Of note, the\nsource of supplemental oxygen for the testing is preferably a\nstationary oxygen concentrator rather than wall oxygen\nwhich may lead to underestimation of the oxygen prescrip-\ntion.196,197\nWhile oximetry monitoring in the home setting\nhas been evaluated in small studies for assessing both eligi-\nbility for LTOT and adequacy of oxygenation,198\u2013204\nsuch an\napproach requires additional resources and it remains\nuncertain whether it leads to better patient health outcomes.\nb. Nocturnal hypoxaemia\nOvernight pulse oximetry can be used for assessment of\nnocturnal hypoxaemia, as well as for evaluation of nocturnal\noxygen prescription in patients on LTOT.205\u2013210\nPulse oxi-\nmeters with onboard memory capable of recording \u22658 h of\ndata are suitable for this purpose, with data analysis provid-\ning estimates of average oxygenation overnight.1\nNocturnal\npolysomnography (in laboratory or home-based) is required if\nthere are concerns of sleep disordered breathing contributing\nto nocturnal hypoxaemia to allow appropriate management.\nc. Exertional desaturation\nExercise tests are performed for assessment of exertional\ndesaturation and prescription of supplemental oxygen dur-\ning activities. The 6-min walk test (6MWT) is the most\ncommonly used exercise test in clinical practice and has\nbeen extensively used in clinical research regarding ambula-\ntory oxygen therapy, acknowledging some limitations in its\nperformance.211\u2013213\nSupplemental oxygen should be titrated\nduring the test to determine the prescription of oxygen flow\nrequired to maintain SpO2 >88%.214\nTo assess the effects of\nsupplemental oxygen (including on dyspnoea severity and\nwalk distance), a 6MWT using an air-filled cylinder is\nrecommended to mitigate the known placebo effect.215\nWhile other exercise tests, such as shuttle walk tests, and\nassessments during domestic activities have been studied for\nevaluation of exertional desaturation,216\u2013218\ntheir utility for pre-\nscribing domiciliary oxygen therapy is yet to be established.\nd. Reassessment\nRegular reassessments following initiation of domiciliary\noxygen therapy are required in order to assess patients\u2019\nongoing oxygen needs over time.189,219\nApproximately 10%\u2013\n58% of patients were no longer eligible for LTOT during re-\nevaluation at a range of follow-up duration between\n1 month and 1 year.220\u2013222\nWhile the optimal interval for\nreassessment is yet to be established, a period between 6 and\n12 MCDONALD ET AL.\n12 months is suitable for stable patients.220,223\nPatients with\nrecent hospitalized acute exacerbation of the underlying dis-\nease for which LTOT has been prescribed may require reas-\nsessment within 90 days of discharge, which is similar to\nthat for patients who are prescribed STOT.\nEducation and support provision for\ndomiciliary oxygen therapy\nPatient education has been shown to improve adherence\nwith and appropriate use of domiciliary oxygen therapy, as\nwell as providing an understanding of the associated safety\nprecautions.224\u2013227\nBoth patients and clinicians express the\nneed for education about domiciliary oxygen ther-\napy.177,181,182,228\nKey information includes equipment types,\nhow and when to use the prescribed oxygen therapy, setting\nappropriate treatment expectations and safety aspects with\nusing oxygen therapy, as well as information about available\nsupport and follow-up. Patients and caregivers are increas-\ningly accessing health information online. Of note, much of\nthe online content about domiciliary oxygen therapy is of a\nlow-to-moderate standard only, which is unsuitable for the\ngeneral population.229\nProvision of regular support follow-\ning initiation of domiciliary oxygen therapy, such as via tele-\nmonitoring and home visits, has been shown to improve\nmental-wellbeing and HRQoL and to reduce health care uti-\nlization, although additional resources are required.230\u2013233\nRecommendations for assessment and support\nfor domiciliary oxygen therapy.\nNew recommendations.\n\u2022 Appropriate assessment should be conducted for\nevaluation of different types of domiciliary oxy-\ngen therapy:\n\u000e LTOT: ABG\n\u000e NOT: Nocturnal pulse oximetry with \u22658-h\nrecording time, with polysomnography being\nconsidered for those at risk of sleep disordered\nbreathing\n\u000e Ambulatory oxygen therapy: Exercise tests,\nwith 6MWTs being preferred, as well as a dys-\npnoea score\n\u000e STOT: If STOT is recommended for persistent\nhypoxaemia at hospital discharge, reassessment\nshould be organized within 30\u201390 days post-\ndischarge, as many patients will no longer\nrequire oxygen therapy\n\u2022 Reassessment post-initiation of domiciliary oxy-\ngen therapy to determine ongoing need and ade-\nquacy of oxygen prescription is recommended at\nan interval of 6\u201312 months for stable patients and\nfollowing hospitalization for acute exacerbation\nof the underlying disease\n\u2022 Patient and caregiver education is an essential\ncomponent of the prescription of domiciliary\noxygen therapy.\nAREAS FOR FUTURE RESEARCH\nAs highlighted in the literature review for this Guideline,\nlimited evidence exists to guide the clinical use of domicili-\nary oxygen therapy in adults. There is an urgent need to\nestablish medium and long-term treatment effects (mortal-\nity, exercise capacity, HRQoL, symptoms, psychological\nwell-being, biomarkers of oxidative stress and inflammation)\nand cost-effectiveness of different types of oxygen therapy in\npatients with different chronic respiratory diseases who are\noptimally managed with contemporary medical therapies.\nWith technological advances, the role of home monitor-\ning through the use of wearable devices and newer oxygen\ndelivery devices such as hNHF-O2 should be evaluated.\nCross-disciplinary collaborations are needed to allow the\ndevelopment of novel, portable and ergonomic oxygen deliv-\nery devices that meet high oxygen requirements. There is\nalso a need to understand the current model of care and\ngaps in assessment and provision of domiciliary oxygen\ntherapy and ongoing care in Australia and New Zealand.\nACKNOWLEDGEMENTS\nWe would like to thank John Blakey and Michael Elizalde\nfor their contribution to document development. Open\naccess publishing facilitated by The University of Mel-\nbourne, as part of the Wiley - The University of Melbourne\nagreement via the Council of Australian University\nLibrarians.\nCONFLICT OF INTEREST STATEMENT\nNo funding was received to support the development of this\nGuideline. CFM reports appointments as Clinical Advisor,\nDomiciliary Oxygen Program, State-Wide Equipment\nProgram, VIC; Chair of the COPD National Program Lung\nFoundation Australia; Member of the COPD-X Guidelines\nCommittee Lung Foundation Australia; Member of the\nTGA Ventilator Expert Group; Member of Clinical Execu-\ntive Austin Health; and Medical Director of the Institute for\nBreathing and Sleep. CFM received grants from NHMRC,\nMRFF, GSK Investigator-sponsored Scheme, Institute for\nBreathing and Sleep and The Prince Charles Hospital Foun-\ndation. CFM is the Editor in Chief of Respiratory Medicine\nToday and Deputy Editor for Respirology and was excluded\nfrom all editorial decision-making related to the acceptance\nand publication of this article. CB received Travel Grants\nfrom TSANZ, Fisher and Paykel Healthcare, the St George\nInstitute of Health and reports volunteer roles in TSANZ\nVictorian Branch, TSANZ Respiratory Nurse SIG, TSANZ\nProfessional Standards Committee, ASA Education\nTSANZ ADULT HOME OXYGEN GUIDELINE 13\nCommittee and ASA Sleep Nurse Chair. BRM is Clinical\nAdvisor, Domiciliary Oxygen Program, State-Wide Equip-\nment Program, VIC. NS received grants from NHMRC,\nMRFF, Cancer Council Australia, Industry grant from\nFisher& Paykel Healthcare, Philanthropic grants from Win-\ndermere Foundation, Lung Foundation Australia, Lord\nMayor\u2019s Foundation Melbourne, PACT Grant-in-Aid. NS is\nBoard Director TSANZ, Board Director Victorian Doctor\u2019s\nProgram, European Respiratory Society Co-Chair Guide-\nlines Committee. NS received consulting fees from The Lim-\nbic and Orchard Consulting; speaker\u2019s fees from GSK,\nBoehringer Ingelheim, Astra Zeneca, Fisher Paykel Health-\ncare, Health Ed; travel support from Chiesi and Boehringer\nIngelheim; and equipment for investigator-initiated clinical\ntrials from Fisher Paykel Healthcare. NS is an Advisory\nBoard member for Respirology and was excluded from all\neditorial decision-making related to the acceptance and pub-\nlication of this article. LT reports consulting fees from Boeh-\nringer Ingelheim, and speaker fees from Erbe.\nElektromedizinGmbH. YHK reports non-financial support\nfrom Air Liquide Healthcare outside the submitted work;\ngrants from NHMRC, MRFF, Austin Medical Research\nFoundation, Lung Foundation Australia, TSANZ and RACP;\nYHK is Board Director TSANZ; guidelines methodologist\nATS; Associate Editor European Respiratory Journal, and\nClinical Advisor, Domiciliary Oxygen Program, State-Wide\nEquipment Program, VIC. JS, SA, HD and MM have no\nconflicts of interest to declare.\nDATA AVAILABILITY STATEMENT\nData sharing is not applicable to this article as no new data\nwere created or analyzed in this study.\nORCID\nChristine F. McDonald https:\/\/orcid.org\/0000-0001-6481-\n3391\nNatasha Smallwood https:\/\/orcid.org\/0000-0002-3403-\n3586\nLauren Troy https:\/\/orcid.org\/0000-0002-7426-336X\nYet Hong Khor https:\/\/orcid.org\/0000-0002-5434-9342\nLINKED CONTENT\nThis publication is linked to a related article. To view this\narticle, visit https:\/\/doi.org\/10.1111\/resp.14794\nREFERENCES\n1. 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Continuous oxygen monitoring\u2014a better way to prescribe\nlong-term oxygen therapy. Respir Med. 2005;99:1386\u201392.\n203. Faria I, Gaspar C, Zamith M, Matias I, das Neves RC, Rodrigues F,\net al. TELEMOLD project: oximetry and exercise telemonitoring to\nimprove long-term oxygen therapy. Telemed J E Health. 2014;20:\n626\u201332.\n204. Rodrigues MP, Vissoci CM, Rosa SP, Negreiros SBC. 24-hour hypoxia\nand pulmonary hypertension in patients with idiopathic pulmonary\nfibrosis. Open Respir Med J. 2017;11:11\u20136.\n205. Ayache M, Strohl KP. High interrater reliability of overnight pulse\noximetry interpretation among inexperienced physicians using a\nstructured template. J Clin Sleep Med. 2018;14:541\u20138.\n206. Carroll N, Walshaw MJ, Evans CC, Hind CR. Nocturnal oxygen desa-\nturation in patients using long-term oxygen therapy for chronic air-\nflow limitation. Respir Med. 1990;84:199\u2013201.\n207. Nisbet M, Eaton T, Lewis C, Fergusson W, Kolbe J. Overnight pre-\nscription of oxygen in long term oxygen therapy: time to reconsider\nthe guidelines? Thorax. 2006;61:779\u201382.\n208. Plywaczewski R, Sliwinski P, Nowinski A, Kaminski D, Zielinski J.\nIncidence of nocturnal desaturation while breathing oxygen in COPD\npatients undergoing long-term oxygen therapy. Chest. 2000;117:\n679\u201383.\n209. Samolski D, Tarrega J, Anton A, Mayos M, Marti S, Farrero E, et al.\nSleep hypoventilation due to increased nocturnal oxygen flow in\nhypercapnic COPD patients. Respirology. 2010;15:283\u20138.\n210. Tarrega J, Guell R, Anton A, Mayos M, Farre A, Jerez FR, et al. Are\ndaytime arterial blood gases a good reflection of nighttime gas\nexchange in patients on long-term oxygen therapy? Respir Care. 2002;\n47:882\u20136.\n211. Chatterjee AB, Rissmiller RW, Meade K, Paladenech C, Conforti J,\nAdair NE, et al. Reproducibility of the 6-minute walk test for ambula-\ntory oxygen prescription. Respiration. 2010;79:121\u20137.\n212. Sanchez-Morillo D, Lara-Dona A, Priego-Torres B, Morales-\nGonzalez M, Montoro-Ballesteros F, Leon-Jimenez A. Portable oxygen\ntherapy: is the 6-minute walking test overestimating the actual\noxygen needs? J Clin Med. 2020;9:1\u201312.\n213. Carone M, Patessio A, Appendini L, Purro A, Czernicka E,\nZanaboni S, et al. Comparison of invasive and noninvasive saturation\nmonitoring in prescribing oxygen during exercise in COPD patients.\nEur Respir J. 1997;10:446\u201351.\n214. Lourido-Cebreiro T, Gonzalez-Barcala FJ, Alvarez-Dobano JM,\nPereiro-Brea T, Abelleira-Paris R, Valdes L. Need for portable oxygen\ntitration during 6-minute walk tests. Arch Bronconeumol. 2019;55:\n539\u201340.\n215. Lock SH, Paul EA, Rudd RM, Wedzicha JA. Portable oxygen therapy:\nassessment and usage. Respir Med. 1991;85:407\u201312.\n216. Lewko A, Marshall J, Garrod R. Ambulatory oxygen therapy assess-\nment: a comparative study of incremental shuttle and 6-minute walk-\ning tests. Physiotherapy. 2007;93:261\u20136.\n217. Sandland CJ, Morgan MD, Singh SJ. Detecting oxygen desaturation in\npatients with COPD: incremental versus endurance shuttle walking.\nRespir Med. 2008;102:1148\u201352.\n218. Sant\u2019Anna T, Donaria L, Hernandes NA, Furlanetto KC, Barbosa DS,\nGosselink R, et al. Oxygen desaturation in daily life and during a\nlaboratory-based protocol of activities of daily living in COPD: is there\nrelationship? Lung. 2018;196:19\u201326.\n219. Lourido-Cebreiro T, Gonzalez-Barcala FJ, Rabade C, Abelleira-\nParis R, Pereiro-Brea T, Valdes L. Progress after the withdrawal of\nhome oxygen therapy. The profile of patients requiring reintroduc-\ntion. Arch Bronconeumol. 2019;55:663\u20135.\n220. Gorecka D, Sliwinski P, Zielinski J. Adherence to entry criteria and\none year experience of long-term oxygen therapy in Poland. Eur\nRespir J. 1992;5:848\u201352.\nTSANZ ADULT HOME OXYGEN GUIDELINE 19\n221. Loutsios C, Logan G, Deeming C, Powrie D, Davison A. One blood\ngas is not enough to assess a patient for ltot-how to kiss goodbye to\ncirca 10 million in England. Thorax. 2010;65:A171.\n222. Oba Y, Salzman GA, Willsie SK. Reevaluation of continuous oxygen\ntherapy after initial prescription in patients with chronic obstructive\npulmonary disease. Respir Care. 2000;45:401\u20136.\n223. Cottrell JJ, Openbrier D, Lave JR, Paul C, Garland JL. Home oxygen\ntherapy. A comparison of 2- vs 6-month patient reevaluation. Chest.\n1995;107:358\u201361.\n224. Atis S, Tutluoglu B, Bugdayci R. Characteristics and compliance of\npatients receiving long-term oxygen therapy (LTOT) in Turkey. Mon-\naldi Arch Chest Dis. 2001;56:105\u20139.\n225. Peckham DG, McGibbon K, Tonkinson J, Plimbley G, Pantin C.\nImprovement in patient compliance with long-term oxygen therapy\nfollowing formal assessment with training. Respir Med. 1998;92:\n1203\u20136.\n226. Pepin JL, Barjhoux CE, Deschaux C, Brambilla C. Long-term oxygen\ntherapy at home. Compliance with medical prescription and effective\nuse of therapy. ANTADIR Working Group on Oxygen Therapy. Asso-\nciation Nationale de Traitement a Domicile des Insuffisants Respira-\ntories. Chest. 1996;109:1144\u201350.\n227. Dogan U, Ovayolu N. The effects of health education given by nurses\nto COPD patients on the daily oxygen concentrator usage time. Adv\nRespir Med. 2017;85:15\u201321.\n228. Jacobs SS, Lindell KO, Collins EG, Garvey CM, Hernandez C,\nMcLaughlin S, et al. Patient perceptions of the adequacy of supple-\nmental oxygen therapy. Results of the American Thoracic Society\nNursing Assembly Oxygen Working Group Survey. Ann Am Thorac\nSoc. 2018;15:24\u201332.\n229. Ang HL, Tan HH, Logie KM, McDonald CF, Khor YH. Online patient\ninformation on domiciliary oxygen therapy: an evaluation of quality,\nsuitability, reliability, readability, and content. Chest. 2022;161:\n483\u201391.\n230. Burioka N, Yamamoto A, Morimoto M, Yamasaki A, Hirayama Y,\nTakata M. Health-related quality of life in patients on home oxygen\ntherapy with telemonitoring. Yonago Acta Med. 2020;63:132\u20134.\n231. Clini E, Vitacca M, Foglio K, Simoni P, Ambrosino N. Long-term\nhome care programmes may reduce hospital admissions in COPD\nwith chronic hypercapnia. Eur Respir J. 1996;9:1605\u201310.\n232. Prieto-Centurion V, Basu S, Bracken NE, Casaburi R, Gallardo R,\nGonzalez V, et al. Comparative effectiveness of a PEer-led supplemen-\ntal oxygen InfoLine for patients and CAregivers (PELICAN).\nAm J Respir Crit Care Med. 2018;197:1009\u201317.\n233. Yu YL, Zheng XS, Han XX, Sun MJ. The application value of continuous\nnursing for home oxygen therapy of patients in the stable phase of chronic\nobstructive pulmonary disease. Eur Rev Med Pharmacol Sci. 2017;21:67\u201372.\nSUPPORTING INFORMATION\nAdditional supporting information can be found online in\nthe Supporting Information section at the end of this article.\nHow to cite this article: McDonald CF, Serginson J,\nAlShareef S, Buchan C, Davies H, Miller BR, et al.\nThoracic Society of Australia and New Zealand\nclinical practice guideline on adult home oxygen\ntherapy. Respirology. 2024. https:\/\/doi.org\/10.1111\/\nresp.14793\n20 MCDONALD ET AL.","pure_content":"C L I N I C A L P R A C T I C E G U I D E L I N E\nThoracic Society of Australia and New Zealand clinical practice\nguideline on adult home oxygen therapy\nChristine F. McDonald1,2,3\n| John Serginson4,5\n| Saad AlShareef6\n|\nCatherine Buchan7,8\n| Huw Davies9\n| Belinda R. Miller8,10\n| Maitri Munsif1,2,3\n|\nNatasha Smallwood7,8\n| Lauren Troy11,12,13\n| Yet Hong Khor1,2,3,7\n1\nDepartment of Respiratory and Sleep Medicine, Austin Health, Heidelberg, Victoria, Australia\n2\nInstitute for Breathing and Sleep, Heidelberg, Victoria, Australia\n3\nFaculty of Medicine, University of Melbourne, Melbourne, Victoria, Australia\n4\nDepartment of Respiratory Medicine, Sunshine Coast Health, Birtinya, Queensland, Australia\n5\nSchool of Nursing, Midwifery & Social Work, University of Queensland, St Lucia, Queensland, Australia\n6\nDepartment of Medicine, College of Medicine, Imam Mohammad Ibn Saud Islamic University (IMSIU), Riyadh, Saudi Arabia\n7\nRespiratory Research@Alfred, Central Clinical School, Monash University, Melbourne, Victoria, Australia\n8\nDepartment of Respiratory Medicine, Alfred Health, Melbourne, Victoria, Australia\n9\nRespiratory and Sleep Services, Flinders Medical Centre, Southern Adelaide Local Health Network, South Australia, Australia\n10\nCentral Clinical School, Monash University, Melbourne, Victoria, Australia\n11\nDepartment of Respiratory and Sleep Medicine, Royal Prince Alfred Hospital, Camperdown, New South Wales, Australia\n12\nSydney Medical School, Faculty of Medicine and Health, University of Sydney, Sydney, New South Wales, Australia\n13\nInstitute for Academic Medicine, Royal Prince Alfred Hospital, Camperdown, New South Wales, Australia\nCorrespondence\nChristine F. McDonald\ncmcdo@unimelb.edu.au\nHandling Editors: Philip Bardin and Paul\nReynolds\nAbstract\nThis Thoracic Society of Australia and New Zealand Guideline on the provision of\nhome oxygen therapy in adults updates a previous Guideline from 2015. The\nGuideline is based upon a systematic review and meta-analysis of literature to\nSeptember 2022 and the strength of recommendations is based on GRADE meth-\nodology. Long-term oxygen therapy (LTOT) is recommended for its mortality ben-\nefit for patients with COPD and other chronic respiratory diseases who have\nconsistent evidence of significant hypoxaemia at rest (PaO2 \u2264 55 mm Hg or PaO2\n\u226459 mm Hg in the presence of hypoxaemic sequalae) while in a stable state. Evi-\ndence does not support the use of LTOT for patients with COPD who have moder-\nate hypoxaemia or isolated nocturnal hypoxaemia. In the absence of hypoxaemia,\nthere is no evidence that oxygen provides greater palliation of breathlessness than\nair. Evidence does not support the use of supplemental oxygen therapy during pul-\nmonary rehabilitation in those with COPD and exertional desaturation but normal\nresting arterial blood gases. Both positive and negative effects of LTOT have been\ndescribed, including on quality of life. Education about how and when to use oxy-\ngen therapy in order to maximize its benefits, including the use of different deliv-\nery devices, expectations and limitations of therapy and information about hazards\nand risks associated with its use are key when embarking upon this treatment.\nK E Y W O R D S\nclinical respiratory medicine, hypoxaemia, long-term oxygen therapy, oxygen guideline, oxygen therapy\nReceived: 5 December 2023 Accepted: 27 June 2024\nDOI: 10.1111\/resp.14793\nThis is an open access article under the terms of the Creative Commons Attribution-NonCommercial License, which permits use, distribution and reproduction in any medium,\nprovided the original work is properly cited and is not used for commercial purposes.\n\u00a9 2024 The Author(s). Respirology published by John Wiley & Sons Australia, Ltd on behalf of Asian Pacific Society of Respirology.\nRespirology. 2024;1\u201320. wileyonlinelibrary.com\/journal\/resp 1\nINTRODUCTION\nThis Thoracic Society of Australia and New Zealand\n(TSANZ) Clinical Practice Guideline updates previous\nevidence-based guidance published by the Society on the use\nof domiciliary oxygen therapy for adults in the community.1\nThe Guideline is intended for use by health care profes-\nsionals, as well as government agencies and other providers\nof domiciliary oxygen therapy.\nThe Guideline includes broad recommendations for the\nuse of domiciliary oxygen therapy, including: long-term con-\ntinuous oxygen therapy, nocturnal oxygen therapy, ambulatory\noxygen therapy, palliative oxygen therapy, short-term oxygen\ntherapy and oxygen for specific indications, including during\npulmonary rehabilitation, air travel, acute asthma and other.\nThe Guideline also reviews the evidence base for guid-\nance on different oxygen delivery devices, considerations of\nsafety and risks associated with using domiciliary oxygen\ntherapy, initial assessment and follow-up of domiciliary oxy-\ngen therapy and education provision.\nMETHODS\nWorking Party formation\nFollowing a call for expressions of interest, a multidisciplinary\nand geographically diverse group of TSANZ members was\nappointed to the Working Party including adult respiratory\nand sleep physicians, a respiratory and sleep nurse consultant,\na respiratory nurse practitioner and a methodologist, with con-\ntributions during the early phase of development from a phys-\niotherapist and an additional adult respiratory and sleep\nphysician (see Table S1 in the Supporting Information for\nmembership details).\nLiterature review\nKey topic areas were identified by the Working Party to define\nthe scope and priorities of the Guideline (Table S2 in the Sup-\nporting Information). A literature search was conducted using\nOvid MEDLINE, EMBASE, CINAHL, Cochrane Database of\nSystematic Reviews and Cochrane Central Register of Con-\ntrolled Trials, from inception. The initial search was conducted\nin February 2021 and updated in September 2022. For the full\nsearch strategies and results, see Table S3 and Figure S1 in the\nSupporting Information, respectively.\nInclusion and exclusion criteria for study selection are\nlisted in Table S4 in the Supporting Information. Briefly,\nonly original English language research articles were\nincluded. All working party members were involved in the\nliterature appraisal. Sequential review of titles and abstracts\nfollowed by full-text articles was performed by two members\nindependently to identify eligible citations. Data extraction\nwas performed by one member using a standardized data\nextraction form, which was verified by a second member.\nEvidence synthesis and appraisal\nExisting data from relevant guidelines and systematic\nreviews of long-term oxygen therapy (LTOT) and ambula-\ntory oxygen therapy were reviewed, checked and incorpo-\nrated into the evidence synthesis with additional studies\nidentified from the literature search. Meta-analyses using\nrandom-effects models were performed for nocturnal oxy-\ngen therapy using Review Manager (RevMan, version 5.4;\nthe Cochrane Collaboration), as this had not been per-\nformed in previous guidelines and systematic reviews. Nar-\nrative synthesis of identified literature was performed for the\nremaining sections.\nRisk-of-bias assessment of all included studies was\nevaluated independently by two members using risk\nassessment tools according to the Cochrane Handbook\nfor Systematic Reviews of Interventions for randomized\nand non-randomized intervention trials and the\nNewcastle-Ottawa scale for observational studies. Dis-\nagreements were resolved by a third member if required.\nFor grading of recommendations regarding different types\nof oxygen therapy the GRADE approach was adopted\nwith consideration of study design, imprecision, indirect-\nness, inconsistency, publication bias, risk of bias and\nother aspects (effect magnitude, dose\u2013response gradients\nand confounders biasing toward an opposite effect). The\nstrength of recommendations was graded as strong and\nweak based on consensus discussion, with the level of evi-\ndence being classified as high, moderate, low and very\nlow.2\nRecommendations concerning oxygen delivery\ndevices, safety considerations when using domiciliary\noxygen therapy, initial assessment, education provision\nand follow-up of patients receiving domiciliary oxygen\ntherapy were developed based on consensus discussion\nfollowing literature review.\nPeer review and dissemination\nThis Guideline underwent joint peer review by TSANZ and\nRespirology and will be reviewed by TSANZ for currency\nwithin 36\u201348 months. Once published, this Guideline is\nintended for dissemination through the TSANZ website and\neducational program.\nLONG-TERM CONTINUOUS OXYGEN\nTHERAPY\nChronic obstructive pulmonary disease\na. Severe resting hypoxaemia\nThere have not been any high-quality randomized con-\ntrolled trials (RCTs) of LTOT for severe resting hypoxaemia\nsince the landmark Nocturnal Oxygen Therapy Trial\n(NOTT) and Medical Research Council (MRC) trial were\n2 MCDONALD ET AL.\nreported in the 1980s (Table S5 in the Supporting Informa-\ntion). Criteria for entry to the NOTT were PaO2 \u226455 mm\nHg with or without hypercapnia or PaO2 \u226459 mm Hg in the\npresence of cor pulmonale, haematocrit \u226555% or electrocar-\ndiographic evidence of P pulmonale on two measurements\nover a 3-week exacerbation free period.3\nThe trial enrolled\n203 patients with stable hypoxaemia who were randomized\nto nocturnal or continuous oxygen therapy (concentrator\nplus portable oxygen) with follow-up for 3 years or until\ndeath. Overall mortality in the nocturnal group was signifi-\ncantly higher at 1.94 times that in the continuous oxygen\ntherapy group, with the latter averaging 18 h of\noxygen usage per 24 h. The MRC trial included 87 hypercap-\nnic patients with COPD and PaO2 40\u201360 mm Hg on two\nmeasurements over a 3-week exacerbation-free observation\nperiod.4\nIn this unblinded study, patients received oxygen\nvia concentrator for 15 h\/day (without portable oxygen) or\nno oxygen at all. Patients were followed for 5 years or until\ndeath. Nineteen of the 43 treated patients died during\nfollow-up compared with 30 out of 45 controls.4\nThere have\nbeen no head-to-head studies examining what the appropri-\nate duration of continuous oxygen therapy should be. In a\nprospective Swedish cohort study of 2249 patients with\nCOPD, no mortality difference was observed between\npatients who were prescribed oxygen for 24 h or 15 h\nper day.5\nFew studies have evaluated the impact of LTOT on hos-\npitalization. In an Egyptian observational study, LTOT fol-\nlowing hospital discharge after exacerbation of COPD\nreduced hospitalizations and improved health-related qual-\nity of life (HRQoL),6\nwhile in an Australian study, bed days\nper patient year of follow-up of a cohort of patients with\nchronic airflow limitation were reduced by 35% after the\nintroduction of LTOT.7\nIn a retrospective Swedish study\nthere was no difference in hospitalization between the two\ndurations of therapy\u201415 h versus 24 h.8\nEvidence regarding other treatment effects of LTOT in\npatients with COPD remains limited. Although modest\nand comparable improvements in neuropsychological tests\ncompared to baseline were demonstrated after 6 months\nof either continuous or nocturnal oxygen therapy in a sub-\nset of the NOTT, no appreciable changes were found in\nself-reported general emotional status or HRQoL.9\nSimi-\nlarly, no HRQoL effect of LTOT was found after 6 months\nof LTOT in a United Kingdom (UK) study.10\nIn a\nNew Zealand study of two groups of patients with COPD,\none fulfilling criteria for and started on LTOT (as per the\nNOTT study3\n) and the second not fulfilling criteria and\ncontinuing with usual care, HRQoL was worse at baseline\nin the LTOT group and showed significant improvements\nat 2 and 6 months, while the non-LTOT group showed a\nprogressive decline.11\nb. Moderate resting hypoxaemia\nBenefits of LTOT in patients with COPD and moderate\nresting hypoxaemia remain unproven, where varying\ndefinitions of \u2018moderate\u2019 are used in this context (Table S6\nin the Supporting Information). A Polish study of\n135 patients with COPD and resting PaO2 56\u201365 mm Hg,\nrandomly assigned to LTOT 17 h\/day versus no LTOT\nfound no difference in cumulative survival,12\nand no reduc-\ntion in hospitalizations was found in a Danish study com-\nparing pre- and post-oxygen hospitalizations after at least\n1 month of continuous oxygen therapy in patients with\nPaO2 55\u201371 mm Hg.13\nSimilar results to these two earlier\nstudies were found in the long-term oxygen treatment trial\n(LOTT) where 738 patients with COPD and resting SpO2\n89%\u201393% were randomized to continuous oxygen or no\noxygen.14\nInitial recruitment was slow and entry criteria\nwere expanded to also include patients who desaturated only\nduring exercise. Treatments included oxygen 24 h per day\n(via stationary and portable devices) for moderate resting\nhypoxaemia and nocturnal and exertional oxygen in the case\nof exercise desaturation only. No differences between groups\nwere found for the primary composite outcome of death or\nhospitalization for COPD or for any secondary outcome.\nOther chronic respiratory and cardiac diseases\nThere are limited published clinical trials evaluating treatment\neffects of LTOT beyond patients with COPD (Table S7 in the\nSupporting Information), which are summarized below.\na. Heart failure\nIn a UK RCT, 139 patients with heart failure and New York\nHeart Association (NYHA) class III\/IV symptoms were ran-\ndomized to receive 6 months of LTOT 15 h\/day versus no\ntreatment.15\nNo benefit was observed in any outcome mea-\nsure at 6 months, although the Minnesota Living with Heart\nFailure score was lower at 3 months in the LTOT group.\nb. Chronic thromboembolic pulmonary hypertension\n(CTEPH)\nIn a crossover study of 30 patients with CTEPH and exer-\ntional desaturation without resting hypoxaemia randomized\nto oxygen >16 h\/day via concentrator (mean usage 13.2 h\/\nday) or identical concentrator modified to provide 21% oxy-\ngen over 5 weeks, there was a statistically significant\nimprovement of 19 m in 6-min walk distance on room air\n(although this was less than the minimal important differ-\nence), compared with 1 m for the placebo air group.16\nThere were improvements in HRQoL with between-group\ndifference of 6 points for SF-36 physical functioning and\nNYHA functional class, compared with air.\nc. Kyphoscoliosis\nIn a prospective observational study of 244 patients with\nrespiratory failure due to kyphoscoliosis, LTOT was infe-\nrior to mechanical ventilation at home for survival.17\nTSANZ ADULT HOME OXYGEN GUIDELINE 3\nRecommendations for LTOT.\nUnchanged from previous Guideline.\n\u2022 Long-term continuous oxygen therapy aimed at\nimproving survival is recommended for suitable\npatients with awake resting PaO2 on room air\nconsistently \u226455 mm Hg, or PaO2 \u2264 59 mm Hg\nin the presence of cor pulmonale, haematocrit\n\u226555% or ECG evidence of P pulmonale during an\nexacerbation free period who have\n\u000e COPD, (Strength of recommendation: Strong;\nEvidence: Moderate)\n\u000e other conditions, including but not limited to\nchronic respiratory or cardiac diseases\n(Strength of recommendation: Strong; Evi-\ndence: Low)\n\u2022 Safety considerations should be included in\npatient-centric discussions of LTOT initiation,\nincluding both physical and psychological\nimpacts (Tables S5\u2013S7 in the Supporting Infor-\nmation and see \u2018Safety considerations\u2019 section)\nChanged from previous Guideline-new\nrecommendation.\n\u2022 Long-term continuous oxygen therapy is not\nrecommended for patients with COPD and mod-\nerate resting hypoxaemia (i.e., PaO2 56\u201359 mm\nHg in the absence of cor pulmonale, haematocrit\n\u226555% or ECG evidence of p pulmonale)\n(Strength of recommendation: Strong; Evidence:\nLow). Extrapolating from this, and in the absence\nof evidence, long-term continuous oxygen is not\nrecommended for patients with moderate hypox-\naemia due to other conditions\nNOCTURNAL OXYGEN THERAPY\nNocturnal hypoxaemia may occur in the absence of day-\ntime hypoxaemia in patients with chronic respiratory\nand cardiac diseases, with or without associated sleep\ndisordered breathing. Nocturnal hypoxaemia has been\nlinked with poorer prognosis, disease progression and\ndevelopment of pulmonary hypertension in patients\nwith COPD, interstitial lung disease (ILD) and cystic\nfibrosis (CF).18\u201321\nChronic obstructive pulmonary disease\nThree RCTs including a total of 183 patients with COPD\nand isolated nocturnal hypoxaemia investigated the impact\nof nocturnal oxygen therapy (NOT) on survival and\nprogression to LTOT,22\u201324\nincluding the International Noc-\nturnal Oxygen trial (INOX). Meta-analyses of these studies\nshowed no impact of nocturnal oxygen therapy on 3-year\nsurvival and\/or progression to LTOT (Figure S2 in the Sup-\nporting Information), with a similar absence of effects\nobserved for secondary endpoints in the INOX trial includ-\ning hospitalizations, acute exacerbation rates or HRQoL.22\nConflicting results were reported regarding the impact of\nNOT on invasively measured pulmonary haemodynamics in\nthe two smaller studies.23,24\nSeveral small crossover studies of NOT versus room air\nin patients with COPD and varying degrees of nocturnal\noxygen desaturation failed to demonstrate any benefit with\nrespect to sleep quality or daytime exercise performance\n(Table S8 in the Supporting Information). A small study\ncomparing nasal continuous positive airway pressure\n(CPAP) with entrained oxygen at 1.5 L\/min against CPAP\nand room air on three single overnight studies in 10 hypox-\naemic male patients with COPD-OSA overlap showed\nimproved oxygenation and abolition of obstructive events\nwith the combination intervention of CPAP and oxygen,\ncompared with CPAP and room air.25\nHeart failure\nMultiple short- and long-term studies have compared NOT\nwith different controls (medical air, room air, or no treat-\nment) in patients with heart failure and associated Cheyne\nStokes respiration (Table S9 in the Supporting Information).\nTwo RCTs of NOT versus air for 6\u201312 months in patients\nwith heart failure demonstrated consistent improvements in\nindices of sleep disordered breathing, but conflicting impacts\non HRQoL, functional status and left ventricular ejection\nfraction.26,27\nSimilar benefits in sleep indices were observed\nin a meta-analysis of two RCTs including a total of\n76 patients assigned to NOT or room air during sleep over\n12 weeks (Figure S3 in the Supporting Information).28,29\nA\nfollow-up survey sub-study of these Japanese studies\nreported economic benefits with NOT resulting in total\nmedical cost-reduction, which was primarily related to\nreduced hospital bed-days.30\nFindings from several small crossover, before-and-after\nand uncontrolled studies support the benefit of NOT over\nroom air for treating obstructive and central sleep apnoea,\nwith variable impact on HRQoL measures, cognition, car-\ndiac function and daytime exercise performance (Table S9\nin the Supporting Information). In-laboratory single-night\nstudies also consistently show an improvement in mean\nsleep oxygenation, overall apnoea-hypopnoea index (AHI)\nand central AHI with NOT (Table S9 in the Supporting\nInformation). Cardiac arrhythmias and heart rate variability\nwere not attenuated with NOT compared with room air in\nthese studies, however, heterogeneity in individual respon-\nsiveness has been observed.31\u201333\nNocturnal oxygen therapy has also been evaluated\nagainst CPAP and adaptive servoventilation (ASV) in two\n4 MCDONALD ET AL.\nstudies of patients with heart failure. With small sample\nsizes and limited intervention periods of 12 weeks, neither\nstudy demonstrated clear superiority for either interven-\ntion with respect to indirect measures of right ventricular\nstrain, pulmonary haemodynamics or exercise capacity,\nalthough there was a greater reduction in AHI with CPAP\nor ASV than with NOT.34,35\nObstructive sleep apnoea\nUncomplicated obstructive sleep apnoea (OSA) is typically\nmanaged with risk factor mitigation, and CPAP therapy. Alter-\nnative therapeutic strategies including NOT have been studied\n(Table S10 in the Supporting Information). One large RCT\nevaluated CPAP versus NOT at 2 L\/min versus education only\nin an OSA population with cardiovascular disease or multiple\ncardiac risk factors over 12 weeks.36,37\nThis study demonstrated\nreduced blood pressure and improvements in sleepiness, men-\ntal health, social functioning and depressive symptoms in the\nCPAP group, but no impact with lifestyle education alone or\nNOT.36,37\nPhysical function as assessed by the SF-36 question-\nnaire, however, was superior in the NOT group, compared\nwith the CPAP group. Short-term studies comparing NOT\nwith CPAP in patients with OSA have generally confirmed\nsuperiority of CPAP over NOT for sleep quality, neuropsycho-\nlogical and cardiovascular endpoints,38\u201340\nexcept for one\nreporting improved depression scores from baseline in subjects\nassigned to NOT but not in CPAP or sham CPAP groups.41\nOther chronic respiratory diseases\nThere are limited published clinical trials evaluating treat-\nment effects of NOT in patients with CF and ILD\n(Table S11 in the Supporting Information).\na. Cystic fibrosis\nSmall studies of single-night NOT in adults with CF and iso-\nlated nocturnal hypoxaemia suggested a modest improve-\nment in oxygenation compared with room air, however,\nwith consequent elevations in transcutaneous CO2\nlevels.42\u201344\nIn an Australian RCT of non-invasive ventilation\n(NIV) with or without entrained oxygen versus low-flow\nNOT alone over 12 months in patients with nocturnal\nhypoxaemia45\nthose receiving NIV with or without oxygen\nhad a greater event-free survival compared with the NOT\ngroup, with events defined as worsening hypercapnia, death\nor lung transplantation.\nb. Interstitial lung disease\nWhile a recent Delphi survey of international ILD\nexperts supported the use of NOT in patients with ILD\nwith isolated nocturnal hypoxaemia,46\nthere has only\nbeen one published paper evaluating this therapy.47\nIn\nthis case\u2013controlled study over two nights at 2240 m\naltitude, 19 patients who received oxygen during sleep\nhad improved mean SpO2 and reduced heart and respi-\nratory rates during sleep, compared to those on\nroom air.\nRecommendations for NOT.\nMajor changes from previous Guideline.\nThe previous Guideline recommended NOT for\na subgroup of patients with lung disease and associ-\nated sleep-related hypoxaemia (desaturating to\n\u226488% for more than a third of total sleep time) but\nwithout severe daytime hypoxaemia, in particular\nfor those with evidence of hypoxic sequelae such as\npulmonary hypertension and polycythaemia, based\non weak evidence.1\nThis recommendation has been\nupdated based on recent literature as follows:\n\u2022 Nocturnal oxygen therapy is not recommended\nfor nocturnal hypoxaemia in the absence of day-\ntime hypoxaemia and\/or sleep disordered breath-\ning in patients who have:\n\u000e COPD, (Strength of recommendation: Weak;\nEvidence: Low)\n\u000e other chronic respiratory conditions (Strength\nof recommendation: Weak; Evidence:\nVery low)\n\u2022 Nocturnal oxygen therapy is recommended as\nsecond-line treatment for patients with\nchronic heart failure and persistent Cheyne\nStokes respiration after medical optimisation\nand consideration of CPAP as a treatment\noption (Strength of recommendation: Strong;\nEvidence: Moderate)\n\u2022 Nocturnal oxygen therapy is not recommended\nas first-line treatment for patients with OSA\n(Strength of recommendation: Strong; Evidence:\nModerate) although it may be considered in those\nwho are intolerant of CPAP (Strength of recom-\nmendation: Weak; Evidence: Very low).\nAMBULATORY OXYGEN THERAPY\nAmbulatory oxygen therapy can be used as either a\ncomponent of LTOT for patients with resting hypoxae-\nmia or in isolation for patients with exertional hypoxae-\nmia without resting hypoxaemia where benefit in terms\nTSANZ ADULT HOME OXYGEN GUIDELINE 5\nof exercise capacity or dyspnoea is demonstrated.\nAcross cohorts of patients with isolated exertional\nhypoxaemia, however, evidence for preferred laboratory-\nbased testing modalities, thresholds for clinical response\nand evidence for long-term therapeutic benefit based\nupon in-laboratory assessments is limited.\nChronic obstructive pulmonary disease\nThere have been no RCTs evaluating ambulatory oxygen\ntherapy in patients with COPD since the last TSANZ\nGuideline (Tables S12 and S13 in the Supporting Infor-\nmation). For patients with resting hypoxaemia needing\nLTOT, provision of ambulatory oxygen therapy in addi-\ntion to a stationary oxygen concentrator may assist with\nachieving a longer duration of oxygen treatment in\norder to maximize the benefits of LTOT.3\nFor patients\nwith isolated exertional hypoxaemia or without evidence\nof resting or exertional hypoxaemia, while acute benefits\nincluding improved oxygenation, exercise capacity (fre-\nquently measured as 6-min walk distance) and dyspnoea\nhave been demonstrated in some studies of supplemen-\ntal oxygen during in-laboratory exercise tests, there is\nno evidence suggestive of short-term or long-term\neffects on symptoms, HRQoL, healthcare utilization or\nsurvival for ambulatory oxygen therapy. A recent retro-\nspective observational study of 174 patients with iso-\nlated exertional desaturation showed no difference in\nsurvival over a median of 55 months between patients\nwith or without improved 6-min walk distance using\nambulatory oxygen therapy.48\nInterstitial lung disease\nNo studies evaluated effects of LTOT or ambulatory\noxygen therapy in patients with ILD and chronic resting\nhypoxaemia. For patients with isolated exertional hypoxae-\nmia, an unblinded crossover study of 2 weeks of ambulatory\noxygen therapy in 84 patients showed improved HRQoL,\ncompared to no treatment.49\nAs in similar studies of\npatients with COPD, acute benefits of improved\nexercise capacity were observed with supplemental oxygen\nduring in-laboratory exercise tests, without consistent\nchanges in dyspnoea scores (Table S14 in the Supporting\nInformation).\nOther chronic respiratory and cardiac diseases\nThere are limited in-laboratory studies of supplemental oxy-\ngen during exercise tests in patients with other chronic\nrespiratory diseases and cardiac diseases, demonstrating\ninconsistent effects on symptoms and exercise capacity\n(Table S15 in the Supporting Information).\nRecommendations for ambulatory oxygen\ntherapy.\nUnchanged from previous Guideline.\n\u2022 Ambulatory oxygen therapy is recommended to\nmaximize the benefits of LTOT in those fulfilling\ncriteria for LTOT. (Strength of recommendation:\nStrong; Evidence: Low)\n\u2022 Ambulatory oxygen therapy may be recom-\nmended for suitable patients with lung diseases\nwithout severe resting hypoxaemia and during an\nexacerbation-free period, who have exertional\nhypoxaemia (desaturation to \u226488% during exer-\ncise tests such as the 6-min walk test [6MWT])\nwhere improvement is demonstrated in exercise\ncapacity or level of dyspnoea. (Strength of recom-\nmendation: Weak; Evidence: Low).\n\u2022 While the use of ambulatory oxygen therapy may\nallow outdoor access and encourage physical\nactivities, it is associated with physical challenges\ndue to equipment weight and non-ergonomic\ndesign, as well as psychosocial stresses (Table S16\nin the Supporting Information and see \u2018Safety\nconsiderations\u2019 section). Adequate education and\ndiscussion with patients and their caregivers are\nneeded to support treatment decision-making for\nthe prescription and use of ambulatory oxygen\ntherapy.\nPALLIATIVE OXYGEN THERAPY\nPalliative oxygen therapy refers to domiciliary oxygen ther-\napy prescribed for the relief of dyspnoea in patients with\nlife-limiting illness who may not have hypoxaemia.\nIn five of six studies, including one multicentre inter-\nnational RCT of 239 patients,50\npalliative oxygen therapy\nshowed no significant difference in reduction of dyspnoea\ncompared to either medical air or no control (Table S17\nin the Supporting Information).50\u201354\nThe studied popula-\ntions and settings included patients with and without\nhypoxaemia, and with malignant and non-malignant ill-\nnesses, who were evaluated for domiciliary or inpatient\nusage, as well as during in-laboratory assessments. In the\nlarge RCT of stable patients with life-limiting illness and\nsevere dyspnoea, no differences were found in HRQoL or\nsleep parameters between oxygen and air at 2 L\/min via\nstationary concentrators for at least 15 h per day for\n7 days.50\nA retrospective cohort study showed that domi-\nciliary oxygen therapy was not significantly associated\nwith survival in patients with advanced cancer and low\noxygen saturation.55\n6 MCDONALD ET AL.\nAlthough there is no high-quality evidence demonstrat-\ning that palliative oxygen therapy reduces dyspnoea, some\npatients do appear to derive benefit from oxygen therapy. In\none pre- and post-study of patients referred to palliative\ncare, which showed no significant difference in mean dys-\npnoea after 1\u20132 weeks of domiciliary oxygen therapy, a sub-\nset of 150 patients amongst 413 showed 20% or greater\nimprovements in dyspnoea score.54\nHowever, no underlying diagnostic or demographic fac-\ntors could be identified as predicting responders at 1 week.54\nCaregivers for people receiving domiciliary oxygen\ntherapy for refractory dyspnoea in a palliative setting\nreported conflicting feelings. Many felt extreme distress\nat witnessing refractory dyspnoea and felt oxygen ful-\nfilled critical and beneficial roles in this context, but\nalso reported burden in loss of patient autonomy and\ncost.56\nClinicians similarly report mixed opinions on the\nrole of palliative oxygen therapy to treat dyspnoea.57\u201359\nIn a randomized crossover laboratory study of\n51 patients with advanced cancer and dyspnoea, there\nwas no difference in patient preference for medical air\nor oxygen therapy.52\nRecommendations for palliative oxygen therapy.\nMinor changes from previous Guideline.\nPalliative oxygen therapy is not recommended to\ntreat patients with severe dyspnoea and a life-\nlimiting illness who do not have severe resting\nhypoxaemia. (Strength of recommendation: Strong;\nEvidence: Low).\nSHORT-TERM OXYGEN THERAPY\nThe provision of domiciliary oxygen to patients who remain\nsignificantly hypoxaemic, typically at rest, upon hospital dis-\ncharge, has been termed short-term oxygen therapy (STOT).\nThe rationale for STOT provision lies in the concern that\nongoing hypoxaemia may have adverse outcomes. There is a\npaucity of studies to support its use (Table S18 in the Sup-\nporting Information) and potential adverse effects include\nrisk of worsened underlying hypercapnia in the setting of\nunstable respiratory disease, patient safety and risk consider-\nations such as fire and burns (described later), as well as\nincreased healthcare costs. Nevertheless, hypoxaemia and\nthe requirement for domiciliary oxygen therapy at discharge\nhave been reported as independent predictors of long-term\nmortality in patients hospitalized for acute exacerbation of\nCOPD.60\nMore recently, STOT has been used to facilitate early\ndischarge and outpatient management of patients with\nCOVID-19 pneumonia at times of scarce hospital resources,\nwhich is not covered in this Guideline.61\nPrescribing eligibility and reassessment\nfor STOT\nEligibility criteria for STOT are not standardized and thus\nare likely to vary across health services. Reported criteria\nfor STOT provision are often derived directly from those\nused to assess eligibility for LTOT for severe resting\nhypoxaemia, using arterial blood gas measurements of\nPaO2 \u226455 mm Hg or 56\u201359 mm Hg with evidence of hyp-\noxic end-organ damage.62\u201366\nThere is no evidence of the\nbenefits or otherwise of prescription of STOT for ambula-\ntion alone.\nIt is well-recognized that hypoxaemia may resolve after\nan acute illness, and that unnecessary ongoing oxygen use\nincurs significant resource costs and potential patient\nadverse events. Previous studies reported that 40%\u201380% of\npatients on STOT did not meet criteria for LTOT at subse-\nquent assessment at a range of 30\u201390 days post hospital dis-\ncharge.62\u201364,66\u201368\nAdditionally, appropriate reassessment for\neligibility for LTOT occurred in only 43%\u201362% of patients\ndischarged on STOT.64,66,67\nDifferent societies and expert\ngroups consistently recommend reassessment of oxygena-\ntion status within 90 days of hospital discharge,69,70\npending\nfurther studies. Predictors of progression of patients to\nLTOT from STOT have not been well identified.64,65\nRecommendations for STOT.\nNew recommendations.\nThere is a paucity of evidence-based data to guide\ndecision-making with respect to STOT. However,\nongoing provision of STOT may be justified if the\nbenefits of alleviating hypoxaemia in an individual\npatient are deemed to outweigh the potential risks\nof domiciliary oxygen therapy.\n\u2022 Short-term oxygen therapy may be recommended\nfor patients with persistent severe resting hypox-\naemia at hospital discharge. The use of LTOT\nprescribing criteria in the assessment for STOT is\nrecommended as a pragmatic approach. (Strength\nof recommendation: Weak; Evidence: Very low)\n\u2022 Reassessment for oxygen requirement should be\nconducted between 30 and 90 days post discharge\nand when stable. (Strength of recommendation:\nStrong; Evidence: Very low)\n\u2022 Education regarding oxygen therapy should be\nprovided to patients and their caregivers prior to\ndischarge, including realistic expectations of its\neffects. In addition, patients and their caregivers\nshould be informed of the need for reassessment\nTSANZ ADULT HOME OXYGEN GUIDELINE 7\nof oxygenation status post discharge and the\npotential withdrawal of oxygen therapy if no lon-\nger indicated.\nSPECIFIC INDICATIONS: EXERCISE\nTRAINING, AIR TRAVEL, ACUTE ASTHMA,\nHEADACHE\nExercise training\nThe effects of supplemental oxygen during exercise\ntraining have been primarily studied in patients with COPD\n(Table S19 in the Supporting Information). Since the last\nTSANZ guideline, a multicentre RCT demonstrated\nimproved exercise endurance and HRQoL after 24 sessions of\nexercise training over 8 weeks with oxygen or air delivered at\n5 L\/min in 111 patients with COPD and exertional desatura-\ntion, with no between-group differences identified.71\nSimilar\nfindings were observed in a number of small RCTs with\nmoderate-to-high risk of bias in patients with COPD who had\nvarying oxygen requirements72\u201377\nwhile one small study that\nincluded patients with chronic respiratory failure from a range\nof causes on LTOT demonstrated greater improvement in\n6MWD following pulmonary rehabilitation with heated,\nhumidified nasal high flow oxygen (hNHF-O2) compared with\noxygen via standard nasal cannula at 6 L\/min.78\nOf note, there\nmay be benefits of exercise training with supplemental oxygen\nin a selected population of patients with COPD, exertional\ndesaturation and positive acute response to supplemental oxy-\ngen during exercise tests.79\nThis warrants further evaluation.\nRecommendations for exercise training.\nMajor changes from previous Guideline.\n\u2022 Supplemental oxygen is not recommended for\nexercise training in patients with COPD not ful-\nfilling LTOT criteria. (Strength of recommenda-\ntion: Strong; Evidence: Low).\n\u2022 There are insufficient data to make recom-\nmendations regarding the use of oxygen for\nexercise training in other chronic respiratory\nconditions\nAir travel\nCabin pressures of commercial passenger aircraft range\nup to 2500 m above sea level ambient pressures during\nstandard operating conditions, which is analogous to\nbreathing 15% oxygen at sea level.1\nA small number of\nstudies have explored the impact of oxygen therapy on\nPaO2 at high altitude in patients with chronic respira-\ntory disease.80\u201384\nMost were experimental studies simu-\nlating a commercial aircraft cabin altitude of 8000 ft\nand administered supplemental oxygen via different\ndelivery methods, including continuous flow via a nasal\ncannula, an oxygen-conserving device, portable oxygen\nconcentrator (POC), or Venturi mask (Table S20 in the\nSupporting Information). Oxygen administration signifi-\ncantly increased PaO2 at altitude in some80\u201382\nbut not\nall studies,83\nwith results appearing to be affected by the\noxygen delivery method. In a survey of patients using\nLTOT who had flown with supplemental oxygen,84\nthe\nmajority found it complicated their travel in terms of\naccessing required information and organization,\nalthough four-fifths stated they would fly again.\nAs a practical approach, individuals with resting oxy-\ngen saturation \u226595% are unlikely to require in-flight sup-\nplemental oxygen.85,86\nFor other individuals, in-flight\noxygen should be considered, particularly for those with\nprevious significant intolerance to air travel, such as the\nrequirement for mid-air emergency oxygen or diversion,\nor who are using LTOT. Of note, neither resting sea level\noxygen saturation nor lung function reliably predicts\nhypoxaemia or complications of air travel in patients with\nrespiratory disease.86\u201388\nA hypoxic challenge test, also\nknown as an altitude simulation test, can be performed to\nprovide a more accurate evaluation of altitude oxygena-\ntion and prescription of in-flight supplemental oxygen for\nmaintaining PaO2 >50 mm Hg or oxygen saturation\n>85%, particularly in those with existing hypercapnia or\nat risk thereof.85,89,90\nRecommendations for air travel.\nMinor changes from previous Guideline.\n\u2022 Consideration of supplemental oxygen during\nair travel is recommended, where a traveller\nfulfils criteria for requiring LTOT (without\nevidence of hypercapnia) or has a demon-\nstrated fall in PaO2 to <50 mm Hg or SpO2\nto <85% during a hypoxic challenge test.\n(Strength of recommendation: Strong; Evi-\ndence: Low).\nAcute asthma\nThere is one prospective observational study showing that\nthe availability of domiciliary oxygen for administration\nat the start of an asthma attack reduced the risk of death\nin individuals at high risk for recurrent life-threatening\n8 MCDONALD ET AL.\nasthmatic attacks (Table S20 in the Supporting\nInformation).91\nRecommendations for acute asthma.\nMinor changes from previous Guideline.\n\u2022 Domiciliary oxygen therapy for acute use while\nawaiting medical attention can be considered in\npatients with previous near-fatal asthmatic\nattacks, at high risk of a future fatal asthmatic\nattack, or in patients with episodic acute asthma\nliving in isolated areas. (Strength of recommenda-\ntion: Weak; Evidence: Very low)\nHeadache\nSupplemental oxygen therapy has been studied for treatment of\nacute episodes of chronic headache (Table S20 in the Supporting\nInformation). Inhaled oxygen at a flow rate of \u226510 L\/min was\nfound to be effective in treating acute attacks of cluster head-\nache92,93\nand acute migraine94\nin randomized crossover trials,\nbut not for medication overuse headache in a case series.95\nRecommendations for headache.\nMajor changes from previous Guideline.\n\u2022 Intermittent inhaled high-flow oxygen (100% at\n10\u201315 L\/min via a non-rebreather mask) can be\noffered to patients to treat acute cluster headache\nattacks and acute migraine. (Strength of recom-\nmendation: Strong; Evidence: Low).\nDOMICILIARY OXYGEN DELIVERY\nOxygen therapy sources and equipment for improving the effi-\nciency of oxygen use are key to domiciliary oxygen delivery. In\nrecent years, domiciliary use of humidified nasal high-flow oxy-\ngen (hNHF-O2) has been explored. While there has been inter-\nest in the development of novel devices for auto-titration,96\u2013100\nremote control,101\ncompliance monitoring,102\u2013104\nand alterna-\ntive sources of oxygen therapy,105\nthey remain yet to be avail-\nable for commercial use.\nSources of domiciliary oxygen delivery\nSources of domiciliary oxygen delivery can be divided into\nstationary and ambulatory (Table S21 in the Supporting\nInformation). While liquid oxygen systems are used in some\ncountries,106\u2013108\nthey are not available for domiciliary use in\nAustralia and New Zealand.\nStationary oxygen source\nStationary oxygen concentrators remain the major source for\nproviding LTOT within the home. They are floor-standing\ndevices powered by the domestic electricity supply and provide\nan oxygen concentration of 90%\u201395%.1\nThe maximum flow\ndelivery of stationary oxygen concentrators is typically 5 L\/min\nwith some being capable of delivering up to 10 L\/min, although\nthe percentage of oxygen falls with increasing flow rate.109,110\nWith the use of 9 m extension tubing, patients can move\naround the home, but it is important to note that increasing\ntubing length beyond 30 m can result in a fall in the concentra-\ntion of delivered oxygen,111,112\nin addition to the potential haz-\nard of tripping or falling. Performance of stationary oxygen\nconcentrators can be affected by their working duration, with\nlower oxygen concentration associated with longer working\nduration,110,113\nindicating the importance of regular device\nchecks and servicing.\nAmbulatory oxygen source\nIn Australia and New Zealand, there are two sources for\nambulatory oxygen, with compressed oxygen cylinders of\nvarying sizes being the most common and POCs of different\nmodels being increasingly used in recent years. Compressed\noxygen cylinders contain 100% pure oxygen delivered at\nflow rates ranging between 1 and 6 L\/min, whereas POCs\nare rechargeable lightweight devices that generally deliver\noxygen concentrations of \u226590% in pulsed doses and\/or con-\ntinuous flow. Of note, POCs offer a range of numbered flow\nsettings that vary across models. These are not equivalent to\nthe numbered flow rate for compressed oxygen cylinders\n(e.g., setting of 1 for POC is not equivalent to flow rate of\n1 L\/min for compressed oxygen cylinder). Different POC\nmodels vary in their weight and size, oxygen pulse delivery,\nbattery life and performance at altitude (Table S21 in the\nSupporting Information).114\u2013117\nStudies comparing the performance of compressed oxy-\ngen cylinders and various POCs during in-laboratory assess-\nments and short-term domiciliary use in patients with\ndifferent respiratory diseases generally revealed similar dys-\npnoea scores, HRQoL, oxygenation capacity and 6-min walk\ndistances between cylinders and POCs, although there were\nsome between-study variations (Table S21 in the Supporting\nInformation).118\u2013128\nPOCs are preferred over compressed\noxygen cylinders for their portability and ease of use,\nalthough these factors may be of less concern for younger\npatients.123,125,127,128\nOf note, POCs have potential limita-\ntions with regard to battery life and oxygenation capacity,\nparticularly for patients requiring high flow settings,\ngiven their lower oxygen concentration delivery. The trans-\nportability of the ambulatory oxygen source may affect\nTSANZ ADULT HOME OXYGEN GUIDELINE 9\npatients\u2019 exercise capacity and dyspnoea level, noting that\ncarrying the device in a backpack may be favoured over\nusing a trolley or shoulder strap.129\u2013131\nEfficient use of oxygen\nEfficient oxygen use can be achieved by using oxygen con-\nserving devices (OCDs), including demand oxygen delivery\nsystems and specialized oxygen-conserving nasal cannulae.\nThese devices allow breath-triggered oxygen pulse delivery\nearly in inspiration to reduce gas wastage during expiration\ncompared to continuous flow. The efficiency of maintaining\nadequate oxygenation at lower oxygen usage yields practical\nbenefits, including extended cylinder range or the same\nrange with smaller and lighter cylinders, resulting in reduced\ncumulative refilling costs. There have been few advances in\nthis area since the last TSANZ Guideline (Table S22 in the\nSupporting Information).\nThe volume, delivery waveform and frequency vary\nacross different OCD models, which are given as either a\npre-set pulse volume (some or all breaths) or a pre-set\nminute volume averaged by respiratory rate that can affect\noxygen delivery during exertion.132\nThe specialized nasal\ncannula with a pendant-shaped reservoir allows its filling\nwith oxygen during exhalation and delivers a bolus\nentrained from the reservoir early in the subsequent inspira-\ntion. Compared to conventional nasal cannulae, it has been\nshown to enable adequate oxygenation at reduced mean\noxygen flow rates at 33%\u201350%133\u2013135\nand improved exercise\ntolerance for the same oxygen usage.136,137\nOf note, the\nadjustment in the oxygen flow rate for OCDs or oxygen-\nconserving nasal cannulae cannot be predicted based on the\nprescribed or current continuous flow rate, nor are these\nconsistent between different OCD models.132,136,138\u2013142\nHumidified nasal high-flow devices\nHumidified nasal high-flow devices deliver heated, humidi-\nfied oxygen (hNHF-O2) via wide-bore nasal cannulae (high\nflow nasal cannulae [HFNC]), with delivered concentrations\nof up to 100% and flow rates of up to 70 L\/min. These\ndevices have primarily been used in hospitals, including for\ndelivery of warm humidified air. The focus here is on their\nuse in the home (Table S23 in the Supporting Information).\nOne RCT of 200 patients with COPD and chronic\nhypoxaemic respiratory failure showed a reduction in exac-\nerbations in those using hNHF-O2 at 20 L\/min for an aver-\nage of 6 h\/day in addition to LTOT compared to those\nreceiving LTOT alone at 12 months, with no difference in\nmortality between the groups.143\nAnother study using at\nleast overnight HFNC with daytime LTOT versus LTOT\nalone showed a reduction in the rate of and increased\ntime to moderate-to-severe exacerbation in those with\nmoderate-to-severe disease and daytime hypercapnia over\n12 months.144\nPost-hoc analyses from a previous RCT sug-\ngested potential benefits of hNHF-O2 in selected patients\nwith severe COPD and chronic hypoxaemic respiratory fail-\nure with recurrent exacerbations.145\nCompared to LTOT,\nhNHF-O2 was found to improve HRQoL in patients with\nCOPD in two RCTs over 12 months, and in a randomized\ncrossover trial after 6 weeks of therapy.143,144,146\nHowever,\nvarying effects of hNHF-O2 on dyspnoea were reported\nin studies of different trial designs and patient\npopulations.143,146\u2013148\nIn terms of physiological effects on\ngas exchange and respiratory rates, hNHF-O2 was found to\nachieve at least comparable oxygenation levels in compari-\nson to LTOT,146,147,149\nreduced arterial partial pressure or\ntranscutaneous carbon dioxide levels at rest, during exercise\nand overnight,143,146,147,149\u2013152\nand reduced respiratory\nrate.147,152\nSerious adverse events have not been reported with the\ndomiciliary use of hNHF-O2.144,146\nNoise generated by hNHF-O2 devices is a common com-\nplaint which may be addressed through the use of filters\ndesigned for noise reduction.153\nFactors reported by patients\naffecting adherence with domiciliary hNHF-O2 in a RCT\nincluded perceived symptom and functional improvement,\nas well as perceived safety and familiarity with the device.154\nNevertheless, some patients reported preference for\nLTOT over hNHF-O2 with respect to dyspnoea and device\ninterface comfort.152\nCost evaluations in a New Zealand\nhealthcare setting showed cost-effectiveness and savings of\nup to $5535 NZD per patient-year associated with domicili-\nary hNHF-O2 compared to usual care (including LTOT) in\npatients with severe COPD,155\nwith similar cost-effectiveness\nreported in a European study.156\nRecommendations for sources of domiciliary oxy-\ngen delivery.\nNew recommendations.\n\u2022 Stationary concentrators are the recommended\nmeans of delivering oxygen in the home\n\u2022 Portable oxygen concentrators can be used as\nsources of ambulatory oxygen therapy, with titra-\ntion required to determine adequate oxygenation\nfor the specific prescribed device\n\u2022 Oxygen conserving devices (OCDs), including\ndemand oxygen delivery systems and specialized\noxygen-conserving nasal cannulae, can be used to\nachieve efficient oxygen use. Oxygen titration is\nneeded to determine the appropriate settings for\nthe individual with the specific OCD model\n\u2022 Routine use of domiciliary hNHF-O2 is not\nrecommended, although it may be considered on\na case-by-case basis, particularly in patients with\nCOPD and frequent exacerbations.\n10 MCDONALD ET AL.\nSAFETY CONSIDERATIONS\nThere are potential safety concerns and risks associated with\nthe use of domiciliary oxygen therapy. These include burns,\nfires, falls and other health consequences including the\ndevelopment of hypercapnia, as well as physical and psycho-\nlogical impacts on patients and caregivers (Tables S24 and\nS25 in the Supporting Information).\nFires and burns\nThere are limited published prospective safety studies on the\nrisks of burns in patients using domiciliary oxygen ther-\napy,157,158\nwith the majority being reported in retrospective\nstudies including case series and observational studies\n(Table S24 in the Supporting Information). Smoking by the\npatient or by others, is a major cause of burns and fires\nattributed to the use of domiciliary oxygen therapy, with\nother sources of ignition related to open flames such as dur-\ning cooking.159\u2013161\nBurns may be facial or to other external parts of the\nbody, but also include inhalation injuries in up to 39% of\npatients intubated for burns arising from domiciliary oxygen\ntherapy.162\u2013165\nDeaths as a result of fires and burns in the setting of\ndomiciliary oxygen therapy use have been reported, with a\nmean average hospital stay of 3.6 days in those with minor\nburns.157,159\u2013161,163,165\u2013167\nFalls\nThere is little data regarding the risk of falls associated\nwith using domiciliary oxygen therapy (Table S25 in the\nSupporting Information), although it is likely significant\ngiven the patient populations have high levels of frailty\nand multimorbidities.168\u2013170\nThis risk is of particular con-\ncern for patients who are cognitively, physically and\/or\nvisually impaired. An Australian observational study\nreported three cases of hospitalizations for falls associated\nwith domiciliary oxygen tubing over 4 years of follow-up\nin 291 patients on LTOT, with one complicated by\nfracture.171\nHypercapnia\nWhile worsening hypercapnia is a potential risk associated\nwith domiciliary supplemental oxygen therapy, this does not\nappear to be of significant concern in most patients. Specific\npopulations at risk of hypercapnic respiratory failure\n(including, but not limited to those with advanced suppura-\ntive lung diseases, chest wall deformities, severe obesity and\noverlapping sleep-disordered breathing), may require closer\nsurveillance and consideration of specialized respiratory fail-\nure support.\nOther health consequences\nA single case\u2013control study reported no differences in smell\nand taste for patients with COPD who were treated and not\ntreated with domiciliary oxygen therapy.172\nThree experimental\ncase\u2013control studies explored the impact of supplemental oxy-\ngen on systemic redox balance in patients with COPD.173\u2013175\nTwo studies reported significant increases in proinflamma-\ntory or oxidative stress biomarkers using supplemental\noxygen,173,174\nwith administration of the antioxidant N-\nacetylcysteine in one study reversing erythrocyte protein\noxidation.174\nThe third study did not detect any difference\nin the oxidative stress biomarker isofuran between patients\nreceiving and not receiving supplemental oxygen therapy.175\nPhysical and psychological impacts on patients\nand caregivers\nQualitative studies and surveys have explored the impact of\nusing domiciliary oxygen therapy on patients and caregivers\n(Tables S5\u2013S7, S16 and S25 in the Supporting Information).\nStigma associated with domiciliary oxygen therapy is com-\nmonly reported by patients.176\u2013178\nSome patients, who had\nused LTOT for more than 12 months, described poor self-\nimage and sadness,179\nwhile other patients and caregivers\nreported increased social activity and perceived improve-\nments in health status and capacity to participate in daily\nactivities as a result of LTOT.180\nThe use of domiciliary oxy-\ngen therapy also fails to meet patients\u2019 treatment\nexpectations.176,181,182\nAdverse impacts during daily living, as well as psycho-\nlogical and physical challenges, associated with using domi-\nciliary oxygen therapy affect both patients and their\ncaregivers.181\u2013185\nRecommendations regarding safety and risk\nconsiderations.\nSafety factors are essential considerations in the\nprescription of domiciliary oxygen therapy. Educa-\ntion and verbal and written information should be\nprovided to all patients, caregivers and any co-\ninhabitants.\nUnchanged from previous Guideline.\n\u2022 Oxygen should not be prescribed in patients who\ncontinue to smoke\nNew recommendations.\n\u2022 Oxygen should not be used in close proximity to\nnaked flames and other potential ignition sources\nincluding e-cigarettes\n\u2022 Caregivers and others should be advised not to\nsmoke in proximity to people using domiciliary\noxygen therapy\nTSANZ ADULT HOME OXYGEN GUIDELINE 11\n\u2022 Adherence with smoking abstinence can be mon-\nitored with urinary cotinine, and\/or carboxyhae-\nmoglobin and carbon monoxide measurements\n\u2022 Consideration should be given to withdrawing\ndomiciliary oxygen therapy if the user continues\nto smoke, or if there are other concerns regarding\nfire risk\n\u2022 Home visits by healthcare personnel may be an\nopportunity to provide additional information\nregarding fire and falls risks\n\u2022 Potential psychosocial impact of domiciliary oxy-\ngen therapy should be considered and discussed\nwith patients and caregivers as indicated\n\u2022 Potential risk of hypercapnia should be consid-\nered on a case-by-case basis\nASSESSMENT AND SUPPORT FOR\nDOMICILIARY OXYGEN THERAPY\nAssessment and support are key components for prescribing\ndomiciliary oxygen therapy (Table S26 in the Supporting\nInformation). In Australia and New Zealand, government-\nfunded domiciliary oxygen therapy is generally prescribed\nby a respiratory physician, general physician, cardiologist or\npaediatrician, with additional approval from a specified\nrespiratory physician required in some jurisdictions.1\nIn\nselected states of Australia and in New Zealand, oncologists,\ngeriatricians, palliative care specialists and nurse practi-\ntioners (respiratory) are listed as approved prescribers for\ndomiciliary oxygen therapy.1\nFor patients who reside in aged\ncare facilities, domiciliary oxygen may be ordered by any\nregistered medical officer.1\nThe availability of a domiciliary\noxygen therapy clinic, which may assist with appropriate\nassessment, prescription, support and follow-up of patients\nconsidered for domiciliary oxygen therapy varies across\nregions.68,186\u2013189\nOxygenation status assessment\na. Resting hypoxaemia\nRoom air arterial blood gas (ABG) analysis at rest is\nrequired to ascertain the presence of severe resting hypoxae-\nmia. After the patient is rested for 5\u201310 min breathing room\nair and an Allen\u2019s test is performed, an arterial sample using\na small 25-gauge needle without anaesthetic should be\nobtained by a trained operator experienced in the technique.\nThis approach will minimize pain and associated trauma,\nalthough patient preference should be considered.1\nOf note,\nusing a topical anaesthetic has not been demonstrated to\nreduce pain associated with radial artery sampling.190,191\nWhile pulse oximeters are non-invasive and easily available,\nmeasurements of oxygen saturation do not provide an accu-\nrate estimation of PaO2, and should only be used for screen-\ning purposes.192\u2013195\nIn order to determine the optimal\noxygen prescription to achieve SpO2 >90% or PaO2\n>60 mm Hg, assessment with pulse oximetry or repeat ABG\non supplemental oxygen may be performed. In patients with\na background or at risk of hypercapnia, assessments using\nABG on supplemental oxygen are required. Of note, the\nsource of supplemental oxygen for the testing is preferably a\nstationary oxygen concentrator rather than wall oxygen\nwhich may lead to underestimation of the oxygen prescrip-\ntion.196,197\nWhile oximetry monitoring in the home setting\nhas been evaluated in small studies for assessing both eligi-\nbility for LTOT and adequacy of oxygenation,198\u2013204\nsuch an\napproach requires additional resources and it remains\nuncertain whether it leads to better patient health outcomes.\nb. Nocturnal hypoxaemia\nOvernight pulse oximetry can be used for assessment of\nnocturnal hypoxaemia, as well as for evaluation of nocturnal\noxygen prescription in patients on LTOT.205\u2013210\nPulse oxi-\nmeters with onboard memory capable of recording \u22658 h of\ndata are suitable for this purpose, with data analysis provid-\ning estimates of average oxygenation overnight.1\nNocturnal\npolysomnography (in laboratory or home-based) is required if\nthere are concerns of sleep disordered breathing contributing\nto nocturnal hypoxaemia to allow appropriate management.\nc. Exertional desaturation\nExercise tests are performed for assessment of exertional\ndesaturation and prescription of supplemental oxygen dur-\ning activities. The 6-min walk test (6MWT) is the most\ncommonly used exercise test in clinical practice and has\nbeen extensively used in clinical research regarding ambula-\ntory oxygen therapy, acknowledging some limitations in its\nperformance.211\u2013213\nSupplemental oxygen should be titrated\nduring the test to determine the prescription of oxygen flow\nrequired to maintain SpO2 >88%.214\nTo assess the effects of\nsupplemental oxygen (including on dyspnoea severity and\nwalk distance), a 6MWT using an air-filled cylinder is\nrecommended to mitigate the known placebo effect.215\nWhile other exercise tests, such as shuttle walk tests, and\nassessments during domestic activities have been studied for\nevaluation of exertional desaturation,216\u2013218\ntheir utility for pre-\nscribing domiciliary oxygen therapy is yet to be established.\nd. Reassessment\nRegular reassessments following initiation of domiciliary\noxygen therapy are required in order to assess patients\u2019\nongoing oxygen needs over time.189,219\nApproximately 10%\u2013\n58% of patients were no longer eligible for LTOT during re-\nevaluation at a range of follow-up duration between\n1 month and 1 year.220\u2013222\nWhile the optimal interval for\nreassessment is yet to be established, a period between 6 and\n12 MCDONALD ET AL.\n12 months is suitable for stable patients.220,223\nPatients with\nrecent hospitalized acute exacerbation of the underlying dis-\nease for which LTOT has been prescribed may require reas-\nsessment within 90 days of discharge, which is similar to\nthat for patients who are prescribed STOT.\nEducation and support provision for\ndomiciliary oxygen therapy\nPatient education has been shown to improve adherence\nwith and appropriate use of domiciliary oxygen therapy, as\nwell as providing an understanding of the associated safety\nprecautions.224\u2013227\nBoth patients and clinicians express the\nneed for education about domiciliary oxygen ther-\napy.177,181,182,228\nKey information includes equipment types,\nhow and when to use the prescribed oxygen therapy, setting\nappropriate treatment expectations and safety aspects with\nusing oxygen therapy, as well as information about available\nsupport and follow-up. Patients and caregivers are increas-\ningly accessing health information online. Of note, much of\nthe online content about domiciliary oxygen therapy is of a\nlow-to-moderate standard only, which is unsuitable for the\ngeneral population.229\nProvision of regular support follow-\ning initiation of domiciliary oxygen therapy, such as via tele-\nmonitoring and home visits, has been shown to improve\nmental-wellbeing and HRQoL and to reduce health care uti-\nlization, although additional resources are required.230\u2013233\nRecommendations for assessment and support\nfor domiciliary oxygen therapy.\nNew recommendations.\n\u2022 Appropriate assessment should be conducted for\nevaluation of different types of domiciliary oxy-\ngen therapy:\n\u000e LTOT: ABG\n\u000e NOT: Nocturnal pulse oximetry with \u22658-h\nrecording time, with polysomnography being\nconsidered for those at risk of sleep disordered\nbreathing\n\u000e Ambulatory oxygen therapy: Exercise tests,\nwith 6MWTs being preferred, as well as a dys-\npnoea score\n\u000e STOT: If STOT is recommended for persistent\nhypoxaemia at hospital discharge, reassessment\nshould be organized within 30\u201390 days post-\ndischarge, as many patients will no longer\nrequire oxygen therapy\n\u2022 Reassessment post-initiation of domiciliary oxy-\ngen therapy to determine ongoing need and ade-\nquacy of oxygen prescription is recommended at\nan interval of 6\u201312 months for stable patients and\nfollowing hospitalization for acute exacerbation\nof the underlying disease\n\u2022 Patient and caregiver education is an essential\ncomponent of the prescription of domiciliary\noxygen therapy.\nAREAS FOR FUTURE RESEARCH\nAs highlighted in the literature review for this Guideline,\nlimited evidence exists to guide the clinical use of domicili-\nary oxygen therapy in adults. There is an urgent need to\nestablish medium and long-term treatment effects (mortal-\nity, exercise capacity, HRQoL, symptoms, psychological\nwell-being, biomarkers of oxidative stress and inflammation)\nand cost-effectiveness of different types of oxygen therapy in\npatients with different chronic respiratory diseases who are\noptimally managed with contemporary medical therapies.\nWith technological advances, the role of home monitor-\ning through the use of wearable devices and newer oxygen\ndelivery devices such as hNHF-O2 should be evaluated.\nCross-disciplinary collaborations are needed to allow the\ndevelopment of novel, portable and ergonomic oxygen deliv-\nery devices that meet high oxygen requirements. There is\nalso a need to understand the current model of care and\ngaps in assessment and provision of domiciliary oxygen\ntherapy and ongoing care in Australia and New Zealand.\nACKNOWLEDGEMENTS\nWe would like to thank John Blakey and Michael Elizalde\nfor their contribution to document development. Open\naccess publishing facilitated by The University of Mel-\nbourne, as part of the Wiley - The University of Melbourne\nagreement via the Council of Australian University\nLibrarians.\nCONFLICT OF INTEREST STATEMENT\nNo funding was received to support the development of this\nGuideline. CFM reports appointments as Clinical Advisor,\nDomiciliary Oxygen Program, State-Wide Equipment\nProgram, VIC; Chair of the COPD National Program Lung\nFoundation Australia; Member of the COPD-X Guidelines\nCommittee Lung Foundation Australia; Member of the\nTGA Ventilator Expert Group; Member of Clinical Execu-\ntive Austin Health; and Medical Director of the Institute for\nBreathing and Sleep. CFM received grants from NHMRC,\nMRFF, GSK Investigator-sponsored Scheme, Institute for\nBreathing and Sleep and The Prince Charles Hospital Foun-\ndation. CFM is the Editor in Chief of Respiratory Medicine\nToday and Deputy Editor for Respirology and was excluded\nfrom all editorial decision-making related to the acceptance\nand publication of this article. CB received Travel Grants\nfrom TSANZ, Fisher and Paykel Healthcare, the St George\nInstitute of Health and reports volunteer roles in TSANZ\nVictorian Branch, TSANZ Respiratory Nurse SIG, TSANZ\nProfessional Standards Committee, ASA Education\nTSANZ ADULT HOME OXYGEN GUIDELINE 13\nCommittee and ASA Sleep Nurse Chair. BRM is Clinical\nAdvisor, Domiciliary Oxygen Program, State-Wide Equip-\nment Program, VIC. NS received grants from NHMRC,\nMRFF, Cancer Council Australia, Industry grant from\nFisher& Paykel Healthcare, Philanthropic grants from Win-\ndermere Foundation, Lung Foundation Australia, Lord\nMayor\u2019s Foundation Melbourne, PACT Grant-in-Aid. NS is\nBoard Director TSANZ, Board Director Victorian Doctor\u2019s\nProgram, European Respiratory Society Co-Chair Guide-\nlines Committee. NS received consulting fees from The Lim-\nbic and Orchard Consulting; speaker\u2019s fees from GSK,\nBoehringer Ingelheim, Astra Zeneca, Fisher Paykel Health-\ncare, Health Ed; travel support from Chiesi and Boehringer\nIngelheim; and equipment for investigator-initiated clinical\ntrials from Fisher Paykel Healthcare. NS is an Advisory\nBoard member for Respirology and was excluded from all\neditorial decision-making related to the acceptance and pub-\nlication of this article. LT reports consulting fees from Boeh-\nringer Ingelheim, and speaker fees from Erbe.\nElektromedizinGmbH. YHK reports non-financial support\nfrom Air Liquide Healthcare outside the submitted work;\ngrants from NHMRC, MRFF, Austin Medical Research\nFoundation, Lung Foundation Australia, TSANZ and RACP;\nYHK is Board Director TSANZ; guidelines methodologist\nATS; Associate Editor European Respiratory Journal, and\nClinical Advisor, Domiciliary Oxygen Program, State-Wide\nEquipment Program, VIC. JS, SA, HD and MM have no\nconflicts of interest to declare.\nDATA AVAILABILITY STATEMENT\nData sharing is not applicable to this article as no new data\nwere created or analyzed in this study.\nORCID\nChristine F. McDonald https:\/\/orcid.org\/0000-0001-6481-\n3391\nNatasha Smallwood https:\/\/orcid.org\/0000-0002-3403-\n3586\nLauren Troy https:\/\/orcid.org\/0000-0002-7426-336X\nYet Hong Khor https:\/\/orcid.org\/0000-0002-5434-9342\nLINKED CONTENT\nThis publication is linked to a related article. To view this\narticle, visit https:\/\/doi.org\/10.1111\/resp.14794\nREFERENCES\n1. 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Breaden K, Collier A, Litster C, Allcroft P, Currow DC, Phillips JL.\nStigma and the in(visible) perspectives and expectations of home oxy-\ngen therapy among people with chronic breathlessness syndrome: a\nqualitative study. Palliat Med. 2019;33:82\u201390.\n177. Khor YH, Goh NSL, McDonald CF, Holland AE. Oxygen therapy for\ninterstitial lung disease: physicians\u2019 perceptions and experiences. Ann\nAm Thorac Soc. 2017;14:1772\u20138.\n178. Karki A, Morante J, Cervellione KL, Ullah T, Patel V, Fein AM. Oxy-\ngen indications and utilization in a diverse, urban community setting.\nJ Cardiopulm Rehabil Prev. 2020;40:438\u201340.\n179. Bueno GH, Campos CJG, Turato ER, Paschoal IA, Vallada\u0303o LS,\nBaltieri L, et al. Experiences in elderly people with chronic obstructive\npulmonary disease in relation to the use of long-term home oxygen\ntherapy: a qualitative study about feelings attributed to therapy. BMC\nPulm Med. 2022;22:96.\n18 MCDONALD ET AL.\n180. Goldbart J, Yohannes AM, Woolrych R, Caton S. \u2019It is not going to\nchange his life but it has picked him up\u2019: a qualitative study of per-\nspectives on long term oxygen therapy for people with chronic\nobstructive pulmonary disease. Health Qual Life Outcomes. 2013;\n11:124.\n181. Cleries X, Sola M, Chiner E, Escarrabill J, Collaborative Group of\nSEPAR 2014\/2015 Year of the Chronic Patient and Home Respiratory\nTherapy for Evaluating the patient Experience. Defining patient and\ncaregivers\u2019 experience of home oxygen therapy. Arch Bronconeumol.\n2016;52:131\u20137.\n182. Khor YH, Goh NSL, McDonald CF, Holland AE. Oxygen therapy for\ninterstitial lung disease. A mismatch between patient expectations and\nexperiences. Ann Am Thorac Soc. 2017;14:888\u201395.\n183. Kampelmacher MJ, Van Kesteren RG, Alsbach GPJ, Melissant CF,\nWynne HJ, Douze JMC, et al. Characteristics and complaints of\npatients prescribed long-term oxygen therapy in The Netherlands.\nRespir Med. 1998;92:70\u20135.\n184. Ring L, Danielson E. Patients\u2019 experiences of long-term oxygen ther-\napy. J Adv Nurs. 1997;26:337\u201344.\n185. Graney BA, Wamboldt FS, Baird S, Churney T, Fier K, Korn M, et al.\nInformal caregivers experience of supplemental oxygen in pulmonary\nfibrosis. Health Qual Life Outcomes. 2017;15:133.\n186. Montner P, Sergent M, Case E, Douglas M, Griego E, Martinez F, et al.\nTQI in the Albuquerque veterans affairs medical Center\u2019s long-term oxy-\ngen therapy program. Jt Comm J Qual Improv. 1998;24:203\u201311.\n187. O\u2019Donnell C, Davis P, McDonnell T. Oxygen therapy in Ireland: a\nNationwide review of delivery, monitoring and cost implications. Ir\nMed J. 2019;112:933.\n188. Turner AM, Sen S, Steeley C, Khan Y, Sweeney P, Richards Y, et al.\nEvaluation of oxygen prescription in relation to hospital admission\nrate in patients with chronic obstructive pulmonary disease. BMC\nPulm Med. 2014;14:127.\n189. McKeon JL, Saunders NA, Murree-Allen K. Domiciliary oxygen: ratio-\nnalization of supply in the hunter region from 1982-1986. Med J\nAustralia. 1987;146:73\u20138.\n190. Tran NQ, Pretto JJ, Worsnop CJ. A randomized controlled trial of the\neffectiveness of topical amethocaine in reducing pain during arterial\npuncture. Chest. 2002;122:1357\u201360.\n191. Aaron SD, Vandemheen KL, Naftel SA, Lewis MJ, Rodger MA. Topi-\ncal tetracaine prior to arterial puncture: a randomized, placebo-\ncontrolled clinical trial. Respir Med. 2003;97:1195\u20139.\n192. Carlin BW, Clausen JL, Ries AL. The use of cutaneous oximetry in the\nprescription of long-term oxygen therapy. Chest. 1988;94:239\u201341.\n193. Ekkernkamp E, Welte L, Schmoor C, Huttmann SE, Dreher M,\nWindisch W, et al. Spot check analysis of gas exchange: invasive ver-\nsus noninvasive methods. Respiration. 2015;89:294\u2013303.\n194. Roberts CM, Bugler JR, Melchor R, Hetzel MR, Spiro SG. Value of\npulse oximetry in screening for long-term oxygen therapy require-\nment. Eur Respir J. 1993;6:559\u201362.\n195. Roberts CM, Franklin J, O\u2019Neill A, Roberts RP, Ide J, Hanley ML,\net al. Screening patients in general practice with COPD for long-term\ndomiciliary oxygen requirement using pulse oximetry. Respir Med.\n1998;92:1265\u20138.\n196. Bolton CE, Annandale JA, Ebden P. Comparison of an oxygen concen-\ntrator and wall oxygen in the assessment of patients undergoing long\nterm oxygen therapy assessment. Chron Respir Dis. 2006;3:49\u201351.\n197. Dheda K, Lim K, Ollivere B, Leftley J, Lampe FC, Salisbury A, et al.\nAssessments for oxygen therapy in COPD: are we under correcting\narterial oxygen tensions? Eur Respir J. 2004;24:954\u20137.\n198. Morrison D, Skwarski KM, MacNee W. The adequacy of oxygena-\ntion in patients with hypoxic chronic obstructive pulmonary dis-\nease treated with long-term domiciliary oxygen. Respir Med. 1997;\n91:287\u201391.\n199. Pilling J, Cutaia M. Ambulatory oximetry monitoring in patients with\nsevere COPD: a preliminary study. Chest. 1999;116:314\u201321.\n200. Abdulla J, Godtfredsen N, Pisinger C, Wennike P, Tonnesen P. Ade-\nquacy of oxygenation in a group of Danish patients with COPD on\nlong-term oxygen therapy. Monaldi Arch Chest Dis. 2000;55:279\u201382.\n201. Fussell KM, Ayo DS, Branca P, Rogers JT, Rodriguez M, Light RW.\nAssessing need for long-term oxygen therapy: a comparison of con-\nventional evaluation and measures of ambulatory oximetry monitor-\ning. Respir Care. 2003;48:115\u20139.\n202. Zhu Z, Barnette RK, Fussell KM, Michael Rodriguez R, Canonico A,\nLight RW. Continuous oxygen monitoring\u2014a better way to prescribe\nlong-term oxygen therapy. Respir Med. 2005;99:1386\u201392.\n203. Faria I, Gaspar C, Zamith M, Matias I, das Neves RC, Rodrigues F,\net al. TELEMOLD project: oximetry and exercise telemonitoring to\nimprove long-term oxygen therapy. Telemed J E Health. 2014;20:\n626\u201332.\n204. Rodrigues MP, Vissoci CM, Rosa SP, Negreiros SBC. 24-hour hypoxia\nand pulmonary hypertension in patients with idiopathic pulmonary\nfibrosis. Open Respir Med J. 2017;11:11\u20136.\n205. Ayache M, Strohl KP. High interrater reliability of overnight pulse\noximetry interpretation among inexperienced physicians using a\nstructured template. J Clin Sleep Med. 2018;14:541\u20138.\n206. Carroll N, Walshaw MJ, Evans CC, Hind CR. Nocturnal oxygen desa-\nturation in patients using long-term oxygen therapy for chronic air-\nflow limitation. Respir Med. 1990;84:199\u2013201.\n207. Nisbet M, Eaton T, Lewis C, Fergusson W, Kolbe J. Overnight pre-\nscription of oxygen in long term oxygen therapy: time to reconsider\nthe guidelines? Thorax. 2006;61:779\u201382.\n208. Plywaczewski R, Sliwinski P, Nowinski A, Kaminski D, Zielinski J.\nIncidence of nocturnal desaturation while breathing oxygen in COPD\npatients undergoing long-term oxygen therapy. Chest. 2000;117:\n679\u201383.\n209. Samolski D, Tarrega J, Anton A, Mayos M, Marti S, Farrero E, et al.\nSleep hypoventilation due to increased nocturnal oxygen flow in\nhypercapnic COPD patients. Respirology. 2010;15:283\u20138.\n210. Tarrega J, Guell R, Anton A, Mayos M, Farre A, Jerez FR, et al. Are\ndaytime arterial blood gases a good reflection of nighttime gas\nexchange in patients on long-term oxygen therapy? Respir Care. 2002;\n47:882\u20136.\n211. Chatterjee AB, Rissmiller RW, Meade K, Paladenech C, Conforti J,\nAdair NE, et al. Reproducibility of the 6-minute walk test for ambula-\ntory oxygen prescription. Respiration. 2010;79:121\u20137.\n212. Sanchez-Morillo D, Lara-Dona A, Priego-Torres B, Morales-\nGonzalez M, Montoro-Ballesteros F, Leon-Jimenez A. Portable oxygen\ntherapy: is the 6-minute walking test overestimating the actual\noxygen needs? J Clin Med. 2020;9:1\u201312.\n213. Carone M, Patessio A, Appendini L, Purro A, Czernicka E,\nZanaboni S, et al. Comparison of invasive and noninvasive saturation\nmonitoring in prescribing oxygen during exercise in COPD patients.\nEur Respir J. 1997;10:446\u201351.\n214. Lourido-Cebreiro T, Gonzalez-Barcala FJ, Alvarez-Dobano JM,\nPereiro-Brea T, Abelleira-Paris R, Valdes L. Need for portable oxygen\ntitration during 6-minute walk tests. Arch Bronconeumol. 2019;55:\n539\u201340.\n215. Lock SH, Paul EA, Rudd RM, Wedzicha JA. Portable oxygen therapy:\nassessment and usage. Respir Med. 1991;85:407\u201312.\n216. Lewko A, Marshall J, Garrod R. Ambulatory oxygen therapy assess-\nment: a comparative study of incremental shuttle and 6-minute walk-\ning tests. Physiotherapy. 2007;93:261\u20136.\n217. Sandland CJ, Morgan MD, Singh SJ. Detecting oxygen desaturation in\npatients with COPD: incremental versus endurance shuttle walking.\nRespir Med. 2008;102:1148\u201352.\n218. Sant\u2019Anna T, Donaria L, Hernandes NA, Furlanetto KC, Barbosa DS,\nGosselink R, et al. Oxygen desaturation in daily life and during a\nlaboratory-based protocol of activities of daily living in COPD: is there\nrelationship? Lung. 2018;196:19\u201326.\n219. Lourido-Cebreiro T, Gonzalez-Barcala FJ, Rabade C, Abelleira-\nParis R, Pereiro-Brea T, Valdes L. Progress after the withdrawal of\nhome oxygen therapy. The profile of patients requiring reintroduc-\ntion. Arch Bronconeumol. 2019;55:663\u20135.\n220. Gorecka D, Sliwinski P, Zielinski J. Adherence to entry criteria and\none year experience of long-term oxygen therapy in Poland. Eur\nRespir J. 1992;5:848\u201352.\nTSANZ ADULT HOME OXYGEN GUIDELINE 19\n221. Loutsios C, Logan G, Deeming C, Powrie D, Davison A. One blood\ngas is not enough to assess a patient for ltot-how to kiss goodbye to\ncirca 10 million in England. Thorax. 2010;65:A171.\n222. Oba Y, Salzman GA, Willsie SK. Reevaluation of continuous oxygen\ntherapy after initial prescription in patients with chronic obstructive\npulmonary disease. Respir Care. 2000;45:401\u20136.\n223. Cottrell JJ, Openbrier D, Lave JR, Paul C, Garland JL. Home oxygen\ntherapy. A comparison of 2- vs 6-month patient reevaluation. Chest.\n1995;107:358\u201361.\n224. Atis S, Tutluoglu B, Bugdayci R. Characteristics and compliance of\npatients receiving long-term oxygen therapy (LTOT) in Turkey. Mon-\naldi Arch Chest Dis. 2001;56:105\u20139.\n225. Peckham DG, McGibbon K, Tonkinson J, Plimbley G, Pantin C.\nImprovement in patient compliance with long-term oxygen therapy\nfollowing formal assessment with training. Respir Med. 1998;92:\n1203\u20136.\n226. Pepin JL, Barjhoux CE, Deschaux C, Brambilla C. Long-term oxygen\ntherapy at home. Compliance with medical prescription and effective\nuse of therapy. ANTADIR Working Group on Oxygen Therapy. Asso-\nciation Nationale de Traitement a Domicile des Insuffisants Respira-\ntories. Chest. 1996;109:1144\u201350.\n227. Dogan U, Ovayolu N. The effects of health education given by nurses\nto COPD patients on the daily oxygen concentrator usage time. Adv\nRespir Med. 2017;85:15\u201321.\n228. Jacobs SS, Lindell KO, Collins EG, Garvey CM, Hernandez C,\nMcLaughlin S, et al. Patient perceptions of the adequacy of supple-\nmental oxygen therapy. Results of the American Thoracic Society\nNursing Assembly Oxygen Working Group Survey. Ann Am Thorac\nSoc. 2018;15:24\u201332.\n229. Ang HL, Tan HH, Logie KM, McDonald CF, Khor YH. Online patient\ninformation on domiciliary oxygen therapy: an evaluation of quality,\nsuitability, reliability, readability, and content. Chest. 2022;161:\n483\u201391.\n230. Burioka N, Yamamoto A, Morimoto M, Yamasaki A, Hirayama Y,\nTakata M. Health-related quality of life in patients on home oxygen\ntherapy with telemonitoring. Yonago Acta Med. 2020;63:132\u20134.\n231. Clini E, Vitacca M, Foglio K, Simoni P, Ambrosino N. Long-term\nhome care programmes may reduce hospital admissions in COPD\nwith chronic hypercapnia. Eur Respir J. 1996;9:1605\u201310.\n232. Prieto-Centurion V, Basu S, Bracken NE, Casaburi R, Gallardo R,\nGonzalez V, et al. Comparative effectiveness of a PEer-led supplemen-\ntal oxygen InfoLine for patients and CAregivers (PELICAN).\nAm J Respir Crit Care Med. 2018;197:1009\u201317.\n233. Yu YL, Zheng XS, Han XX, Sun MJ. The application value of continuous\nnursing for home oxygen therapy of patients in the stable phase of chronic\nobstructive pulmonary disease. Eur Rev Med Pharmacol Sci. 2017;21:67\u201372.\nSUPPORTING INFORMATION\nAdditional supporting information can be found online in\nthe Supporting Information section at the end of this article.\nHow to cite this article: McDonald CF, Serginson J,\nAlShareef S, Buchan C, Davies H, Miller BR, et al.\nThoracic Society of Australia and New Zealand\nclinical practice guideline on adult home oxygen\ntherapy. Respirology. 2024. https:\/\/doi.org\/10.1111\/\nresp.14793\n20 MCDONALD ET AL.","is_draft":"0","editor_type":"4","file_path":"\/docker_production\/zgvd51\/article\/e13amDwk\/article_file\/2024 TSANZ\u4e34\u5e8a\u5b9e\u8df5\u6307\u5357\uff1a\u6210\u4eba\u5bb6\u5ead\u6c27\u7597.pdf","add_time":"1757143015","update_time":"1757143079"},"pure_content":"C L I N I C A L P R A C T I C E G U I D E L I N E\nThoracic Society of Australia and New Zealand clinical practice\nguideline on adult home oxygen therapy\nChristine F. McDonald1,2,3\n| John Serginson4,5"},{"id":"610664","string_id":"a7lBKGwA","status":"1","parent_id":"610654","slug":"Comparison-of-pulsed-versus-continuous-oxygen","order":"0","name":"Comparison of pulsed versus continuous oxygen","type":"2","cover":"","cover_alt":"","desc":null,"website":"","contact":"","seo_title":"","seo_keyword":"","seo_desc":"","share_switch":"0","share_code":"","author":"","published_time":"1757143081","add_time":"1757143059","update_time":"1757143081","corp_auth_id":"0","verify_code_auth_id":"0","editor_type":"4","file_type":"pdf","auth_id":"[\"610664\", \"610654\"]","content":{"content_id":"610664","content":"\u00a9 2017 Chen et al. This work is published and licensed by Dove Medical Press Limited. The full terms of this license are available at https:\/\/www.dovepress.com\/terms.php\nand incorporate the Creative Commons Attribution \u2013 Non Commercial (unported, v3.0) License (http:\/\/creativecommons.org\/licenses\/by-nc\/3.0\/). By accessing the work you\nhereby accept the Terms. Non-commercial uses of the work are permitted without any further permission from Dove Medical Press Limited, provided the work is properly attributed. For permission\nfor commercial use of this work, please see paragraphs 4.2 and 5 of our Terms (https:\/\/www.dovepress.com\/terms.php).\nInternational Journal of COPD 2017:12 2559\u20132571\nInternational Journal of COPD Dovepress\nsubmit your manuscript | www.dovepress.com\nDovepress\n2559\nO r i g i n a l R e s e a r c h\nopen access to scientific and medical research\nOpen Access Full Text Article\nhttp:\/\/dx.doi.org\/10.2147\/COPD.S141976\nComparison of pulsed versus continuous oxygen\ndelivery using realistic adult nasal airway replicas\nJohn Z Chen1\nIra M Katz2\nMarine Pichelin2\nKaixian Zhu3\nGeorges Caillibotte2\nMichelle L Noga4\nWarren H Finlay1\nAndrew R Martin1\n1\nDepartment of Mechanical\nEngineering, University of Alberta,\nEdmonton, AB, Canada; 2\nMedical\nR&D, Air Liquide Sant\u00e9 International,\nCentre de Recherche Paris-Saclay, Les\nLoges-en-Josas, 3\nCentre Explor!, Air\nLiquide Healthcare, Gentilly, France;\n4\nRadiology and Diagnostic Imaging,\nUniversity of Alberta, Edmonton,\nAB, Canada\nBackground: Portable oxygen concentrators (POCs) typically include pulse flow (PF) modes\nto conserve oxygen. The primary aims of this study were to develop a predictive in vitro model\nfor inhaled oxygen delivery using a set of realistic airway replicas, and to compare PF for a\ncommercial POC with steady flow (SF) from a compressed oxygen cylinder.\nMethods: Experiments were carried out using a stationary compressed oxygen cylinder, a POC,\nand 15 adult nasal airway replicas based on airway geometries derived from medical images.\nOxygen delivery via nasal cannula was tested at PF settings of 2.0 and 6.0, and SF rates of 2.0 and\n6.0 L\/min. A test lung simulated three breathing patterns representative of a chronic obstructive\npulmonary disease patient at rest, during exercise, and while asleep. Volume-averaged fraction\nof inhaled oxygen (Fi\nO2\n) was calculated by analyzing oxygen concentrations sampled at the exit\nof each replica and inhalation flow rates over time. POC pulse volumes were also measured\nusing a commercial O2\nconserver test system to attempt to predict Fi\nO2\nfor PF.\nResults: Relative volume-averaged Fi\nO2\nusing PF ranged from 68% to 94% of SF values,\nincreasing with breathing frequency and tidal volume. Three of 15 replicas failed to trigger\nthe POC when used with the sleep breathing pattern at the 2.0 setting, and four of 15 replicas\nfailed to trigger at the 6.0 setting. Fi\nO2\nvalues estimated from POC pulse characteristics followed\nsimilar trends but were lower than those derived from airway replica experiments.\nConclusion: For the POC tested, PF delivered similar, though consistently lower, volume-\naveraged Fi\nO2\nthan SF rates equivalent to nominal PF settings. Assessment of PF oxygen delivery\nusing POC pulse characteristics alone may be insufficient; testing using airway replicas is useful\nin identifying possible cases of failure and may provide a better assessment of Fi\nO2\n.\nKeywords: long term oxygen therapy (LTOT), ambulatory oxygen, portable oxygen concen-\ntrator (POC)\nIntroduction\nPortable oxygen concentrators (POCs) are devices developed relatively recently in\nresponse to demand for a lightweight, portable source of supplemental oxygen.1\nWhile\nmost frequently prescribed to patients needing long-term oxygen therapy (LTOT),\nPOCs can play a role in any application requiring a source of supplemental oxygen.\nFor example, POCs have been evaluated as a possible solution to supplemental oxygen\nrequirements in military settings2\nand high altitude environments.3,4\nA recent study\nshowed that chronic obstructive pulmonary disease (COPD) patients requiring LTOT\ngenerally prefer a single source POC over a combined stationary and portable oxygen\nsource both in the home and during activity, citing the practicality of the system as\nits main advantage.5\nPOCs primarily deliver oxygen in one of two modes: steady flow (SF) and pulse\nflow (PF), with the most recent generation of lightweight devices (,5 lb) offering only\nCorrespondence: Andrew R Martin\n10-324, Donadeo Innovation Centre\nfor Engineering, University of Alberta,\nEdmonton, AB T6G 1H9, Canada\nTel +1 780 492 9012\nEmail andrew.martin@ualberta.ca\nNumber of times this article has been viewed\nThis article was published in the following Dove Press journal:\nInternational Journal of COPD\n24 August 2017\nInternational Journal of COPD 2017:12\nsubmit your manuscript | www.dovepress.com\nDovepress\nDovepress\n2560\nChen et al\nPF mode.6,7\nWhile SF remains the more straightforward of the\ntwo options, continuous delivery throughout the breath leads\nto a significant fraction of delivered oxygen being lost to the\nambient air, never reaching the patient\u2019s lungs.1\nIn contrast,\nPF aims to improve efficiency by limiting oxygen delivery\nonly to times when patient inspiration can be detected, and\ndelivering oxygen as a bolus, or pulse, early in the breath\nso that the fraction of oxygen exhaled from the anatomical\ndead space is reduced.\nIdeally, PF modes provide a volume of oxygen for inhala-\ntion equivalent to the volume of supplemental oxygen inhaled\nat a given SF rate. In light of this, oxygen delivery at varied\nPF settings for commercial POCs is frequently interpreted as\nnominally equal to that which would be achieved at equiva-\nlent SF rates; for example, a PF setting of 1.0 corresponds\nto an SF rate of 1.0 L\/min, a PF setting of 2.0 to SF rate of\n2.0 L\/min, etc.8\nHowever, the total oxygen volume adminis-\ntered over a complete breathing cycle is typically less for PF\nthan SF, owing to the efficiencies gained by synchronizing\noxygen delivery with patient inspiration.\nSince PF\/SF equivalency is dependent upon a number of\nshifting variables, conclusively demonstrating such equiva-\nlency can be a difficult task.9\nFurthermore, as standards of\nequivalency may currently vary between manufacturers, dif-\nferent POC devices may deliver different volumes of oxygen\nat nominally the same PF setting.1\nWhile some clinical\nstudies have suggested equivalence of PF and SF oxygen\ndelivery,10,11\nothers have reported differences.12,13\nRecent\nstudies have shown that in pairs of nominally equivalent\nPF\/SF settings, PF fraction of inspired oxygen (Fi\nO2\n) was\nconsistently lower than SF Fi\nO2\n.13\u201316\nFor evaluating administration of medical aerosols to the\nlungs, in vitro benchtop testing using realistic or idealized\n3D-printed airway replicas has proven valuable in providing\na fast, convenient, and noninvasive research and development\ntool compared to in vivo studies.6,7,17,18\nThese realistic airway\nreplicas, derived from medical imaging, are more representa-\ntive of human upper airways compared with highly simplified\ngeometries that have been previously used for evaluating\ninhaled concentrations of medical gases.16,19\nTesting with mul-\ntiple replicas can aid in accounting for variability in the airway\ngeometry of different patients; that is, intersubject variability.17\nIn addition, benchtop experiments permit precise control of\nsimulatedbreathingpatterns,eliminatingasignificantsourceof\nvariance that may be present during in vivo human studies.\nTo our knowledge, no work has been done to date compar-\ning the differences between SF and PF oxygen administration\nfrom POCs using realistic airway replicas. Accordingly, the\nprimary aims of the present study are to develop a predictive\nin vitro model for inhaled oxygen delivery using a set of\n15 realistic adult nasal airway replicas, and then to compare\nSF and PF for a widely used commercial POC. To this end,\nwe developed a testing protocol that measures the real-time\noxygen concentration at the outlet (trachea) of the airway\nreplica, which can then be integrated with the instantaneous\ninspiratory flow rate to determine a volume-averaged Fi\nO2\nover the course of inspiration. Volume-averaged Fi\nO2\ncan be\nused as a common basis for comparison between nominally\nequivalent settings of SF and PF. We further aimed to\ndevelop an algorithm to estimate PF Fi\nO2\nbased on pulse\ncharacteristics, tidal volume, and upper airway volume.\nThese estimated values can be compared with Fi\nO2\nvalues\nderived from oxygen concentration measurements.\nMethods\nRealistic airway replicas\nFifteen adult nasal airway replicas built in acrylic plastic\nusing rapid prototyping were used in the present study. Each\nreplica included air passages starting from the nares through\nthe entrance to the trachea. Five of the airway replicas were\nbased on magnetic resonance (MR) images as previously\nreported,20\nwhile the remaining 10 replicas were based on a\nnew set of anonymized high resolution computed tomography\n(CT) scans acquired retrospectively from patients scanned\nfor clinical purposes unrelated to the nasal passage at the\nUniversity of Alberta Hospital, with Health Research Ethics\nBoard approval. All CT scans were reviewed by an expert\nradiologist and the nasal passage considered normal. The MR\nimages and CT scans used to build the replicas did not con-\ntain any identifying information. CT scans were segmented\nusing Mimics software (Materialise, Leuven, Belgium) and\nreplicas were built from plastic (Objet VeroGray RGD850;\nStratsys, Ltd., Eden Prairie, MN, USA) using a PolyJet\n3D printer (Objet Eden 350V High Resolution 3D Printer;\nStratsys, Ltd., Eden Prairie, MN, USA). Segmented 3D\nairways based on both the MR and CT images are presented\nin Figure 1. Geometric parameters for each of the 15 replicas\nwere obtained using MeshLab (Visual Computing Labora-\ntory, Istituto di Scienza e Tecnologie dell\u2019Informazione,\nItaly) and ParaView (Kitware, Clifton Park, NY, USA).\nThese parameters are shown in Table 1.\nRepresentative breathing patterns\nTo simulate tidal breathing, airway replicas were connected\nto a lung simulator (ASL 5000 Breathing Simulator; IngMar\nMedical, Pittsburgh, PA, USA), as shown schematically\nInternational Journal of COPD 2017:12 submit your manuscript | www.dovepress.com\nDovepress\nDovepress\n2561\nPulsed versus continuous oxygen in airway replicas\nin Figure 2. Plastic tubing with 22 mm internal diameter\nconnected the replica outlet to the lung simulator. The total\ninternal volume of this tubing was 135 cm3\n, representative\nof the conducting airway volume from the trachea to the\ngas-exchange regions of the lungs for an average adult with\n3 L functional residual capacity.21\nTo capture a range of activity levels in daily life, we\nused three different breathing patterns representative of a\nCOPD patient on LTOT at rest, doing light exercise, and\nwhile asleep. Inspiratory and expiratory phases of the breath\nwere represented using sinusoidal flow patterns with one\nhalf sinusoid for inspiration and another half sinusoid for\nexpiration. Sinusoidal breathing patterns have been used\npreviously to approximate human breathing.22\u201326\nInspiration\nand expiration flow rates were derived using tidal volume\n(VT\n), inspiratory time (TI\n), expiratory time (TE\n), and breath-\ning frequency (f). Values of each of these parameters for\nthe three breathing patterns are shown in Table 2. The rest\nand exercise breathing parameters were chosen based on\naverage values reported previously by Chatila et al27\nfor\n10 patients with COPD at baseline (rest) and while on low\nSF rate (2.5\u20136 L\/min) oxygen while performing light exercise\non a cycle ergometer. Parameters for the sleep breathing\npattern were chosen based on average values measured by\nHudgel et al28\nfor 13 COPD patients while asleep.\nFlow rate and oxygen concentration\nmeasurements\nExperiments were carried out using a Philips SimplyGo POC\n(Philips Respironics, Murrysville, PA, USA) and a cylinder\nsource of 100% oxygen (Praxair Canada, Mississauga, ON,\nCanada). A test lung simulated the three different breathing\npatterns, each for ~50 breathing cycles. Oxygen delivery in\neach of the replicas via a nasal cannula (Hudson RCI adult\nFigure 1 Solid 3D nose\u2013throat airways of the 15 replicas tested in the present study.\nNote: The top row displays airways derived from MRI, while the bottom two rows display airways derived from CT images.\nAbbreviations: CT, computed tomography; MRI, magnetic resonance imaging.\n6XEMHFW\u000305,\u0015 6XEMHFW\u000305,\u0018 6XEMHFW\u000305,\u0019 6XEMHFW\u000305,\u001b 6XEMHFW\u000305,\u001c\n6XEMHFW\u0003&7\u0014 6XEMHFW\u0003&7\u0015 6XEMHFW\u0003&7\u0016 6XEMHFW\u0003&7\u0017 6XEMHFW\u0003&7\u0018\n6XEMHFW\u0003&7\u0019 6XEMHFW\u0003&7\u001a 6XEMHFW\u0003&7\u001b 6XEMHFW\u0003&7\u001c 6XEMHFW\u0003&7\u0014\u0013\nTable 1 Airway replica volumes and surface areas for 15 adult\nnasal airway replicas\nSubject Sex Age (years) Volume (cm3\n) Surface area (cm2\n)\nMRI2 F \u2013 44.6 287\nMRI5 F \u2013 35.9 235\nMRI6 M \u2013 50.1 313\nMRI8 M \u2013 47.3 289\nMRI9 M \u2013 45.3 250\nCT1 M 60 60.0 343\nCT2 F 50 73.1 315\nCT3 M 57 59.2 320\nCT4 M 54 71.9 349\nCT5 M 60 50.1 280\nCT6 F 72 59.1 321\nCT7 M 62 56.3 308\nCT8 M 63 61.9 326\nCT9 M 27 48.1 276\nCT10 F 56 53.2 265\nAbbreviations: CT, computed tomography; MRI, magnetic resonance imaging;\nM, male; F, female.\nInternational Journal of COPD 2017:12\nsubmit your manuscript | www.dovepress.com\nDovepress\nDovepress\n2562\nChen et al\nnasal cannula; Teleflex Medical, Research Triangle Park, NC,\nUSA) was first tested at SF rates from the cylinder source\nof 2.0 and 6.0 L\/min, and then at nominal PF settings of\n2.0 and 6.0. SimplyGo features two different PF operating\nmodes: pulse mode and sleep mode. Sleep mode is similar\nto pulse mode, but features more sensitive breath detection,\nlower pulse amplitude, and longer pulse duration aimed to\nimprove comfort during sleeping. The sleep breathing pattern\nwas tested using both pulse mode and sleep mode in order to\ncomprehensively evaluate potential device performance.\nThe volume of the chamber of the test lung was recorded\nduring simulated breathing at a sampling frequency of 512 Hz\nusing the ASL 5000 software. Oxygen concentrations were\nmeasured using a GA-200 CO2\nand O2\nGas Analyzer (iWorx,\nDover, NH, USA), and were corrected for delay and time\nconstant, which was done by approximating the concentra-\ntion as a first order system and following methods outlined\nin Langer et al.26\nWe assumed that the step response of the\ngas analyzer could be well approximated by a first order\nexponential function. The time constant for this exponen-\ntial function, which is defined as the time required for the\nresponse of the system to reach 63% of its final value as\nthe result of a step increase, was measured to be 227 ms in\npreliminary experiments by rapidly switching supply to the\ngas analyzer via a three-way stopcock between two different\ngas mixtures of known concentration (in this case, air and\n100% oxygen).\nCalculation of SF and PF Fi\nO2\nThe flow rate of oxygen passing through the trachea over\ntime was calculated by multiplying inspiration flow rate,\nknown at each time point, with the measured real-time\noxygen concentrations at the same time point. Inspiration\nstart and end times were identified as times when flow rates\ncrossed 0. These oxygen flow rates were then numerically\nintegrated using the trapezoidal rule from the start to the end\nof inspiration to determine a volume of oxygen inhaled per\nbreath. VT\nwas also calculated from inspiration flow rates\nusing a similar procedure. The volume of inhaled oxygen\nwas then divided by VT\nto obtain a volume-averaged value\nFigure 2 Schematic of experimental apparatus.\nNote: Arrows indicate direction of oxygen flow.\n1DVDO\u0003DLUZD\\\nUHSOLFD\n\/XQJ\u0003VLPXODWRU\n\/XQJ\u0003VLPXODWRU\nFRQWURO\u0003ODSWRS\n2[\\JHQ\nDQDO\\]HU\n3RUWDEOH\u0003R[\\JHQ\nFRQFHQWUDWRU\n'HVNWRS\u0003FRPSXWHU\nTable 2 Breathing parameters of representative breathing\nprofiles for COPD patients at rest, doing light exercise, and while\nasleep\nRest Exercise Sleep\nTidal volume, VT\n(mL) 640 800 520\nInspiratory time, TI\n(s) 1.20 0.96 1.79\nExpiratory time, TE\n(s) 2.33 1.77 2.93\nBreathing frequency, f (breaths\/min) 17 22 13\nAbbreviation: COPD, chronic obstructive pulmonary disease.\nInternational Journal of COPD 2017:12 submit your manuscript | www.dovepress.com\nDovepress\nDovepress\n2563\nPulsed versus continuous oxygen in airway replicas\nfor Fi\nO2\nfor that breath. Fi\nO2\nfor each combination of replica\nand oxygen delivery condition was taken as the average of\nfive consecutive breaths after a steady state in expiratory\noxygen concentration was observed (at least 50 breaths).\nVariability between average Fi\nO2\nvalues obtained in experi-\nments repeated on separate days of testing was found in\npreliminary testing to be of similar magnitude as variability\nbetween individual breaths.\nMeasurement of pulse characteristics\nA 1130 series O2\nConserver Testing System (Hans Rudolph\nInc, Shawnee, KS, USA) was used to obtain oxygen pulse\nvolumes, durations, and delays for both the 2.0 and 6.0\nsettings of the POC using the breathing frequency of\neach breathing pattern shown in Table 3. SimplyGo was\nconnected to the testing system using a standard 2.1 mm\nsingle lumen cannula. Data were recorded as the average\nof 10 successive pulses for each breathing pattern\/setting\ncombination. Variance around reported averages was very\nsmall. The oxygen concentration of the pulse itself was\nmeasured to be 94% across all breathing pattern\/setting\ncombinations.\nPrediction of PF Fi\nO2\nThe model used in this study to estimate PF Fi\nO2\ndepends on\nthe following parameters: the tidal volume VT\n, the ambient\noxygen fraction XO2,ambient\n, the volume of the airway replica\nVreplica\n, the total volume of the \u201clower conducting airways\u201d VLA\n(represented by the tubing connecting the airway replica to\nthe lung simulator), the oxygen fraction of the pulse XO2,pulse\n,\nand the volume of the pulse Vpulse\n.\nBreathing was modeled with the assumption that\nexhaled gas in the anatomical dead space, consisting of\nupper and lower conducting airways at end-expiration, is\nimmediately re-inhaled, and that none of the pulse remains\nin the anatomical dead space of the airways at the start of\nexpiration. That is, pulse timing is assumed to be ideal, in\nthat all oxygen delivered in the pulse reaches peripheral\nregions of the lungs (in the present experiments repre-\nsented by the lung simulator). Following re-inhalation of\ngas from the anatomical dead space, the remainder of the\nbreath consists of the oxygen pulse and entrained ambi-\nent air. Over multiple breathing cycles, the gas mixture\ncontained within the cylinder of the lung simulator will\napproach some steady-state concentration, XO2,c\n.\nTo derive the equation for XO2,c\n, it was noted that in this\nsteady state the volume of oxygen entering the lung simula-\ntor, VO2,I\n, must be equal to the volume of oxygen that exits,\nVO2,E\n. Therefore\nV V\nO I O E\n2 2\n0\n, ,\n\u2212 =\n\b\n(1)\nBased on the assumptions made above, this equation can\nbe rewritten as\nV X V X\nV V V X V X\nAW O c pulse O pulse\nT AW pulse O mbient T O\n2 2\n2 2\n, ,\n, ,\n( )\n+\n+ \u2212 \u2212 \u2212\na c\nc\n= 0\n\b\n(2)\nwhere VAW\n, the total volume of the airways (including the\nreplica), is given by\nV V V\nAW LA replica\n= +\n\b\n(3)\nRearranging, one can solve for XO2,c\nX X\nV\nV V\nX X\nO c O ambient\npulse\nT AW\nO pulse O ambient\n2 2 2 2\n, , , ,\n( )\n= +\n\u2212\n\u2212\n\b\n(4)\nTo find Fi\nO2\nas measured and reported in the present\nexperiments, one needs to take into account the volume\nTable 3 SimplyGo oxygen pulse characteristics at pulse flow setting numbers of 2.0 and 6.0 using various breathing frequencies\nBreath\nfrequency\nf=13 breaths\/min f=17 breaths\/min f=22 breaths\/min\nPulse\nsetting\nPulse\nvolume (mL)\nPulse\ndelay (ms)\nPulse\nduration (ms)\nPulse\nvolume (mL)\nPulse\ndelay (ms)\nPulse\nduration (ms)\nPulse\nvolume (mL)\nPulse\ndelay (ms)\nPulse\nduration (ms)\nPulse\nmode 2.0\n23.8 110 291 23.8 114 290 22.7 111 320\nPulse\nmode 6.0\n68.7 110 479 68.8 113 480 66.8 109 613\nSleep\nmode 2.0\n28.9 109 582 22.2 110 449 38.2 109 764\nSleep\nmode 6.0\n85.7 108 613 66.5 103 479 112.5 104 793\nInternational Journal of COPD 2017:12\nsubmit your manuscript | www.dovepress.com\nDovepress\nDovepress\n2564\nChen et al\nof oxygen passing the trachea, rather than that reaching\nthe lung simulator. Therefore, recently exhaled oxygen\nremaining in VLA\nprior to the start of inspiration does not\nneed to be accounted for. Fi\nO2\ncan then be estimated by cal-\nculating the total volume of oxygen passing the trachea and\ndividing by VT\n:\nFO\ni pulse O pulse replica O c\nT replica pulse\n2 2 2\n= +\n+ \u2212 \u2212\n[\n( )\n, ,\nV X V X\nV V V XO\nO ambient T\n2,\n] V\n\b\n(5)\nFi\nO2\nwas calculated in this manner using each of the\n15 different replica volumes and then averaged to give\na single value. Averaged predicted values of Fi\nO2\n, based\non measured pulse characteristics, were then compared to\naverage values measured using the realistic replicas and\nlung simulator.\nPressure drop measurements\nIn most POCs, breaths are detected using an internal pressure\nsensor that measures a reduction in pressure monitored at the\noxygen supply tubing (the triggering pressure) corresponding\nto the start of inhalation. Pressure drops across each airway\nreplica were measured at the cannula based on methods out-\nlined in Moore et al.29\nAn adult nasal cannula was inserted\ninto the nostrils of each replica. The cannula was connected\nto a differential manometer (HHP-103; OMEGA Engineer-\ning, Norwalk, CT, USA) measuring the difference between\nthe cannula and atmospheric pressure. A vacuum was con-\nnected to each replica and a valve used to control inhalation\nflow rate, which was monitored using a mass flowmeter (TSI\nMass Flowmeter 4043; TSI Inc, Shoreview, MN, USA).\nPressure drops were measured at flow rates of 10, 20, 30,\nand 40 L\/min.\nResults\nOxygen concentration and flow rate\nwaveforms\nFigure 3 shows oxygen concentrations and inspiration\nflow rates at the trachea for the selected replicas plotted\nagainst time. As a matter of convention, positive flow rates\nindicate inspiration and negative flow rates indicate exha-\nlation. Oxygen concentration waveforms could be broadly\nclassified as falling into one of three groups: waveforms\nindicating SF oxygen delivery, Figure 3A; waveforms\nindicating complete pulse delivery (the entire pulse reaches\nFigure 3 Example of oxygen mole fraction and flow rate waveforms indicating (A) steady flow oxygen delivery, (B) complete pulse delivery, and (C) incomplete pulse\ndelivery.\nNotes: Waveforms were selected from experiments conducted using subject CT7 with the sleep breathing pattern (A) and (C), and using subject CT9 with the rest breathing\npattern (B). Positive flow rates indicate inspiration; negative flow rates indicate expiration. Numbers indicate points of interest in the oxygen waveform: (1) maximum\ninspiratory oxygen fraction; (2) minimum inspiratory oxygen fraction; (3) oxygen fraction changing through onset of exhalation; (4) oxygen fraction rising\/falling to end-\nexpiratory value.\n$\n7LPH\u0003 V\n\u00b1\u0019\u0013\u0013 \u0013\u0011\u0014\u001c\n\u0013\u0011\u0015\u0014\n\u0013\u0011\u0015\u0016\n\u0013\u0011\u0015\u001a\n\u0013\u0011\u0015\u0018\n\u0013\u0011\u0015\u001c\n\u0013\u0011\u0016\u0018\n\u0013\u0011\u0016\u0014\n\u0013\u0011\u0016\u0016\n\u0015\u0016\u0017\n\u0015\u0016\u0015\n\u0015\u0016\u0013\n\u0015\u0015\u001b\n\u0015\u0015\u0019\n\u0015\u0015\u0017\n\u0015\u0015\u0015\n\u0015\u0015\u0013\n\u00b1\u0017\u0013\u0013\n\u00b1\u0015\u0013\u0013\n\u0013\n\u0019\u0013\u0013\n\u0015\u0013\u0013\n\u001b\u0013\u0013\n\u0017\u0013\u0013\n\u0014\u000f\u0013\u0013\u0013\n)ORZ\u0003UDWH\u0003\nP\/\u0012V\n2[\\JHQ\u0003IUDFWLRQ\n7LPH\u0003 V\n\u00b1\u0017\u0013\u0013\n\u00b1\u0016\u0013\u0013\n\u00b1\u0015\u0013\u0013\n\u00b1\u0014\u0013\u0013\n\u0013\n\u0014\u0013\u0013\n\u0015\u0013\u0013\n\u0016\u0013\u0013\n\u0017\u0013\u0013\n\u0018\u0013\u0013\n\u0013\u0011\u0015\u0016\n\u0013\u0011\u0015\u001b\n\u0013\u0011\u0016\u0016\n\u0013\u0011\u0016\u001b\n\u0013\u0011\u0017\u0016\n\u0013\u0011\u0017\u001b\n\u0015\u0016\u0017\n\u0015\u0016\u0015\n\u0015\u0016\u0013\n\u0015\u0015\u001b\n\u0015\u0015\u0019\n\u0015\u0015\u0017\n\u0015\u0015\u0015\n\u0015\u0015\u0013\n)ORZ\u0003UDWH\u0003\nP\/\u0012V\n2[\\JHQ\u0003IUDFWLRQ\n7LPH\u0003 V\n\u00b1\u0017\u0013\u0013\n\u00b1\u0016\u0013\u0013\n\u00b1\u0015\u0013\u0013\n\u00b1\u0014\u0013\u0013\n\u0013\n\u0014\u0013\u0013\n\u0015\u0013\u0013\n\u0016\u0013\u0013\n\u0017\u0013\u0013\n\u0018\u0013\u0013\n\u0013\u0011\u0014\u001c\n\u0015\u0016\u0017\n\u0015\u0016\u0015\n\u0015\u0016\u0013\n\u0015\u0015\u001b\n\u0015\u0015\u0019\n\u0015\u0015\u0017\n\u0015\u0015\u0015\n\u0015\u0015\u0013\n\u0013\u0011\u0015\u0014\n\u0013\u0011\u0015\u0016\n\u0013\u0011\u0015\u001a\n\u0013\u0011\u0015\u0018\n\u0013\u0011\u0015\u001c\n\u0013\u0011\u0016\u0018\n\u0013\u0011\u0016\u0014\n\u0013\u0011\u0016\u0016\n)ORZ\u0003UDWH\u0003\nP\/\u0012V\n2[\\JHQ\u0003IUDFWLRQ\n%\n&\n\u0014\n\u0014\n\u0014\n\u0015\n\u0015\n\u0015\n\u0016\n\u0016\n\u0016\n\u0017\n\u0017\n\u0017\n)ORZ\u0003UDWH 2[\\JHQ\u0003IUDFWLRQ\nInternational Journal of COPD 2017:12 submit your manuscript | www.dovepress.com\nDovepress\nDovepress\n2565\nPulsed versus continuous oxygen in airway replicas\nthe internal cylinder of the lung simulator), Figure 3B; and\nwaveforms indicating incomplete pulse delivery (a portion\nof the pulse remains in the anatomical dead space and is\nexhaled), Figure 3C.\nContinuous oxygen delivery waveforms (Figure 3A) were\ncharacterized by the presence of two peaks over the course\nof inspiration, one large, sharp peak occurring shortly after\nthe beginning of inspiration, and another smaller peak at the\nend. The variation in oxygen concentration over the course\nof inspiration for SF can be explained as follows.\n1. The first, taller peak indicates pooling in the anatomic\nreservoir at the end of expiration. Since oxygen flow\ncontinues throughout the entire breath in SF, oxygen will\naccumulate in the upper airways as exhalation ends and\nthe expiratory flow rate approaches zero. This pooled\noxygen is then inhaled at the start of the next inspira-\ntion, which is reflected in the first sharp peak in oxygen\nconcentration.\n2. Once pooled oxygen is inhaled, the inspiration flow rate\nthen increases toward a maximum, and therefore the frac-\ntion of inhaled gas represented by supplementary oxygen\nwill decrease, which is reflected in a steep decrease in\noxygen concentration. Conversely, as the inspiration flow\nrate passes its maximum and begins to decrease again,\nthe supplementary oxygen fraction in the inhaled gas\nwill increase.\n3. As exhalation begins, gas remaining in the dead space\n(in this case, the tubing connecting the replica to the lung\nsimulator) is immediately exhaled. Due to imperfect\nmixing in the airways, the dead space gas is exhaled on\na first-in, last-out basis and will tend to lower the oxygen\nconcentration. In other words, any comparatively low-\noxygen gas (inhaled when the inspiration flow rate was\nhigh) remaining in the tubing will be further from the\ntrachea than high-oxygen gas (inhaled when the inspira-\ntion flow rate was low).\n4. Finally, as exhalation proceeds, the oxygen concentration\napproaches the constant oxygen concentration found in\nthe internal chamber of the lung simulator.\nOn the other hand, oxygen concentration waveforms\nindicating complete pulse delivery (Figure 3B) can be identi-\nfied by the presence of a single peak occurring near, but not\ncoinciding with, the beginning of inspiration. Unlike the SF\ncase, no pooling exists since oxygen delivery does not occur\nif no inspiratory effort is detected. The variation in oxygen\nconcentration over the course of inspiration for complete\npulse delivery can be explained as follows.\n1. Here, the single peak at the start of inspiration indicates the\npassageofthepulsefromthePOCandthroughthetrachea.\nThe sharp initial decrease in oxygen concentration shortly\nfollowing the start of inspiration is due to the delay\nbetween the start of the inspiratory effort and its detec-\ntion by the POC, along with the transit time of the pulse\nthrough the upper airways.\n2. Once the POC emits the pulse, no further supplementary\noxygen is delivered. Oxygen concentration drops quickly\nto that of ambient air (~21%) and remains there, indicat-\ning that the entire pulse likely reached the lung simulator\nchamber.\n3. Expiration begins, and the gas (mostly ambient air)\nremaining in the dead space (the tubing connecting the\nreplica to the lung simulator) is flushed out.\n4. Oxygen concentration then rises to that of the mixed gas\ninside the lung simulator chamber.\nIncomplete delivery waveforms for PF (Figure 3C)\nproceed similarly to the complete case during the beginning\nof inspiration. However, in this case, a second peak exists\nnear the beginning of exhalation. For incomplete delivery,\na portion of the pulse remains in the dead space tubing con-\nnecting the replica to the lung simulator, which is exhaled\nimmediately, creating the second peak.\nThe number of replicas indicating incomplete pulse\ndelivery as a fraction of the total is shown in Table 4.\nSF and PF Fi\nO2\nFigures 4 and 5 show comparisons of Fi\nO2\nbetween nomi-\nnally equivalent PF settings (both pulse and sleep mode for\nthe sleep breathing pattern) and SF flow rates. For the sleep\nbreathing pattern, three of the replicas failed to trigger the\nPOC (ie, no breathing was detected) at pulse mode setting\n2.0, and four replicas failed to trigger the device at pulse\nmode setting 6.0. At sleep mode settings of 2.0 and 6.0, only\none replica failed to trigger the device. Fi\nO2\nvalues measured\nfor replicas and breathing patterns which failed to trigger the\nPOC were excluded in the calculation of the average values\nreported in Figure 3A and B.\nMean PF Fi\nO2\nranged from 68% to 94% of mean val-\nues obtained for nominally equivalent SF rates, generally\nTable 4 Number of breathing replicas indicating incomplete\npulse delivery out of the total number of replicas used to\ncalculate volume-averaged fraction of inspired oxygen (Fi\nO2\n) at\neach setting\/breathing pattern combination\nPOC setting Rest Exercise Sleep\nPulse mode 2.0 0\/15 0\/15 2\/12\nPulse mode 6.0 1\/15 2\/15 3\/11\nSleep mode 2.0 N\/A N\/A 5\/14\nSleep mode 6.0 N\/A N\/A 5\/14\nAbbreviations: N\/A, not applicable; POC, portable oxygen concentrator.\nInternational Journal of COPD 2017:12\nsubmit your manuscript | www.dovepress.com\nDovepress\nDovepress\n2566\nChen et al\ndecreasing with minute ventilation. Despite differences in\nairway volume and internal surface area, variability between\nreplicas remained small compared to the mean (standard\ndeviation ,5% relative to the mean).\nPressure drop measurements\nFigure 6 shows the variation of pressure drop at the cannula\nfor each of the 15 replicas with a steady inhalation flow rate.\nDifferences between replicas increased sharply with increas-\ning flow rate. On the whole, most MR imaging replicas tended\ntoward the low end of pressure drops.\nPredicting PF Fi\nO2\nPF Fi\nO2\nvalues estimated using Equation 5 and PF Fi\nO2\nvalues derived from airway replica experiments are plotted\nin Figure 7. Overall, Equation 5 consistently overpredicted\naverage Fi\nO2\n, but by a small margin. This margin increased as\nthe setting number increased from 2.0 to 6.0 for both pulse\nmode and sleep mode, but no definite trend was observed as\nthe breathing pattern was varied.\nDiscussion\nWe developed an in vitro model that enabled us to measure\nreal-time Fi\nO2\nvalues at the trachea while maintaining precise\ncontrol of both breathing rate and tidal volume. This model\nwas used to compare oxygen delivery between SF and PF\ndelivery modes of a commercial POC under realistic trigger-\ning conditions, and to determine if oxygen pulse characteris-\ntics could adequately predict PF oxygen delivery.\nComparison with the in vivo case\nSince Fi\nO2\nvaries over the course of a breath during deliv-\nery of supplemental oxygen, it is challenging to accurately\nmeasure the amount of oxygen inhaled per breath in vivo.\nO\u2019Reilly Nugent et al30\nmonitored oxygen concentration at the\ntrachea in vivo (sampled through a catheter) during oxygen\ndelivery via nasal cannula for 20 adult subjects throughout\ninspiration, and calculated time-averaged Fi\nO2\nvalues. For\nsubjects breathing at a rate of 15 breaths\/min receiving\nsupplemental SF oxygen at a rate of 2.0 L\/min, time-averaged\ntracheal Fi\nO2\nranged from 25% to 32%. When applying a\nsimilar time-averaging procedure to oxygen concentration\nFigure 4 Comparison of volume-averaged Fi\nO2\nat SF 2.0 L\/min and PF setting\nnumber 2.0, averaged over n different airway replicas, measured using five successive\nbreaths per replica.\nNotes: For exercise and rest breathing patterns, n=15. For the sleep breathing\npattern combined with pulse mode, n=12; with sleep mode, n=14. Error bars\nindicate one standard deviation.\nAbbreviations: Fi\nO2\n, fraction of inspired oxygen; SF, steady flow; PF, pulse flow.\n\u0016\u0015\n\u0015\u0013\n\u0015\u0015\n\u0015\u0017\n\u0015\u0019\n\u0015\u001b\n\u0016\u0013\n5HVW\n([HUFLVH\n%UHDWKLQJ\u0003SDWWHUQ\n)\nL\n2\n\u0015\n\u0003\n\b\n6OHHS\n6) 3XOVH\u0003PRGH 6OHHS\u0003PRGH\n\u0018\u0013\n\u0015\u0013\n\u0015\u0018\n\u0016\u0013\n\u0016\u0018\n\u0017\u0013\n\u0017\u0018\n5HVW\n([HUFLVH\n%UHDWKLQJ\u0003SDWWHUQ\n)\nL\n2\n\u0015\n\u0003\n\b\n6OHHS\n6) 3XOVH\u0003PRGH 6OHHS\u0003PRGH\nFigure 5 Comparison of volume-averaged Fi\nO2\nat SF 6.0 L\/min and PF setting\nnumber 6.0, averaged over n different airway replicas, measured using five successive\nbreaths per replica.\nNotes: For exercise and rest breathing patterns, n=15. For the sleep breathing\npattern combined with pulse mode, n=11; with sleep mode, n=14. Error bars\nindicate one standard deviation.\nAbbreviations: Fi\nO2\n, fraction of inspired oxygen; SF, steady flow; PF, pulse flow.\nFigure 6 Pressure drop measured at the cannula as a function of inspiratory flow\nrate, averaged over three measurements for all 5 MRI subjects.\nNote: Error bars represent one standard deviation.\nAbbreviations: CT, computed tomography; MRI, magnetic resonance imaging.\n\u0013\n\u0013\n\u0014\u0013\n\u0014\u0013\n\u0015\u0013\n\u0015\u0013\n\u0016\u0013\n,QVSLUDWRU\\\u0003IORZ\u0003UDWH\u0003 \/\u0012PLQ\n3UHVVXUH\u0003GURS\u0003DW\nFDQQXOD\u0003\n3D\n\u0016\u0013\n\u0017\u0013\n\u0017\u0013\n\u0018\u0013\n\u0018\u0013\n\u0019\u0013\n\u001a\u0013\n\u001b\u0013\n\u001c\u0013\n\u0014\u0013\u0013\n6XEMHFW\u0003&7\u0014\n6XEMHFW\u0003&7\u0015\n6XEMHFW\u0003&7\u0016\n6XEMHFW\u0003&7\u0017\n6XEMHFW\u0003&7\u0018\n6XEMHFW\u0003&7\u0019\n6XEMHFW\u0003&7\u001a\n6XEMHFW\u0003&7\u001b\n6XEMHFW\u0003&7\u001c\n6XEMHFW\u0003&7\u0014\u0013\n6XEMHFW\u000305,\u0015\n6XEMHFW\u000305,\u0018\n6XEMHFW\u000305,\u0019\n6XEMHFW\u000305,\u001b\n6XEMHFW\u000305,\u001c\nInternational Journal of COPD 2017:12 submit your manuscript | www.dovepress.com\nDovepress\nDovepress\n2567\nPulsed versus continuous oxygen in airway replicas\ndata at similar settings (SF 2.0 L\/min, 13 and 17 breaths\/min)\nobtained during in vitro experiments in the present study,\nwe obtained an Fi\nO2\nrange of 26%\u201331%, which is in good\nagreement with the in vivo data.\nOn the other hand, the volume-averaged Fi\nO2\nreported in\nthe present study is consistently 1%\u20133% O2\n(absolute) lower\nthan our own calculated time-averaged values. The volume-\naveraged values are considered to be more pertinent here to\nsupplemental oxygen delivery compared to procedures that\nsimply average by time, as high instantaneous inhaled oxygen\nconcentrations may coincide with relatively low inspiratory\nflow rates near the start of the breath (and thus simple time-\naveraging procedures overweigh the contribution of these\ntransient peaks in concentration).\nThese considerations touch on what Fi\nO2\nactually rep-\nresents. Waldau et al31\nnote that\nthe efficacy of oxygen therapy can be evaluated by a number\nof methods that reflect different steps in the oxygenation\nprocess depending on the sampling site.\nIn other words, Fi\nO2\nhas been considered as the concentra-\ntion of inspired oxygen anywhere from a position within\nthe patient interface to the alveoli (estimated based on\nmeasurements in the exhalation gas).31,32\nIt has been noted that\nmeasurements in the upper airways can be compromised by\nincomplete mixing of oxygen with inhaled air such that \u201cgas\ncan be sampled at a more distal point, preferably the trachea,\nwhere gas mixing is more assured.\u201d33\nRegarding estimates\nbased on exhaled gas, homogeneous gas distribution in the\nlung must be assumed; an assumption that certainly does\nnot apply for all patients. Thus, the bench model employed\nhere where flow and concentration measured in the trachea\nare measured and integrated over the whole breath allows\nfor a very robust approach that can account for variations in\nbreathing parameters and delivery devices. Further account-\ning for myriad factors affecting alveolar gas concentrations\nand oxygen uptake, including gas transport and mixing\nthrough the airspaces of the lung and the diffusion capacity\nof the lung, may be best left to computational modeling.9\nIn vitro measurement of tracheal oxygen concentrations\nover the breath, as presented here for example, in Figure 3,\nwould serve as valuable input to such computational models.\nIn clinical practice, noting both the variability in oxygen\ndelivery to the trachea measured in the present study with\nexisting delivery systems, plus the additional intersubject\nand intrasubject variability that surely exists in oxygen\nFigure 7 Comparison of volume-averaged Fi\nO2\nestimated from airway experiments and Fi\nO2\npredicted using pulse characteristics.\nNotes: Airway experiment Fi\nO2\nvalues were averaged over n airway replicas, measured using five successive breaths per replica. For all experiments with exercise and rest\nbreathing patterns, n=15. For the sleep breathing pattern combined with pulse mode setting number 2.0, n=12; with pulse mode setting number 6.0, n=11; with sleep mode\nsetting numbers 2.0 and 6.0, n=14. Error bars indicate one standard deviation.\nAbbreviation: Fi\nO2\n, fraction of inspired oxygen.\n([HUFLVH\nSXOVH\nPRGH\u0003\u0015\u0011\u0013\n\u0015\u0013\n\u0015\u0018\n\u0016\u0013\n\u0016\u0018\n\u0017\u0013\n\u0017\u0018\n([HUFLVH\nSXOVH\nPRGH\u0003\u0019\u0011\u0013\n5HVW\nSXOVH\nPRGH\u0003\u0015\u0011\u0013\n5HVW\nSXOVH\nPRGH\u0003\u0019\u0011\u0013\n%UHDWKLQJ\u0003SDWWHUQ\u0003DQG\u0003GHYLFH\u0003VHWWLQJ\n)\nL\n2\n\u0015\n\u0003\n\b\n6OHHS\nSXOVH\nPRGH\u0003\u0015\u0011\u0013\n6OHHS\nSXOVH\nPRGH\u0003\u0019\u0011\u0013\n6OHHS\nVOHHS\nPRGH\u0003\u0015\u0011\u0013\n6OHHS\nVOHHS\nPRGH\u0003\u0019\u0011\u0013\n$LUZD\\\u0003H[SHULPHQWV 3XOVH\u0003FKDUDFWHULVWLFV\nInternational Journal of COPD 2017:12\nsubmit your manuscript | www.dovepress.com\nDovepress\nDovepress\n2568\nChen et al\ntransport and diffusion capacity, evaluation of oxygenation\non an individual and ongoing basis, for example, using pulse\noximetry, is advisable.\nBreath detection in POCs\nChatburn and Williams found that trigger pressures in five\ncommercial POCs ranged from 14 to 22 Pa.14\nSince inspira-\ntory flow rates in the sleep breathing pattern reach a maxi-\nmum of ~27 L\/min, Figure 6 implies that at or below that\nflow rate, a commercial POC would be unlikely to detect the\ninitiation of a breath in several of the replicas (,10 Pa).\nWhile the exact mechanisms of and conditions for breath\ndetection in this specific POC are unknown, given that, in\ngeneral, negative pressure sensors are frequently used for\nbreath detection in POCs, we hypothesize that a low pres-\nsure drop at the nasal cannula may contribute to problems\nin POC breath detection.\nComparison of SF and PF delivery\nPF Fi\nO2\nvalues are consistently lower than those at equivalent\nSF rates. This difference increased with decreasing minute\nventilation (ie, with the sleep breathing pattern having the\ngreatest difference). The higher pulse volumes delivered\nby the sleep mode relative to pulse mode translated into\nrelatively higher (but still not equivalent to SF) Fi\nO2\nvalues,\ndespite a higher prevalence of incomplete pulse delivery\nwhen using the sleep mode. Our data show that, for the\nSimplyGo POC, the nominal PF setting and the SF flow rate\nare not equivalent when assessed using Fi\nO2\n.\nThe increased prevalence of incomplete pulse delivery\nin the sleep breathing pattern very likely contributes to the\nminute ventilation-PF\/SF trend described above. As part of\nthe oxygen bolus remains in the upper airways at the start\nof exhalation, Fi\nO2\nwill be lower as a result.\nAt first glance, one might expect that the increased breath-\ning frequency of the high minute ventilation exercise breath-\ning pattern would lead to more frequent incomplete pulse\ndeliveries (on account of shortened breathing times). While\nwe did observe some cases of incomplete pulse delivery in\nthe exercise case due to the above effect, these instances still\nremained more infrequent than in the sleep case. This may be\ndue to two factors: 1) the time taken for an oxygen pulse to\narrive at the trachea in sleep breathing patterns is the longest\nof all three patterns, and 2) measured pulse durations were\nsignificantly longer for the sleep breathing pattern than they\nwere for the other two patterns. While measurement of pulse\ncharacteristics using the O2\nConserver Test System confirmed\nthe latter factor, rigorous demonstration of the former factor,\nthe influence of pulse arrival time, would require the ability\nto distinguish oxygen in the emitted pulse from oxygen\nentrained from ambient air. This was not possible given our\nexperimental setup. To qualitatively demonstrate the effect\nof pulse arrival time, we can utilize Figure 2. Sudden drops\nin oxygen concentration near the start of inspiration occur\ndue to the temporary absence of supplemental oxygen. When\nconcentration increases again, the pulse has arrived at the\ntrachea. Therefore, in pulse delivery oxygen waveforms,\nthe time it takes for the oxygen concentration to arrive at a\ntemporary minimum after the start of inspiration indicates\nroughly how long it takes the pulse to arrive at the trachea.\nIn Figure 3C (sleep breathing pattern), these times tend\nto be much longer than those in Figure 3B (rest breathing\npattern). If one considers changes in inspiration flow rates\nbetween these two breathing patterns, this is to be expected.\nBecause the ramp-up of inspiration flow rate slows down as\nminute ventilation decreases, the negative pressure trigger\nthreshold is reached later in the course of inspiration. Pulse\narrival times will also vary due to differences in individual\nairway geometries; thus, only some of the airway replicas\ntested resulted in incomplete pulse delivery.\nThe commercial O2\nConserver Test System is able to\nmeasure a pulse delay, representative of the time required\nfor a pulse to arrive at the machine measured from when the\nmachine attempts to trigger the POC. These pulse delays were\nconstant across all breathing frequencies tested (110 ms);\nhowever, the ramp-up of flow rate is absent in the O2\nCon-\nserver Test System testing protocol; thus, these pulse delays\nare not equivalent to the pulse arrival times discussed above.\nUse of realistic airway replicas, as in the present experiments,\ntherefore provides a test platform through which interac-\ntion between simulated breathing patterns and nasal airway\ngeometry can be explored, and may be more representative of\nin vivo oxygen delivery via nasal cannula. Even so, the ability\nof the limited set of 15 realistic nose\u2013throat airway replicas\nused herein to adequately capture variability in airway geom-\netry in the much larger population of COPD patients receiving\nsupplemental oxygen is unknown. Accordingly, variation\nbetween replicas in volume-averaged Fi\nO2\n(Figures 4 and\n5), in triggering pressure measured at the cannula (Figure 6),\nand in complete versus incomplete pulse delivery (Table 4),\nshould be interpreted as illustrative, rather than representa-\ntive, of variability occurring in the larger population.\nAnother difference between SF and PF delivery is in the\npooling effect of the anatomic reservoir during SF delivery.\nZhou and Chatburn examined the effect of elimination of\nthe anatomic reservoir on Fi\nO2\nin SF oxygen delivery.16\nInternational Journal of COPD 2017:12 submit your manuscript | www.dovepress.com\nDovepress\nDovepress\n2569\nPulsed versus continuous oxygen in airway replicas\nThey found that Fi\nO2\nwas reduced in breathing in which\nthe pooling effect of the anatomic reservoir was removed.\nIn those breathing waveforms, expiratory flow was not\nallowed to slowly decay to zero, which shortened the period\nof time in which expiratory flow was sufficiently low to per-\nmit supplemental oxygen to pool in the nasal airway. In the\npresent study, the time needed for expiratory flow to reach\nzero is shorter in the exercise breathing pattern than in the rest\nor sleep breathing patterns, on account of an increased tidal\nvolume and breathing rate. Therefore, one would expect the\nmagnitude of the pooling effect to increase as the tidal volume\nand breathing rate decrease. The effect of the anatomic\nreservoir would be greatest for the sleep breathing pattern\nand smallest for the exercise breathing pattern. In contrast,\nbecause of the absence of end-expiratory oxygen flow, the\nanatomic reservoir has no effect on oxygen delivery in PF.\nAs such, one would expect the discrepancy between SF and\nPF Fi\nO2\nto grow as tidal volume decreases and breathing\nslows down, as observed in Figures 3 and 4.\nPredicting PF Fi\nO2\nbased on pulse\ncharacteristics\nPF Fi\nO2\nestimated using real-time oxygen concentrations\nand PF Fi\nO2\ncalculated by way of Equation 5 using pulse\ncharacteristics were generally in agreement. However, since\nabsolute differences in Fi\nO2\nof 1% may be clinically signifi-\ncant in long-term therapy, we can conclude that while usage\nof pulse characteristics alone is sufficient to predict oxygen\ndelivery for many conditions, testing using realistic airway\nreplicas is still useful in some cases where calculation using\npulse characteristics might significantly overpredict POC per-\nformance (eg, sleeping patients at high setting numbers).\nStudy limitations\nAlthough the present testing methodology can be seen as\nan improvement of past attempts to precisely quantify the\namount of oxygen inspired during supplemental oxygen\ntherapy, several limitations can be noted. First, the results\npresented above are specific to a single POC, and therefore\ndo not reflect the performance of POCs in general. Expanded\ntesting, using the present methodology, may provide valuable\ninformation describing relative oxygen delivery from differ-\nent POCs operating at nominally equivalent pulse settings.\nIn addition, medical images upon which the airway rep-\nlicas are based were acquired in awake subjects during tidal\nbreathing. Therefore, they do not encompass any changes to\nthe upper airway geometry that may occur during sleep or at\nhigh minute ventilation during exercise.\nFurther, the lack of oxygen uptake in the test lung places\na limit on our ability to accurately predict Fi\nO2\nin a clinical,\nrather than benchtop, setting. Because breathing involves\nre-inhalation of gas from the conducting airways, the concen-\ntration of oxygen exhaled from gas-exchange regions of the\nlungs, and subsequently re-inhaled, is relevant in determin-\ning Fi\nO2\n. As there is no analog present for alveolar oxygen\nuptake in the lung simulator used in this study, any amount\nof supplementary oxygen supplied will, over time, increase\nthe inner chamber oxygen concentration (analogous to the\nalveolar oxygen concentration). In the in vivo case, oxygen is\nconstantly being removed through the alveoli into the blood,\nthus decreasing the oxygen concentration of the exhaled gas.\nTo demonstrate this effect, we can consider what happens\nwhen Equation 1 is modified to include a nonzero term for\noxygen uptake into the blood.\nV X V X V V V X\nV X\nAW O c pulse O pulse T AW pulse O ambient\nT O\n2 2 2\n2\n, , ,\n( )\n(\n+ + \u2212 \u2212\n\u2212 ,\n, ,\n)\nc O uptake\n+ =\nV 2\n0\n\b(6)\nVO2,uptake\nrepresents a volume of oxygen that is drawn into the\nblood in a single breath. Rearranging Equation 6, we can\nobtain a modified version of Equation 4.\nX\nX\nV\nV V\nX X\nV\nO c\nO ambient\npulse\nT AW\nO pulse O ambient\nO\n2\n2 2 2\n2\n,\n, , ,\n,\n( )\n=\n+\n\u2212\n\u2212 \u2212\nu\nuptake\nT AW\nV V\n\u2212\n\b (7)\nSince all values in the final term on the right hand side\nof Equation 7 are greater than zero, XO2,c\ncalculated using\nEquation 7 will always be lower than XO2,c\ncalculated using\nEquation 4.\nIncomplete pulse delivery also has implications on\noxygen delivery to the lungs beyond what is observed in its\neffect on Fi\nO2\nevaluated at the trachea. In cases of incom-\nplete pulse delivery, less of the pulse is able to travel past\nthe trachea and into the lungs. However, our reported Fi\nO2\n\u00ad\u00ad\nvalues do not account for a portion of the oxygen pulse that\nis immediately exhaled from the dead space of the tracheo-\nbronchial airways. When assessing oxygen delivery to the\ngas-exchange regions of the lungs, modeling the transport of\noxygen from the trachea through a multi-generation airway\ntree may provide a more complete picture.9\nAdditional future work may also involve comparisons of\noxygen delivery in closed versus open mouth breathing, in\nchildren versus adults, or in diseased versus healthy lungs.\nInternational Journal of COPD 2017:12\nsubmit your manuscript | www.dovepress.com\nDovepress\nDovepress\n2570\nChen et al\nThe effect of mouth breathing versus nose breathing, or open\nversus closed mouth position,31\nis especially relevant during\nsleep and exercise.\nConclusion\nThis study examined a benchtop testing method for assessing\nPOC performance using realistic airway models and real-\ntime monitoring of inspired oxygen concentrations at the\ntrachea. Testing using nasal airway replicas derived from\nmedical imaging and simulated breathing patterns permitted\noxygen delivery from a POC to be evaluated under realistic\ntriggering conditions.\nBased on the measurement of volume-averaged tra-\ncheal Fi\nO2\nfor the POC studied, PF delivered consistently\nlower amounts of oxygen than SF at flow rates equivalent\nto nominal PF settings. Differences were largest when the\nhigher PF setting was combined with breathing parameters\ntypical of sleeping patients. We hypothesize that this differ-\nence is primarily due to two factors: 1) the increased effect\nof oxygen pooling for SF in the anatomic reservoir during\nslower, shallower breathing, and 2) a delay in the arrival of\nthe pulse, which leads to retention in the upper airways and\nexhalation of part of the oxygen bolus.\nAcknowledgments\nThe authors would like to thank Cole Christianson for his\nwork in measuring airway replica pressure drops, Kelvin\nDuong for his help in analyzing raw data, Eric Bracke for con-\ntributions to building the CT replicas, and Dr Jo\u00eblle Texereau\nfor reviewing and providing helpful comments on an earlier\nversion of this manuscript. This work was funded by Air\nLiquide and by Alberta Economic Development and Trade\nand benefited from an equipment grant from the Canadian\nNatural Sciences and Engineering Research Council.\nDisclosure\nIMK, MP, KZ, and GC are current employees of Air Liquide,\na major provider of home oxygen therapy. The authors report\nno other conflicts of interest in this work.\nReferences\n1. McCoy R. Oxygen-conserving techniques and devices. Respir Care.\n2000;45(1):95.\n2. Gustafson JD, Yang S, Blakeman TC, Dorlac WC, Branson R. Pulsed\ndosed delivery of oxygen in mechanically ventilated pigs with acute lung\ninjury. J Trauma Acute Care Surg. 2013;75(5):775.\n3. Blakeman TC, Rodriquez D, Britton TJ, Johannigman JA, Petro MC,\nBranson RD. Evaluation of oxygen concentrators and chemical oxygen\ngenerators at altitude and temperature extremes. Mil Med. 2016;\n181(5 Suppl):160\u2013168.\n4. Blakeman TC, Rodriquez D, Gerlach TW, Dorlac WC, Johannigman JA,\nBranson RD. Oxygen requirement to reverse altitude-induced\nhypoxemia with continuous flow and pulsed dose oxygen. Aerosp\nMed Hum Perform. 2015;86(4):351\u2013356.\n5. Y\u00e1\u00f1ez AM, Prat JP, \u00c1lvarez-Sala JL, et al. 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Pediatr Pulmonol. 1997;23(4):249\u2013260.\nInternational Journal of COPD\nPublish your work in this journal\nSubmit your manuscript here: http:\/\/www.dovepress.com\/international-journal-of-chronic-obstructive-pulmonary-disease-journal\nThe International Journal of COPD is an international, peer-reviewed\njournal of therapeutics and pharmacology focusing on concise rapid\nreporting of clinical studies and reviews in COPD. Special focus is given\nto the pathophysiological processes underlying the disease, intervention\nprograms, patient focused education, and self management protocols.\nThis journal is indexed on PubMed Central, MedLine and CAS. The\nmanuscript management system is completely online and includes a\nvery quick and fair peer-review system, which is all easy to use. Visit\nhttp:\/\/www.dovepress.com\/testimonials.php to read real quotes from\npublished authors.\nInternational Journal of COPD 2017:12 submit your manuscript | www.dovepress.com\nDovepress\nDovepress\nDovepress\n2571\nPulsed versus continuous oxygen in airway replicas\n26. Langer AW, Hutcheson JS, Charlton JD, McCubbin JA, Obrist PA,\nStoney CM. On-line minicomputerized measurement of cardiopulmo-\nnary function on a breath by breath basis. Psychophysiology. 1985;22(1):\n50\u201358.\n27. Chatila W, Nugent T, Vance G, Gaughan J, Criner GJ. The effects of\nhigh-flow vs low-flow oxygen on exercise in advanced obstructive\nairways disease. Chest. 2004;126(4):1108\u20131115.\n28. Hudgel DW, Martin RJ, Capehart M, Johnson B, Hill P. Contribution\nof hypoventilation to sleep oxygen desaturation in chronic obstructive\npulmonary disease. J Appl Physiol. 1983;55(3):669\u2013677.\n29. Moore CP, Finlay WH, Martin AR. Investigating intersubject variability\nin pulsed oxygen delivery using adult nasal airway replicas. Am J Respir\nCrit Care Med. 2015;191:A5811.\n30. O\u2019Reilly Nugent A, Kelly PT, Stanton J, Swanney MP, Graham B,\nBeckert L. Measurement of oxygen concentration delivered via nasal\ncannulae by tracheal sampling. Respirology. 2014;19(4):538\u2013543.\n31. Waldau T, Larsen VH, Bonde J. Evaluation of five oxygen delivery\ndevices in spontaneously breathing subjects by oxygraphy. Anaesthesia.\n1998;53:256\u2013263.\n32. Wettstein RB, Shelledy DC, Peters JI. Delivered oxygen concentra-\ntions using low-flow and high-flow nasal cannulas. Respir Care. 2005;\n50(5):604\u2013609.\n33. Casaburi R. Assessing the dose of supplemental oxygen: let us compare\nmethodologies. Respir Care. 2005;50(5):594\u2013595.","pure_content":"\u00a9 2017 Chen et al. This work is published and licensed by Dove Medical Press Limited. The full terms of this license are available at https:\/\/www.dovepress.com\/terms.php\nand incorporate the Creative Commons Attribution \u2013 Non Commercial (unported, v3.0) License (http:\/\/creativecommons.org\/licenses\/by-nc\/3.0\/). By accessing the work you\nhereby accept the Terms. Non-commercial uses of the work are permitted without any further permission from Dove Medical Press Limited, provided the work is properly attributed. For permission\nfor commercial use of this work, please see paragraphs 4.2 and 5 of our Terms (https:\/\/www.dovepress.com\/terms.php).\nInternational Journal of COPD 2017:12 2559\u20132571\nInternational Journal of COPD Dovepress\nsubmit your manuscript | www.dovepress.com\nDovepress\n2559\nO r i g i n a l R e s e a r c h\nopen access to scientific and medical research\nOpen Access Full Text Article\nhttp:\/\/dx.doi.org\/10.2147\/COPD.S141976\nComparison of pulsed versus continuous oxygen\ndelivery using realistic adult nasal airway replicas\nJohn Z Chen1\nIra M Katz2\nMarine Pichelin2\nKaixian Zhu3\nGeorges Caillibotte2\nMichelle L Noga4\nWarren H Finlay1\nAndrew R Martin1\n1\nDepartment of Mechanical\nEngineering, University of Alberta,\nEdmonton, AB, Canada; 2\nMedical\nR&D, Air Liquide Sant\u00e9 International,\nCentre de Recherche Paris-Saclay, Les\nLoges-en-Josas, 3\nCentre Explor!, Air\nLiquide Healthcare, Gentilly, France;\n4\nRadiology and Diagnostic Imaging,\nUniversity of Alberta, Edmonton,\nAB, Canada\nBackground: Portable oxygen concentrators (POCs) typically include pulse flow (PF) modes\nto conserve oxygen. The primary aims of this study were to develop a predictive in vitro model\nfor inhaled oxygen delivery using a set of realistic airway replicas, and to compare PF for a\ncommercial POC with steady flow (SF) from a compressed oxygen cylinder.\nMethods: Experiments were carried out using a stationary compressed oxygen cylinder, a POC,\nand 15 adult nasal airway replicas based on airway geometries derived from medical images.\nOxygen delivery via nasal cannula was tested at PF settings of 2.0 and 6.0, and SF rates of 2.0 and\n6.0 L\/min. A test lung simulated three breathing patterns representative of a chronic obstructive\npulmonary disease patient at rest, during exercise, and while asleep. Volume-averaged fraction\nof inhaled oxygen (Fi\nO2\n) was calculated by analyzing oxygen concentrations sampled at the exit\nof each replica and inhalation flow rates over time. POC pulse volumes were also measured\nusing a commercial O2\nconserver test system to attempt to predict Fi\nO2\nfor PF.\nResults: Relative volume-averaged Fi\nO2\nusing PF ranged from 68% to 94% of SF values,\nincreasing with breathing frequency and tidal volume. Three of 15 replicas failed to trigger\nthe POC when used with the sleep breathing pattern at the 2.0 setting, and four of 15 replicas\nfailed to trigger at the 6.0 setting. Fi\nO2\nvalues estimated from POC pulse characteristics followed\nsimilar trends but were lower than those derived from airway replica experiments.\nConclusion: For the POC tested, PF delivered similar, though consistently lower, volume-\naveraged Fi\nO2\nthan SF rates equivalent to nominal PF settings. Assessment of PF oxygen delivery\nusing POC pulse characteristics alone may be insufficient; testing using airway replicas is useful\nin identifying possible cases of failure and may provide a better assessment of Fi\nO2\n.\nKeywords: long term oxygen therapy (LTOT), ambulatory oxygen, portable oxygen concen-\ntrator (POC)\nIntroduction\nPortable oxygen concentrators (POCs) are devices developed relatively recently in\nresponse to demand for a lightweight, portable source of supplemental oxygen.1\nWhile\nmost frequently prescribed to patients needing long-term oxygen therapy (LTOT),\nPOCs can play a role in any application requiring a source of supplemental oxygen.\nFor example, POCs have been evaluated as a possible solution to supplemental oxygen\nrequirements in military settings2\nand high altitude environments.3,4\nA recent study\nshowed that chronic obstructive pulmonary disease (COPD) patients requiring LTOT\ngenerally prefer a single source POC over a combined stationary and portable oxygen\nsource both in the home and during activity, citing the practicality of the system as\nits main advantage.5\nPOCs primarily deliver oxygen in one of two modes: steady flow (SF) and pulse\nflow (PF), with the most recent generation of lightweight devices (,5 lb) offering only\nCorrespondence: Andrew R Martin\n10-324, Donadeo Innovation Centre\nfor Engineering, University of Alberta,\nEdmonton, AB T6G 1H9, Canada\nTel +1 780 492 9012\nEmail andrew.martin@ualberta.ca\nNumber of times this article has been viewed\nThis article was published in the following Dove Press journal:\nInternational Journal of COPD\n24 August 2017\nInternational Journal of COPD 2017:12\nsubmit your manuscript | www.dovepress.com\nDovepress\nDovepress\n2560\nChen et al\nPF mode.6,7\nWhile SF remains the more straightforward of the\ntwo options, continuous delivery throughout the breath leads\nto a significant fraction of delivered oxygen being lost to the\nambient air, never reaching the patient\u2019s lungs.1\nIn contrast,\nPF aims to improve efficiency by limiting oxygen delivery\nonly to times when patient inspiration can be detected, and\ndelivering oxygen as a bolus, or pulse, early in the breath\nso that the fraction of oxygen exhaled from the anatomical\ndead space is reduced.\nIdeally, PF modes provide a volume of oxygen for inhala-\ntion equivalent to the volume of supplemental oxygen inhaled\nat a given SF rate. In light of this, oxygen delivery at varied\nPF settings for commercial POCs is frequently interpreted as\nnominally equal to that which would be achieved at equiva-\nlent SF rates; for example, a PF setting of 1.0 corresponds\nto an SF rate of 1.0 L\/min, a PF setting of 2.0 to SF rate of\n2.0 L\/min, etc.8\nHowever, the total oxygen volume adminis-\ntered over a complete breathing cycle is typically less for PF\nthan SF, owing to the efficiencies gained by synchronizing\noxygen delivery with patient inspiration.\nSince PF\/SF equivalency is dependent upon a number of\nshifting variables, conclusively demonstrating such equiva-\nlency can be a difficult task.9\nFurthermore, as standards of\nequivalency may currently vary between manufacturers, dif-\nferent POC devices may deliver different volumes of oxygen\nat nominally the same PF setting.1\nWhile some clinical\nstudies have suggested equivalence of PF and SF oxygen\ndelivery,10,11\nothers have reported differences.12,13\nRecent\nstudies have shown that in pairs of nominally equivalent\nPF\/SF settings, PF fraction of inspired oxygen (Fi\nO2\n) was\nconsistently lower than SF Fi\nO2\n.13\u201316\nFor evaluating administration of medical aerosols to the\nlungs, in vitro benchtop testing using realistic or idealized\n3D-printed airway replicas has proven valuable in providing\na fast, convenient, and noninvasive research and development\ntool compared to in vivo studies.6,7,17,18\nThese realistic airway\nreplicas, derived from medical imaging, are more representa-\ntive of human upper airways compared with highly simplified\ngeometries that have been previously used for evaluating\ninhaled concentrations of medical gases.16,19\nTesting with mul-\ntiple replicas can aid in accounting for variability in the airway\ngeometry of different patients; that is, intersubject variability.17\nIn addition, benchtop experiments permit precise control of\nsimulatedbreathingpatterns,eliminatingasignificantsourceof\nvariance that may be present during in vivo human studies.\nTo our knowledge, no work has been done to date compar-\ning the differences between SF and PF oxygen administration\nfrom POCs using realistic airway replicas. Accordingly, the\nprimary aims of the present study are to develop a predictive\nin vitro model for inhaled oxygen delivery using a set of\n15 realistic adult nasal airway replicas, and then to compare\nSF and PF for a widely used commercial POC. To this end,\nwe developed a testing protocol that measures the real-time\noxygen concentration at the outlet (trachea) of the airway\nreplica, which can then be integrated with the instantaneous\ninspiratory flow rate to determine a volume-averaged Fi\nO2\nover the course of inspiration. Volume-averaged Fi\nO2\ncan be\nused as a common basis for comparison between nominally\nequivalent settings of SF and PF. We further aimed to\ndevelop an algorithm to estimate PF Fi\nO2\nbased on pulse\ncharacteristics, tidal volume, and upper airway volume.\nThese estimated values can be compared with Fi\nO2\nvalues\nderived from oxygen concentration measurements.\nMethods\nRealistic airway replicas\nFifteen adult nasal airway replicas built in acrylic plastic\nusing rapid prototyping were used in the present study. Each\nreplica included air passages starting from the nares through\nthe entrance to the trachea. Five of the airway replicas were\nbased on magnetic resonance (MR) images as previously\nreported,20\nwhile the remaining 10 replicas were based on a\nnew set of anonymized high resolution computed tomography\n(CT) scans acquired retrospectively from patients scanned\nfor clinical purposes unrelated to the nasal passage at the\nUniversity of Alberta Hospital, with Health Research Ethics\nBoard approval. All CT scans were reviewed by an expert\nradiologist and the nasal passage considered normal. The MR\nimages and CT scans used to build the replicas did not con-\ntain any identifying information. CT scans were segmented\nusing Mimics software (Materialise, Leuven, Belgium) and\nreplicas were built from plastic (Objet VeroGray RGD850;\nStratsys, Ltd., Eden Prairie, MN, USA) using a PolyJet\n3D printer (Objet Eden 350V High Resolution 3D Printer;\nStratsys, Ltd., Eden Prairie, MN, USA). Segmented 3D\nairways based on both the MR and CT images are presented\nin Figure 1. Geometric parameters for each of the 15 replicas\nwere obtained using MeshLab (Visual Computing Labora-\ntory, Istituto di Scienza e Tecnologie dell\u2019Informazione,\nItaly) and ParaView (Kitware, Clifton Park, NY, USA).\nThese parameters are shown in Table 1.\nRepresentative breathing patterns\nTo simulate tidal breathing, airway replicas were connected\nto a lung simulator (ASL 5000 Breathing Simulator; IngMar\nMedical, Pittsburgh, PA, USA), as shown schematically\nInternational Journal of COPD 2017:12 submit your manuscript | www.dovepress.com\nDovepress\nDovepress\n2561\nPulsed versus continuous oxygen in airway replicas\nin Figure 2. Plastic tubing with 22 mm internal diameter\nconnected the replica outlet to the lung simulator. The total\ninternal volume of this tubing was 135 cm3\n, representative\nof the conducting airway volume from the trachea to the\ngas-exchange regions of the lungs for an average adult with\n3 L functional residual capacity.21\nTo capture a range of activity levels in daily life, we\nused three different breathing patterns representative of a\nCOPD patient on LTOT at rest, doing light exercise, and\nwhile asleep. Inspiratory and expiratory phases of the breath\nwere represented using sinusoidal flow patterns with one\nhalf sinusoid for inspiration and another half sinusoid for\nexpiration. Sinusoidal breathing patterns have been used\npreviously to approximate human breathing.22\u201326\nInspiration\nand expiration flow rates were derived using tidal volume\n(VT\n), inspiratory time (TI\n), expiratory time (TE\n), and breath-\ning frequency (f). Values of each of these parameters for\nthe three breathing patterns are shown in Table 2. The rest\nand exercise breathing parameters were chosen based on\naverage values reported previously by Chatila et al27\nfor\n10 patients with COPD at baseline (rest) and while on low\nSF rate (2.5\u20136 L\/min) oxygen while performing light exercise\non a cycle ergometer. Parameters for the sleep breathing\npattern were chosen based on average values measured by\nHudgel et al28\nfor 13 COPD patients while asleep.\nFlow rate and oxygen concentration\nmeasurements\nExperiments were carried out using a Philips SimplyGo POC\n(Philips Respironics, Murrysville, PA, USA) and a cylinder\nsource of 100% oxygen (Praxair Canada, Mississauga, ON,\nCanada). A test lung simulated the three different breathing\npatterns, each for ~50 breathing cycles. Oxygen delivery in\neach of the replicas via a nasal cannula (Hudson RCI adult\nFigure 1 Solid 3D nose\u2013throat airways of the 15 replicas tested in the present study.\nNote: The top row displays airways derived from MRI, while the bottom two rows display airways derived from CT images.\nAbbreviations: CT, computed tomography; MRI, magnetic resonance imaging.\n6XEMHFW\u000305,\u0015 6XEMHFW\u000305,\u0018 6XEMHFW\u000305,\u0019 6XEMHFW\u000305,\u001b 6XEMHFW\u000305,\u001c\n6XEMHFW\u0003&7\u0014 6XEMHFW\u0003&7\u0015 6XEMHFW\u0003&7\u0016 6XEMHFW\u0003&7\u0017 6XEMHFW\u0003&7\u0018\n6XEMHFW\u0003&7\u0019 6XEMHFW\u0003&7\u001a 6XEMHFW\u0003&7\u001b 6XEMHFW\u0003&7\u001c 6XEMHFW\u0003&7\u0014\u0013\nTable 1 Airway replica volumes and surface areas for 15 adult\nnasal airway replicas\nSubject Sex Age (years) Volume (cm3\n) Surface area (cm2\n)\nMRI2 F \u2013 44.6 287\nMRI5 F \u2013 35.9 235\nMRI6 M \u2013 50.1 313\nMRI8 M \u2013 47.3 289\nMRI9 M \u2013 45.3 250\nCT1 M 60 60.0 343\nCT2 F 50 73.1 315\nCT3 M 57 59.2 320\nCT4 M 54 71.9 349\nCT5 M 60 50.1 280\nCT6 F 72 59.1 321\nCT7 M 62 56.3 308\nCT8 M 63 61.9 326\nCT9 M 27 48.1 276\nCT10 F 56 53.2 265\nAbbreviations: CT, computed tomography; MRI, magnetic resonance imaging;\nM, male; F, female.\nInternational Journal of COPD 2017:12\nsubmit your manuscript | www.dovepress.com\nDovepress\nDovepress\n2562\nChen et al\nnasal cannula; Teleflex Medical, Research Triangle Park, NC,\nUSA) was first tested at SF rates from the cylinder source\nof 2.0 and 6.0 L\/min, and then at nominal PF settings of\n2.0 and 6.0. SimplyGo features two different PF operating\nmodes: pulse mode and sleep mode. Sleep mode is similar\nto pulse mode, but features more sensitive breath detection,\nlower pulse amplitude, and longer pulse duration aimed to\nimprove comfort during sleeping. The sleep breathing pattern\nwas tested using both pulse mode and sleep mode in order to\ncomprehensively evaluate potential device performance.\nThe volume of the chamber of the test lung was recorded\nduring simulated breathing at a sampling frequency of 512 Hz\nusing the ASL 5000 software. Oxygen concentrations were\nmeasured using a GA-200 CO2\nand O2\nGas Analyzer (iWorx,\nDover, NH, USA), and were corrected for delay and time\nconstant, which was done by approximating the concentra-\ntion as a first order system and following methods outlined\nin Langer et al.26\nWe assumed that the step response of the\ngas analyzer could be well approximated by a first order\nexponential function. The time constant for this exponen-\ntial function, which is defined as the time required for the\nresponse of the system to reach 63% of its final value as\nthe result of a step increase, was measured to be 227 ms in\npreliminary experiments by rapidly switching supply to the\ngas analyzer via a three-way stopcock between two different\ngas mixtures of known concentration (in this case, air and\n100% oxygen).\nCalculation of SF and PF Fi\nO2\nThe flow rate of oxygen passing through the trachea over\ntime was calculated by multiplying inspiration flow rate,\nknown at each time point, with the measured real-time\noxygen concentrations at the same time point. Inspiration\nstart and end times were identified as times when flow rates\ncrossed 0. These oxygen flow rates were then numerically\nintegrated using the trapezoidal rule from the start to the end\nof inspiration to determine a volume of oxygen inhaled per\nbreath. VT\nwas also calculated from inspiration flow rates\nusing a similar procedure. The volume of inhaled oxygen\nwas then divided by VT\nto obtain a volume-averaged value\nFigure 2 Schematic of experimental apparatus.\nNote: Arrows indicate direction of oxygen flow.\n1DVDO\u0003DLUZD\\\nUHSOLFD\n\/XQJ\u0003VLPXODWRU\n\/XQJ\u0003VLPXODWRU\nFRQWURO\u0003ODSWRS\n2[\\JHQ\nDQDO\\]HU\n3RUWDEOH\u0003R[\\JHQ\nFRQFHQWUDWRU\n'HVNWRS\u0003FRPSXWHU\nTable 2 Breathing parameters of representative breathing\nprofiles for COPD patients at rest, doing light exercise, and while\nasleep\nRest Exercise Sleep\nTidal volume, VT\n(mL) 640 800 520\nInspiratory time, TI\n(s) 1.20 0.96 1.79\nExpiratory time, TE\n(s) 2.33 1.77 2.93\nBreathing frequency, f (breaths\/min) 17 22 13\nAbbreviation: COPD, chronic obstructive pulmonary disease.\nInternational Journal of COPD 2017:12 submit your manuscript | www.dovepress.com\nDovepress\nDovepress\n2563\nPulsed versus continuous oxygen in airway replicas\nfor Fi\nO2\nfor that breath. Fi\nO2\nfor each combination of replica\nand oxygen delivery condition was taken as the average of\nfive consecutive breaths after a steady state in expiratory\noxygen concentration was observed (at least 50 breaths).\nVariability between average Fi\nO2\nvalues obtained in experi-\nments repeated on separate days of testing was found in\npreliminary testing to be of similar magnitude as variability\nbetween individual breaths.\nMeasurement of pulse characteristics\nA 1130 series O2\nConserver Testing System (Hans Rudolph\nInc, Shawnee, KS, USA) was used to obtain oxygen pulse\nvolumes, durations, and delays for both the 2.0 and 6.0\nsettings of the POC using the breathing frequency of\neach breathing pattern shown in Table 3. SimplyGo was\nconnected to the testing system using a standard 2.1 mm\nsingle lumen cannula. Data were recorded as the average\nof 10 successive pulses for each breathing pattern\/setting\ncombination. Variance around reported averages was very\nsmall. The oxygen concentration of the pulse itself was\nmeasured to be 94% across all breathing pattern\/setting\ncombinations.\nPrediction of PF Fi\nO2\nThe model used in this study to estimate PF Fi\nO2\ndepends on\nthe following parameters: the tidal volume VT\n, the ambient\noxygen fraction XO2,ambient\n, the volume of the airway replica\nVreplica\n, the total volume of the \u201clower conducting airways\u201d VLA\n(represented by the tubing connecting the airway replica to\nthe lung simulator), the oxygen fraction of the pulse XO2,pulse\n,\nand the volume of the pulse Vpulse\n.\nBreathing was modeled with the assumption that\nexhaled gas in the anatomical dead space, consisting of\nupper and lower conducting airways at end-expiration, is\nimmediately re-inhaled, and that none of the pulse remains\nin the anatomical dead space of the airways at the start of\nexpiration. That is, pulse timing is assumed to be ideal, in\nthat all oxygen delivered in the pulse reaches peripheral\nregions of the lungs (in the present experiments repre-\nsented by the lung simulator). Following re-inhalation of\ngas from the anatomical dead space, the remainder of the\nbreath consists of the oxygen pulse and entrained ambi-\nent air. Over multiple breathing cycles, the gas mixture\ncontained within the cylinder of the lung simulator will\napproach some steady-state concentration, XO2,c\n.\nTo derive the equation for XO2,c\n, it was noted that in this\nsteady state the volume of oxygen entering the lung simula-\ntor, VO2,I\n, must be equal to the volume of oxygen that exits,\nVO2,E\n. Therefore\nV V\nO I O E\n2 2\n0\n, ,\n\u2212 =\n\b\n(1)\nBased on the assumptions made above, this equation can\nbe rewritten as\nV X V X\nV V V X V X\nAW O c pulse O pulse\nT AW pulse O mbient T O\n2 2\n2 2\n, ,\n, ,\n( )\n+\n+ \u2212 \u2212 \u2212\na c\nc\n= 0\n\b\n(2)\nwhere VAW\n, the total volume of the airways (including the\nreplica), is given by\nV V V\nAW LA replica\n= +\n\b\n(3)\nRearranging, one can solve for XO2,c\nX X\nV\nV V\nX X\nO c O ambient\npulse\nT AW\nO pulse O ambient\n2 2 2 2\n, , , ,\n( )\n= +\n\u2212\n\u2212\n\b\n(4)\nTo find Fi\nO2\nas measured and reported in the present\nexperiments, one needs to take into account the volume\nTable 3 SimplyGo oxygen pulse characteristics at pulse flow setting numbers of 2.0 and 6.0 using various breathing frequencies\nBreath\nfrequency\nf=13 breaths\/min f=17 breaths\/min f=22 breaths\/min\nPulse\nsetting\nPulse\nvolume (mL)\nPulse\ndelay (ms)\nPulse\nduration (ms)\nPulse\nvolume (mL)\nPulse\ndelay (ms)\nPulse\nduration (ms)\nPulse\nvolume (mL)\nPulse\ndelay (ms)\nPulse\nduration (ms)\nPulse\nmode 2.0\n23.8 110 291 23.8 114 290 22.7 111 320\nPulse\nmode 6.0\n68.7 110 479 68.8 113 480 66.8 109 613\nSleep\nmode 2.0\n28.9 109 582 22.2 110 449 38.2 109 764\nSleep\nmode 6.0\n85.7 108 613 66.5 103 479 112.5 104 793\nInternational Journal of COPD 2017:12\nsubmit your manuscript | www.dovepress.com\nDovepress\nDovepress\n2564\nChen et al\nof oxygen passing the trachea, rather than that reaching\nthe lung simulator. Therefore, recently exhaled oxygen\nremaining in VLA\nprior to the start of inspiration does not\nneed to be accounted for. Fi\nO2\ncan then be estimated by cal-\nculating the total volume of oxygen passing the trachea and\ndividing by VT\n:\nFO\ni pulse O pulse replica O c\nT replica pulse\n2 2 2\n= +\n+ \u2212 \u2212\n[\n( )\n, ,\nV X V X\nV V V XO\nO ambient T\n2,\n] V\n\b\n(5)\nFi\nO2\nwas calculated in this manner using each of the\n15 different replica volumes and then averaged to give\na single value. Averaged predicted values of Fi\nO2\n, based\non measured pulse characteristics, were then compared to\naverage values measured using the realistic replicas and\nlung simulator.\nPressure drop measurements\nIn most POCs, breaths are detected using an internal pressure\nsensor that measures a reduction in pressure monitored at the\noxygen supply tubing (the triggering pressure) corresponding\nto the start of inhalation. Pressure drops across each airway\nreplica were measured at the cannula based on methods out-\nlined in Moore et al.29\nAn adult nasal cannula was inserted\ninto the nostrils of each replica. The cannula was connected\nto a differential manometer (HHP-103; OMEGA Engineer-\ning, Norwalk, CT, USA) measuring the difference between\nthe cannula and atmospheric pressure. A vacuum was con-\nnected to each replica and a valve used to control inhalation\nflow rate, which was monitored using a mass flowmeter (TSI\nMass Flowmeter 4043; TSI Inc, Shoreview, MN, USA).\nPressure drops were measured at flow rates of 10, 20, 30,\nand 40 L\/min.\nResults\nOxygen concentration and flow rate\nwaveforms\nFigure 3 shows oxygen concentrations and inspiration\nflow rates at the trachea for the selected replicas plotted\nagainst time. As a matter of convention, positive flow rates\nindicate inspiration and negative flow rates indicate exha-\nlation. Oxygen concentration waveforms could be broadly\nclassified as falling into one of three groups: waveforms\nindicating SF oxygen delivery, Figure 3A; waveforms\nindicating complete pulse delivery (the entire pulse reaches\nFigure 3 Example of oxygen mole fraction and flow rate waveforms indicating (A) steady flow oxygen delivery, (B) complete pulse delivery, and (C) incomplete pulse\ndelivery.\nNotes: Waveforms were selected from experiments conducted using subject CT7 with the sleep breathing pattern (A) and (C), and using subject CT9 with the rest breathing\npattern (B). Positive flow rates indicate inspiration; negative flow rates indicate expiration. Numbers indicate points of interest in the oxygen waveform: (1) maximum\ninspiratory oxygen fraction; (2) minimum inspiratory oxygen fraction; (3) oxygen fraction changing through onset of exhalation; (4) oxygen fraction rising\/falling to end-\nexpiratory value.\n$\n7LPH\u0003 V\n\u00b1\u0019\u0013\u0013 \u0013\u0011\u0014\u001c\n\u0013\u0011\u0015\u0014\n\u0013\u0011\u0015\u0016\n\u0013\u0011\u0015\u001a\n\u0013\u0011\u0015\u0018\n\u0013\u0011\u0015\u001c\n\u0013\u0011\u0016\u0018\n\u0013\u0011\u0016\u0014\n\u0013\u0011\u0016\u0016\n\u0015\u0016\u0017\n\u0015\u0016\u0015\n\u0015\u0016\u0013\n\u0015\u0015\u001b\n\u0015\u0015\u0019\n\u0015\u0015\u0017\n\u0015\u0015\u0015\n\u0015\u0015\u0013\n\u00b1\u0017\u0013\u0013\n\u00b1\u0015\u0013\u0013\n\u0013\n\u0019\u0013\u0013\n\u0015\u0013\u0013\n\u001b\u0013\u0013\n\u0017\u0013\u0013\n\u0014\u000f\u0013\u0013\u0013\n)ORZ\u0003UDWH\u0003\nP\/\u0012V\n2[\\JHQ\u0003IUDFWLRQ\n7LPH\u0003 V\n\u00b1\u0017\u0013\u0013\n\u00b1\u0016\u0013\u0013\n\u00b1\u0015\u0013\u0013\n\u00b1\u0014\u0013\u0013\n\u0013\n\u0014\u0013\u0013\n\u0015\u0013\u0013\n\u0016\u0013\u0013\n\u0017\u0013\u0013\n\u0018\u0013\u0013\n\u0013\u0011\u0015\u0016\n\u0013\u0011\u0015\u001b\n\u0013\u0011\u0016\u0016\n\u0013\u0011\u0016\u001b\n\u0013\u0011\u0017\u0016\n\u0013\u0011\u0017\u001b\n\u0015\u0016\u0017\n\u0015\u0016\u0015\n\u0015\u0016\u0013\n\u0015\u0015\u001b\n\u0015\u0015\u0019\n\u0015\u0015\u0017\n\u0015\u0015\u0015\n\u0015\u0015\u0013\n)ORZ\u0003UDWH\u0003\nP\/\u0012V\n2[\\JHQ\u0003IUDFWLRQ\n7LPH\u0003 V\n\u00b1\u0017\u0013\u0013\n\u00b1\u0016\u0013\u0013\n\u00b1\u0015\u0013\u0013\n\u00b1\u0014\u0013\u0013\n\u0013\n\u0014\u0013\u0013\n\u0015\u0013\u0013\n\u0016\u0013\u0013\n\u0017\u0013\u0013\n\u0018\u0013\u0013\n\u0013\u0011\u0014\u001c\n\u0015\u0016\u0017\n\u0015\u0016\u0015\n\u0015\u0016\u0013\n\u0015\u0015\u001b\n\u0015\u0015\u0019\n\u0015\u0015\u0017\n\u0015\u0015\u0015\n\u0015\u0015\u0013\n\u0013\u0011\u0015\u0014\n\u0013\u0011\u0015\u0016\n\u0013\u0011\u0015\u001a\n\u0013\u0011\u0015\u0018\n\u0013\u0011\u0015\u001c\n\u0013\u0011\u0016\u0018\n\u0013\u0011\u0016\u0014\n\u0013\u0011\u0016\u0016\n)ORZ\u0003UDWH\u0003\nP\/\u0012V\n2[\\JHQ\u0003IUDFWLRQ\n%\n&\n\u0014\n\u0014\n\u0014\n\u0015\n\u0015\n\u0015\n\u0016\n\u0016\n\u0016\n\u0017\n\u0017\n\u0017\n)ORZ\u0003UDWH 2[\\JHQ\u0003IUDFWLRQ\nInternational Journal of COPD 2017:12 submit your manuscript | www.dovepress.com\nDovepress\nDovepress\n2565\nPulsed versus continuous oxygen in airway replicas\nthe internal cylinder of the lung simulator), Figure 3B; and\nwaveforms indicating incomplete pulse delivery (a portion\nof the pulse remains in the anatomical dead space and is\nexhaled), Figure 3C.\nContinuous oxygen delivery waveforms (Figure 3A) were\ncharacterized by the presence of two peaks over the course\nof inspiration, one large, sharp peak occurring shortly after\nthe beginning of inspiration, and another smaller peak at the\nend. The variation in oxygen concentration over the course\nof inspiration for SF can be explained as follows.\n1. The first, taller peak indicates pooling in the anatomic\nreservoir at the end of expiration. Since oxygen flow\ncontinues throughout the entire breath in SF, oxygen will\naccumulate in the upper airways as exhalation ends and\nthe expiratory flow rate approaches zero. This pooled\noxygen is then inhaled at the start of the next inspira-\ntion, which is reflected in the first sharp peak in oxygen\nconcentration.\n2. Once pooled oxygen is inhaled, the inspiration flow rate\nthen increases toward a maximum, and therefore the frac-\ntion of inhaled gas represented by supplementary oxygen\nwill decrease, which is reflected in a steep decrease in\noxygen concentration. Conversely, as the inspiration flow\nrate passes its maximum and begins to decrease again,\nthe supplementary oxygen fraction in the inhaled gas\nwill increase.\n3. As exhalation begins, gas remaining in the dead space\n(in this case, the tubing connecting the replica to the lung\nsimulator) is immediately exhaled. Due to imperfect\nmixing in the airways, the dead space gas is exhaled on\na first-in, last-out basis and will tend to lower the oxygen\nconcentration. In other words, any comparatively low-\noxygen gas (inhaled when the inspiration flow rate was\nhigh) remaining in the tubing will be further from the\ntrachea than high-oxygen gas (inhaled when the inspira-\ntion flow rate was low).\n4. Finally, as exhalation proceeds, the oxygen concentration\napproaches the constant oxygen concentration found in\nthe internal chamber of the lung simulator.\nOn the other hand, oxygen concentration waveforms\nindicating complete pulse delivery (Figure 3B) can be identi-\nfied by the presence of a single peak occurring near, but not\ncoinciding with, the beginning of inspiration. Unlike the SF\ncase, no pooling exists since oxygen delivery does not occur\nif no inspiratory effort is detected. The variation in oxygen\nconcentration over the course of inspiration for complete\npulse delivery can be explained as follows.\n1. Here, the single peak at the start of inspiration indicates the\npassageofthepulsefromthePOCandthroughthetrachea.\nThe sharp initial decrease in oxygen concentration shortly\nfollowing the start of inspiration is due to the delay\nbetween the start of the inspiratory effort and its detec-\ntion by the POC, along with the transit time of the pulse\nthrough the upper airways.\n2. Once the POC emits the pulse, no further supplementary\noxygen is delivered. Oxygen concentration drops quickly\nto that of ambient air (~21%) and remains there, indicat-\ning that the entire pulse likely reached the lung simulator\nchamber.\n3. Expiration begins, and the gas (mostly ambient air)\nremaining in the dead space (the tubing connecting the\nreplica to the lung simulator) is flushed out.\n4. Oxygen concentration then rises to that of the mixed gas\ninside the lung simulator chamber.\nIncomplete delivery waveforms for PF (Figure 3C)\nproceed similarly to the complete case during the beginning\nof inspiration. However, in this case, a second peak exists\nnear the beginning of exhalation. For incomplete delivery,\na portion of the pulse remains in the dead space tubing con-\nnecting the replica to the lung simulator, which is exhaled\nimmediately, creating the second peak.\nThe number of replicas indicating incomplete pulse\ndelivery as a fraction of the total is shown in Table 4.\nSF and PF Fi\nO2\nFigures 4 and 5 show comparisons of Fi\nO2\nbetween nomi-\nnally equivalent PF settings (both pulse and sleep mode for\nthe sleep breathing pattern) and SF flow rates. For the sleep\nbreathing pattern, three of the replicas failed to trigger the\nPOC (ie, no breathing was detected) at pulse mode setting\n2.0, and four replicas failed to trigger the device at pulse\nmode setting 6.0. At sleep mode settings of 2.0 and 6.0, only\none replica failed to trigger the device. Fi\nO2\nvalues measured\nfor replicas and breathing patterns which failed to trigger the\nPOC were excluded in the calculation of the average values\nreported in Figure 3A and B.\nMean PF Fi\nO2\nranged from 68% to 94% of mean val-\nues obtained for nominally equivalent SF rates, generally\nTable 4 Number of breathing replicas indicating incomplete\npulse delivery out of the total number of replicas used to\ncalculate volume-averaged fraction of inspired oxygen (Fi\nO2\n) at\neach setting\/breathing pattern combination\nPOC setting Rest Exercise Sleep\nPulse mode 2.0 0\/15 0\/15 2\/12\nPulse mode 6.0 1\/15 2\/15 3\/11\nSleep mode 2.0 N\/A N\/A 5\/14\nSleep mode 6.0 N\/A N\/A 5\/14\nAbbreviations: N\/A, not applicable; POC, portable oxygen concentrator.\nInternational Journal of COPD 2017:12\nsubmit your manuscript | www.dovepress.com\nDovepress\nDovepress\n2566\nChen et al\ndecreasing with minute ventilation. Despite differences in\nairway volume and internal surface area, variability between\nreplicas remained small compared to the mean (standard\ndeviation ,5% relative to the mean).\nPressure drop measurements\nFigure 6 shows the variation of pressure drop at the cannula\nfor each of the 15 replicas with a steady inhalation flow rate.\nDifferences between replicas increased sharply with increas-\ning flow rate. On the whole, most MR imaging replicas tended\ntoward the low end of pressure drops.\nPredicting PF Fi\nO2\nPF Fi\nO2\nvalues estimated using Equation 5 and PF Fi\nO2\nvalues derived from airway replica experiments are plotted\nin Figure 7. Overall, Equation 5 consistently overpredicted\naverage Fi\nO2\n, but by a small margin. This margin increased as\nthe setting number increased from 2.0 to 6.0 for both pulse\nmode and sleep mode, but no definite trend was observed as\nthe breathing pattern was varied.\nDiscussion\nWe developed an in vitro model that enabled us to measure\nreal-time Fi\nO2\nvalues at the trachea while maintaining precise\ncontrol of both breathing rate and tidal volume. This model\nwas used to compare oxygen delivery between SF and PF\ndelivery modes of a commercial POC under realistic trigger-\ning conditions, and to determine if oxygen pulse characteris-\ntics could adequately predict PF oxygen delivery.\nComparison with the in vivo case\nSince Fi\nO2\nvaries over the course of a breath during deliv-\nery of supplemental oxygen, it is challenging to accurately\nmeasure the amount of oxygen inhaled per breath in vivo.\nO\u2019Reilly Nugent et al30\nmonitored oxygen concentration at the\ntrachea in vivo (sampled through a catheter) during oxygen\ndelivery via nasal cannula for 20 adult subjects throughout\ninspiration, and calculated time-averaged Fi\nO2\nvalues. For\nsubjects breathing at a rate of 15 breaths\/min receiving\nsupplemental SF oxygen at a rate of 2.0 L\/min, time-averaged\ntracheal Fi\nO2\nranged from 25% to 32%. When applying a\nsimilar time-averaging procedure to oxygen concentration\nFigure 4 Comparison of volume-averaged Fi\nO2\nat SF 2.0 L\/min and PF setting\nnumber 2.0, averaged over n different airway replicas, measured using five successive\nbreaths per replica.\nNotes: For exercise and rest breathing patterns, n=15. For the sleep breathing\npattern combined with pulse mode, n=12; with sleep mode, n=14. Error bars\nindicate one standard deviation.\nAbbreviations: Fi\nO2\n, fraction of inspired oxygen; SF, steady flow; PF, pulse flow.\n\u0016\u0015\n\u0015\u0013\n\u0015\u0015\n\u0015\u0017\n\u0015\u0019\n\u0015\u001b\n\u0016\u0013\n5HVW\n([HUFLVH\n%UHDWKLQJ\u0003SDWWHUQ\n)\nL\n2\n\u0015\n\u0003\n\b\n6OHHS\n6) 3XOVH\u0003PRGH 6OHHS\u0003PRGH\n\u0018\u0013\n\u0015\u0013\n\u0015\u0018\n\u0016\u0013\n\u0016\u0018\n\u0017\u0013\n\u0017\u0018\n5HVW\n([HUFLVH\n%UHDWKLQJ\u0003SDWWHUQ\n)\nL\n2\n\u0015\n\u0003\n\b\n6OHHS\n6) 3XOVH\u0003PRGH 6OHHS\u0003PRGH\nFigure 5 Comparison of volume-averaged Fi\nO2\nat SF 6.0 L\/min and PF setting\nnumber 6.0, averaged over n different airway replicas, measured using five successive\nbreaths per replica.\nNotes: For exercise and rest breathing patterns, n=15. For the sleep breathing\npattern combined with pulse mode, n=11; with sleep mode, n=14. Error bars\nindicate one standard deviation.\nAbbreviations: Fi\nO2\n, fraction of inspired oxygen; SF, steady flow; PF, pulse flow.\nFigure 6 Pressure drop measured at the cannula as a function of inspiratory flow\nrate, averaged over three measurements for all 5 MRI subjects.\nNote: Error bars represent one standard deviation.\nAbbreviations: CT, computed tomography; MRI, magnetic resonance imaging.\n\u0013\n\u0013\n\u0014\u0013\n\u0014\u0013\n\u0015\u0013\n\u0015\u0013\n\u0016\u0013\n,QVSLUDWRU\\\u0003IORZ\u0003UDWH\u0003 \/\u0012PLQ\n3UHVVXUH\u0003GURS\u0003DW\nFDQQXOD\u0003\n3D\n\u0016\u0013\n\u0017\u0013\n\u0017\u0013\n\u0018\u0013\n\u0018\u0013\n\u0019\u0013\n\u001a\u0013\n\u001b\u0013\n\u001c\u0013\n\u0014\u0013\u0013\n6XEMHFW\u0003&7\u0014\n6XEMHFW\u0003&7\u0015\n6XEMHFW\u0003&7\u0016\n6XEMHFW\u0003&7\u0017\n6XEMHFW\u0003&7\u0018\n6XEMHFW\u0003&7\u0019\n6XEMHFW\u0003&7\u001a\n6XEMHFW\u0003&7\u001b\n6XEMHFW\u0003&7\u001c\n6XEMHFW\u0003&7\u0014\u0013\n6XEMHFW\u000305,\u0015\n6XEMHFW\u000305,\u0018\n6XEMHFW\u000305,\u0019\n6XEMHFW\u000305,\u001b\n6XEMHFW\u000305,\u001c\nInternational Journal of COPD 2017:12 submit your manuscript | www.dovepress.com\nDovepress\nDovepress\n2567\nPulsed versus continuous oxygen in airway replicas\ndata at similar settings (SF 2.0 L\/min, 13 and 17 breaths\/min)\nobtained during in vitro experiments in the present study,\nwe obtained an Fi\nO2\nrange of 26%\u201331%, which is in good\nagreement with the in vivo data.\nOn the other hand, the volume-averaged Fi\nO2\nreported in\nthe present study is consistently 1%\u20133% O2\n(absolute) lower\nthan our own calculated time-averaged values. The volume-\naveraged values are considered to be more pertinent here to\nsupplemental oxygen delivery compared to procedures that\nsimply average by time, as high instantaneous inhaled oxygen\nconcentrations may coincide with relatively low inspiratory\nflow rates near the start of the breath (and thus simple time-\naveraging procedures overweigh the contribution of these\ntransient peaks in concentration).\nThese considerations touch on what Fi\nO2\nactually rep-\nresents. Waldau et al31\nnote that\nthe efficacy of oxygen therapy can be evaluated by a number\nof methods that reflect different steps in the oxygenation\nprocess depending on the sampling site.\nIn other words, Fi\nO2\nhas been considered as the concentra-\ntion of inspired oxygen anywhere from a position within\nthe patient interface to the alveoli (estimated based on\nmeasurements in the exhalation gas).31,32\nIt has been noted that\nmeasurements in the upper airways can be compromised by\nincomplete mixing of oxygen with inhaled air such that \u201cgas\ncan be sampled at a more distal point, preferably the trachea,\nwhere gas mixing is more assured.\u201d33\nRegarding estimates\nbased on exhaled gas, homogeneous gas distribution in the\nlung must be assumed; an assumption that certainly does\nnot apply for all patients. Thus, the bench model employed\nhere where flow and concentration measured in the trachea\nare measured and integrated over the whole breath allows\nfor a very robust approach that can account for variations in\nbreathing parameters and delivery devices. Further account-\ning for myriad factors affecting alveolar gas concentrations\nand oxygen uptake, including gas transport and mixing\nthrough the airspaces of the lung and the diffusion capacity\nof the lung, may be best left to computational modeling.9\nIn vitro measurement of tracheal oxygen concentrations\nover the breath, as presented here for example, in Figure 3,\nwould serve as valuable input to such computational models.\nIn clinical practice, noting both the variability in oxygen\ndelivery to the trachea measured in the present study with\nexisting delivery systems, plus the additional intersubject\nand intrasubject variability that surely exists in oxygen\nFigure 7 Comparison of volume-averaged Fi\nO2\nestimated from airway experiments and Fi\nO2\npredicted using pulse characteristics.\nNotes: Airway experiment Fi\nO2\nvalues were averaged over n airway replicas, measured using five successive breaths per replica. For all experiments with exercise and rest\nbreathing patterns, n=15. For the sleep breathing pattern combined with pulse mode setting number 2.0, n=12; with pulse mode setting number 6.0, n=11; with sleep mode\nsetting numbers 2.0 and 6.0, n=14. Error bars indicate one standard deviation.\nAbbreviation: Fi\nO2\n, fraction of inspired oxygen.\n([HUFLVH\nSXOVH\nPRGH\u0003\u0015\u0011\u0013\n\u0015\u0013\n\u0015\u0018\n\u0016\u0013\n\u0016\u0018\n\u0017\u0013\n\u0017\u0018\n([HUFLVH\nSXOVH\nPRGH\u0003\u0019\u0011\u0013\n5HVW\nSXOVH\nPRGH\u0003\u0015\u0011\u0013\n5HVW\nSXOVH\nPRGH\u0003\u0019\u0011\u0013\n%UHDWKLQJ\u0003SDWWHUQ\u0003DQG\u0003GHYLFH\u0003VHWWLQJ\n)\nL\n2\n\u0015\n\u0003\n\b\n6OHHS\nSXOVH\nPRGH\u0003\u0015\u0011\u0013\n6OHHS\nSXOVH\nPRGH\u0003\u0019\u0011\u0013\n6OHHS\nVOHHS\nPRGH\u0003\u0015\u0011\u0013\n6OHHS\nVOHHS\nPRGH\u0003\u0019\u0011\u0013\n$LUZD\\\u0003H[SHULPHQWV 3XOVH\u0003FKDUDFWHULVWLFV\nInternational Journal of COPD 2017:12\nsubmit your manuscript | www.dovepress.com\nDovepress\nDovepress\n2568\nChen et al\ntransport and diffusion capacity, evaluation of oxygenation\non an individual and ongoing basis, for example, using pulse\noximetry, is advisable.\nBreath detection in POCs\nChatburn and Williams found that trigger pressures in five\ncommercial POCs ranged from 14 to 22 Pa.14\nSince inspira-\ntory flow rates in the sleep breathing pattern reach a maxi-\nmum of ~27 L\/min, Figure 6 implies that at or below that\nflow rate, a commercial POC would be unlikely to detect the\ninitiation of a breath in several of the replicas (,10 Pa).\nWhile the exact mechanisms of and conditions for breath\ndetection in this specific POC are unknown, given that, in\ngeneral, negative pressure sensors are frequently used for\nbreath detection in POCs, we hypothesize that a low pres-\nsure drop at the nasal cannula may contribute to problems\nin POC breath detection.\nComparison of SF and PF delivery\nPF Fi\nO2\nvalues are consistently lower than those at equivalent\nSF rates. This difference increased with decreasing minute\nventilation (ie, with the sleep breathing pattern having the\ngreatest difference). The higher pulse volumes delivered\nby the sleep mode relative to pulse mode translated into\nrelatively higher (but still not equivalent to SF) Fi\nO2\nvalues,\ndespite a higher prevalence of incomplete pulse delivery\nwhen using the sleep mode. Our data show that, for the\nSimplyGo POC, the nominal PF setting and the SF flow rate\nare not equivalent when assessed using Fi\nO2\n.\nThe increased prevalence of incomplete pulse delivery\nin the sleep breathing pattern very likely contributes to the\nminute ventilation-PF\/SF trend described above. As part of\nthe oxygen bolus remains in the upper airways at the start\nof exhalation, Fi\nO2\nwill be lower as a result.\nAt first glance, one might expect that the increased breath-\ning frequency of the high minute ventilation exercise breath-\ning pattern would lead to more frequent incomplete pulse\ndeliveries (on account of shortened breathing times). While\nwe did observe some cases of incomplete pulse delivery in\nthe exercise case due to the above effect, these instances still\nremained more infrequent than in the sleep case. This may be\ndue to two factors: 1) the time taken for an oxygen pulse to\narrive at the trachea in sleep breathing patterns is the longest\nof all three patterns, and 2) measured pulse durations were\nsignificantly longer for the sleep breathing pattern than they\nwere for the other two patterns. While measurement of pulse\ncharacteristics using the O2\nConserver Test System confirmed\nthe latter factor, rigorous demonstration of the former factor,\nthe influence of pulse arrival time, would require the ability\nto distinguish oxygen in the emitted pulse from oxygen\nentrained from ambient air. This was not possible given our\nexperimental setup. To qualitatively demonstrate the effect\nof pulse arrival time, we can utilize Figure 2. Sudden drops\nin oxygen concentration near the start of inspiration occur\ndue to the temporary absence of supplemental oxygen. When\nconcentration increases again, the pulse has arrived at the\ntrachea. Therefore, in pulse delivery oxygen waveforms,\nthe time it takes for the oxygen concentration to arrive at a\ntemporary minimum after the start of inspiration indicates\nroughly how long it takes the pulse to arrive at the trachea.\nIn Figure 3C (sleep breathing pattern), these times tend\nto be much longer than those in Figure 3B (rest breathing\npattern). If one considers changes in inspiration flow rates\nbetween these two breathing patterns, this is to be expected.\nBecause the ramp-up of inspiration flow rate slows down as\nminute ventilation decreases, the negative pressure trigger\nthreshold is reached later in the course of inspiration. Pulse\narrival times will also vary due to differences in individual\nairway geometries; thus, only some of the airway replicas\ntested resulted in incomplete pulse delivery.\nThe commercial O2\nConserver Test System is able to\nmeasure a pulse delay, representative of the time required\nfor a pulse to arrive at the machine measured from when the\nmachine attempts to trigger the POC. These pulse delays were\nconstant across all breathing frequencies tested (110 ms);\nhowever, the ramp-up of flow rate is absent in the O2\nCon-\nserver Test System testing protocol; thus, these pulse delays\nare not equivalent to the pulse arrival times discussed above.\nUse of realistic airway replicas, as in the present experiments,\ntherefore provides a test platform through which interac-\ntion between simulated breathing patterns and nasal airway\ngeometry can be explored, and may be more representative of\nin vivo oxygen delivery via nasal cannula. Even so, the ability\nof the limited set of 15 realistic nose\u2013throat airway replicas\nused herein to adequately capture variability in airway geom-\netry in the much larger population of COPD patients receiving\nsupplemental oxygen is unknown. Accordingly, variation\nbetween replicas in volume-averaged Fi\nO2\n(Figures 4 and\n5), in triggering pressure measured at the cannula (Figure 6),\nand in complete versus incomplete pulse delivery (Table 4),\nshould be interpreted as illustrative, rather than representa-\ntive, of variability occurring in the larger population.\nAnother difference between SF and PF delivery is in the\npooling effect of the anatomic reservoir during SF delivery.\nZhou and Chatburn examined the effect of elimination of\nthe anatomic reservoir on Fi\nO2\nin SF oxygen delivery.16\nInternational Journal of COPD 2017:12 submit your manuscript | www.dovepress.com\nDovepress\nDovepress\n2569\nPulsed versus continuous oxygen in airway replicas\nThey found that Fi\nO2\nwas reduced in breathing in which\nthe pooling effect of the anatomic reservoir was removed.\nIn those breathing waveforms, expiratory flow was not\nallowed to slowly decay to zero, which shortened the period\nof time in which expiratory flow was sufficiently low to per-\nmit supplemental oxygen to pool in the nasal airway. In the\npresent study, the time needed for expiratory flow to reach\nzero is shorter in the exercise breathing pattern than in the rest\nor sleep breathing patterns, on account of an increased tidal\nvolume and breathing rate. Therefore, one would expect the\nmagnitude of the pooling effect to increase as the tidal volume\nand breathing rate decrease. The effect of the anatomic\nreservoir would be greatest for the sleep breathing pattern\nand smallest for the exercise breathing pattern. In contrast,\nbecause of the absence of end-expiratory oxygen flow, the\nanatomic reservoir has no effect on oxygen delivery in PF.\nAs such, one would expect the discrepancy between SF and\nPF Fi\nO2\nto grow as tidal volume decreases and breathing\nslows down, as observed in Figures 3 and 4.\nPredicting PF Fi\nO2\nbased on pulse\ncharacteristics\nPF Fi\nO2\nestimated using real-time oxygen concentrations\nand PF Fi\nO2\ncalculated by way of Equation 5 using pulse\ncharacteristics were generally in agreement. However, since\nabsolute differences in Fi\nO2\nof 1% may be clinically signifi-\ncant in long-term therapy, we can conclude that while usage\nof pulse characteristics alone is sufficient to predict oxygen\ndelivery for many conditions, testing using realistic airway\nreplicas is still useful in some cases where calculation using\npulse characteristics might significantly overpredict POC per-\nformance (eg, sleeping patients at high setting numbers).\nStudy limitations\nAlthough the present testing methodology can be seen as\nan improvement of past attempts to precisely quantify the\namount of oxygen inspired during supplemental oxygen\ntherapy, several limitations can be noted. First, the results\npresented above are specific to a single POC, and therefore\ndo not reflect the performance of POCs in general. Expanded\ntesting, using the present methodology, may provide valuable\ninformation describing relative oxygen delivery from differ-\nent POCs operating at nominally equivalent pulse settings.\nIn addition, medical images upon which the airway rep-\nlicas are based were acquired in awake subjects during tidal\nbreathing. Therefore, they do not encompass any changes to\nthe upper airway geometry that may occur during sleep or at\nhigh minute ventilation during exercise.\nFurther, the lack of oxygen uptake in the test lung places\na limit on our ability to accurately predict Fi\nO2\nin a clinical,\nrather than benchtop, setting. Because breathing involves\nre-inhalation of gas from the conducting airways, the concen-\ntration of oxygen exhaled from gas-exchange regions of the\nlungs, and subsequently re-inhaled, is relevant in determin-\ning Fi\nO2\n. As there is no analog present for alveolar oxygen\nuptake in the lung simulator used in this study, any amount\nof supplementary oxygen supplied will, over time, increase\nthe inner chamber oxygen concentration (analogous to the\nalveolar oxygen concentration). In the in vivo case, oxygen is\nconstantly being removed through the alveoli into the blood,\nthus decreasing the oxygen concentration of the exhaled gas.\nTo demonstrate this effect, we can consider what happens\nwhen Equation 1 is modified to include a nonzero term for\noxygen uptake into the blood.\nV X V X V V V X\nV X\nAW O c pulse O pulse T AW pulse O ambient\nT O\n2 2 2\n2\n, , ,\n( )\n(\n+ + \u2212 \u2212\n\u2212 ,\n, ,\n)\nc O uptake\n+ =\nV 2\n0\n\b(6)\nVO2,uptake\nrepresents a volume of oxygen that is drawn into the\nblood in a single breath. Rearranging Equation 6, we can\nobtain a modified version of Equation 4.\nX\nX\nV\nV V\nX X\nV\nO c\nO ambient\npulse\nT AW\nO pulse O ambient\nO\n2\n2 2 2\n2\n,\n, , ,\n,\n( )\n=\n+\n\u2212\n\u2212 \u2212\nu\nuptake\nT AW\nV V\n\u2212\n\b (7)\nSince all values in the final term on the right hand side\nof Equation 7 are greater than zero, XO2,c\ncalculated using\nEquation 7 will always be lower than XO2,c\ncalculated using\nEquation 4.\nIncomplete pulse delivery also has implications on\noxygen delivery to the lungs beyond what is observed in its\neffect on Fi\nO2\nevaluated at the trachea. In cases of incom-\nplete pulse delivery, less of the pulse is able to travel past\nthe trachea and into the lungs. However, our reported Fi\nO2\n\u00ad\u00ad\nvalues do not account for a portion of the oxygen pulse that\nis immediately exhaled from the dead space of the tracheo-\nbronchial airways. When assessing oxygen delivery to the\ngas-exchange regions of the lungs, modeling the transport of\noxygen from the trachea through a multi-generation airway\ntree may provide a more complete picture.9\nAdditional future work may also involve comparisons of\noxygen delivery in closed versus open mouth breathing, in\nchildren versus adults, or in diseased versus healthy lungs.\nInternational Journal of COPD 2017:12\nsubmit your manuscript | www.dovepress.com\nDovepress\nDovepress\n2570\nChen et al\nThe effect of mouth breathing versus nose breathing, or open\nversus closed mouth position,31\nis especially relevant during\nsleep and exercise.\nConclusion\nThis study examined a benchtop testing method for assessing\nPOC performance using realistic airway models and real-\ntime monitoring of inspired oxygen concentrations at the\ntrachea. Testing using nasal airway replicas derived from\nmedical imaging and simulated breathing patterns permitted\noxygen delivery from a POC to be evaluated under realistic\ntriggering conditions.\nBased on the measurement of volume-averaged tra-\ncheal Fi\nO2\nfor the POC studied, PF delivered consistently\nlower amounts of oxygen than SF at flow rates equivalent\nto nominal PF settings. Differences were largest when the\nhigher PF setting was combined with breathing parameters\ntypical of sleeping patients. We hypothesize that this differ-\nence is primarily due to two factors: 1) the increased effect\nof oxygen pooling for SF in the anatomic reservoir during\nslower, shallower breathing, and 2) a delay in the arrival of\nthe pulse, which leads to retention in the upper airways and\nexhalation of part of the oxygen bolus.\nAcknowledgments\nThe authors would like to thank Cole Christianson for his\nwork in measuring airway replica pressure drops, Kelvin\nDuong for his help in analyzing raw data, Eric Bracke for con-\ntributions to building the CT replicas, and Dr Jo\u00eblle Texereau\nfor reviewing and providing helpful comments on an earlier\nversion of this manuscript. This work was funded by Air\nLiquide and by Alberta Economic Development and Trade\nand benefited from an equipment grant from the Canadian\nNatural Sciences and Engineering Research Council.\nDisclosure\nIMK, MP, KZ, and GC are current employees of Air Liquide,\na major provider of home oxygen therapy. The authors report\nno other conflicts of interest in this work.\nReferences\n1. McCoy R. Oxygen-conserving techniques and devices. Respir Care.\n2000;45(1):95.\n2. Gustafson JD, Yang S, Blakeman TC, Dorlac WC, Branson R. Pulsed\ndosed delivery of oxygen in mechanically ventilated pigs with acute lung\ninjury. J Trauma Acute Care Surg. 2013;75(5):775.\n3. Blakeman TC, Rodriquez D, Britton TJ, Johannigman JA, Petro MC,\nBranson RD. Evaluation of oxygen concentrators and chemical oxygen\ngenerators at altitude and temperature extremes. Mil Med. 2016;\n181(5 Suppl):160\u2013168.\n4. Blakeman TC, Rodriquez D, Gerlach TW, Dorlac WC, Johannigman JA,\nBranson RD. Oxygen requirement to reverse altitude-induced\nhypoxemia with continuous flow and pulsed dose oxygen. Aerosp\nMed Hum Perform. 2015;86(4):351\u2013356.\n5. Y\u00e1\u00f1ez AM, Prat JP, \u00c1lvarez-Sala JL, et al. Oxygenation with a single\nportable pulse-dose oxygen-conserving device and combined stationary\nand portable oxygen delivery devices in subjects with COPD. Respir\nCare. 2015;60(3):382\u2013387.\n6. Byron PR, Hindle M, Lange CF, et al. In vivo\u2013in vitro correlations:\npredicting pulmonary drug deposition from pharmaceutical aerosols.\nJ Aerosol Med Pulm Drug Deliv. 2010;23(Suppl 2):S59\u2013S69.\n7. Sandeau J, Katz I, Fodil R, et al. CFD simulation of particle deposition\nin a reconstructed human oral extrathoracic airway for air and helium\u2013\noxygen mixtures. J Aerosol Sci. 2010;41(3):281\u2013294.\n8. Airsep Freestyle Patient Manual. MN123-1 rev E 11\/12. Buffalo, NY,\nUSA: AirSep.\n9. Katz I, Pichelin M, Montesantos S, et al. An in silico analysis of oxygen\nuptake of a mild COPD patient during rest and exercise using a por-\ntable oxygen concentrator. Int J Chron Obstruct Pulmon Dis. 2016;11:\n2427\u20132434.\n10. Garrod R, Bestall E, Paul E, Wedzicha JA. Evaluation of pulsed dose\noxygen during exercise in patients with severe chronic obstructive\npulmonary disease. Thorax. 1999;54:242\u2013244.\n11. CarterR,TashkinD,DjahedB,HathawayE,NicotraB,TiepBL.Demand\noxygen delivery for patients with restrictive lung disease. Chest. 1989;\n96:1307\u20131311.\n12. Braun SR, Spratt G, Graham SC, Ellersieck M. Comparison of six\noxygen delivery systems for COPD patients at rest and during exercise.\nChest. 1992;102:694\u2013698.\n13. Palwai A, Skowronski M, Coreno A, Drummond C, McFadden ER Jr.\nCritical comparisons of the clinical performance of oxygen-conserving\ndevices. Am J Respir Crit Care Med. 2010;181(10):1061\u20131071.\n14. Chatburn RL, Williams TJ. Performance comparison of 4 portable\noxygen concentrators. Respir Care. 2010;55(4):433\u2013442.\n15. Bliss PL, McCoy RW, Adams AB. Characteristics of demand oxygen\ndelivery systems: maximum output and setting recommendations.\nRespir Care. 2004;49(2):160\u2013165.\n16. Zhou S, Chatburn RL. Effect of the anatomic reservoir on low-flow\noxygen delivery via nasal cannula: constant flow versus pulse flow with\nportable oxygen concentrator. Respir Care. 2014;59(8):1199.\n17. Grgic B, Finlay WH, Burnell PKP, Heenan AF. In vitro intersubject\nand intrasubject deposition measurements in realistic mouth\u2013throat\ngeometries. J Aerosol Sci. 2004;35(8):1025\u20131040.\n18. Golshahi L, Vehring R, Noga ML, Finlay WH. In vitro deposition of\nmicrometer-sized particles in the extrathoracic airways of children\nduring tidal oral breathing. J Aerosol Sci. 2013;57:14\u201321.\n19. Martin AR, Katz IM, Lipsitz Y, Terzibachi K, Caillibotte G, Texereau J.\nMethods for evaluation of helium\/oxygen delivery through non-\nrebreather facemasks. Med Gas Res. 2012;2(1):31.\n20. Golshahi L, Noga ML, Thompson RB, Finlay WH. In vitro deposition\nmeasurement of inhaled micrometer-sized particles in extrathoracic\nairways of children and adolescents during nose breathing. J Aerosol\nSci. 2011;35(4):1.\n21. Finlay WH. The Mechanics of Inhaled Pharmaceutical Aerosols: An\nIntroduction. San Diego: Academic Press; 2001.\n22. Knoch M, Wunderlich E. Effect of age related breathing parameters on\nthe performance of a new nebulizer system: an in vitro study. J Aerosol\nMed. 1995;8(3):285\u2013288.\n23. Coates AL, Macneish CF, Allen PD, Ho SL, Lands LC. Do sinusoidal\nmodels of respiration accurately reflect the respiratory events of patients\nbreathing on nebulizers? J Aerosol Med. 1999;12(4):265\u2013273.\n24. Prokop RM, Finlay WH, Stapleton KW. An in vitro technique for\ncalculating the regional dosages of drugs delivered by an ultrasonic\nnebulizer. J Aerosol Sci. 1995;26(5):847\u2013860.\n25. Weber A, Morlin G, Cohen M, Williams-Warren J, Ramsey B,\nSmith A. Effect of nebulizer type and antibiotic concentration on device\nperformance. Pediatr Pulmonol. 1997;23(4):249\u2013260.\nInternational Journal of COPD\nPublish your work in this journal\nSubmit your manuscript here: http:\/\/www.dovepress.com\/international-journal-of-chronic-obstructive-pulmonary-disease-journal\nThe International Journal of COPD is an international, peer-reviewed\njournal of therapeutics and pharmacology focusing on concise rapid\nreporting of clinical studies and reviews in COPD. Special focus is given\nto the pathophysiological processes underlying the disease, intervention\nprograms, patient focused education, and self management protocols.\nThis journal is indexed on PubMed Central, MedLine and CAS. The\nmanuscript management system is completely online and includes a\nvery quick and fair peer-review system, which is all easy to use. Visit\nhttp:\/\/www.dovepress.com\/testimonials.php to read real quotes from\npublished authors.\nInternational Journal of COPD 2017:12 submit your manuscript | www.dovepress.com\nDovepress\nDovepress\nDovepress\n2571\nPulsed versus continuous oxygen in airway replicas\n26. Langer AW, Hutcheson JS, Charlton JD, McCubbin JA, Obrist PA,\nStoney CM. On-line minicomputerized measurement of cardiopulmo-\nnary function on a breath by breath basis. Psychophysiology. 1985;22(1):\n50\u201358.\n27. Chatila W, Nugent T, Vance G, Gaughan J, Criner GJ. The effects of\nhigh-flow vs low-flow oxygen on exercise in advanced obstructive\nairways disease. Chest. 2004;126(4):1108\u20131115.\n28. Hudgel DW, Martin RJ, Capehart M, Johnson B, Hill P. Contribution\nof hypoventilation to sleep oxygen desaturation in chronic obstructive\npulmonary disease. J Appl Physiol. 1983;55(3):669\u2013677.\n29. Moore CP, Finlay WH, Martin AR. Investigating intersubject variability\nin pulsed oxygen delivery using adult nasal airway replicas. Am J Respir\nCrit Care Med. 2015;191:A5811.\n30. O\u2019Reilly Nugent A, Kelly PT, Stanton J, Swanney MP, Graham B,\nBeckert L. Measurement of oxygen concentration delivered via nasal\ncannulae by tracheal sampling. Respirology. 2014;19(4):538\u2013543.\n31. Waldau T, Larsen VH, Bonde J. Evaluation of five oxygen delivery\ndevices in spontaneously breathing subjects by oxygraphy. Anaesthesia.\n1998;53:256\u2013263.\n32. Wettstein RB, Shelledy DC, Peters JI. Delivered oxygen concentra-\ntions using low-flow and high-flow nasal cannulas. Respir Care. 2005;\n50(5):604\u2013609.\n33. Casaburi R. Assessing the dose of supplemental oxygen: let us compare\nmethodologies. Respir Care. 2005;50(5):594\u2013595.","is_draft":"0","editor_type":"4","file_path":"\/docker_production\/zgvd51\/article\/a7lBKGwA\/article_file\/Comparison of pulsed versus continuous oxygen .pdf","add_time":"1757143060","update_time":"1757143080"},"pure_content":"\u00a9 2017 Chen et al. This work is published and licensed by Dove Medical Press Limited. The full terms of this license are available at https:\/\/www.dovepress.com\/terms.php\nand incorporate the Creative C"},{"id":"610665","string_id":"20q12kcQ","status":"1","parent_id":"610654","slug":"Comparison-of-continuous-flow-versus-demand-oxygen-delivery","order":"0","name":"Comparison of continuous flow versus demand oxygen delivery","type":"2","cover":"","cover_alt":"","desc":null,"website":"","contact":"","seo_title":"","seo_keyword":"","seo_desc":"","share_switch":"0","share_code":"","author":"","published_time":"1757143081","add_time":"1757143071","update_time":"1757143081","corp_auth_id":"0","verify_code_auth_id":"0","editor_type":"4","file_type":"pdf","auth_id":"[\"610665\", \"610654\"]","content":{"content_id":"610665","content":"SYSTEMATIC REVIEW\nComparison of continuous \ufb02ow versus demand oxygen delivery\nsystems in patients with COPD: A systematic review\nand meta-analysis\nRAINER GLOECKL,1,2*,\nCHRISTIAN OSADNIK,3,4* LISA BIES,2\nDANIELA LEITL,1\nANDREAS-REMBERT KOCZULLA1,5\nAND KLAUS KENN1,5\n1\nInstitute for Pulmonary Rehabilitation Research, Schoen Klinik Berchtesgadener Land, Schoenau am Koenigssee, Germany;\n2\nDepartment of Prevention, Rehabilitation and Sports Medicine, Technical University of Munich (TUM), Munich, Germany;\n3\nDepartment of Physiotherapy, Monash University, Melbourne, VIC, Australia; 4\nMonash Health, Monash Lung and Sleep,\nMelbourne, VIC, Australia; 5\nDepartment of Pulmonary Rehabilitation, Philipps-University of Marburg, German Center for Lung\nResearch (DZL), Marburg, Germany\nABSTRACT\nDemand oxygen delivery systems (DODS) enable pro-\nlongation of liquid oxygen cylinder life compared to\ncontinuous oxygen \ufb02ow (CONT) use. Evidence is lack-\ning, however, regarding their ef\ufb01cacy. This study inves-\ntigated the literature comparing liquid-based CONT to\nDODS in patients with chronic obstructive pulmonary\ndisease (COPD). Four electronic databases were\nsearched from 1980 until January 2018. Primary out-\ncomes were oxyhaemoglobin saturation (SpO2%) at rest\nand during exercise and exercise performance. Risk of\nbias was evaluated using the Cochrane tool. Data were\nanalysed via meta-analysis where possible using the\ngeneric inverse variance method in Revman 5.3 or nar-\nrative synthesis. Ten crossover trials involving\n152 patients with moderate to severe COPD (forced\nexpiratory volume in 1 s (FEV1) range: 27\u201342% pre-\ndicted) were included. There was a large degree of\nuncertainty regarding potential bias related to alloca-\ntion concealment and blinding for all studies. Data from\nthree studies (n = 44) showed no signi\ufb01cant differences\nbetween DODS and CONT in terms of SpO2% at rest\n\u22120.2% (95% CI: \u22120.5% to 0.1%) or during exercise\n\u22120.3% (95% CI: \u22122.1% to 1.5%). The pooled mean dif-\nference of two studies (n = 56) in 6-min walk distance\nwas 5.7 m (95% CI: \u221214.4 to 25.8 m). Findings were\nconsistent between the meta-analysis and narrative syn-\nthesis. These \ufb01ndings from a limited number of studies\nsuggest oxygen delivery via DODS or CONT confers sim-\nilar effects in terms of SpO2% or exercise performance\nin patients with COPD. However, as DODS devices use\nvarious speci\ufb01cations that may yield large intra-\nindividual differences, individual SpO2% testing appears\nadvisable for those considering DODS use.\nKey words: chronic obstrutive pulmonary disease, hypox-\nemia, oxygen therapy, oxygen device.\nINTRODUCTION\nLong-term oxygen therapy (LTOT) for patients with\nchronic obstructive pulmonary disease (COPD) and\nchronic hypoxia is a crucial therapy that aims to\nimprove survival.1,2\nIn these individuals, use of supple-\nmental oxygen during exercise may also be associated\nwith reduced exertional oxyhaemoglobin desaturation\nand increased exercise performance.3\nOxygen therapy is\nusually applied via nasal cannula connected to station-\nary or portable continuous oxygen \ufb02ow (CONT) sys-\ntems, however signi\ufb01cant oxygen wastage occurs due to\nunnecessary \ufb02ow during expiration. This reduces the\nlife of portable liquid-based oxygen devices which may\nsubsequently impair mobility and independence.4\nOxygen conservation devices therefore emerged\n(since the 1980s) with demand oxygen delivery system\n(DODS) being one of the most common technologies.\nDODS deliver a pre-set bolus of oxygen during the \ufb01rst\npart of inspiration,5\ntriggered by a sensor that detects\nnegative pressure within the nares.6\nNo \ufb02ow is pro-\nvided during expiration. However, despite technologi-\ncal advancements and widespread commercial\navailability, evidence regarding the ef\ufb01cacy of DODS\ncompared to CONT has been lacking.7,8\nThis is essential\nto clarify as concerns exist regarding the ability of\nDODS to meet respiratory demands in some situations.\nFor example, dyssynchrony between triggering and\ninspiration may result in poorly timed gas delivery,\nwhile breathing pattern differences between the resting\nstate and active exertion may limit the effectiveness of\nDODS during times of high peak inspiratory \ufb02ow\ndemand such as exercise.\nPortable oxygen concentrators have also recently\nemerged as alternate delivery systems for patients\nCorrespondence: Rainer Gloeckl, Institute for Pulmonary\nRehabilitation Research, Schoen Klinik Berchtesgadener Land,\nMalterhoeh 1, 83471 Schoenau am Koenigssee, Germany.\nEmail: rainer.gloeckl@gmx.de\n*R.G. and C.O. contributed equally to the preparation of the\nmanuscript.\nReceived 30 May 2018; invited to revise 1 August and\n4 October 2018; revised 3 September and 25 October 2018;\naccepted 20 November 2018 (Associate Editor: Melissa\nJ. Benton; Senior Editor: Philip Bardin).\n\u00a9 2018 Asian Paci\ufb01c Society of Respirology Respirology (2018)\ndoi: 10.1111\/resp.13457\nrequiring LTOT. These units deliver oxygen via extrac-\ntion from ambient air rather than from a compressed\nliquid reservoir. While this mechanistic difference may\noffer bene\ufb01ts related to patient convenience and lower\ncylinder costs, it makes head-to-head comparisons\nbetween liquid-based and concentrator systems chal-\nlenging. For example, it would be dif\ufb01cult to ascertain\nwhether differences between portable oxygen concen-\ntrators and liquid cylinders + DODS should be attrib-\nuted to oxygen type, bolus volumes or issues related to\npeak inspiratory \ufb02ow rates.\nTo ensure that clinical decisions regarding oxygen\ndelivery devices are informed by the best available evi-\ndence, it is essential to identify the quality and quantity\nof available literature and ascertain its applicability to\nclinical practice. This study therefore aimed to review\nthe scienti\ufb01c literature comparing the effectiveness of\nliquid oxygen supplementation delivery via CONT or\nDODS at rest and during exercise in patients with COPD.\nMETHODS\nThis review and meta-analysis was performed accord-\ning to the Preferred Reporting Items for Systematic\nReviews and Meta-Analyses (PRISMA) Statement9\nand\nwas registered a priori at the international prospective\nregister of systematic reviews (PROSPERO at www.crd.\nyork.ac.uk under following ID: CRD42018081806).\nData sources and search strategy\nThe electronic databases PubMed (MEDLINE),\nEmbase, LILACS and Cochrane Library were searched\nfrom 1980 until 5 January 2018 with a strategy compris-\ning the following terms: chronic obstructive pulmonary\ndisease OR COPD AND oxygen therapy OR demand\noxygen system OR continuous \ufb02ow system OR oxygen\nconserving device OR long-term oxygen therapy. Refer-\nence lists of included studies were hand-searched for\nadditional literature.\nEligibility criteria\nFull text, original research articles were included if they\ncompared CONT supplemental oxygen delivery to\nDODS (both liquid-based) at rest and\/or during exer-\ncise applied via nasal cannula. Articles must have been\ncontrolled trials published in English or German lan-\nguage involving patients with COPD (or COPD patient\nsubgroup data available if mixed patient disease\ngroups). Studies comparing CONT to air or oxygen con-\ncentrator systems were ineligible, as were book chap-\nters, letters, unpublished work and study protocols.\nOutcomes\nTo identify evidence of physiological bene\ufb01t, this\nreview focused on short-term physiological and func-\ntional outcomes. The primary review outcome was oxy-\nhaemoglobin saturation (SpO2%) recorded at rest and\nduring exercise, derived from arterial blood gas sam-\npling or pulse oximetry. The secondary outcome was\nexercise performance, measured via \ufb01eld walking tests\nsuch as the 6-min walk test (6MWT) or shuttle walk\ntest. As we anticipated that most studies would be of a\n\u2018laboratory\u2019 nature, we did not include broader out-\ncomes such as quality of life (despite their clinical\nrelevance).\nData extraction and risk of bias assessment\nTwo independent reviewers (R.G. and L.B.) screened\npotentially eligible citations on title and abstract and\nclassi\ufb01ed them as \u2018include\u2019, \u2018exclude\u2019 or \u2018maybe\u2019. Those\ndeemed \u2018include\u2019 or \u2018maybe\u2019 were reviewed in full text.\nThe same two authors examined these studies to deter-\nmine suitability for inclusion, with any disagreements\nresolved by a third author (C.O.). A standardized data\ncollection form was used to extract information and out-\ncomes related to included studies. This was conducted\nby one member of the review team (L.B.) and with con-\n\ufb01rmatory checks of accuracy veri\ufb01ed by another team\nmember (D.L.). This template included data for all\nreview outcomes as well as study characteristics related\nto authors, country, year, baseline characteristics of\nstudy population, oxygen device used and CONT and\nDODS settings. The methodological quality of each\nincluded study was assessed using the Cochrane Collab-\noration\u2019s Risk of Bias tool.10\nEach included study was\nrated as low, high or unclear risk of bias by two inde-\npendent reviewers for the domains of selection, perfor-\nmance, detection, attrition, reporting and other bias.\nData analysis\nData were pooled, where possible, for meta-analysis\nusing RevMan 5.3 (The Cochrane Collaboration, Oxford,\nUK). As all included studies were crossover designs, we\nonly meta-analysed data that could be entered via the\ngeneric inverse variance method, and expressed \ufb01ndings\nas mean differences (DODS \u2212 CONT). Data were not\npooled where data were expressed in heterogeneous\nmetrics (e.g. 6MWT vs 12-min walk test (12MWT)).\nFindings deemed unsuitable for meta-analysis were syn-\nthesized narratively and presented in summary tables.\nStatistical heterogeneity was explored between studies\nusing the I2\nstatistic, with results <25% considered low,\n50\u201375% considered moderate and >75% considered\nhigh.11\nData were primarily pooled using a \ufb01xed-effect\nmodel; however, a random-effects model was used\nwhere moderate (or greater) heterogeneity was detected.\nPossible explanations for observed heterogeneity were\nexamined via exploratory sensitivity analyses involving\nremoval of outlying studies. Data related to SpO2% at\nrest and during exercise were pooled separately from\neach other to avoid introducing issues of data duplicity.\nMore Information on data analysis can be found in\nAppendix S1 (Supplementary Information).\nRESULTS\nAn overview of the study selection process (PRISMA\ndiagram) is provided in Figure 1. A total of 726 titles\nwere screened, resulting in the retrieval of 31 full-text\narticles for potential eligibility. Twenty-one studies\nwere excluded due to use of an inappropriate compara-\ntor intervention (e.g. ambient air, oxymizer pendants\n\u00a9 2018 Asian Paci\ufb01c Society of Respirology Respirology (2018)\n2 R Gloeckl et al.\nand oxygen concentrators; n = 18) or non-COPD\npatients (n = 3). The remaining 10 publications12\u201321\nwere included in the qualitative analysis (Table 1).\nThese studies comprised 152 patients with forced expi-\nratory volume in 1 s (FEV1) ranging from 27% to 42%\npredicted. Nine studies included patients with chronic\nhypoxia (partial pressure of oxygen in arterial blood\n(PaO2): 49 to 60 mm Hg at rest on room air) and one\nstudy15\nincluded patients who desaturated more than\n4% during a 6MWT (PaO2: 63 \u0006 9 mm Hg at rest on\nroom air). One study18\nincluded patients with COPD\nand interstitial lung disease; however, COPD-speci\ufb01c\ndata were available.\nRisk of bias assessment\nA summary of risk of bias judgments for included stud-\nies is presented in Figure 2. High risks related to selec-\ntion and performance bias were mostly con\ufb01ned to the\noutcome of exercise performance, as measures of oxy-\ngen saturation were deemed less likely to have been\naffected considering its physiological basis. Non-\nrandomized studies were deemed to be at high risk of\nselection and performance bias; however, the study of\nTiep et al.20\nwas rated unclear for performance bias as\ndata were only available for oxygen saturation. Blinding\nof patients or therapists to knowledge of treatment con-\ndition, whether stated, was not possible for any study\ndue to challenges concealing the audible noise and\nsensation during each oxygen bolus delivery for DODS.\nHigh ratings were only made for studies that included\ndata related to exercise performance. A high degree of\nuncertainty was evident for many domains of the risk\nof bias tool, likely driven by the less stringent reporting\nstandards required by the journals at the time of\npublication.\nPrimary outcome\nData regarding oxygen saturation at rest were available\nfrom six studies of 107 patients (Table 2),12,13,17,18,20,21\nwith three studies12,18,20\nproviding appropriate data for\nmeta-analysis. The pooled mean difference (DODS \u2212\nCONT) in oxygen saturation at rest was \u22120.2% (95% CI:\n\u22120.5% to 0.1%; Fig. 3A). Findings from studies unable\nto be included in the meta-analysis for this outcome\nreported differences ranging between \u22121.3% and 2.0%.\nData regarding oxygen saturation during exercise\nwere available from eight studies of 123 patients\n(Table 2),12\u201315,18\u201321\nwith three studies12,18,20\nproviding\nappropriate data for meta-analysis. The pooled mean\ndifference (DODS \u2212 CONT) in oxygen saturation dur-\ning exercise was \u22120.3% (95% CI: \u22122.1% to 1.5%; Fig. 3B).\nHigh statistical heterogeneity was detected (I2\n= 86%),\nhence a random-effect model was applied. This hetero-\ngeneity was attributable to the study data from Tiep\net al..20\nSensitivity analysis involving removal of this\nstudy from analysis fully corrected this observation\n(I2\n= 0%). Findings from studies unable to be included\nin the meta-analysis for this outcome reported differ-\nences ranging between \u22123.0% and 1.0%.\nSecondary outcome\nData regarding exercise performance were available\nfrom six studies of 107 patients (Table 3),13\u201315,18,19,21\nwith\ntwo studies18,21\nproviding appropriate data for meta-\nanalysis. The pooled mean difference (DODS \u2212 CONT)\nin exercise performance (6MWT distance) was 5.7 m\n(95% CI: \u221214.4 to 25.8 m; Fig. 3C). High statistical het-\nerogeneity was detected (I2\n= 89%), hence a random-\neffect model was applied. As only two studies were\nincluded in this meta-analysis, sensitivity analysis was\nnot indicated. Findings from studies unable to be\nincluded in the meta-analysis for this outcome\nreported highly comparable measures of exercise per-\nformance between groups (Table 3), with the exception\nof the study by Braun et al.13\nThis study evaluated exer-\ncise performance by the less common 12MWT but\nfound consistently higher values for the CONT condi-\ntion compared to three DODS devices. The difference\nranged from \u221262 m for the Oxymatic device to \u2212254 m\nfor the Portamate device, however, these differences\nwere not statistically signi\ufb01cant.\nFigure 1 PRISMA (Preferred Reporting\nItems for Systematic Reviews and Meta-\nAnalyses) diagram of study \ufb02ow.\nRespirology (2018) \u00a9 2018 Asian Paci\ufb01c Society of Respirology\nCONT versus DODS oxygen \ufb02ow in COPD 3\nTable\n1\nCharacteristics\nof\nincluded\nstudies\nAuthor,\nyear,\ncountry\nSample\nsize,\nn\n(sex)\nStudy\ndesign\nAge\nFEV\n1\n(%)\nPaO\n2\nat\nrest\n(mm\nHg)\nDODS\ndevice\ntested\n(manufacturer)\nDODS\nsetting\nCONT\nsetting\nTest\nat\nrest\nTest\nduring\nexercise\nBower,\n1988,\nUSA\n6\n(m\n=\n2,\nf\n=\n4)\nRandomized\ncrossover\n65\n\u0006\n10\nn.a.\n50\n\u0006\n6\nOxygen\nSaver\n(Puritan\nBennett)\nEquivalent\nto\n2\nL\/min\nCONT\nat\nrest\nand\nduring\nexercise\n2\nL\/min\nYes\n5\nmin\nof\ncomfortable\ntreadmill\nwalking\nBraun,\n1992,\nUSA\n10\n(m\n=\n10)\nRandomized\ncrossover\n59\n\u0006\n5\n27\n\u0006\n7\n50\n\u0006\n4\n1)\nOxymatic\n(Chad)\n2)\nPortamate\n(Bunn)\n3)\nOxygen\nsaver\n(Puritan\nBennett)\nO\n2\n\ufb02ow\nrate\nused\nwas\nequivalent\nto\nmanufacturer\nrecommendation\nfor\nthe\nprescribed\nCONT\nrate\nO\n2\n\ufb02ow\nrate\nas\nprescribed\n(mean:\n2.4\nL\/min)\nYes\n12MWT\nFuhrman,\n2004,\nFRA\n13\n(m\n=\n11,\nf\n=\n2)\nRandomized\ncrossover\n62\n\u0006\n10\n36\n\u0006\n12\n60\n\u0006\n5\n1)\nOxiclip\n(Puritan\nBennett)\n2)\nVenture\n(Invacare)\n3)\nVersatile\n(DeVilbiss)\n4)\nImpulse\n(Airsep)\nEquivalent\nto\n3\nL\/min\nCONT\nat\nrest\nand\nduring\nexercise\n3\nL\/min\nYes\n6MWT\nGarrod,\n1999,\nGBR\n14\n(n.a.)\nRandomized\ncrossover\n66\n(50\u201375)\n32\n\u0006\n9\n63\n\u0006\n9\nPulsedose\nEX\n2000\n(DeVilbiss)\nEquivalent\nto\n2\nL\/min\nCONT\nduring\nexercise\n2\nL\/min\nNo\nISWT\nJohann,\n2001,\nGER\n17\n(m\n=\n15,\nf\n=\n2)\nRandomized\ncrossover\n68\n\u0006\n10\n42\n\u0006\n20\n49\n\u0006\n7\n1)\nDOC-2000\n(TransTracheal\nSystems\nInc.)\n2)\nPulsair\n(DeVilbiss)\n3)\nOxytron\n2\n(Weinmann)\nEquivalent\nto\n2\nL\/min\nCONT\nat\nrest\nDOC:\n30\nmL\/inspiration\nPulsair:\n33\nmL\/inspiration\nOxytron:\n35\nmL\/\ninspiration\n2\nL\/min\nYes\nNo\nLangenhof,\n2005,\nGER\n13\n(m\n=\n10,\nf\n=\n3)\nRandomized\ncrossover\n65\n\u0006\n8\n28\n\u0006\n5\n56\n\u0006\n8\n1)\nEX\n3000\n(DeVilbiss)\n2)\nOxytron\n3\n(Weinmann)\nEquivalent\nto\n2\nL\/min\nCONT\nEX\n3000:\n33\nmL\/\ninspiration\nOxytron3:\n20\nmL\/\ninspiration\n2\nL\/min\nYes\nNo\nMarti,\n2013,\nESP\n28\n(m\n=\n23,\nf\n=\n5)\nRandomized\ncrossover\n66\n\u0006\n9\n31\n\u0006\n11\n60\n\u0006\n7\nSpirit\n300\n(Caire\nMedical)\nO\n2\n\ufb02ow\nrate\nwas\nincreased\nup\nto\nequivalence\nof\n6\nL\/min\nCONT\nto\nachieve\nSpO\n2\n\u2265\n90%\nO\n2\n\ufb02ow\nrate\nwas\nincreased\nto\nachieve\nSpO\n2\n\u2265\n90%\nduring\n6MWT\n(median:\n4\nL\/min)\nYes\n6MWT\nRoberts,\n1996,\nGBR\n15\n(m\n=\n9,\nf\n=\n6)\nRandomized\ncrossover\n68\n\u0006\n6\n31\n\u0006\n8\n52\n\u0006\n7\nOxymatic\n201\n(Chad)\nEquivalent\nto\n2\nL\/min\nCONT\nduring\nexercise\n2\nL\/min\nNo\n6MWT\n\u00a9 2018 Asian Paci\ufb01c Society of Respirology Respirology (2018)\n4 R Gloeckl et al.\nDISCUSSION\nThis review highlights a limited body of evidence upon\nwhich to formulate clinical decisions regarding liquid-\nbased oxygen supplementation for patients with COPD.\nThe available data suggest that use of DODS devices\nappear to confer minimal impact upon oxygen satura-\ntion and exercise performance compared to continuous\n\ufb02ow oxygen. These \ufb01ndings were very consistent\nbetween the meta-analysis as well as the raw data pre-\nsented in Tables 2 and 3. This reassures us of their abil-\nity to prolong cylinder life without risking therapeutic\neffectiveness. The study by Tiep et al.20\nwas the only\nnotable exception to this result, which reported \ufb01ndings\nfavouring CONT over DODS. This was one of the two\nTable\n1\nContinued\nAuthor,\nyear,\ncountry\nSample\nsize,\nn\n(sex)\nStudy\ndesign\nAge\nFEV\n1\n(%)\nPaO\n2\nat\nrest\n(mm\nHg)\nDODS\ndevice\ntested\n(manufacturer)\nDODS\nsetting\nCONT\nsetting\nTest\nat\nrest\nTest\nduring\nexercise\nTiep,\n2002,\nUSA\n9\n(n.a.)\nNon-randomized\ncrossover\n67\n\u0006\n7\nn.a.\nn.a.\nOxymatic\n401\n(Chad)\nO\n2\n\ufb02ow\nrate\nwas\nincreased\nbetween\n1\nand\n6\nL\/min\nto\nachieve\nequivalent\nsaturation\nof\nCONT\nOxymatic\n401:\n255\nmL\/\nmin\nO\n2\n\ufb02ow\nrate\nas\nprescribed\n(mean:\n1.7\nL\/min)\nYes\nSubmaximal\ntreadmill\nwalking\nfor\n2\nmin\nat\n1.5mi\/h\nWeber,\n2006,\nGER\n27\n(m\n=\n12,\nf\n=\n15)\nNon-randomized\ncrossover\n66\n\u0006\n9\n44\n\u0006\n18\n55\n\u0006\n7\nSpirit\n300\n(Caire\nMedical)\nEquivalent\nto\n2\nL\/min\nCONT\n2\nL\/min\nNo\n6MWT\n6MWT,\n6-min\nwalk\ntest;\n12MWT,\n12-min\nwalk\ntest;\nCONT,\ncontinuous\noxygen\n\ufb02ow;\nDODS,\ndemand\noxygen\ndelivery\nsystem;\nf,\nfemale;\nFEV\n1\n,\nforced\nexpiratory\nvolume\nin\n1\ns;\nISWT,\nincre-\nmental\nshuttle\nwalk\ntest;\nm,\nmale;\nn.a.,\nnot\navailable;\nPaO\n2\n,\npartial\npressure\nof\noxygen\nin\narterial\nblood;\nSpO\n2\n,\noxyhaemoglobin\nsaturation.\nFigure 2 Risk of bias summary for included studies (red shad-\ning denotes high risk of bias, yellow shading denotes unclear\nrisk of bias and green denotes low risk of bias).\nRespirology (2018) \u00a9 2018 Asian Paci\ufb01c Society of Respirology\nCONT versus DODS oxygen \ufb02ow in COPD 5\nTable 2 Raw data for oxygen saturation at rest and during exercise from studies comparing DODS and CONT\nDODS CONT\nMean SD n Mean SD n\nAt rest Bower, 1988 (Oxygen Saver) 94.7 1.8 6 94.8 1.3 6\nBraun, 1992 (Oxymatic) 91.3 2.8 10\nBraun, 1992 (Portamate) 91.4 2.5 10 90.3 3.2 10\nBraun, 1992 (Oxygen Saver) 92.3 3.7 10\nJohann, 2001 (DOC-2000) 89.5 1.0 17 92.0 1.0 17\nJohann, 2001 (Oxytron) 89.7 1.0 17\nJohann, 2001 (Pulsair) 92.5 1.0 17\nLangenhof, 2005 (DeVilbiss 3000) 94.5 3.2 13 94.8 3.2 13\nLangenhof, 2005 (Oxitron3) 93.5 2.6 13 94.8 2.1 13\nMarti, 2013 (Spirit 300) 95.6 1.1 28 95.9 1.1 28\nTiep, 2002 (Oxymatic) 93.7 2.1 10 93.8 1.9 10\nWeber, 2006 (Spirit 300) 93.3 2.7 27 93.7 2.5 27\nDuring exercise Bower, 1988 (Oxygen Saver) 94.0 2 6 93.0 5.0 6\nBraun, 1992 (Oxymatic) 89.8 3.1 10\nBraun, 1992 (Portamate) 88.4 2.8 10 90.3 3.1 10\nBraun, 1992 (Oxygen Saver) 90.8 3.4 10\nFuhrman, 2004 (Impulse) 93.9 2.7 13 94.4 2.3 13\nFuhrman, 2004 (Oxiclip) 94.2 2.3 13\nFuhrman, 2004 (Venture) 94.7 2.5 13\nFuhrman 2004 (Versatile) 94.9 2.2 13\nGarrod, 1999 (Pulsedose EX 2000) 85.6 7.4 14 87.6 5.9 14\nMarti, 2013 (Spirit 300) 89.4 1.6 28 89.4 1.6 28\nRoberts, 1996 (Oxymatic) 78.0 9.8 15 81.0 9.6 15\nTiep, 2002 (Oxymatic) 90.5 3.8 10 93.1 3.1 10\nWeber, 2006 (Spirit 300) 88.2 5.7 27 87.9 6.8 27\nSpeci\ufb01c device names are listed in parentheses. Bold font denotes studies contributing data for quantitative meta-analysis.\nCONT, continuous oxygen \ufb02ow; DODS, demand oxygen delivery system.\nFigure 3 Forest plots of comparisons between continuous oxygen \ufb02ow (CONT) versus demand oxygen delivery systems (DODS)\nfor oxyhaemoglobin saturation (SpO2, %) at rest (A), during exercise (B) and for exercise performance (6-min walk distance, m) (C).\nSpeci\ufb01c device names are listed in parentheses.\n\u00a9 2018 Asian Paci\ufb01c Society of Respirology Respirology (2018)\n6 R Gloeckl et al.\nnon-randomized studies, with the CONT condition\napplied consistently prior to DODS. This raises the pos-\nsibility of a test sequence effect. The small magnitude of\nmean difference (DODS \u2212 CONT) in oxygen saturation\n(2.5%) for this study, however, lies within the range of\naccepted measurement error for pulse oximetry. The\nclinical relevance of this \ufb01nding is therefore question-\nable.22\nThe only other study to report a signi\ufb01cant dif-\nference between systems was that of Weber et al.,21\nwhere a mean difference of 16 m on 6MWT favouring\nDODS, although this was less than the 30 m threshold\nof a minimal important difference.23\nDespite good congruency between DODS and\nCONT \ufb01ndings across most studies, the degree of\nindividual patient variability within studies was nota-\nbly high. For example, DODS use was observed to be\nassociated with oxygen desaturations in excess of 20%\nduring exercise in one study15\nbut substantially less\nduring CONT use. Tiep et al.20\nobserved inferior\nresults with DODS during exercise in 60% of partici-\npants, but noted partial diminishment when oxygen\ndelivery settings were increased. Variability to such an\nextent suggests that the effect of DODS devices cannot\nbe accurately estimated at the level of the individual.\nFactors such as mouth breathing, especially during\nexercise, may play an important role in identifying\nsubgroups with greater need for individual evaluation\nprior to DODS implementation due to the risk of inef-\nfectively triggering oxygen boluses.\nAn important factor to consider with respect to evalu-\nating DODS suitability is the ever-increasing array of\ndevice manufacturers, features and speci\ufb01cations. For\nexample, bolus volume can vary from 15 to 100 mL and\nbolus duration from 50 to 900 ms. Earlier timing of oxy-\ngen delivery within the inspiration phase has been\nshown to associate with better oxygenation.24\nStudies\nincluded in this meta-analysis used different devices\nand, in several cases, indeterminable DODS setting.\nTwo studies used a device that releases an oxygen bolus\nduring every second inspiration phase16,19\n, two studies\nincreased DODS level to achieve an oxygen saturation\nabove 90%18,20\n, while all other studies used unspeci\ufb01ed\nequations to calculate DODS oxygen \ufb02ow rates consid-\nered to be (at least theoretically) equivalent to the com-\nparator of 2\u20133 L\/min CONT. This implies they are not\ncomparable from one manufacturer or model to\nanother. It would therefore seem advisable to consider\nthat DODS device prescription for LTOT be undertaken\nin conjunction with oxygen saturation monitoring dur-\ning measures of exercise or activities of daily living\nwhile using the device under consideration.6\nA principal function of DODS devices is prolongation\nof cylinder life. Economic bene\ufb01ts may therefore be\nconferred due to reductions in total oxygen consump-\ntion and home deliveries. Estimates of cost savings\nhave ranged from 11% to 55% when DODS devices\nwere compared to CONT,12,25\u201327\nreiterating not all\nDODS devices are equal. Patients with COPD are also\nhighly impaired in their daily physical activities. Those\nwith severe COPD but no LTOT report 50% lower phys-\nical activity levels compared to healthy elderly people.28\nLTOT is an independent determinant for physical inac-\ntivity29\nand those with COPD who use LTOT are even\nmore inactive (79% lower), despite similar lung func-\ntion impairment.28\nMany COPD patients report dif\ufb01cul-\nties carrying portable continuous \ufb02ow oxygen systems\ndue to heavy cylinder weight.30\nThe reduced bulk and\nweight offered by DODS in conjunction with smaller\n(but longer lasting) cylinders is a preferable option18\nthat may contribute to improvements in physical activ-\nity levels. The potential translation of such adaptations\ninto daily life is an important and plausible mechanism\nthat may be further enhanced via emerging lightweight\nportable concentrators. No such studies have, however,\nbeen conducted for this purpose.\nIt is important to note that all studies included\nwithin this review were conducted in a laboratory set-\nting. This controlled environment enables accurate\nevaluation of physiological parameters essential for the\nprimary aim of such studies, however does not mimic\ncommunity-based daily life. Additionally, no included\nstudy evaluated patient-reported outcomes such as\nquality of life. This signi\ufb01cantly understates the impor-\ntance of such outcomes to clinical decision-makers.\nTable 3 Raw data for exercise performance from studies comparing DODS and CONT\nDODS CONT\nMean SD n Mean SD n\n12MWD Braun 1992 (Oxymatic) 1076 616 10 1138 455 10\nBraun 1992 (Portamate) 884 535\nBraun 1992 (Oxygen Saver) 936 424\nFuhrman 2004 (Impulse) 257 88 13 257 93 13\n6MWD Fuhrman 2004 (Oxiclip) 260 93\nFuhrman 2004 (Venture) 253 85\nFuhrman 2004 (Versatile) 267 100\nMarti 2013 (Spirit 300) 348 12 28 352 12 28\nRoberts 1996 (Oxymatic) 283 89 15 295 89 15\nWeber 2006 (Spirit 300) 289 83 27 272 72 27\nSWT Garrod 1999 (Pulsedose EX 2000) 208 110 14 204 106 14\nSpeci\ufb01c device names are listed in parentheses. Bold font denotes studies contributing data for quantitative meta-analysis.\n6MWD, 6-min walk distance; 12MWD, 12-min walk distance; CONT, continuous oxygen \ufb02ow; DODS, demand oxygen delivery\nsystem; SWT, shuttle walk test.\nRespirology (2018) \u00a9 2018 Asian Paci\ufb01c Society of Respirology\nCONT versus DODS oxygen \ufb02ow in COPD 7\nFuture reviews seeking to determine the multidimen-\nsional impact of LTOT on daily life (beyond the scope\nof the present review) would require altered methodol-\nogy such as the inclusion of studies that did not need\nto involve direct head-to-head comparisons between\nCONT and DOD.\nThe effect of nocturnal DODS use has also seldom\nbeen explored, with very few studies of small sample\nsizes investigating DODS during sleep.12,31\nOne study\nfound no clinical difference in oxygen saturation com-\npared to CONT; however, dramatic oxygen desatura-\ntion (up to 11 percentage points) was observed in\nsome subjects using DODS attributed to ineffective trig-\ngering.31\nNo sound evidence-based recommendations\ncan presently be made to inform decisions regarding\nthe effectiveness of DODS devices at night.\nDespite robust methodology, this review resulted in a\nsynthesis of data from 10 studies of 152 patients with\nCOPD, with only 107 patients included in the meta-\nanalysis for SpO2 at rest. This pooled sample size\nappears modest, but must be considered with respect to\nthe inherent trial designs of the included studies. All\nincluded studies were crossover trials, which is appro-\npriate to investigate the research questions addressed in\nthis review. The advantages afforded by participants act-\ning as their own controls (e.g. reduced outcome variabil-\nity and greater statistical power) re\ufb02ect, however, as a\nlower pooled yield. The review \ufb01ndings may also need\nto be interpreted with caution due to the uncertain rele-\nvance of some included studies dating as far back as\n1988. To the best of the authors\u2019 knowledge, only 7 of\n17 (41%) DODS devices included in this review are cur-\nrently commercially available. The modern clinical envi-\nronment is increasingly observing a rise of portable\noxygen concentrators. As these devices have different\nmechanistic capabilities to liquid-based CONT and\nDODS devices, and were not considered within the\nscope of the present review, we do not promote extrapo-\nlation of \ufb01ndings to such devices. Finally, while patients\nwith COPD represent the largest patient population\nusing LTOT, extrapolation of \ufb01ndings to other chronic\nrespiratory conditions may be fraught with risk due to\nknown differences in respiratory pathophysiology.\nIn conclusion, DODS devices appear to offer similar\neffects to CONT systems in maintaining oxygen satura-\ntion at rest and during exercise, with similar effects\nupon exercise performance. The limited amount of\nhigh-quality data and large degree of individual vari-\nability, however, means overall effects may not be\naccurately estimated at the individual level. Decisions\nregarding DODS use for LTOT should be made in con-\njunction with oxygen saturation monitoring during\nmeasures of exercise or activities of daily living for spe-\nci\ufb01c devices under consideration. Further research is\nindicated to address the signi\ufb01cant gap in the literature\nidenti\ufb01ed via this review in order to facilitate evidence-\nbased medicine in this area.\nAbbreviations: , 6MWT, 6-min walk test; 12MWT, 12-min walk\ntest; CONT, continuous oxygen \ufb02ow; DODS, demand oxygen\ndelivery system; FEV1, forced expiratory volume in 1 s; LTOT,\nlong-term oxygen therapy; PaO2, partial pressure of oxygen in\narterial blood; PRISMA, Preferred Reporting Items for\nSystematic Reviews and Meta-Analyses; SpO2, oxyhaemoglobin\nsaturation.\nREFERENCES\n1 Continuous or nocturnal oxygen therapy in hypoxemic chronic\nobstructive lung disease: a clinical trial. Nocturnal Oxygen Therapy\nTrial Group. Ann. Intern. 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Demand\noxygen delivery during exercise. Chest 1987; 91: 15\u201320.\n26 Mecikalski M, Shigeoka JW. A demand valve conserves oxygen in subjects\nwith chronic obstructive pulmonary disease. Chest 1984; 86: 667\u201370.\n27 Rinow ME, Saltzman AR. Effectiveness of a new oxygen demand\nvalve in chronic hypoxemia. Chest 1986; 90: 204\u20137.\n28 Sandland CJ, Singh SJ, Curcio A, Jones PM, Morgan MD. A pro\ufb01le\nof daily activity in chronic obstructive pulmonary disease.\nJ. Cardiopulm. Rehabil. 2005; 25: 181\u20133.\n29 Langer D, Cebria i Iranzo MA, Burtin C, Verleden SE,\nVanaudenaerde BM, Troosters T, Decramer M, Verleden GM,\nGosselink R. Determinants of physical activity in daily life in\ncandidates for lung transplantation. Respir. Med. 2012; 106:\n747\u201354.\n30 Arnold E, Bruton A, Donovan-Hall M, Fenwick A, Dibb B,\nWalker E. Ambulatory oxygen: why do COPD patients not use their\nportable systems as prescribed? A qualitative study. BMC Pulm.\nMed. 2011; 11: 9.\n31 Chatburn RL, Lewarski JS, McCoy RW. Nocturnal oxygenation\nusing a pulsed-dose oxygen-conserving device compared to con-\ntinuous \ufb02ow. Respir. Care 2006; 51: 252\u20136.\nSupplementary Information\nAdditional supplementary information can be accessed via\nthe html version of this article at the publisher\u2019s website.\nAppendix S1 Methods.\nRespirology (2018) \u00a9 2018 Asian Paci\ufb01c Society of Respirology\nCONT versus DODS oxygen \ufb02ow in COPD 9","pure_content":"SYSTEMATIC REVIEW\nComparison of continuous \ufb02ow versus demand oxygen delivery\nsystems in patients with COPD: A systematic review\nand meta-analysis\nRAINER GLOECKL,1,2*,\nCHRISTIAN OSADNIK,3,4* LISA BIES,2\nDANIELA LEITL,1\nANDREAS-REMBERT KOCZULLA1,5\nAND KLAUS KENN1,5\n1\nInstitute for Pulmonary Rehabilitation Research, Schoen Klinik Berchtesgadener Land, Schoenau am Koenigssee, Germany;\n2\nDepartment of Prevention, Rehabilitation and Sports Medicine, Technical University of Munich (TUM), Munich, Germany;\n3\nDepartment of Physiotherapy, Monash University, Melbourne, VIC, Australia; 4\nMonash Health, Monash Lung and Sleep,\nMelbourne, VIC, Australia; 5\nDepartment of Pulmonary Rehabilitation, Philipps-University of Marburg, German Center for Lung\nResearch (DZL), Marburg, Germany\nABSTRACT\nDemand oxygen delivery systems (DODS) enable pro-\nlongation of liquid oxygen cylinder life compared to\ncontinuous oxygen \ufb02ow (CONT) use. Evidence is lack-\ning, however, regarding their ef\ufb01cacy. This study inves-\ntigated the literature comparing liquid-based CONT to\nDODS in patients with chronic obstructive pulmonary\ndisease (COPD). Four electronic databases were\nsearched from 1980 until January 2018. Primary out-\ncomes were oxyhaemoglobin saturation (SpO2%) at rest\nand during exercise and exercise performance. Risk of\nbias was evaluated using the Cochrane tool. Data were\nanalysed via meta-analysis where possible using the\ngeneric inverse variance method in Revman 5.3 or nar-\nrative synthesis. Ten crossover trials involving\n152 patients with moderate to severe COPD (forced\nexpiratory volume in 1 s (FEV1) range: 27\u201342% pre-\ndicted) were included. There was a large degree of\nuncertainty regarding potential bias related to alloca-\ntion concealment and blinding for all studies. Data from\nthree studies (n = 44) showed no signi\ufb01cant differences\nbetween DODS and CONT in terms of SpO2% at rest\n\u22120.2% (95% CI: \u22120.5% to 0.1%) or during exercise\n\u22120.3% (95% CI: \u22122.1% to 1.5%). The pooled mean dif-\nference of two studies (n = 56) in 6-min walk distance\nwas 5.7 m (95% CI: \u221214.4 to 25.8 m). Findings were\nconsistent between the meta-analysis and narrative syn-\nthesis. These \ufb01ndings from a limited number of studies\nsuggest oxygen delivery via DODS or CONT confers sim-\nilar effects in terms of SpO2% or exercise performance\nin patients with COPD. However, as DODS devices use\nvarious speci\ufb01cations that may yield large intra-\nindividual differences, individual SpO2% testing appears\nadvisable for those considering DODS use.\nKey words: chronic obstrutive pulmonary disease, hypox-\nemia, oxygen therapy, oxygen device.\nINTRODUCTION\nLong-term oxygen therapy (LTOT) for patients with\nchronic obstructive pulmonary disease (COPD) and\nchronic hypoxia is a crucial therapy that aims to\nimprove survival.1,2\nIn these individuals, use of supple-\nmental oxygen during exercise may also be associated\nwith reduced exertional oxyhaemoglobin desaturation\nand increased exercise performance.3\nOxygen therapy is\nusually applied via nasal cannula connected to station-\nary or portable continuous oxygen \ufb02ow (CONT) sys-\ntems, however signi\ufb01cant oxygen wastage occurs due to\nunnecessary \ufb02ow during expiration. This reduces the\nlife of portable liquid-based oxygen devices which may\nsubsequently impair mobility and independence.4\nOxygen conservation devices therefore emerged\n(since the 1980s) with demand oxygen delivery system\n(DODS) being one of the most common technologies.\nDODS deliver a pre-set bolus of oxygen during the \ufb01rst\npart of inspiration,5\ntriggered by a sensor that detects\nnegative pressure within the nares.6\nNo \ufb02ow is pro-\nvided during expiration. However, despite technologi-\ncal advancements and widespread commercial\navailability, evidence regarding the ef\ufb01cacy of DODS\ncompared to CONT has been lacking.7,8\nThis is essential\nto clarify as concerns exist regarding the ability of\nDODS to meet respiratory demands in some situations.\nFor example, dyssynchrony between triggering and\ninspiration may result in poorly timed gas delivery,\nwhile breathing pattern differences between the resting\nstate and active exertion may limit the effectiveness of\nDODS during times of high peak inspiratory \ufb02ow\ndemand such as exercise.\nPortable oxygen concentrators have also recently\nemerged as alternate delivery systems for patients\nCorrespondence: Rainer Gloeckl, Institute for Pulmonary\nRehabilitation Research, Schoen Klinik Berchtesgadener Land,\nMalterhoeh 1, 83471 Schoenau am Koenigssee, Germany.\nEmail: rainer.gloeckl@gmx.de\n*R.G. and C.O. contributed equally to the preparation of the\nmanuscript.\nReceived 30 May 2018; invited to revise 1 August and\n4 October 2018; revised 3 September and 25 October 2018;\naccepted 20 November 2018 (Associate Editor: Melissa\nJ. Benton; Senior Editor: Philip Bardin).\n\u00a9 2018 Asian Paci\ufb01c Society of Respirology Respirology (2018)\ndoi: 10.1111\/resp.13457\nrequiring LTOT. These units deliver oxygen via extrac-\ntion from ambient air rather than from a compressed\nliquid reservoir. While this mechanistic difference may\noffer bene\ufb01ts related to patient convenience and lower\ncylinder costs, it makes head-to-head comparisons\nbetween liquid-based and concentrator systems chal-\nlenging. For example, it would be dif\ufb01cult to ascertain\nwhether differences between portable oxygen concen-\ntrators and liquid cylinders + DODS should be attrib-\nuted to oxygen type, bolus volumes or issues related to\npeak inspiratory \ufb02ow rates.\nTo ensure that clinical decisions regarding oxygen\ndelivery devices are informed by the best available evi-\ndence, it is essential to identify the quality and quantity\nof available literature and ascertain its applicability to\nclinical practice. This study therefore aimed to review\nthe scienti\ufb01c literature comparing the effectiveness of\nliquid oxygen supplementation delivery via CONT or\nDODS at rest and during exercise in patients with COPD.\nMETHODS\nThis review and meta-analysis was performed accord-\ning to the Preferred Reporting Items for Systematic\nReviews and Meta-Analyses (PRISMA) Statement9\nand\nwas registered a priori at the international prospective\nregister of systematic reviews (PROSPERO at www.crd.\nyork.ac.uk under following ID: CRD42018081806).\nData sources and search strategy\nThe electronic databases PubMed (MEDLINE),\nEmbase, LILACS and Cochrane Library were searched\nfrom 1980 until 5 January 2018 with a strategy compris-\ning the following terms: chronic obstructive pulmonary\ndisease OR COPD AND oxygen therapy OR demand\noxygen system OR continuous \ufb02ow system OR oxygen\nconserving device OR long-term oxygen therapy. Refer-\nence lists of included studies were hand-searched for\nadditional literature.\nEligibility criteria\nFull text, original research articles were included if they\ncompared CONT supplemental oxygen delivery to\nDODS (both liquid-based) at rest and\/or during exer-\ncise applied via nasal cannula. Articles must have been\ncontrolled trials published in English or German lan-\nguage involving patients with COPD (or COPD patient\nsubgroup data available if mixed patient disease\ngroups). Studies comparing CONT to air or oxygen con-\ncentrator systems were ineligible, as were book chap-\nters, letters, unpublished work and study protocols.\nOutcomes\nTo identify evidence of physiological bene\ufb01t, this\nreview focused on short-term physiological and func-\ntional outcomes. The primary review outcome was oxy-\nhaemoglobin saturation (SpO2%) recorded at rest and\nduring exercise, derived from arterial blood gas sam-\npling or pulse oximetry. The secondary outcome was\nexercise performance, measured via \ufb01eld walking tests\nsuch as the 6-min walk test (6MWT) or shuttle walk\ntest. As we anticipated that most studies would be of a\n\u2018laboratory\u2019 nature, we did not include broader out-\ncomes such as quality of life (despite their clinical\nrelevance).\nData extraction and risk of bias assessment\nTwo independent reviewers (R.G. and L.B.) screened\npotentially eligible citations on title and abstract and\nclassi\ufb01ed them as \u2018include\u2019, \u2018exclude\u2019 or \u2018maybe\u2019. Those\ndeemed \u2018include\u2019 or \u2018maybe\u2019 were reviewed in full text.\nThe same two authors examined these studies to deter-\nmine suitability for inclusion, with any disagreements\nresolved by a third author (C.O.). A standardized data\ncollection form was used to extract information and out-\ncomes related to included studies. This was conducted\nby one member of the review team (L.B.) and with con-\n\ufb01rmatory checks of accuracy veri\ufb01ed by another team\nmember (D.L.). This template included data for all\nreview outcomes as well as study characteristics related\nto authors, country, year, baseline characteristics of\nstudy population, oxygen device used and CONT and\nDODS settings. The methodological quality of each\nincluded study was assessed using the Cochrane Collab-\noration\u2019s Risk of Bias tool.10\nEach included study was\nrated as low, high or unclear risk of bias by two inde-\npendent reviewers for the domains of selection, perfor-\nmance, detection, attrition, reporting and other bias.\nData analysis\nData were pooled, where possible, for meta-analysis\nusing RevMan 5.3 (The Cochrane Collaboration, Oxford,\nUK). As all included studies were crossover designs, we\nonly meta-analysed data that could be entered via the\ngeneric inverse variance method, and expressed \ufb01ndings\nas mean differences (DODS \u2212 CONT). Data were not\npooled where data were expressed in heterogeneous\nmetrics (e.g. 6MWT vs 12-min walk test (12MWT)).\nFindings deemed unsuitable for meta-analysis were syn-\nthesized narratively and presented in summary tables.\nStatistical heterogeneity was explored between studies\nusing the I2\nstatistic, with results <25% considered low,\n50\u201375% considered moderate and >75% considered\nhigh.11\nData were primarily pooled using a \ufb01xed-effect\nmodel; however, a random-effects model was used\nwhere moderate (or greater) heterogeneity was detected.\nPossible explanations for observed heterogeneity were\nexamined via exploratory sensitivity analyses involving\nremoval of outlying studies. Data related to SpO2% at\nrest and during exercise were pooled separately from\neach other to avoid introducing issues of data duplicity.\nMore Information on data analysis can be found in\nAppendix S1 (Supplementary Information).\nRESULTS\nAn overview of the study selection process (PRISMA\ndiagram) is provided in Figure 1. A total of 726 titles\nwere screened, resulting in the retrieval of 31 full-text\narticles for potential eligibility. Twenty-one studies\nwere excluded due to use of an inappropriate compara-\ntor intervention (e.g. ambient air, oxymizer pendants\n\u00a9 2018 Asian Paci\ufb01c Society of Respirology Respirology (2018)\n2 R Gloeckl et al.\nand oxygen concentrators; n = 18) or non-COPD\npatients (n = 3). The remaining 10 publications12\u201321\nwere included in the qualitative analysis (Table 1).\nThese studies comprised 152 patients with forced expi-\nratory volume in 1 s (FEV1) ranging from 27% to 42%\npredicted. Nine studies included patients with chronic\nhypoxia (partial pressure of oxygen in arterial blood\n(PaO2): 49 to 60 mm Hg at rest on room air) and one\nstudy15\nincluded patients who desaturated more than\n4% during a 6MWT (PaO2: 63 \u0006 9 mm Hg at rest on\nroom air). One study18\nincluded patients with COPD\nand interstitial lung disease; however, COPD-speci\ufb01c\ndata were available.\nRisk of bias assessment\nA summary of risk of bias judgments for included stud-\nies is presented in Figure 2. High risks related to selec-\ntion and performance bias were mostly con\ufb01ned to the\noutcome of exercise performance, as measures of oxy-\ngen saturation were deemed less likely to have been\naffected considering its physiological basis. Non-\nrandomized studies were deemed to be at high risk of\nselection and performance bias; however, the study of\nTiep et al.20\nwas rated unclear for performance bias as\ndata were only available for oxygen saturation. Blinding\nof patients or therapists to knowledge of treatment con-\ndition, whether stated, was not possible for any study\ndue to challenges concealing the audible noise and\nsensation during each oxygen bolus delivery for DODS.\nHigh ratings were only made for studies that included\ndata related to exercise performance. A high degree of\nuncertainty was evident for many domains of the risk\nof bias tool, likely driven by the less stringent reporting\nstandards required by the journals at the time of\npublication.\nPrimary outcome\nData regarding oxygen saturation at rest were available\nfrom six studies of 107 patients (Table 2),12,13,17,18,20,21\nwith three studies12,18,20\nproviding appropriate data for\nmeta-analysis. The pooled mean difference (DODS \u2212\nCONT) in oxygen saturation at rest was \u22120.2% (95% CI:\n\u22120.5% to 0.1%; Fig. 3A). Findings from studies unable\nto be included in the meta-analysis for this outcome\nreported differences ranging between \u22121.3% and 2.0%.\nData regarding oxygen saturation during exercise\nwere available from eight studies of 123 patients\n(Table 2),12\u201315,18\u201321\nwith three studies12,18,20\nproviding\nappropriate data for meta-analysis. The pooled mean\ndifference (DODS \u2212 CONT) in oxygen saturation dur-\ning exercise was \u22120.3% (95% CI: \u22122.1% to 1.5%; Fig. 3B).\nHigh statistical heterogeneity was detected (I2\n= 86%),\nhence a random-effect model was applied. This hetero-\ngeneity was attributable to the study data from Tiep\net al..20\nSensitivity analysis involving removal of this\nstudy from analysis fully corrected this observation\n(I2\n= 0%). Findings from studies unable to be included\nin the meta-analysis for this outcome reported differ-\nences ranging between \u22123.0% and 1.0%.\nSecondary outcome\nData regarding exercise performance were available\nfrom six studies of 107 patients (Table 3),13\u201315,18,19,21\nwith\ntwo studies18,21\nproviding appropriate data for meta-\nanalysis. The pooled mean difference (DODS \u2212 CONT)\nin exercise performance (6MWT distance) was 5.7 m\n(95% CI: \u221214.4 to 25.8 m; Fig. 3C). High statistical het-\nerogeneity was detected (I2\n= 89%), hence a random-\neffect model was applied. As only two studies were\nincluded in this meta-analysis, sensitivity analysis was\nnot indicated. Findings from studies unable to be\nincluded in the meta-analysis for this outcome\nreported highly comparable measures of exercise per-\nformance between groups (Table 3), with the exception\nof the study by Braun et al.13\nThis study evaluated exer-\ncise performance by the less common 12MWT but\nfound consistently higher values for the CONT condi-\ntion compared to three DODS devices. The difference\nranged from \u221262 m for the Oxymatic device to \u2212254 m\nfor the Portamate device, however, these differences\nwere not statistically signi\ufb01cant.\nFigure 1 PRISMA (Preferred Reporting\nItems for Systematic Reviews and Meta-\nAnalyses) diagram of study \ufb02ow.\nRespirology (2018) \u00a9 2018 Asian Paci\ufb01c Society of Respirology\nCONT versus DODS oxygen \ufb02ow in COPD 3\nTable\n1\nCharacteristics\nof\nincluded\nstudies\nAuthor,\nyear,\ncountry\nSample\nsize,\nn\n(sex)\nStudy\ndesign\nAge\nFEV\n1\n(%)\nPaO\n2\nat\nrest\n(mm\nHg)\nDODS\ndevice\ntested\n(manufacturer)\nDODS\nsetting\nCONT\nsetting\nTest\nat\nrest\nTest\nduring\nexercise\nBower,\n1988,\nUSA\n6\n(m\n=\n2,\nf\n=\n4)\nRandomized\ncrossover\n65\n\u0006\n10\nn.a.\n50\n\u0006\n6\nOxygen\nSaver\n(Puritan\nBennett)\nEquivalent\nto\n2\nL\/min\nCONT\nat\nrest\nand\nduring\nexercise\n2\nL\/min\nYes\n5\nmin\nof\ncomfortable\ntreadmill\nwalking\nBraun,\n1992,\nUSA\n10\n(m\n=\n10)\nRandomized\ncrossover\n59\n\u0006\n5\n27\n\u0006\n7\n50\n\u0006\n4\n1)\nOxymatic\n(Chad)\n2)\nPortamate\n(Bunn)\n3)\nOxygen\nsaver\n(Puritan\nBennett)\nO\n2\n\ufb02ow\nrate\nused\nwas\nequivalent\nto\nmanufacturer\nrecommendation\nfor\nthe\nprescribed\nCONT\nrate\nO\n2\n\ufb02ow\nrate\nas\nprescribed\n(mean:\n2.4\nL\/min)\nYes\n12MWT\nFuhrman,\n2004,\nFRA\n13\n(m\n=\n11,\nf\n=\n2)\nRandomized\ncrossover\n62\n\u0006\n10\n36\n\u0006\n12\n60\n\u0006\n5\n1)\nOxiclip\n(Puritan\nBennett)\n2)\nVenture\n(Invacare)\n3)\nVersatile\n(DeVilbiss)\n4)\nImpulse\n(Airsep)\nEquivalent\nto\n3\nL\/min\nCONT\nat\nrest\nand\nduring\nexercise\n3\nL\/min\nYes\n6MWT\nGarrod,\n1999,\nGBR\n14\n(n.a.)\nRandomized\ncrossover\n66\n(50\u201375)\n32\n\u0006\n9\n63\n\u0006\n9\nPulsedose\nEX\n2000\n(DeVilbiss)\nEquivalent\nto\n2\nL\/min\nCONT\nduring\nexercise\n2\nL\/min\nNo\nISWT\nJohann,\n2001,\nGER\n17\n(m\n=\n15,\nf\n=\n2)\nRandomized\ncrossover\n68\n\u0006\n10\n42\n\u0006\n20\n49\n\u0006\n7\n1)\nDOC-2000\n(TransTracheal\nSystems\nInc.)\n2)\nPulsair\n(DeVilbiss)\n3)\nOxytron\n2\n(Weinmann)\nEquivalent\nto\n2\nL\/min\nCONT\nat\nrest\nDOC:\n30\nmL\/inspiration\nPulsair:\n33\nmL\/inspiration\nOxytron:\n35\nmL\/\ninspiration\n2\nL\/min\nYes\nNo\nLangenhof,\n2005,\nGER\n13\n(m\n=\n10,\nf\n=\n3)\nRandomized\ncrossover\n65\n\u0006\n8\n28\n\u0006\n5\n56\n\u0006\n8\n1)\nEX\n3000\n(DeVilbiss)\n2)\nOxytron\n3\n(Weinmann)\nEquivalent\nto\n2\nL\/min\nCONT\nEX\n3000:\n33\nmL\/\ninspiration\nOxytron3:\n20\nmL\/\ninspiration\n2\nL\/min\nYes\nNo\nMarti,\n2013,\nESP\n28\n(m\n=\n23,\nf\n=\n5)\nRandomized\ncrossover\n66\n\u0006\n9\n31\n\u0006\n11\n60\n\u0006\n7\nSpirit\n300\n(Caire\nMedical)\nO\n2\n\ufb02ow\nrate\nwas\nincreased\nup\nto\nequivalence\nof\n6\nL\/min\nCONT\nto\nachieve\nSpO\n2\n\u2265\n90%\nO\n2\n\ufb02ow\nrate\nwas\nincreased\nto\nachieve\nSpO\n2\n\u2265\n90%\nduring\n6MWT\n(median:\n4\nL\/min)\nYes\n6MWT\nRoberts,\n1996,\nGBR\n15\n(m\n=\n9,\nf\n=\n6)\nRandomized\ncrossover\n68\n\u0006\n6\n31\n\u0006\n8\n52\n\u0006\n7\nOxymatic\n201\n(Chad)\nEquivalent\nto\n2\nL\/min\nCONT\nduring\nexercise\n2\nL\/min\nNo\n6MWT\n\u00a9 2018 Asian Paci\ufb01c Society of Respirology Respirology (2018)\n4 R Gloeckl et al.\nDISCUSSION\nThis review highlights a limited body of evidence upon\nwhich to formulate clinical decisions regarding liquid-\nbased oxygen supplementation for patients with COPD.\nThe available data suggest that use of DODS devices\nappear to confer minimal impact upon oxygen satura-\ntion and exercise performance compared to continuous\n\ufb02ow oxygen. These \ufb01ndings were very consistent\nbetween the meta-analysis as well as the raw data pre-\nsented in Tables 2 and 3. This reassures us of their abil-\nity to prolong cylinder life without risking therapeutic\neffectiveness. The study by Tiep et al.20\nwas the only\nnotable exception to this result, which reported \ufb01ndings\nfavouring CONT over DODS. This was one of the two\nTable\n1\nContinued\nAuthor,\nyear,\ncountry\nSample\nsize,\nn\n(sex)\nStudy\ndesign\nAge\nFEV\n1\n(%)\nPaO\n2\nat\nrest\n(mm\nHg)\nDODS\ndevice\ntested\n(manufacturer)\nDODS\nsetting\nCONT\nsetting\nTest\nat\nrest\nTest\nduring\nexercise\nTiep,\n2002,\nUSA\n9\n(n.a.)\nNon-randomized\ncrossover\n67\n\u0006\n7\nn.a.\nn.a.\nOxymatic\n401\n(Chad)\nO\n2\n\ufb02ow\nrate\nwas\nincreased\nbetween\n1\nand\n6\nL\/min\nto\nachieve\nequivalent\nsaturation\nof\nCONT\nOxymatic\n401:\n255\nmL\/\nmin\nO\n2\n\ufb02ow\nrate\nas\nprescribed\n(mean:\n1.7\nL\/min)\nYes\nSubmaximal\ntreadmill\nwalking\nfor\n2\nmin\nat\n1.5mi\/h\nWeber,\n2006,\nGER\n27\n(m\n=\n12,\nf\n=\n15)\nNon-randomized\ncrossover\n66\n\u0006\n9\n44\n\u0006\n18\n55\n\u0006\n7\nSpirit\n300\n(Caire\nMedical)\nEquivalent\nto\n2\nL\/min\nCONT\n2\nL\/min\nNo\n6MWT\n6MWT,\n6-min\nwalk\ntest;\n12MWT,\n12-min\nwalk\ntest;\nCONT,\ncontinuous\noxygen\n\ufb02ow;\nDODS,\ndemand\noxygen\ndelivery\nsystem;\nf,\nfemale;\nFEV\n1\n,\nforced\nexpiratory\nvolume\nin\n1\ns;\nISWT,\nincre-\nmental\nshuttle\nwalk\ntest;\nm,\nmale;\nn.a.,\nnot\navailable;\nPaO\n2\n,\npartial\npressure\nof\noxygen\nin\narterial\nblood;\nSpO\n2\n,\noxyhaemoglobin\nsaturation.\nFigure 2 Risk of bias summary for included studies (red shad-\ning denotes high risk of bias, yellow shading denotes unclear\nrisk of bias and green denotes low risk of bias).\nRespirology (2018) \u00a9 2018 Asian Paci\ufb01c Society of Respirology\nCONT versus DODS oxygen \ufb02ow in COPD 5\nTable 2 Raw data for oxygen saturation at rest and during exercise from studies comparing DODS and CONT\nDODS CONT\nMean SD n Mean SD n\nAt rest Bower, 1988 (Oxygen Saver) 94.7 1.8 6 94.8 1.3 6\nBraun, 1992 (Oxymatic) 91.3 2.8 10\nBraun, 1992 (Portamate) 91.4 2.5 10 90.3 3.2 10\nBraun, 1992 (Oxygen Saver) 92.3 3.7 10\nJohann, 2001 (DOC-2000) 89.5 1.0 17 92.0 1.0 17\nJohann, 2001 (Oxytron) 89.7 1.0 17\nJohann, 2001 (Pulsair) 92.5 1.0 17\nLangenhof, 2005 (DeVilbiss 3000) 94.5 3.2 13 94.8 3.2 13\nLangenhof, 2005 (Oxitron3) 93.5 2.6 13 94.8 2.1 13\nMarti, 2013 (Spirit 300) 95.6 1.1 28 95.9 1.1 28\nTiep, 2002 (Oxymatic) 93.7 2.1 10 93.8 1.9 10\nWeber, 2006 (Spirit 300) 93.3 2.7 27 93.7 2.5 27\nDuring exercise Bower, 1988 (Oxygen Saver) 94.0 2 6 93.0 5.0 6\nBraun, 1992 (Oxymatic) 89.8 3.1 10\nBraun, 1992 (Portamate) 88.4 2.8 10 90.3 3.1 10\nBraun, 1992 (Oxygen Saver) 90.8 3.4 10\nFuhrman, 2004 (Impulse) 93.9 2.7 13 94.4 2.3 13\nFuhrman, 2004 (Oxiclip) 94.2 2.3 13\nFuhrman, 2004 (Venture) 94.7 2.5 13\nFuhrman 2004 (Versatile) 94.9 2.2 13\nGarrod, 1999 (Pulsedose EX 2000) 85.6 7.4 14 87.6 5.9 14\nMarti, 2013 (Spirit 300) 89.4 1.6 28 89.4 1.6 28\nRoberts, 1996 (Oxymatic) 78.0 9.8 15 81.0 9.6 15\nTiep, 2002 (Oxymatic) 90.5 3.8 10 93.1 3.1 10\nWeber, 2006 (Spirit 300) 88.2 5.7 27 87.9 6.8 27\nSpeci\ufb01c device names are listed in parentheses. Bold font denotes studies contributing data for quantitative meta-analysis.\nCONT, continuous oxygen \ufb02ow; DODS, demand oxygen delivery system.\nFigure 3 Forest plots of comparisons between continuous oxygen \ufb02ow (CONT) versus demand oxygen delivery systems (DODS)\nfor oxyhaemoglobin saturation (SpO2, %) at rest (A), during exercise (B) and for exercise performance (6-min walk distance, m) (C).\nSpeci\ufb01c device names are listed in parentheses.\n\u00a9 2018 Asian Paci\ufb01c Society of Respirology Respirology (2018)\n6 R Gloeckl et al.\nnon-randomized studies, with the CONT condition\napplied consistently prior to DODS. This raises the pos-\nsibility of a test sequence effect. The small magnitude of\nmean difference (DODS \u2212 CONT) in oxygen saturation\n(2.5%) for this study, however, lies within the range of\naccepted measurement error for pulse oximetry. The\nclinical relevance of this \ufb01nding is therefore question-\nable.22\nThe only other study to report a signi\ufb01cant dif-\nference between systems was that of Weber et al.,21\nwhere a mean difference of 16 m on 6MWT favouring\nDODS, although this was less than the 30 m threshold\nof a minimal important difference.23\nDespite good congruency between DODS and\nCONT \ufb01ndings across most studies, the degree of\nindividual patient variability within studies was nota-\nbly high. For example, DODS use was observed to be\nassociated with oxygen desaturations in excess of 20%\nduring exercise in one study15\nbut substantially less\nduring CONT use. Tiep et al.20\nobserved inferior\nresults with DODS during exercise in 60% of partici-\npants, but noted partial diminishment when oxygen\ndelivery settings were increased. Variability to such an\nextent suggests that the effect of DODS devices cannot\nbe accurately estimated at the level of the individual.\nFactors such as mouth breathing, especially during\nexercise, may play an important role in identifying\nsubgroups with greater need for individual evaluation\nprior to DODS implementation due to the risk of inef-\nfectively triggering oxygen boluses.\nAn important factor to consider with respect to evalu-\nating DODS suitability is the ever-increasing array of\ndevice manufacturers, features and speci\ufb01cations. For\nexample, bolus volume can vary from 15 to 100 mL and\nbolus duration from 50 to 900 ms. Earlier timing of oxy-\ngen delivery within the inspiration phase has been\nshown to associate with better oxygenation.24\nStudies\nincluded in this meta-analysis used different devices\nand, in several cases, indeterminable DODS setting.\nTwo studies used a device that releases an oxygen bolus\nduring every second inspiration phase16,19\n, two studies\nincreased DODS level to achieve an oxygen saturation\nabove 90%18,20\n, while all other studies used unspeci\ufb01ed\nequations to calculate DODS oxygen \ufb02ow rates consid-\nered to be (at least theoretically) equivalent to the com-\nparator of 2\u20133 L\/min CONT. This implies they are not\ncomparable from one manufacturer or model to\nanother. It would therefore seem advisable to consider\nthat DODS device prescription for LTOT be undertaken\nin conjunction with oxygen saturation monitoring dur-\ning measures of exercise or activities of daily living\nwhile using the device under consideration.6\nA principal function of DODS devices is prolongation\nof cylinder life. Economic bene\ufb01ts may therefore be\nconferred due to reductions in total oxygen consump-\ntion and home deliveries. Estimates of cost savings\nhave ranged from 11% to 55% when DODS devices\nwere compared to CONT,12,25\u201327\nreiterating not all\nDODS devices are equal. Patients with COPD are also\nhighly impaired in their daily physical activities. Those\nwith severe COPD but no LTOT report 50% lower phys-\nical activity levels compared to healthy elderly people.28\nLTOT is an independent determinant for physical inac-\ntivity29\nand those with COPD who use LTOT are even\nmore inactive (79% lower), despite similar lung func-\ntion impairment.28\nMany COPD patients report dif\ufb01cul-\nties carrying portable continuous \ufb02ow oxygen systems\ndue to heavy cylinder weight.30\nThe reduced bulk and\nweight offered by DODS in conjunction with smaller\n(but longer lasting) cylinders is a preferable option18\nthat may contribute to improvements in physical activ-\nity levels. The potential translation of such adaptations\ninto daily life is an important and plausible mechanism\nthat may be further enhanced via emerging lightweight\nportable concentrators. No such studies have, however,\nbeen conducted for this purpose.\nIt is important to note that all studies included\nwithin this review were conducted in a laboratory set-\nting. This controlled environment enables accurate\nevaluation of physiological parameters essential for the\nprimary aim of such studies, however does not mimic\ncommunity-based daily life. Additionally, no included\nstudy evaluated patient-reported outcomes such as\nquality of life. This signi\ufb01cantly understates the impor-\ntance of such outcomes to clinical decision-makers.\nTable 3 Raw data for exercise performance from studies comparing DODS and CONT\nDODS CONT\nMean SD n Mean SD n\n12MWD Braun 1992 (Oxymatic) 1076 616 10 1138 455 10\nBraun 1992 (Portamate) 884 535\nBraun 1992 (Oxygen Saver) 936 424\nFuhrman 2004 (Impulse) 257 88 13 257 93 13\n6MWD Fuhrman 2004 (Oxiclip) 260 93\nFuhrman 2004 (Venture) 253 85\nFuhrman 2004 (Versatile) 267 100\nMarti 2013 (Spirit 300) 348 12 28 352 12 28\nRoberts 1996 (Oxymatic) 283 89 15 295 89 15\nWeber 2006 (Spirit 300) 289 83 27 272 72 27\nSWT Garrod 1999 (Pulsedose EX 2000) 208 110 14 204 106 14\nSpeci\ufb01c device names are listed in parentheses. Bold font denotes studies contributing data for quantitative meta-analysis.\n6MWD, 6-min walk distance; 12MWD, 12-min walk distance; CONT, continuous oxygen \ufb02ow; DODS, demand oxygen delivery\nsystem; SWT, shuttle walk test.\nRespirology (2018) \u00a9 2018 Asian Paci\ufb01c Society of Respirology\nCONT versus DODS oxygen \ufb02ow in COPD 7\nFuture reviews seeking to determine the multidimen-\nsional impact of LTOT on daily life (beyond the scope\nof the present review) would require altered methodol-\nogy such as the inclusion of studies that did not need\nto involve direct head-to-head comparisons between\nCONT and DOD.\nThe effect of nocturnal DODS use has also seldom\nbeen explored, with very few studies of small sample\nsizes investigating DODS during sleep.12,31\nOne study\nfound no clinical difference in oxygen saturation com-\npared to CONT; however, dramatic oxygen desatura-\ntion (up to 11 percentage points) was observed in\nsome subjects using DODS attributed to ineffective trig-\ngering.31\nNo sound evidence-based recommendations\ncan presently be made to inform decisions regarding\nthe effectiveness of DODS devices at night.\nDespite robust methodology, this review resulted in a\nsynthesis of data from 10 studies of 152 patients with\nCOPD, with only 107 patients included in the meta-\nanalysis for SpO2 at rest. This pooled sample size\nappears modest, but must be considered with respect to\nthe inherent trial designs of the included studies. All\nincluded studies were crossover trials, which is appro-\npriate to investigate the research questions addressed in\nthis review. The advantages afforded by participants act-\ning as their own controls (e.g. reduced outcome variabil-\nity and greater statistical power) re\ufb02ect, however, as a\nlower pooled yield. The review \ufb01ndings may also need\nto be interpreted with caution due to the uncertain rele-\nvance of some included studies dating as far back as\n1988. To the best of the authors\u2019 knowledge, only 7 of\n17 (41%) DODS devices included in this review are cur-\nrently commercially available. The modern clinical envi-\nronment is increasingly observing a rise of portable\noxygen concentrators. As these devices have different\nmechanistic capabilities to liquid-based CONT and\nDODS devices, and were not considered within the\nscope of the present review, we do not promote extrapo-\nlation of \ufb01ndings to such devices. Finally, while patients\nwith COPD represent the largest patient population\nusing LTOT, extrapolation of \ufb01ndings to other chronic\nrespiratory conditions may be fraught with risk due to\nknown differences in respiratory pathophysiology.\nIn conclusion, DODS devices appear to offer similar\neffects to CONT systems in maintaining oxygen satura-\ntion at rest and during exercise, with similar effects\nupon exercise performance. The limited amount of\nhigh-quality data and large degree of individual vari-\nability, however, means overall effects may not be\naccurately estimated at the individual level. Decisions\nregarding DODS use for LTOT should be made in con-\njunction with oxygen saturation monitoring during\nmeasures of exercise or activities of daily living for spe-\nci\ufb01c devices under consideration. Further research is\nindicated to address the signi\ufb01cant gap in the literature\nidenti\ufb01ed via this review in order to facilitate evidence-\nbased medicine in this area.\nAbbreviations: , 6MWT, 6-min walk test; 12MWT, 12-min walk\ntest; CONT, continuous oxygen \ufb02ow; DODS, demand oxygen\ndelivery system; FEV1, forced expiratory volume in 1 s; LTOT,\nlong-term oxygen therapy; PaO2, partial pressure of oxygen in\narterial blood; PRISMA, Preferred Reporting Items for\nSystematic Reviews and Meta-Analyses; SpO2, oxyhaemoglobin\nsaturation.\nREFERENCES\n1 Continuous or nocturnal oxygen therapy in hypoxemic chronic\nobstructive lung disease: a clinical trial. Nocturnal Oxygen Therapy\nTrial Group. Ann. Intern. 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Demand\noxygen delivery during exercise. Chest 1987; 91: 15\u201320.\n26 Mecikalski M, Shigeoka JW. A demand valve conserves oxygen in subjects\nwith chronic obstructive pulmonary disease. Chest 1984; 86: 667\u201370.\n27 Rinow ME, Saltzman AR. Effectiveness of a new oxygen demand\nvalve in chronic hypoxemia. Chest 1986; 90: 204\u20137.\n28 Sandland CJ, Singh SJ, Curcio A, Jones PM, Morgan MD. A pro\ufb01le\nof daily activity in chronic obstructive pulmonary disease.\nJ. Cardiopulm. Rehabil. 2005; 25: 181\u20133.\n29 Langer D, Cebria i Iranzo MA, Burtin C, Verleden SE,\nVanaudenaerde BM, Troosters T, Decramer M, Verleden GM,\nGosselink R. Determinants of physical activity in daily life in\ncandidates for lung transplantation. Respir. Med. 2012; 106:\n747\u201354.\n30 Arnold E, Bruton A, Donovan-Hall M, Fenwick A, Dibb B,\nWalker E. Ambulatory oxygen: why do COPD patients not use their\nportable systems as prescribed? A qualitative study. BMC Pulm.\nMed. 2011; 11: 9.\n31 Chatburn RL, Lewarski JS, McCoy RW. Nocturnal oxygenation\nusing a pulsed-dose oxygen-conserving device compared to con-\ntinuous \ufb02ow. Respir. Care 2006; 51: 252\u20136.\nSupplementary Information\nAdditional supplementary information can be accessed via\nthe html version of this article at the publisher\u2019s website.\nAppendix S1 Methods.\nRespirology (2018) \u00a9 2018 Asian Paci\ufb01c Society of Respirology\nCONT versus DODS oxygen \ufb02ow in COPD 9","is_draft":"0","editor_type":"4","file_path":"\/docker_production\/zgvd51\/article\/20q12kcQ\/article_file\/Comparison of continuous flow versus demand oxygen delivery.pdf","add_time":"1757143072","update_time":"1757143081"},"pure_content":"SYSTEMATIC REVIEW\nComparison of continuous \ufb02ow versus demand oxygen delivery\nsystems in patients with COPD: A systematic review\nand meta-analysis\nRAINER GLOECKL,1,2*,\nCHRISTIAN OSADNIK,3,4* LISA BIES,"},{"id":"610666","string_id":"zQCdKgK3","status":"1","parent_id":"610654","slug":"hua-liao-xing-fei-yan-jian-zhi-xing-fei-yan-yang-liao-yu-wu-hua-202304","order":"0","name":"\u5316\u7597\u6027\u80ba\u708e\uff08\u95f4\u8d28\u6027\u80ba\u708e\uff09\u6c27\u7597\u4e0e\u96fe\u5316202304","type":"2","cover":"","cover_alt":"","desc":null,"website":"","contact":"","seo_title":"","seo_keyword":"","seo_desc":"","share_switch":"0","share_code":"","author":"","published_time":"1757145571","add_time":"1757143262","update_time":"1757145571","corp_auth_id":"0","verify_code_auth_id":"0","editor_type":"4","file_type":"pdf","auth_id":"[\"610666\", \"610654\"]","content":{"content_id":"610666","content":"\u5316\u7597\u6027\u80ba\u708e\u4e0e\u6c27\u7597\n\u5316\u7597\u5f15\u8d77\u7684\u95f4\u8d28\u6027\u80ba\u708e\uff0c\u80fd\u5426\u6cbb\u6108\u9700\u6839\u636e\u95f4\u8d28\u6027\u80ba\u708e\u7684\u53d1\u75c5\u673a\u5236\u548c\u4e25\u91cd\u7a0b\u5ea6\u800c\u5b9a 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90%\u3002\u7f8e\u56fd\u80f8\u79d1\u5b66\u4f1a\uff08ATS\uff09\u4e34\u5e8a\u5b9e\u8df5\u6307\u5357\u5efa\u8bae\u5bf9\u4e8e\u60a3\u6709\u4e25\u91cd\u6162\u6027\u9759\u606f\u72b6\u6001\u4e0b\u4f4e\u6c27\u8840\u75c7\u7684\u6210\u5e74\u60a3\u8005 \uff0c\u5e94\u8fdb\u884c\u81f3 \u5c1115h\/d\u7684\u957f\u671f\u5bb6\u5ead\u6c27\u7597\u30022015\u5e74\u82f1\u56fd\n\u80f8\u79d1\u5b66\u4f1a\uff08BTS) \u6307\u5357\u5efa\u8bae PaO2 \uff1c55mmHg\u7684\u60a3\u8005\u5e94\u8fdb\u884c\u957f\u671f\u6c27\u7597\u3002\n\u63a8\u8350\u5065\u54085\u5347\u5236\u6c27\u673a\n3. \u65e0\u521b\u6b63\u538b\u901a\u6c14\uff08non-invasive positive pressure ventila- tion NPPV\uff09\u662f\u6307\u4e0d\u7ecf\u4eba\u5de5\u6c14\u9053\uff08\u6c14\u7ba1\u63d2\u7ba1\u6216\u6c14\u7ba1\u5207\u5f00\uff09\u8fdb 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\u7ecf\u6d4e\u6307\u6807\u51fa\u73b0\u590d\u82cf\u8ff9\u8c61\n1\u6708\u9996\u5468\uff0c\u5317\u4e0a\u5e7f\u6df1\u7b4910\n\u4e2a\u91cd\u70b9\u57ce\u5e021\u7684\u5730\u94c1\u65e5\u5747\u5ba2\n\u6d41\u8f8312\u6708\u540c\u671f\u4e0a\u6da830%\n\u6625\u8fd0\u9996\u5468\uff0c\u56fd\u5185\u5ba2\u8fd0\u822a\u73ed\n\u91cf\u65e5\u5747\u7834\u4e07\u73ed\u6b21\uff0c\u540c\u6bd4\u589e\n\u957f12%\uff0c\u6bd421\u5e74\u589e\u957f57%\n\u65e5\u5747\n\u7834\u4e07\n\u51fa\u884c\uff1a\u5ba2\u6d41\u9010\u6b65\u6062\u590d\n\u81ea\u653f\u7b56\u653e\u5f00\u4ee5\u6765\u4eba\u6c11\u5e01\n\u5151\u7f8e\u5143\u6c47\u7387\u7d2f\u8ba1\u4e0a\u6da8\u8d85\n\u8fc78%\uff0c\u4e00\u5ea6\u5347\u78346.69\nA\u80a1\u5e02\u573a23\u5e74\u5143\u65e6\u4ee5\u6765\n\u8fde\u7eed6\u5929\u4e0a\u6da8\n\u91d1\u878d\uff1a\u6c47\u7387\u4e0eA\u80a1\u8fce\u6765\u826f\u597d\u5f00\u5c40\n+30%\n\u591a\u65e5\n\u8fde\u6da8\n\u4eba\u6c11\u5e01\n\u53cd\u5f39\n\u6d88\u8d39\uff1a\u6625\u8282\u5404\u884c\u4e1a\u6d88\u8d39\u5448\u73b0\u590d\u82cf\n23\u5e74\u6625\u8282\u5047\u671f\uff0c\u5546\u54c1\u6d88\n\u8d39\u548c\u670d\u52a1\u6d88\u8d39\u540c\u6bd4\u5206\u522b\n\u589e\u957f10%\u548c13.5%\n\u53cc\u4f4d\u6570\n\u589e\u957f\n\u591a\u65b9\u4e50\u89c2\u9884\u6d4b\n\u6625\u8282\u6863\u7535\u5f71\u7968\u623f67.6\n\u4ebf\u5143\uff0c\u540c\u6bd4\u589e\u957f\n11.9%\n\u5386\u53f2\n\u7b2c\u4e8c\u9ad8\n\u6625\u8282\u5047\u671f\u5168\u56fd\u56fd\u5185\u65c5\u6e38\n\u51fa\u6e38\u4eba\u6b21\uff0c\u5df2\u6062\u590d\u81f3\n2019\u5e74\u540c\u671f\u768488.6%\n\u6587\u65c5\n\u590d\u82cf\n23\u5e741\u6708\u4efd\u4e2d\u56fd\u96f6\u552e\n\u4e1a\u666f\u6c14\u6307\u6570\u4e3a50.3%\u3002\n\u73af\u6bd4\u6500\u53471.6%\n\u96f6\u552e\n\u666f\u6c14\n\u6500\u5347\nGDP\uff1a\u589e\u957f\u5c06\u8fbe5%\n\u6d88\u8d39\u54c1\u96f6\u552e\u603b\u989d\uff1a50\u4e07\u4ebf\u5143\n\u2022 \u82f1\u56fd\u300a\u91d1\u878d\u65f6\u62a5\u300b\n\u9884\u6d4b\uff0c\u4e2d\u56fd23\u5e74\n\u6d88\u8d39\u54c1\u96f6\u552e\u603b\u989d\n\u5c06\u589e\u957f11%\uff0c\u9884\n\u8ba1\u8fbe\u523050\u4e07\u4ebf\u5143\n\u2022 \u8054\u5408\u56fd1\u670825\u65e5\u53d1\n\u5e03\u300a2023\u5e74\u4e16\u754c\n\u7ecf\u6d4e\u5f62\u52bf\u4e0e\u5c55\u671b\u300b\n\u9884\u6d4b2023\u5e74\u4e2d\u56fd\n\u7ecf\u6d4e\u589e\u957f\u5c06\u4f1a\u52a0\u901f\uff0c\n\u8fbe\u52304.8%\n\u2022 \u591a\u5bb6\u5916\u8d44\u673a\u6784\u4e5f\u53d1\n\u8868\u4e50\u89c2\u9884\u6d4b\n\u6765\u6e90\uff1a\u56fd\u5bb6\u7a0e\u52a1\u5c40\uff1b\u56fd\u5bb6\u7535\u5f71\u5c40\uff1b\u4e2d\u56fd\u5546\u4e1a\u8054\u5408\u4f1a\u7b49\u516c\u5f00\u6570\u636e\uff1bBCG\u5206\u6790\u3002\n1. 10\u4e2a\u57ce\u5e02\u6db5\u76d6\u5317\u4eac\u3001\u4e0a\u6d77\u3001\u5e7f\u5dde\u3001\u6df1\u5733\u3001\u6210\u90fd\u3001\u91cd\u5e86\u3001\u5357\u4eac\u3001\u6b66\u6c49\u3001\u5929\u6d25\u3001\u897f\u5b89\u3002\n5\nCopyright\n\u00a9\n2022\nby\nBoston\nConsulting\nGroup.\nAll\nrights\nreserved.\n\u9884\u8ba1\u52302030\u5e74\uff0c\u4e2d\u56fd\u5c06\u518d\u589e\u52a08,000\u4e07\u4e2d\u4ea7\u53ca\u4ee5\u4e0a\u4eba\u53e3\uff0c\u5176\u4e2d\u8d85\u8fc770%\n\u65b0\u589e\u4e2d\u4ea7\u6765\u81ea\u4e8e\u4f4e\u7ebf\u57ce\u5e02\n\u6765\u6e90\uff1aBCG MAC Database \u4eba\u53e3\u6570\u636e\u5e93\u6a21\u578b\uff1bBCG\u5206\u6790\u3002\n1. 2022\u5e74\u7684\u5b9a\u4e49\u6807\u51c6\uff0c\u6bcf\u5e74\u6309\u7167CPI=2.5%\u7684\u9884\u671f\u5bf9\u5b9a\u4e49\u6807\u51c6\u8fdb\u884c\u8c03\u6574\u3002\n147\n308\n2022\u4f30\n23\n1,413\n\u4e2d\u4ea7 [9.5K-15.5K)\n325\n290\n\u4e0a\u5c42\u4e2d\u4ea7 [15.5K-29.9K)\n433\n173\n2025\u4f30\n29\n186\n339\n288\n1,401\n403\n157\n2030\u4f30\n166\n\u5bcc\u88d5\u9636\u5c42 >=29.9K\n195\n\u65b0\u5174\u4e2d\u4ea7 [6.6K-9.5K)\n\u4e0a\u5347\u4e00\u65cf [3.6K-6.6K)\n\u4f4e\u6536\u5165 <3.6K\n287\n458\n18\n1,410\n2022\u5e74\u52302030\u5e74\uff0c\u9884\u8ba1\u65b0\u589e8,000\u4e07\u4e2d\u4ea7\u53ca\u4ee5\u4e0a\u4eba\u53e3\n\u5168\u4e2d\u56fd\u4eba\u53e3\u7684\u6536\u5165\u9636\u5c42\u53d8\u5316\n\u5355\u4f4d\uff1a\u767e\u4e07\u4eba\uff0c\u6536\u5165\u9636\u5c42\uff08\u4eba\u6c11\u5e01\u5143\uff0c\u6708\u5747\u5bb6\u5ead\u7a0e\u540e\u53ef\u652f\u914d\u6536\u51651\uff09\n97\n(20%)\n61\n(13%)\n553\n134\n(28%)\n67\n(12%)\n68\n(14%)\n473\n112\n(24%)\n2022\u4f30\n110\n(20%)\nTier 5-7\n183\n(33%)\n83\n(15%)\nTier 4\n110\n(19%)\n2030\u4f30\nTier 1\nTier 2\nTier 3\n8000\u4e07\u589e\u91cf\n\u65b0\u589e\u4e2d\u4ea7\u53ca\u4ee5\u4e0a\u4eba\u53e3\u7684\u57ce\u5e02\u7ea7\u522b\u5206\u5e03\n\u5355\u4f4d\uff1a\u767e\u4e07\u4eba\n\u6700\u591a\u7684\u65b0\u589e\u4e2d\u4ea7\u53ca\u4ee5\u4e0a\u4eba\u53e3\u6765\u81ea\u4e8e\u4e09\u7ebf\u57ce\u5e02\n6\nCopyright\n\u00a9\n2022\nby\nBoston\nConsulting\nGroup.\nAll\nrights\nreserved.\n\u533b\u7597\n\u4fdd\u5065\n\u4e2a\u62a4\n\u5bb6\u6e05\n\u751f\u9c9c\n\u6709\u673a\n26%\n5%\n\u5305\u88c5\n\u996e\u98df\n20%\n20%\n2%\n27%\n11%\n\u62a4\u80a4\n\u5f69\u5986\n\u5927\u5c0f\n\u5bb6\u7535\n\u6570\u7801\n\u4ea7\u54c1\n7%\n-8%\n\u6c7d\u8f66\n\u6c7d\u914d\n13%\n\u8fd0\u52a8\n\u88c5\u5907\n13%\n5%\n\u4f11\u95f2\n\u670d\u9970\n-3%\n\u5962\u4f88\u54c1\n\u7406\u8d22\n\u4ea7\u54c1\n-9%\n-4%\n\u8d2d\u623f\n\u88c5\u4fee\n\u4e3d\u4eba\n\u670d\u52a1\n6%\n\u5174\u8da3\n\u57f9\u8bad\n\u5230\u5bb6\n\u670d\u52a1\n-10%\n\u4e13\u4e1a\n\u57f9\u8bad\n\u65f6\u5c1a\u4e0e\u5962\u4f88 \u6295\u8d44 \u751f\u6d3b\u670d\u52a1\/\u4f53\u9a8c\n\u54c1\u8d28\u6d88\u8d39\u52bf\u5934\u66f4\u731b\uff1a\u4e2d\u56fd\u6d88\u8d39\u8005\u4ecd\u7136\u5448\u73b0\u51fa\u4e3a\u201c\u66f4\u9ad8\u54c1\u8d28\u652f\n\u4ed8\u6ea2\u4ef7\u201d\u7684\u610f\u613f\uff0c\u5bf9\u54c1\u8d28\u7684\u8ffd\u6c42\u6a2a\u8de8\u5927\u591a\u6570\u6d88\u8d39\u54c1\u7c7b\n\u5404\u54c1\u7c7b\u672a\u676512\u4e2a\u6708\u9884\u671f\u4ef7\u683c\u610f\u613f\u53d8\u5316\u7684\u4eba\u6570\u51c0\u6bd4\u4f8b\uff08%\uff09\n\u4eba\u6570\n\u51c0\u6bd4\u4f8b\n\uff08%\uff09\n\u51c0\u6bd4\u4f8b(%) = \u8be5\u54c1\u7c7b\u9009\u62e9\u4ef7\u683c\u5347\u7ea7\u7684\u4eba\u6570\u5360\u6bd4(%) - \u8be5\u54c1\u7c7b\u9009\u62e9\u4ef7\u683c\u964d\u7ea7\u7684\u4eba\u6570\u5360\u6bd4(%)\n\u51c0\u6bd4\u4f8b\u4e3a\u6b63\u5219\u8868\u793a\u6d88\u8d39\u8005\u5bf9\u54c1\u7c7b\u6709\u5347\u7ea7\u610f\u613f\uff0c\u4e3a\u8d1f\u8868\u793a\u6d88\u8d39\u8005\u5bf9\u54c1\u7c7b\u504f\u5411\u964d\u7ea7\uff0c\u6570\u503c\u8d8a\u9ad8\u8868\u793a\u610f\u613f\u8d8a\u5f3a\u70c8\n\u6765\u6e90\uff1aBCG\u6d88\u8d39\u8005\u6d1e\u5bdf\u667a\u5e93-\u4e2d\u56fd\u672a\u6765\u6d88\u8d39\u8005\u8c03\u7814\uff08\u8c03\u7814\u65f6\u95f42022\u5e7410\u6708\uff0c\u6837\u672c\u91cfN=9,000\uff09\uff1bBCG\u5206\u6790\u3002\n\u98df\u54c1\n\u996e\u6599\n\u4e2a\u4eba\u53ca\u5bb6\u5ead\n\u65e5\u5316\u7528\u54c1\n\u5bb6\u5c45\u5bb6\u7535\n\u8010\u7528\u54c1\n\u533b\u7597\n\u4fdd\u5065\n\u504f\u5411\u4ef7\u683c\u5347\u7ea7\n\u504f\u5411\u4ef7\u683c\u964d\u7ea7\n7\nCopyright\n\u00a9\n2022\nby\nBoston\nConsulting\nGroup.\nAll\nrights\nreserved.\n\u4e2d\u56fd\u5f53\u524d\u603b\u4eba\u53e3\u768480%\u662f\u7531\u56db\u4e2a\u4e16\u4ee3\u6784\u6210\uff0c\u5176\u4e2dX\u548cY\u4e16\u4ee3\u7684\n\u4eba\u53e3\u6570\u91cf\u548c\u603b\u6536\u5165\u5360\u6bd4\u5747\u6392\u4f4d\u66f4\u9ad8\n\u6765\u6e90\uff1a\u7b2c\u4e03\u6b21\u5168\u56fd\u4eba\u53e3\u666e\u67e5\uff0c\u4e2d\u56fd2021\u7edf\u8ba1\u5e74\u9274\uff1bBCG\u6d88\u8d39\u8005\u6d1e\u5bdf\u667a\u5e93-\u4e2d\u56fd\u672a\u6765\u6d88\u8d39\u8005\u8c03\u7814\uff08\u8c03\u7814\u65f6\u95f42022\u5e7410\u6708\uff0c\u6837\u672c\u91cfN=9,000\uff09\uff1bBCG\u5206\u6790\u3002\n1. \u56db\u4e2a\u4e16\u4ee3\u7684\u6536\u5165\u8d21\u732e\u52a0\u603b=100%\uff0c\u56db\u4e2a\u4e16\u4ee3\u4ee5\u5916\u7684\u4eba\u7fa4\u6536\u5165\u5360\u6bd4\u5c11\uff0c\u4e0d\u7eb3\u5165\u6536\u5165\u5206\u6790\u3002\u6536\u5165\u57fa\u4e8eBCG CCI\u5b9a\u91cf\u8c03\u7814\u95ee\u5377\u7ed3\u679c\u6d4b\u7b97\u30022. \u4ee52023\u5e74\u8bb0\uff0c\u5404\u4e16\u4ee3\u5468\u5c81\u4e3a\uff0c\u5a74\u513f\u6f6e59-73\u5468\u5c81\uff0c\nX\u4e16\u4ee344-58\u5468\u5c81\uff0c Y\u4e16\u4ee329-43\u5468\u5c81\uff0cZ\u4e16\u4ee314-28\u5468\u5c81\u30023. \u672c\u62a5\u544a\u7814\u7a76\u7684Z\u4e16\u4ee3\u4ec5\u9650\u4e8e18\u5c81\u53ca\u4ee5\u4e0a\u3002\n\u6309\u5e74\u9f84\u5206\u56db\u4e2a\u4e16\u4ee3\u7684\u4eba\u53e3\u6570\u91cf\uff0c\u4eba\u53e3\u5360\u6bd4\uff0c\u6536\u5165\u5360\u6bd41\n1.2\u4ebf 8%\n2.5\u4ebf 18%\n3.3\u4ebf 23%\n3.2\u4ebf 22%\n2.3\u4ebf 17%\n1.7\u4ebf 12%\n1949\u5e74\u53ca\u4ee5\u524d -\n1950-1964\u5e74 \u5a74\u513f\u6f6e2\n1965-1979\u5e74 X\u4e16\u4ee32\n1980-1994\u5e74 Y\u4e16\u4ee32\n1995-2009\u5e743 Z\u4e16\u4ee32\n2010\u5e74\u53ca\u4ee5\u540e \u03b1\u4e16\u4ee3\n\u51fa\u751f\u5e74\u4efd \u4e16\u4ee3 \u4eba\u53e3\u6570\u91cf \u4eba\u53e3\u5360\u6bd4\n22%\n34%\n28%\n16%\n\u6536\u5165\u5360\u6bd41\n80%\n\u603b\u4eba\u53e3\n8\nCopyright\n\u00a9\n2022\nby\nBoston\nConsulting\nGroup.\nAll\nrights\nreserved.\n\u56db\u4e2a\u4e16\u4ee3\u7684\u4e2d\u56fd\u6d88\u8d39\u8005\u6210\u957f\u65f6\u671f\u7ecf\u5386\u8fe5\u5f02\uff0c\u4ece\u800c\u5f62\u6210\u4e86\u4e0d\n\u540c\u7684\u7fa4\u4f53\u8bb0\u5fc6\u3001\u4ef7\u503c\u53d6\u5411\u548c\u6d88\u8d39\u504f\u597d\n\u4e16\u4ee3\u5e74\u4efd\u5b9a\u4e49\n\u4e16\u4ee3\u6982\u8ff0\nZ\u4e16\u4ee31\n1995-2009\u5e74\u51fa\u751f\nY\u4e16\u4ee31\n1980-1994\u5e74\u51fa\u751f\nX\u4e16\u4ee31\n1965-1979\u5e74\u51fa\u751f\n\u5a74\u513f\u6f6e1\n1950-1964\u5e74\u51fa\u751f\n1950\n1960\n1965\n1970\n1975\n1980\n1985\n1990\n1995\n2000\n2005\n2010 1955\n1978\u5e74\n\u6539\u9769\n\u5f00\u653e\n\u5f00\u542f\n1964\u5e74\n\u539f\u5b50\u5f39\n\u8bd5\u7206\n\u6210\u529f\n1982\u5e74\n\u8ba1\u5212\n\u751f\u80b2\n\u8fdb\u5165\n\u56fd\u7b56\n1986\u5e74\n\u4e49\u52a1\n\u6559\u80b2\n\u5b9e\u65bd\n1992\u5e74\n\u623f\u6539\n\u5168\u9762\n\u542f\u52a8\n1994\u5e74\n\u63a5\u5165\n\u56fd\u9645\n\u7f51\u7edc\n1949\u5e74\n\u5efa\u56fd\n\u4e4b\u521d\n1959-61\u5e74\n\u4e09\u5e74\n\u81ea\u7136\n\u707e\u5bb3\n1971\u5e74\n\u8ba1\u5212\n\u751f\u80b2\n\u5f00\u59cb\n\u5ba3\u4f20\n2004\u5e74\n\u7b2c\u4e09\u65b9\n\u652f\u4ed8\n\u5de5\u5177\n\u63a8\u51fa\n2011\u5e74\n\u624b\u673a\u7aef\n\u793e\u4ea4\n\u5e94\u7528\n\u63a8\u51fa\n2001\u5e74\n\u52a0\u5165\n\u4e16\u8d38\n\u7ec4\u7ec7\n1999\u5e74\nPC\u7aef\n\u793e\u4ea4\n\u5e94\u7528\n\u63a8\u51fa\n\u5a74\u513f\u6f6e\uff1a\u751f\u4e8e\u7269\u8d28\u76f8\u5bf9\u532e\u4e4f\u7684\n\u65f6\u671f\uff0c\u793e\u4f1a\u548c\u7ecf\u6d4e\u9605\u5386\u4e30\u5bcc\uff0c\n\u5403\u82e6\u8010\u52b3\uff0c\u6709\u6d53\u539a\u7684\u96c6\u4f53\u548c\u5bb6\n\u5ead\u610f\u8bc6\nX\u4e16\u4ee3\uff1a\u6539\u9769\u6d6a\u6f6e\u7684\u4e2d\u575a\u529b\u91cf\uff0c\n\u901a\u8fc7\u5f00\u9614\u773c\u754c\uff0c\u52aa\u529b\u594b\u6597\uff0c\u5b8c\n\u6210\u793e\u4f1a\u548c\u4e2a\u4eba\u7684\u539f\u59cb\u8d22\u5bcc\u79ef\u7d2f\nY\u4e16\u4ee3\uff1a\u7b2c\u4e00\u4ee3\u72ec\u751f\u5b50\u5973\uff0c\u53d7\n\u76ca\u4e8e\u4e49\u52a1\u6559\u80b2\u7684\u666e\u53ca\uff0c\u6210\u957f\u4e8e\nPC\u7aef\u53d1\u5c55\u65f6\u671f\uff0c\u7ecf\u5386\u57ce\u5e02\u5316\u8fc1\n\u5f99\nZ\u4e16\u4ee3\uff1a\u6570\u5b57\u5316\u539f\u4f4f\u6c11\uff0c\u51fa\u751f\u4e8e\n\u5168\u7403\u5316\u7684\u9ad8\u901f\u53d1\u5c55\u65f6\u671f\uff0c\u4e60\u60ef\n\u4e8e\u901a\u8fc7\u624b\u673a\u7aef\u63a5\u6536\u6d77\u91cf\u4fe1\u606f\n2015\n2020\n2017\u5e74\n\u77ed\u89c6\u9891\n\u5e73\u53f0\n\u5174\u8d77\n2014\u5e74\n\u624b\u673a\u7aef\n\u4e0a\u7f51\n\u4eba\u6570\n\u8d85PC\n\u7cbe\u795e\u4e16\u754c\u6269\u5bb9\u7684\u4e00\u4ee3 \u7269\u8d28\u8d22\u5bcc\u79ef\u7d2f\u7684\u4e00\u4ee3\n\u81ea\u6211\u53d1\u5c55\u63d0\u901f\u7684\u4e00\u4ee3 \u575a\u5fcd\u5949\u732e\u7684\u4e00\u4ee3\n\u6765\u6e90\uff1a\u516c\u5f00\u8d44\u6599\uff1bBCG\u5206\u6790\u3002\n1. \u4ee52023\u5e74\u8bb0\uff0c\u5404\u4e16\u4ee3\u5468\u5c81\u4e3a\uff0c\u5a74\u513f\u6f6e59-73\u5468\u5c81\uff0cX\u4e16\u4ee344-58\u5468\u5c81\uff0cY\u4e16\u4ee329-43\u5468\u5c81\uff0cZ\u4e16\u4ee314-28\u5468\u5c81\u3002\n9\nCopyright\n\u00a9\n2022\nby\nBoston\nConsulting\nGroup.\nAll\nrights\nreserved.\n\u6559\u80b2\u80cc\u666f\n\u672c\u79d1\u53ca\u4ee5\u4e0a\u5b66\u5386\uff08\u6307\u65701\uff09\n\u4e2a\u4eba\u6536\u5165\n\u6708\u5747\u7a0e\u540e\u53ef\u652f\u914d\uff08\u6307\u65701\uff09\n\u804c\u4e1a\u80cc\u666f\n\u7ba1\u7406\u6216\u4e13\u4e1a\u5c97\u4f4d\uff08\u6307\u65701\uff09\nZ\u4e16\u4ee3\nY\u4e16\u4ee3\nX\u4e16\u4ee3\n\u5a74\u513f\u6f6e\nZ\u4e16\u4ee3\nY\u4e16\u4ee3\nX\u4e16\u4ee3\n\u5a74\u513f\u6f6e\nX\u4e16\u4ee3\nZ\u4e16\u4ee3\nY\u4e16\u4ee3\n\u5a74\u513f\u6f6e\n\u201cZ\u4e16\u4ee3\u201d\u53d7\u6559\u80b2\u7a0b\u5ea6\u6700\u9ad8\uff0c\u201cX\u4e16\u4ee3\u201d\u804c\u4e1a\u80cc\u666f\u548c\u6536\u5165\u76f8\n\u5bf9\u6700\u9ad8\nZ\u4e16\u4ee3\nX\u4e16\u4ee3\nY\u4e16\u4ee3\n\u5a74\u513f\u6f6e\n\u6765\u6e90\uff1aBCG\u6d88\u8d39\u8005\u6d1e\u5bdf\u667a\u5e93-\u4e2d\u56fd\u672a\u6765\u6d88\u8d39\u8005\u8c03\u7814\uff08\u8c03\u7814\u65f6\u95f42022\u5e7410\u6708\uff0c\u6837\u672c\u91cfN=9,000\uff09\uff1bBCG\u5206\u6790\u3002\n1. \u6307\u6570=\u67d0\u4e2a\u4eba\u7fa4\u7684\u7279\u5f81\u503c\/\u603b\u4f53\u4eba\u7fa4\u7684\u5e73\u5747\u503c*100\u3002\n\u2022 \u53d7\u6559\u80b2\u7a0b\u5ea6\u6700\u9ad8\n\u2022 \u6b63\u7ecf\u5386\u6821\u56ed\u5230\u804c\u573a\u7684\u8f6c\u6362\n\u2022 \u5f00\u59cb\u62e5\u6709\u72ec\u7acb\u6536\u5165\n\u2022 \u53d7\u6559\u80b2\u7a0b\u5ea6\u8f83\u9ad8\n\u2022 \u5360\u636e\u7684\u804c\u4e1a\u5730\u4f4d\u65e5\u76ca\u589e\u9ad8\n\u2022 \u6536\u5165\u968f\u4e4b\u4e0d\u65ad\u589e\u957f\n\u2022 \u53d7\u6559\u80b2\u7a0b\u5ea6\u8f83\u4f4e\n\u2022 \u5360\u636e\u7684\u804c\u4e1a\u5730\u4f4d\u4f9d\u7136\u6700\u9ad8\n\u2022 \u6536\u5165\u6c34\u5e73\u6700\u9ad8\n\u2022 \u53d7\u6559\u80b2\u7a0b\u5ea6\u6700\u4f4e\n\u2022 \u90e8\u5206\u5df2\u7ecf\u8fdb\u5165\u4e86\u9000\u4f11\u72b6\u6001\n\u2022 \u6536\u5165\u6c34\u5e73\u8f83\u9ad8 \u9ad8\n\u4f4e \u9ad8\n\u4f4e \u9ad8\n\u4f4e\n\u5747\u503c\u6c34\u5e73 \u5747\u503c\u6c34\u5e73 \u5747\u503c\u6c34\u5e73\nCopyright\n\u00a9\n2022\nby\nBoston\nConsulting\nGroup.\nAll\nrights\nreserved.\n10\n\u76ee\u5f55\n\u542f\u793a\u672a\u6765\uff1a\u5168\u9762\u770b\u5f85\u5ba2\u7fa4\uff0c\u8ffd\u8e2a\u4e16\u4ee3\u52a8\u9759\n\u4ee3\u9645\u7279\u5f81\uff1a\u65f6\u4ee3\u53d8\u8fc1\u4e0b\u7684\u4ee3\u9645\u9700\u6c42\u548c\u5dee\u5f02\n\u5b8f\u89c2\u80cc\u666f\uff1a\u4e2d\u56fd\u6d88\u8d39\u97e7\u6027\u53ca\u4e16\u4ee3\u4eba\u7fa4\u8fc1\u79fb\n11\nCopyright\n\u00a9\n2022\nby\nBoston\nConsulting\nGroup.\nAll\nrights\nreserved.\nZ\u4e16\u4ee3\uff1a\u5708\u5c42\u521b\u751f\uff0c\u6cbb\u6108\u4eab\u4e50\nY\u4e16\u4ee3\uff1a\u4e13\u4e1a\u52a9\u529b\uff0c\u7701\u65f6\u589e\u6548\nX\u4e16\u4ee3\uff1a\u8eab\u4efd\u793e\u4ea4\uff0c\u54c1\u8d28\u5f70\u663e\n\u5a74\u513f\u6f6e\uff1a\u7ebf\u4e0a\u4e50\u6d3b\uff0c\u4e2d\u5f0f\u517b\u751f\n12\nCopyright\n\u00a9\n2022\nby\nBoston\nConsulting\nGroup.\nAll\nrights\nreserved.\n\u50a8\u84c4\u610f\u613f\n\u4eba\u6570\u5360\u6bd4\u51c0\u503c\uff08\u589e\u52a0%-\u51cf\u5c11%\uff09\n\u6d88\u8d39\u610f\u613f\n\u4eba\u6570\u5360\u6bd4\u51c0\u503c\uff08\u589e\u52a0%-\u51cf\u5c11%\uff09\n\u6295\u8d44\u610f\u613f\n\u4eba\u6570\u5360\u6bd4\u51c0\u503c\uff08\u589e\u52a0%-\u51cf\u5c11%\uff09\nX\u4e16\u4ee3\u672a\u96e8\u7ef8\u7f2a\uff0c\u4e3b\u52a8\u63d0\u9ad8\u6297\u98ce\u9669\u80fd\u529b\uff1bZ\u4e16\u4ee3\u5728\u6709\u9650\u7684\u80fd\u529b\n\u8303\u56f4\u5185\u60f3\u82b1\u5c31\u82b1\n\u6765\u6e90\uff1aBCG\u6d88\u8d39\u8005\u6d1e\u5bdf\u667a\u5e93-\u4e2d\u56fd\u672a\u6765\u6d88\u8d39\u8005\u8c03\u7814\uff08\u8c03\u7814\u65f6\u95f42022\u5e7410\u6708\uff0c\u6837\u672c\u91cfN=9,000\uff09\uff1bBCG\u5206\u6790\u3002\n\u7f29\u51cf\u987a\u5e8f\uff1a\u6295\u8d44>\u50a8\u84c4>\u6d88\u8d39\n\u7f29\u51cf\u987a\u5e8f\uff1a\u6295\u8d44>\u50a8\u84c4>\u6d88\u8d39\n\u7f29\u51cf\u987a\u5e8f\uff1a\u6d88\u8d39>\u6295\u8d44>\u50a8\u84c4\n\u7f29\u51cf\u987a\u5e8f\uff1a\u6295\u8d44>\u6d88\u8d39>\u50a8\u84c4\nZ\u4e16\u4ee3\nX\u4e16\u4ee3\nY\u4e16\u4ee3\n\u5a74\u513f\u6f6e\nZ\u4e16\u4ee3\nY\u4e16\u4ee3\nX\u4e16\u4ee3\n\u5a74\u513f\u6f6e\nZ\u4e16\u4ee3\nX\u4e16\u4ee3\nY\u4e16\u4ee3\n\u5a74\u513f\u6f6e\n\u9ad8\n\u4f4e \u9ad8\n\u4f4e \u9ad8\n\u4f4e\n\u5747\u503c\u6c34\u5e73-6.1% \u5747\u503c\u6c34\u5e73-10.6% \u5747\u503c\u6c34\u5e73-7.5%\nZ\u4e16\u4ee3\nX\u4e16\u4ee3\nY\u4e16\u4ee3\n\u5a74\u513f\u6f6e\n13\nCopyright\n\u00a9\n2022\nby\nBoston\nConsulting\nGroup.\nAll\nrights\nreserved.\nX\u548cY\u4e16\u4ee3\u5728\u5927\u591a\u6570\u54c1\u7c7b\u4e0a\u5e74\u6d88\u8d39\u652f\u51fa\u90fd\u9886\u5148\u4e8e\u5176\u4ed6\u4e24\u4e2a\u4e16\u4ee3\uff0c\n\u662f\u672a\u6765\u6d88\u8d39\u4e3b\u529b\n\u6765\u6e90\uff1aBCG\u6d88\u8d39\u8005\u6d1e\u5bdf\u667a\u5e93-\u4e2d\u56fd\u672a\u6765\u6d88\u8d39\u8005\u8c03\u7814\uff08\u8c03\u7814\u65f6\u95f42022\u5e7410\u6708\uff0c\u6837\u672c\u91cfN=9,000\uff09\uff1bBCG\u5206\u6790\u3002\n1. 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Z\u4e16\u4ee3\u8fd8\u672a\u7ecf\u6d4e\u72ec\u7acb\uff0c\u90e8\u5206\u6d88\u8d39\u7531\u7236\u6bcd\u652f\u51fa\u3002\n82\n113 101 98\nZ\u4e16\u4ee32 \u5a74\u513f\u6f6e\nY\u4e16\u4ee3 X\u4e16\u4ee3\n69\n112\n128\n102\nZ\u4e16\u4ee32 Y\u4e16\u4ee3 X\u4e16\u4ee3 \u5a74\u513f\u6f6e\n76\n106\n134\n84\nZ\u4e16\u4ee32 Y\u4e16\u4ee3 \u5a74\u513f\u6f6e\nX\u4e16\u4ee3\n78\n117 117\n82\nX\u4e16\u4ee3\nZ\u4e16\u4ee32 Y\u4e16\u4ee3 \u5a74\u513f\u6f6e\n\u5747\u503c=100\n\u5747\u503c=100\n\u5747\u503c=100\n\u5747\u503c=100\n\u5065\u5eb7\u4e0e\u751f\u6d3b\u65b9\u5f0f\n\u751f\u6d3b\u5fc5\u9700\u578b\u6d88\u8d39\n\u5e73\u4ef7\u4eab\u53d7\u578b\u6d88\u8d39\n\u9ad8\u7aef\u4ea7\u54c1\u548c\u670d\u52a1\n\u5e74\u4eba\u5747\u54c1\u7c7b\u6d88\u8d39\u7684\u672a\u6765\u9884\u671f\uff08\u6307\u65701\uff09\n\u6d88\u8d39\u6700\u9ad8\u7684\u4e24\u7c7b\u4eba\u7fa4\n\u9ad8\u7aef\u4ea7\u54c1\u670d\u52a1\n\u4f11\u95f2\u65c5\u6e38\uff0c\u5962\u4f88\u54c1\uff0c\n\u6c7d\u8f66\uff0c\u9ad8\u7aef\u9910\u996e\n\u65e5\u5e38\u4eab\u53d7\u578b\n\u5916\u51fa\u5c31\u9910\uff0c\u65e0\u9152\u7cbe\u996e\n\u6599\uff0c\u65f6\u5c1a\u4f11\u95f2\u670d\u9970\uff0c\n\u5927\u5c0f\u5bb6\u7535\u5bb6\u5177\u5bb6\u5c45\n\u5065\u5eb7\u4e0e\u751f\u6d3b\u65b9\u5f0f\n\u81b3\u98df\u8425\u517b\u8865\u5145\u5242\uff0c\u5404\n\u7c7b\u6237\u5916\u6d3b\u52a8\uff0c\u8fd0\u52a8\u978b\n\u53ca\u88c5\u5907\uff0c\u533b\u7f8e\uff0c\u4eba\u5bff\n\u53ca\u5065\u5eb7\u9669\n\u751f\u6d3b\u5fc5\u9700\u578b\n\u751f\u9c9c\u98df\u54c1\u53ca\u534a\u6210\u54c1\u3001\n\u5bb6\u6e05\u53ca\u4e2a\u62a4\n14\nCopyright\n\u00a9\n2022\nby\nBoston\nConsulting\nGroup.\nAll\nrights\nreserved.\n\u56db\u4e2a\u4e16\u4ee3\u7684\u5728\u89c2\u5ff5\u548c\u6001\u5ea6\u4e0a\u4e5f\u5b58\u5728\u9c9c\u660e\u5dee\u5f02\n\u751f\u6d3b\u6001\u5ea6 \u6211\u4eab\u53d7\u72ec\u5904\u65f6\u5149\n\u4fdd\u6301\u4e2a\u6027\u5f88\u91cd\u8981\n\u5e0c\u671b\u4ed6\u4eba\u8ba4\u53ef\u6211\u7684\u6210\u529f\n\u4e2d\u5eb8\u6ca1\u4ec0\u4e48\u4e0d\u597d\n\u6211\u5f88\u9700\u8981\u793e\u4ea4\u548c\u5f52\u5c5e\u611f\n\u793e\u4f1a\u89c2\u5ff5 \u6211\u5173\u5fc3\u548c\u8ba8\u8bba\u56fd\u5bb6\u65f6\u4e8b\n\u5e0c\u671b\u4e0e\u4e2d\u56fd\u6587\u5316\u4fdd\u6301\u8fde\u63a5\n\u6211\u559c\u6b22\u9075\u5b88\u89c4\u5219\n\u6d88\u8d39\u7406\u5ff5 \u613f\u610f\u4e3a\u597d\u4f53\u9a8c\u4e0e\u670d\u52a1\u652f\u4ed8\u6ea2\u4ef7\n\u6211\u7ecf\u5e38\u7292\u8d4f\u81ea\u5df1\n\u503e\u5411\u4e8e\u8d2d\u4e70\u540d\u724c\n\u6d88\u8d39\u524d\u6211\u4f1a\u591a\u65b9\u6536\u96c6\u4fe1\u606f\n\u6211\u603b\u662f\u8bd5\u56fe\u5bfb\u627e\u9ad8\u6027\u4ef7\u6bd4\u9009\u62e9\nZ\u4e16\u4ee3 X\u4e16\u4ee3\nY\u4e16\u4ee3 \u5a74\u513f\u6f6e\n\u76f8\u5bf9\u9ad8\u4e8e\u5747\u503c \u76f8\u5bf9\u4f4e\u4e8e\u5747\u503c\n\u6765\u6e90\uff1aBCG\u6d88\u8d39\u8005\u6d1e\u5bdf\u667a\u5e93-\u4e2d\u56fd\u672a\u6765\u6d88\u8d39\u8005\u8c03\u7814\uff08\u8c03\u7814\u65f6\u95f42022\u5e7410\u6708\uff0c\u6837\u672c\u91cfN=9,000\uff09\uff1bBCG\u5206\u6790\u3002\n\u89c2\u5ff5\u6001\u5ea6\u7684\u91cd\u8981\u6027\u6253\u5206\n\u72ec\u7acb\u4e2a\u6027\u3001\u6587\u5316\u81ea\u4fe1\n\u5bf9\u6210\u529f\u7684\u5b9a\u4e49\u591a\u5143\u5316\n\u6ce8\u91cd\u6027\u4ef7\u6bd4\n\u6ce8\u91cd\u793e\u4ea4\u5f52\u5c5e\u548c\u65f6\u4e8b\n\u8ffd\u5bfb\u4f20\u7edf\u610f\u4e49\u7684\u6210\u529f\n\u4ee5\u201c\u540d\u724c\u201d\u7292\u8d4f\u81ea\u5df1\n\u4f20\u7edf\u4fdd\u5b88\u5e76\u575a\u5b88\u89c4\u5219\n\u5728\u95f2\u6687\u4e2d\u63a2\u7d22\u65b0\u7684\u81ea\u6211\n\u4ee5\u201c\u540d\u724c\u201d\u7292\u8d4f\u81ea\u5df1\n\u5c0a\u91cd\u548c\u9075\u5b88\u89c4\u5219\n\u4fe1\u4efb\u4e13\u4e1a\u54c1\u724c\u548c\u670d\u52a1\n\u8ffd\u6c42\u6548\u679c\u4e0e\u6548\u7387\n15\nCopyright\n\u00a9\n2022\nby\nBoston\nConsulting\nGroup.\nAll\nrights\nreserved.\n\u5174\u8da3\u7231\u597d\u65b9\u9762\uff0c\u5404\u4e16\u4ee3\u7684\u7279\u5f81\u4e5f\u5f88\u663e\u8457\n\u6765\u6e90\uff1a\u6d1e\u5bdf\u89c2\u70b9\u6765\u81ea\u5de8\u91cf\u7b97\u6570\u300c\u767e\u5927\u5174\u8da3\u65cf\u7fa4\u300d 2.0 \u6807\u7b7e\u4f53\u7cfb\uff1bBCG\u5206\u6790\u3002\n\u504f\u597d\u7a0b\u5ea6\n\u9ad8\n\u4f4e\n\u65cf\u7fa4\n\u5b85\u821e\u7c89\n\u4e3b\u673a\u73a9\u5bb6\n\u6f2b\u5c55\u96c6\u90ae\u65cf\n\u65b0\u6f6e\u8fd0\u52a8\u7231\u597d\u8005\n\u6570\u7801\u6444\u5f71\u8fbe\u4eba\n\u659c\u6760\u9752\u5e74\n\u624b\u529e\u6536\u85cf\u5bb6\n\u533b\u7f8e\u7231\u597d\u8005\n\u65cf\u7fa4\n\u8dd1\u53cb\n\u623f\u8f66\u65c5\u884c\u515a\n\u91d1\u66f2\u6b4c\u8ff7\n\u4f11\u95f2\u6e38\u620f\u73a9\u5bb6\n\u745c\u4f3d\u7231\u597d\u8005\n\u5bb6\u7535\u53d1\u70e7\u53cb\n\u8ffd\u5267\u8fbe\u4eba\n\u4e50\u56ed\u5de1\u6e38\u5bb6\n\u65cf\u7fa4\n\u996e\u98df\u517b\u751f\u65cf\n\u533b\u4fdd\u89c4\u5212\u5bb6\n\u7a33\u5065\u7406\u8d22\u5bb6\n\u8dd1\u53cb\n\u7530\u56ed\u6d41\u8fde\u5ba2\n\u5bb6\u5ead\u5f71\u97f3\u515a\n\u98ce\u6295\u5192\u9669\u5bb6\n\u5bb6\u7535\u53d1\u70e7\u53cb\n\u65cf\u7fa4\n\u996e\u98df\u517b\u751f\u65cf\n\u533b\u4fdd\u89c4\u5212\u5bb6\n\u7ea2\u8272\u6587\u5316\u7231\u597d\u8005\n\u5e7f\u573a\u821e\u8fbe\u4eba\n\u65f6\u5c1a\u94f6\u53d1\u65cf\n\u65c5\u5c45\u5019\u9e1f\u4e00\u65cf\n\u94c1\u6746\u519b\u8ff7\n\u751f\u6d3b\u653b\u7565\u5927\u5e08\nZ\u4e16\u4ee3\n\u8ffd\u9010\u5708\u5c42\uff0c\u7d27\u8ddf\u6f6e\u6d41\nX\u4e16\u4ee3\n\u63d0\u5347\u5bb6\u5ead\u751f\u6d3b\u54c1\u8d28\nY\u4e16\u4ee3\n\u5927\u4f17\u5a31\u4e50\uff0c\u6cdb\u8fd0\u52a8\n\u5a74\u513f\u6f6e\n\u6000\u65e7\u7ecf\u5178\uff0c\u4e50\u4eab\u5eb7\u517b\n16\nCopyright\n\u00a9\n2022\nby\nBoston\nConsulting\nGroup.\nAll\nrights\nreserved.\n\u201cZ\u4e16\u4ee3\u201d\u7684\u753b\u50cf\n\u89c2\u5ff5\u6001\u5ea6\n\u4e2a\u6027\u5316\u4e0e\u72ec\u7acb\n\u6210\u957f\u4e8e\u7269\u8d28\u751f\u6d3b\u6781\u5927\u4e30\u5bcc\u4e14\n\u4fe1\u606f\u7206\u70b8\u7684\u65f6\u4ee3\uff0c\u5584\u4e8e\u5bf9\u6bd4\n\u548c\u7814\u7a76\uff0c\u4e0d\u76f2\u4ece\n\u591a\u5143\u5316\u7684\u6210\u529f\u5b9a\u4e49\n\u4f5b\u7cfb\u4e2d\u5eb8\u4e0d\u662f\u8eba\u5e73\uff0c\u800c\u662f\u8ba4\n\u4e3a\u6210\u529f\u7684\u5b9a\u4e49\u662f\u591a\u6837\u7684\uff0c\u4e0d\n\u6267\u8457\u4e8e\u4f20\u7edf\u5b9a\u4e49\u7684\u51fa\u7c7b\u62d4\u8403\n\u6587\u5316\u81ea\u4fe1\n\u5728\u6210\u957f\u4e2d\u89c1\u8bc1\u7956\u56fd\u5f3a\u76db\uff0c\u6b23\n\u8d4f\u4e0e\u4e2d\u56fd\u6587\u5316\u5173\u8054\u7684\u4e1c\u897f\uff0c\n\u6301\u7eed\u884d\u751f\u4e9a\u6587\u5316\u548c\u5c0f\u4f17\u5708\u5c42\n\u6d88\u8d39\u9700\u6c421\n\u2022 \u81ea\u6211\u72ec\u7acb\uff1a\u770b\u91cd\u5f70\u663e\u4e2a\u4eba\u54c1\u5473\uff0c\u62d2\u7edd\u5343\u7bc7\u4e00\u5f8b\n\u2022 \u56de\u5f52\u4eab\u4e50\uff1a\u8ffd\u6c42\u653e\u677e\u6cbb\u6108\uff0c\u8fdc\u79bb\u55a7\u56a3\uff0c\u671f\u5f85\u597d\u73a9\u6709\u8da3\n\u2022 \u57fa\u7840\u529f\u80fd\uff1a\u597d\u7684\u6027\u4ef7\u6bd4\u662f\u6807\u914d\uff0c\u540c\u65f6\u8981\u5feb\u6377\uff0c\u53ef\u9760\n\u6765\u6e90\uff1aBCG\u6d88\u8d39\u8005\u6d1e\u5bdf\u667a\u5e93-\u4e2d\u56fd\u672a\u6765\u6d88\u8d39\u8005\u8c03\u7814\uff08\u8c03\u7814\u65f6\u95f42022\u5e7410\u6708\uff0c\u6837\u672c\u91cfN=9,000\uff09\uff1bBCG\u5206\u6790\u3002\n1. \u6d88\u8d39\u9700\u6c42\u4e0b\u65b9\u4e3a\u6807\u51c6\u5316\u7684\u9700\u6c42\u5f97\u5206\uff0c\u4ee5\u7b2c\u4e00\u4e2a\u7ef4\u5ea6\u4e3a\u4f8b\uff0c\u5206\u503c=0\u8bf4\u660e\u4e0e\u603b\u4f53\u4eba\u7fa4\u6c34\u5e73\u76f8\u5f53\uff0c\u5206\u503c>0\u8bf4\u660e\u66f4\u770b\u91cd\u81ea\u6211\u72ec\u7acb\uff0c\u5206\u503c<0\u8bf4\u660e\u66f4\u770b\u91cd\u878d\u5165\u4ed6\u4eba\u3002\n0\u5206\u503c\u7ebf 0\u5206\u503c\u7ebf 0\u5206\u503c\u7ebf\n17\nCopyright\n\u00a9\n2022\nby\nBoston\nConsulting\nGroup.\nAll\nrights\nreserved.\n\u201cZ\u4e16\u4ee3\u201d\uff1a\u5708\u5c42\u521b\u751f\n\u5708\u5c42 \u6d3b\u52a8 \u5708\u5c42\u5185\u7279\u6709\u7684\u8bed\u8a00\u4f53\u7cfb\n\u4f11\u95f2\u6237\u5916\n\u9732\u8425 Glamping\uff0c\u8425\u5730\uff0cBush Craft\uff0c\u6e29\u6807\uff0cR\u503c\u2026\n\u98de\u76d8 \u6781\u9650\u98de\u76d8\uff0c\u8eb2\u907f\u98de\u76d8\uff0c\u957f\u4f20\uff0c\u8bfb\u79d2\uff0c\u76d8\u6743\u4ea4\u6362\u2026\n\u4e13\u4e1a\u6237\u5916\n\u5f92\u6b65 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0\u5206\u503c\u7ebf\n20\nCopyright\n\u00a9\n2022\nby\nBoston\nConsulting\nGroup.\nAll\nrights\nreserved.\n\u201cY\u4e16\u4ee3\u201d\uff1a\u4e13\u4e1a\u52a9\u529b\n\u4f5c\u4e3a\u72ec\u751f\u5b50\u5973\u7684\u7b2c\u4e00\u4ee3\uff0c\u5728\u6210\u957f\u4e2d\u901a\u5e38\u51dd\u805a\u4e86\u6574\u4e2a\u5bb6\u5ead\u7684\u8d44\u6e90\u548c\u671f\u671b\uff0c\u4e0d\u754f\u7ade\u4e89\uff0c\u52c7\u4e8e\u7ade\u4e89\u7684\u4e00\u4ee3\u3002\u6709\u660e\n\u786e\u7684\u76ee\u6807\u9a71\u52a8\uff0c\u4e60\u60ef\u501f\u529b\u4e13\u4e1a\u670d\u52a1\u548c\u4ea7\u54c1\u6765\u66f4\u597d\u5730\u5b9e\u73b0\u76ee\u6807\uff0c\u5e76\u4e50\u610f\u4e3a\u4e13\u4e1a\u4ed8\u8d39\n\u5168\u65b9\u4f4d\u57f9\u517b\u4e0b\u4e00\u4ee3\uff0c\u4f18\u9009\u4e13\u4e1a\u65b9\u6848\u63d0\u5347\u9e21\u5a03\u6548\u679c\n\u6765\u6e90\uff1a 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Y\u4e16\u4ee3 X\u4e16\u4ee3 \u5a74\u513f\u6f6e\n1 2\n22\nCopyright\n\u00a9\n2022\nby\nBoston\nConsulting\nGroup.\nAll\nrights\nreserved.\n\u201cX\u4e16\u4ee3\u201d\u7684\u753b\u50cf\n\u89c2\u5ff5\u6001\u5ea6\n\u793e\u4ea4\u878d\u5165\u4e0e\u5f52\u5c5e\n\u5bf9\u878d\u5165\u4ed6\u4eba\u975e\u5e38\u770b\u91cd\uff0c\u4ed6\u4eec\n\u79ef\u6781\u7ef4\u62a4\u793e\u4ea4\u5173\u7cfb\uff0c\u5e0c\u671b\u4ece\n\u4e2d\u83b7\u5f97\u5f52\u5c5e\u611f\u4e0e\u8eab\u4efd\u8ba4\u540c\n\u8ffd\u6c42\u4f20\u7edf\u7684\u6210\u529f\n\u5728\u8d22\u5bcc\u548c\u5730\u4f4d\u4e0a\u62d2\u7edd\u4e2d\u5eb8\uff0c\n\u4e89\u5f97\u4f20\u7edf\u5b9a\u4e49\u7684\u6210\u529f\u662f\u4e00\u79cd\n\u5171\u8bc6\n\u4e0e\u65f6\u4ff1\u8fdb\n\u5e76\u4e0d\u5b88\u65e7\uff0c\u613f\u610f\u63a5\u7eb3\u65b0\u89c2\u5ff5\n\u548c\u65b0\u4e8b\u7269\uff0c\u4ee5\u6b64\u5f70\u663e\u81ea\u8eab\u7684\n\u5f00\u653e\u53ca\u4e0e\u65f6\u4ff1\u8fdb\n\u6d88\u8d39\u9700\u6c421\n\u2022 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0\u5206\u503c\u7ebf\n23\nCopyright\n\u00a9\n2022\nby\nBoston\nConsulting\nGroup.\nAll\nrights\nreserved.\n\u201cX\u4e16\u4ee3\u201d\uff1a\u8eab\u4efd\u793e\u4ea4\n\u201cX\u4e16\u4ee3\u201d\u6ce8\u91cd\u793e\u4ea4\u878d\u5165\uff0c\u8ffd\u5bfb\u5e76\u8ba4\u53ef\u4f20\u7edf\u610f\u4e49\u4e0a\u7684\u6210\u529f\u3002\u548cZ\u4e16\u4ee3\u559c\u7231\u7684\u865a\u62df\u4e16\u754c\u793e\u4ea4\u4e0d\u540c\uff0cX\u4e16\u4ee3\u66f4\u5e0c\n\u671b\u5728\u7ebf\u4e0b\u793e\u4ea4\u4e2d\u5f70\u663e\u8eab\u4efd\uff0c\u5bfb\u6c42\u4e0e\u7fa4\u4f53\u7684\u5339\u914d\uff0c\u4fc3\u8fdb\u793e\u4f1a\u5173\u7cfb\u7684\u7ef4\u62a4\n\u4ee5\u201c\u54c1\u724c\u201d\u7292\u8d4f\u81ea\u5df1\n\u4e2d\u9ad8\u7aef\u793e\u4ea4\u878d\u5165\u573a\u6240\u7684\u4e3b\u529b\u5ba2\u7fa4\n\u6765\u6e90\uff1aBCG\u6d88\u8d39\u8005\u6d1e\u5bdf\u667a\u5e93-\u4e2d\u56fd\u672a\u6765\u6d88\u8d39\u8005\u8c03\u7814\uff08\u8c03\u7814\u65f6\u95f42022\u5e7410\u6708\uff0c\u6837\u672c\u91cfN=9,000\uff09\uff1bBCG\u5206\u6790\u3002\n1. 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X\u4e16\u4ee3\u5728\u8d2d\u623f\u8fc7\u7a0b\u4e2d\uff0c\u5bf9\u5c45\u4f4f\u54c1\u8d28\u76f8\u5173\u56e0\u7d20\u7684\u5173\u6ce8\u6700\u9ad8\n0.77\n1.05 1.07\n0.77\nZ\u4e16\u4ee3 Y\u4e16\u4ee3 X\u4e16\u4ee3 \u5a74\u513f\u6f6e\n\u5404\u4e16\u4ee3\u8fc7\u53bb3\u5e74\u8d2d\u4e70\u8fc7\u4f4f\u623f\u7684\u4eba\u6570\u6bd4\u4f8b\uff08%\uff09\n3%\n8%\n11%\n6%\nZ\u4e16\u4ee3 Y\u4e16\u4ee3 \u5a74\u513f\u6f6e\nX\u4e16\u4ee3\n\u5c45\u4f4f\u54c1\u8d28\n\u5173\u6ce8\u6bd4\u4f8b1\n57% 59% 62% 55%\n25\nCopyright\n\u00a9\n2022\nby\nBoston\nConsulting\nGroup.\nAll\nrights\nreserved.\n\u201c\u5a74\u513f\u6f6e\u201d\u7684\u753b\u50cf\n\u89c2\u5ff5\u6001\u5ea6\n\u91cd\u62fe\u81ea\u6211\n\u72ec\u5904\u81ea\u8db3\uff0c\u4e0d\u518d\u9700\u8981\u9891\u7e41\u793e\n\u4ea4\u6216\u5411\u4ed6\u4eba\u8bc1\u660e\u81ea\u5df1\uff0c\u800c\u662f\n\u5fe0\u4e8e\u81ea\u6211\u7684\u9700\u8981\n\u6000\u65e7\u4f20\u7edf\n\u8ba4\u77e5\u548c\u884c\u4e3a\u4e60\u60ef\u4ecd\u504f\u5411\u4f20\u7edf\n\u4e0e\u7a33\u59a5\uff0c\u504f\u5411\u505a\u51fa\u81ea\u5df1\u8ba4\u77e5\n\u8303\u56f4\u5185\u7684\u9009\u62e9\n\u5f00\u542f\u659c\u6760\u4eba\u751f\n\u62e5\u6709\u66f4\u591a\u7684\u95f2\u6687\u65f6\u5149\u548c\u66f4\u5c11\n\u7684\u5bb6\u5ead\u8d1f\u62c5\uff0c\u901a\u8fc7\u57f9\u517b\u5174\u8da3\n\u83b7\u5f97\u4e86\u591a\u91cd\u8eab\u4efd\n\u6d88\u8d39\u9700\u6c421\n\u2022 \u81ea\u6211\u72ec\u7acb\uff1a\u72ec\u5904\u81ea\u8db3\uff0c\u770b\u91cd\u81ea\u5df1\u5bf9\u751f\u6d3b\u7684\u638c\u63a7\u611f\n\u2022 \u7ade\u4e89\u5f15\u9886\uff1a\u9700\u8981\u5f97\u5230\u4ed6\u4eba\u5c0a\u91cd\uff0c\u4f46\u4e5f\u4eab\u53d7\u95f2\u5728\u81ea\u5f97\u7684\u751f\u6d3b\n\u2022 \u8fdb\u9636\u529f\u80fd\uff1a\u4fe1\u8d56\u77e5\u540d\u54c1\u724c\uff0c\u613f\u610f\u4e3a\u597d\u7684\u4f53\u9a8c\u652f\u4ed8\u6ea2\u4ef7\n\u6765\u6e90\uff1aBCG\u6d88\u8d39\u8005\u6d1e\u5bdf\u667a\u5e93-\u4e2d\u56fd\u672a\u6765\u6d88\u8d39\u8005\u8c03\u7814\uff08\u8c03\u7814\u65f6\u95f42022\u5e7410\u6708\uff0c\u6837\u672c\u91cfN=9,000\uff09\uff1bBCG\u5206\u6790\u3002\n1. \u6d88\u8d39\u9700\u6c42\u4e0b\u65b9\u4e3a\u6807\u51c6\u5316\u7684\u9700\u6c42\u5f97\u5206\uff0c\u4ee5\u7b2c\u4e00\u4e2a\u7ef4\u5ea6\u4e3a\u4f8b\uff0c\u5206\u503c=0\u8bf4\u660e\u4e0e\u603b\u4f53\u4eba\u7fa4\u6c34\u5e73\u76f8\u5f53\uff0c\u5206\u503c>0\u8bf4\u660e\u66f4\u770b\u91cd\u81ea\u6211\u72ec\u7acb\uff0c\u5206\u503c<0\u8bf4\u660e\u66f4\u770b\u91cd\u878d\u5165\u4ed6\u4eba\u3002\n0\u5206\u503c\u7ebf 0\u5206\u503c\u7ebf 0\u5206\u503c\u7ebf\n26\nCopyright\n\u00a9\n2022\nby\nBoston\nConsulting\nGroup.\nAll\nrights\nreserved.\n\u201c\u5a74\u513f\u6f6e\u201d\uff1a\u7ebf\u4e0a\u4e50\u6d3b\n17%\n2017\n7%\n4%\n48%\n46%\n14%\n9%\n4%\n2018\n724\n23%\n15%\n10%\n5%\n20%\n2020\n21%\n43%\n2021\n13%\n6%\n41%\n17%\n16%\n7%\n\u5a74\u513f\u6f6e\n49%\nY\u4e16\u4ee3\nX\u4e16\u4ee3\n2019\n27%\n\u5176\u4ed6\u5e74\u9f84\u6bb5\nZ\u4e16\u4ee3\n13%\n25%\n833\n779\n932\n983\n\u201c\u5a74\u513f\u6f6e\u201d\u62e5\u6709\u66f4\u591a\u7684\u95f2\u6687\u65f6\u5149\u548c\u66f4\u5c11\u7684\u5bb6\u5ead\u8d1f\u62c5\uff0c\u4ed6\u4eec\u5f00\u59cb\u91cd\u62fe\u81ea\u6211\uff0c\u5e76\u901a\u8fc7\u62e5\u62b1\u4e92\u8054\u7f51\uff0c\u53d1\u5c55\u51fa\u4e0d\u540c\n\u7684\u5174\u8da3\u7231\u597d\uff0c\u5f00\u542f\u62e5\u6709\u591a\u91cd\u8eab\u4efd\u7684\u659c\u6760\u4eba\u751f\uff0c\u5b9e\u73b0\u8001\u6709\u6240\u4e50\u7684\u4eab\u8001\u751f\u6d3b\n\u4e2d\u56fd\u4e92\u8054\u7f51\u793e\u4ea4\u5e73\u53f0\u4f7f\u7528\u8005\u4eba\u6570\u53ca\u5e74\u9f84\u7ed3\u6784\u53d8\u5316\n\uff08\u5355\u4f4d\uff1a\u767e\u4e07\u4eba\uff09\n\u5360\u6bd4\u53d8\u5316\n-7%\n-9%\n+4%\n+9%\n+3%\n\u6765\u6e90\uff1a BCG\u5206\u6790\uff1beMarketer\u5168\u7403\u5e02\u573a\u7814\u7a76\u673a\u6784\u3002\n\u201c\u5a74\u513f\u6f6e\u201d\u6210\u4e3a\u4e92\u8054\u7f51\u7684\u4e3b\u8981\u589e\u91cf\u6765\u6e90\n\u70ed\u95e8\u8001\u5e74KOL \u4f8b: \u6296\u97f3\u5e73\u53f0\u7c89\u4e1d\u6570\uff08\u4e07\uff09 \u5185\u5bb9\u9898\u6750\n\u6211\u662f\u7530\u59e5\u59e5 3633.1 \u65b0\u519c\u6751\u7684\u8da3\u5473\u751f\u6d3b\n\u53ea\u7a7f\u9ad8\u8ddf\u978b\u7684\n\u6c6a\u5976\u5976\n1399.9 \u8001\u5e74\u7684\u6f6e\u6d41\u7a7f\u642d\n\u8001\u996d\u9aa8 1319.0 \u53a8\u827a\u4e0e\u70f9\u996a\u7684\u6280\u5de7\n\u672b\u90a3\u5927\u53d4 1712.7 \u8001\u5e74\u7684\u7cbe\u81f4\u751f\u6d3b\n\u901a\u8fc7\u4e92\u8054\u7f51\u57f9\u517b\u5174\u8da3\uff0c\u5f00\u542f\u659c\u6760\u4eba\u751f\n\u2022 \u89c6\u9891\u5185\u5bb9\u4ee5\u5176\u6613\u64cd\u4f5c\uff0c\u7b97\u6cd5\u63a8\u8350\uff0c\u6d77\u91cf\u5185\u5bb9\u7b49\u7279\u6027\uff0c\u4e3a\u201c\u5a74\u513f\u6f6e\u201d\u6253\n\u53d1\u95f2\u6687\u65f6\u95f4\u63d0\u4f9b\u4e86\u65b0\u9009\u62e9\uff0c\u4f18\u8d28\u5185\u5bb9\u4e5f\u52a9\u63a8\u4e86\u5174\u8da3\u7684\u57f9\u517b\n\u2022 \u6296\u97f3\u3001\u5feb\u624b\u7b49\u77ed\u89c6\u9891\u5e73\u53f0\u4e0d\u4e4f\u8001\u5e74KOL\uff0c\u4ee5\u94f6\u53d1\u751f\u6d3b\u7684\u65b9\u65b9\u9762\u9762\u4e3a\u9898\n\u6750\uff0c\u62e5\u6709\u4e86\u73b0\u5b9e\u751f\u6d3b\u4e4b\u5916\u7684\u591a\u91cd\u8eab\u4efd\uff0c\u83b7\u5f97\u767e\u4e07\u3001\u5343\u4e07\u7c89\u4e1d\u7684\u559c\u7231\n27\nCopyright\n\u00a9\n2022\nby\nBoston\nConsulting\nGroup.\nAll\nrights\nreserved.\n\u201c\u5a74\u513f\u6f6e\u201d\uff1a\u4e2d\u5f0f\u517b\u751f\n\u89c2\u5ff5\u4f20\u7edf\uff0c\u6ce8\u91cd\u517b\u751f\u7684\u201c\u5a74\u513f\u6f6e\u201d\uff0c\u5bf9\u4fdd\u6301\u957f\u5bff\u548c\u6d3b\u529b\u6000\u6709\u7f8e\u597d\u7684\u613f\u671b\uff0c\u79c9\u6301\u4ee5\u517b\u4e3a\u4e3b\uff0c\u533b\u517b\u7ed3\u5408\u7684\u4e2d\u5f0f\n\u7406\u5ff5\uff0c\u9752\u7750\u836f\u98df\u540c\u6e90\u6982\u5ff5\u7684\u5546\u54c1\n\u6765\u6e90\uff1a 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\u3001X\u4e16\u4ee3\u3001\u5a74\u513f\u6f6e\u7684\u7406\n\u5ff5\u3001\u6001\u5ea6\u3001\u884c\u4e3a\u8fdb\u884c\u6df1\u5165\u7814\u7a76\u5206\u6790\u3002\n25%\n28%\n24%\n23%\n\u4e09\u5230\u4e94\u7ebf\n\u8d85\u4e00\u7ebf\n\u4e8c\u7ebf\n\u65b0\u4e00\u7ebf\n31%\n36%\n26%\n8%\nX\u4e16\u4ee3\nY\u4e16\u4ee31\nZ\u4e16\u4ee3\n\u5a74\u513f\u6f6e\n19%\n20%\n24%\n20%\n17%\n\u5bcc\u88d5\u9636\u5c42\n\u4e0a\u5c42\u4e2d\u4ea7\n\u4e2d\u4ea7\n\u65b0\u5174\u4e2d\u4ea7\n\u4e0a\u5347\u4e00\u65cf\n32%\n7%\n47%\n13%\n\u5df2\u5a5a\uff0c\n\u67091\u4e2a\u5c0f\u5b69\n\u5355\u8eab\n\u5df2\u5a5a\uff0c\n\u6ca1\u6709\u5c0f\u5b69\n\u5df2\u5a5a\uff0c\n\u67092+\u4e2a\u5c0f\u5b69\n49%\n51%\n\u7537\u6027\n\u5973\u6027\n\u6765\u6e90\uff1a BCG\u6d88\u8d39\u8005\u6d1e\u5bdf\u667a\u5e93-\u4e2d\u56fd\u672a\u6765\u6d88\u8d39\u8005\u8c03\u7814\uff08\u8c03\u7814\u65f6\u95f42022\u5e7410\u6708\uff0c\u6837\u672c\u91cfN=9,000\uff09\uff1bBCG\u5206\u6790\u3002\n1. \u53c8\u79f0\u4e3a\u201c\u5343\u79a7\u4e00\u4ee3\u201d\uff1b 2. \u6309\u7167\u6708\u5747\u5bb6\u5ead\u7a0e\u540e\u6536\u5165\uff08\u5143\u4eba\u6c11\u5e01\uff09\u8ba1\uff0c2022\u5e74\u7684\u5b9a\u4e49\u6807\u51c6\u4e3a\u4f4e\u6536\u5165< 3.6K\uff0c\u4e0a\u5347\u4e00\u65cf [3.6K-6.6K)\uff0c\u65b0\u5174\u4e2d\u4ea7 [6.6K-9.5K)\uff0c\u4e2d\u4ea7 [9.5K-15.5K)\uff0c\u4e0a\u5c42\u4e2d\u4ea7\n[15.5K-29.9K)\uff0c\u5bcc\u88d5\u9636\u5c42>= 29.9K\uff0c\u95ee\u5377\u8986\u76d6\u9664\u4f4e\u6536\u5165\u4ee5\u5916\u7684\u6240\u6709\u6536\u5165\u5c42\u7ea7\u3002\n1995-2009\u5e74\u751f\n1980-1994\u5e74\u751f\n1965-1979\u5e74\u751f\n1950-1964\u5e74\u751f\nCopyright\n\u00a9\n2022\nby\nBoston\nConsulting\nGroup.\nAll\nrights\nreserved.\n3\n\u76ee\u5f55\n\u542f\u793a\u672a\u6765\uff1a\u5168\u9762\u770b\u5f85\u5ba2\u7fa4\uff0c\u8ffd\u8e2a\u4e16\u4ee3\u52a8\u9759\n\u4ee3\u9645\u7279\u5f81\uff1a\u65f6\u4ee3\u53d8\u8fc1\u4e0b\u7684\u4ee3\u9645\u9700\u6c42\u548c\u5dee\u5f02\n\u5b8f\u89c2\u80cc\u666f\uff1a\u4e2d\u56fd\u6d88\u8d39\u97e7\u6027\u53ca\u4e16\u4ee3\u4eba\u7fa4\u8fc1\u79fb\n4\nCopyright\n\u00a9\n2022\nby\nBoston\nConsulting\nGroup.\nAll\nrights\nreserved.\n\u968f\u7740\u4e2d\u56fd\u9632\u75ab\u653f\u7b56\u7684\u8c03\u6574\u4f18\u5316\u548c\u6269\u5185\u9700\u3001\u4fc3\u6d88\u8d39\u7684\u653f\u7b56\u65b9\u5411\u660e\u786e\uff0c\u53e0\n\u52a0\u6625\u8282\u5047\u671f\u6548\u5e94\uff0c\u4e2d\u56fd\u7ecf\u6d4e\u6d3b\u529b\u6062\u590d\u521d\u89c1\u7aef\u502a\n2022\u5e7412\u6708\u5728\u4eac\u53ec\u5f00\u4e2d\u592e\n\u7ecf\u6d4e\u4f1a\u8bae\uff0c\u5bf92023\u5e74\u7ecf\u6d4e\n\u8fdb\u884c\u89c4\u5212\u90e8\u7f72\n\u2022 \u5c06\u201c\u7740\u529b\u6269\u5927\u56fd\u5185\u9700\u6c42\u201d\n\u653e\u57282023\u5e74\u7ecf\u6d4e\u5de5\u4f5c\u7684\n\u7b2c\u4e00\u6761\n\u2022 \u5f3a\u8c03\u201c\u8981\u628a\u6062\u590d\u548c\u6269\u5927\n\u6d88\u8d39\u6446\u5728\u4f18\u5148\u4f4d\u7f6e\u201d\n\u2022 \u63d0\u51fa\u4e863\u70b9\u5de5\u4f5c\u8981\u6c42\n\u2013 \u589e\u5f3a\u6d88\u8d39\u80fd\u529b\n\u2013 \u6539\u5584\u6d88\u8d39\u6761\u4ef6\n\u2013 \u521b\u65b0\u6d88\u8d39\u573a\u666f\n\u653f\u7b56\u9f13\u52b1\u6d88\u8d39 \u7ecf\u6d4e\u6307\u6807\u51fa\u73b0\u590d\u82cf\u8ff9\u8c61\n1\u6708\u9996\u5468\uff0c\u5317\u4e0a\u5e7f\u6df1\u7b4910\n\u4e2a\u91cd\u70b9\u57ce\u5e021\u7684\u5730\u94c1\u65e5\u5747\u5ba2\n\u6d41\u8f8312\u6708\u540c\u671f\u4e0a\u6da830%\n\u6625\u8fd0\u9996\u5468\uff0c\u56fd\u5185\u5ba2\u8fd0\u822a\u73ed\n\u91cf\u65e5\u5747\u7834\u4e07\u73ed\u6b21\uff0c\u540c\u6bd4\u589e\n\u957f12%\uff0c\u6bd421\u5e74\u589e\u957f57%\n\u65e5\u5747\n\u7834\u4e07\n\u51fa\u884c\uff1a\u5ba2\u6d41\u9010\u6b65\u6062\u590d\n\u81ea\u653f\u7b56\u653e\u5f00\u4ee5\u6765\u4eba\u6c11\u5e01\n\u5151\u7f8e\u5143\u6c47\u7387\u7d2f\u8ba1\u4e0a\u6da8\u8d85\n\u8fc78%\uff0c\u4e00\u5ea6\u5347\u78346.69\nA\u80a1\u5e02\u573a23\u5e74\u5143\u65e6\u4ee5\u6765\n\u8fde\u7eed6\u5929\u4e0a\u6da8\n\u91d1\u878d\uff1a\u6c47\u7387\u4e0eA\u80a1\u8fce\u6765\u826f\u597d\u5f00\u5c40\n+30%\n\u591a\u65e5\n\u8fde\u6da8\n\u4eba\u6c11\u5e01\n\u53cd\u5f39\n\u6d88\u8d39\uff1a\u6625\u8282\u5404\u884c\u4e1a\u6d88\u8d39\u5448\u73b0\u590d\u82cf\n23\u5e74\u6625\u8282\u5047\u671f\uff0c\u5546\u54c1\u6d88\n\u8d39\u548c\u670d\u52a1\u6d88\u8d39\u540c\u6bd4\u5206\u522b\n\u589e\u957f10%\u548c13.5%\n\u53cc\u4f4d\u6570\n\u589e\u957f\n\u591a\u65b9\u4e50\u89c2\u9884\u6d4b\n\u6625\u8282\u6863\u7535\u5f71\u7968\u623f67.6\n\u4ebf\u5143\uff0c\u540c\u6bd4\u589e\u957f\n11.9%\n\u5386\u53f2\n\u7b2c\u4e8c\u9ad8\n\u6625\u8282\u5047\u671f\u5168\u56fd\u56fd\u5185\u65c5\u6e38\n\u51fa\u6e38\u4eba\u6b21\uff0c\u5df2\u6062\u590d\u81f3\n2019\u5e74\u540c\u671f\u768488.6%\n\u6587\u65c5\n\u590d\u82cf\n23\u5e741\u6708\u4efd\u4e2d\u56fd\u96f6\u552e\n\u4e1a\u666f\u6c14\u6307\u6570\u4e3a50.3%\u3002\n\u73af\u6bd4\u6500\u53471.6%\n\u96f6\u552e\n\u666f\u6c14\n\u6500\u5347\nGDP\uff1a\u589e\u957f\u5c06\u8fbe5%\n\u6d88\u8d39\u54c1\u96f6\u552e\u603b\u989d\uff1a50\u4e07\u4ebf\u5143\n\u2022 \u82f1\u56fd\u300a\u91d1\u878d\u65f6\u62a5\u300b\n\u9884\u6d4b\uff0c\u4e2d\u56fd23\u5e74\n\u6d88\u8d39\u54c1\u96f6\u552e\u603b\u989d\n\u5c06\u589e\u957f11%\uff0c\u9884\n\u8ba1\u8fbe\u523050\u4e07\u4ebf\u5143\n\u2022 \u8054\u5408\u56fd1\u670825\u65e5\u53d1\n\u5e03\u300a2023\u5e74\u4e16\u754c\n\u7ecf\u6d4e\u5f62\u52bf\u4e0e\u5c55\u671b\u300b\n\u9884\u6d4b2023\u5e74\u4e2d\u56fd\n\u7ecf\u6d4e\u589e\u957f\u5c06\u4f1a\u52a0\u901f\uff0c\n\u8fbe\u52304.8%\n\u2022 \u591a\u5bb6\u5916\u8d44\u673a\u6784\u4e5f\u53d1\n\u8868\u4e50\u89c2\u9884\u6d4b\n\u6765\u6e90\uff1a\u56fd\u5bb6\u7a0e\u52a1\u5c40\uff1b\u56fd\u5bb6\u7535\u5f71\u5c40\uff1b\u4e2d\u56fd\u5546\u4e1a\u8054\u5408\u4f1a\u7b49\u516c\u5f00\u6570\u636e\uff1bBCG\u5206\u6790\u3002\n1. 10\u4e2a\u57ce\u5e02\u6db5\u76d6\u5317\u4eac\u3001\u4e0a\u6d77\u3001\u5e7f\u5dde\u3001\u6df1\u5733\u3001\u6210\u90fd\u3001\u91cd\u5e86\u3001\u5357\u4eac\u3001\u6b66\u6c49\u3001\u5929\u6d25\u3001\u897f\u5b89\u3002\n5\nCopyright\n\u00a9\n2022\nby\nBoston\nConsulting\nGroup.\nAll\nrights\nreserved.\n\u9884\u8ba1\u52302030\u5e74\uff0c\u4e2d\u56fd\u5c06\u518d\u589e\u52a08,000\u4e07\u4e2d\u4ea7\u53ca\u4ee5\u4e0a\u4eba\u53e3\uff0c\u5176\u4e2d\u8d85\u8fc770%\n\u65b0\u589e\u4e2d\u4ea7\u6765\u81ea\u4e8e\u4f4e\u7ebf\u57ce\u5e02\n\u6765\u6e90\uff1aBCG MAC Database \u4eba\u53e3\u6570\u636e\u5e93\u6a21\u578b\uff1bBCG\u5206\u6790\u3002\n1. 2022\u5e74\u7684\u5b9a\u4e49\u6807\u51c6\uff0c\u6bcf\u5e74\u6309\u7167CPI=2.5%\u7684\u9884\u671f\u5bf9\u5b9a\u4e49\u6807\u51c6\u8fdb\u884c\u8c03\u6574\u3002\n147\n308\n2022\u4f30\n23\n1,413\n\u4e2d\u4ea7 [9.5K-15.5K)\n325\n290\n\u4e0a\u5c42\u4e2d\u4ea7 [15.5K-29.9K)\n433\n173\n2025\u4f30\n29\n186\n339\n288\n1,401\n403\n157\n2030\u4f30\n166\n\u5bcc\u88d5\u9636\u5c42 >=29.9K\n195\n\u65b0\u5174\u4e2d\u4ea7 [6.6K-9.5K)\n\u4e0a\u5347\u4e00\u65cf [3.6K-6.6K)\n\u4f4e\u6536\u5165 <3.6K\n287\n458\n18\n1,410\n2022\u5e74\u52302030\u5e74\uff0c\u9884\u8ba1\u65b0\u589e8,000\u4e07\u4e2d\u4ea7\u53ca\u4ee5\u4e0a\u4eba\u53e3\n\u5168\u4e2d\u56fd\u4eba\u53e3\u7684\u6536\u5165\u9636\u5c42\u53d8\u5316\n\u5355\u4f4d\uff1a\u767e\u4e07\u4eba\uff0c\u6536\u5165\u9636\u5c42\uff08\u4eba\u6c11\u5e01\u5143\uff0c\u6708\u5747\u5bb6\u5ead\u7a0e\u540e\u53ef\u652f\u914d\u6536\u51651\uff09\n97\n(20%)\n61\n(13%)\n553\n134\n(28%)\n67\n(12%)\n68\n(14%)\n473\n112\n(24%)\n2022\u4f30\n110\n(20%)\nTier 5-7\n183\n(33%)\n83\n(15%)\nTier 4\n110\n(19%)\n2030\u4f30\nTier 1\nTier 2\nTier 3\n8000\u4e07\u589e\u91cf\n\u65b0\u589e\u4e2d\u4ea7\u53ca\u4ee5\u4e0a\u4eba\u53e3\u7684\u57ce\u5e02\u7ea7\u522b\u5206\u5e03\n\u5355\u4f4d\uff1a\u767e\u4e07\u4eba\n\u6700\u591a\u7684\u65b0\u589e\u4e2d\u4ea7\u53ca\u4ee5\u4e0a\u4eba\u53e3\u6765\u81ea\u4e8e\u4e09\u7ebf\u57ce\u5e02\n6\nCopyright\n\u00a9\n2022\nby\nBoston\nConsulting\nGroup.\nAll\nrights\nreserved.\n\u533b\u7597\n\u4fdd\u5065\n\u4e2a\u62a4\n\u5bb6\u6e05\n\u751f\u9c9c\n\u6709\u673a\n26%\n5%\n\u5305\u88c5\n\u996e\u98df\n20%\n20%\n2%\n27%\n11%\n\u62a4\u80a4\n\u5f69\u5986\n\u5927\u5c0f\n\u5bb6\u7535\n\u6570\u7801\n\u4ea7\u54c1\n7%\n-8%\n\u6c7d\u8f66\n\u6c7d\u914d\n13%\n\u8fd0\u52a8\n\u88c5\u5907\n13%\n5%\n\u4f11\u95f2\n\u670d\u9970\n-3%\n\u5962\u4f88\u54c1\n\u7406\u8d22\n\u4ea7\u54c1\n-9%\n-4%\n\u8d2d\u623f\n\u88c5\u4fee\n\u4e3d\u4eba\n\u670d\u52a1\n6%\n\u5174\u8da3\n\u57f9\u8bad\n\u5230\u5bb6\n\u670d\u52a1\n-10%\n\u4e13\u4e1a\n\u57f9\u8bad\n\u65f6\u5c1a\u4e0e\u5962\u4f88 \u6295\u8d44 \u751f\u6d3b\u670d\u52a1\/\u4f53\u9a8c\n\u54c1\u8d28\u6d88\u8d39\u52bf\u5934\u66f4\u731b\uff1a\u4e2d\u56fd\u6d88\u8d39\u8005\u4ecd\u7136\u5448\u73b0\u51fa\u4e3a\u201c\u66f4\u9ad8\u54c1\u8d28\u652f\n\u4ed8\u6ea2\u4ef7\u201d\u7684\u610f\u613f\uff0c\u5bf9\u54c1\u8d28\u7684\u8ffd\u6c42\u6a2a\u8de8\u5927\u591a\u6570\u6d88\u8d39\u54c1\u7c7b\n\u5404\u54c1\u7c7b\u672a\u676512\u4e2a\u6708\u9884\u671f\u4ef7\u683c\u610f\u613f\u53d8\u5316\u7684\u4eba\u6570\u51c0\u6bd4\u4f8b\uff08%\uff09\n\u4eba\u6570\n\u51c0\u6bd4\u4f8b\n\uff08%\uff09\n\u51c0\u6bd4\u4f8b(%) = \u8be5\u54c1\u7c7b\u9009\u62e9\u4ef7\u683c\u5347\u7ea7\u7684\u4eba\u6570\u5360\u6bd4(%) - \u8be5\u54c1\u7c7b\u9009\u62e9\u4ef7\u683c\u964d\u7ea7\u7684\u4eba\u6570\u5360\u6bd4(%)\n\u51c0\u6bd4\u4f8b\u4e3a\u6b63\u5219\u8868\u793a\u6d88\u8d39\u8005\u5bf9\u54c1\u7c7b\u6709\u5347\u7ea7\u610f\u613f\uff0c\u4e3a\u8d1f\u8868\u793a\u6d88\u8d39\u8005\u5bf9\u54c1\u7c7b\u504f\u5411\u964d\u7ea7\uff0c\u6570\u503c\u8d8a\u9ad8\u8868\u793a\u610f\u613f\u8d8a\u5f3a\u70c8\n\u6765\u6e90\uff1aBCG\u6d88\u8d39\u8005\u6d1e\u5bdf\u667a\u5e93-\u4e2d\u56fd\u672a\u6765\u6d88\u8d39\u8005\u8c03\u7814\uff08\u8c03\u7814\u65f6\u95f42022\u5e7410\u6708\uff0c\u6837\u672c\u91cfN=9,000\uff09\uff1bBCG\u5206\u6790\u3002\n\u98df\u54c1\n\u996e\u6599\n\u4e2a\u4eba\u53ca\u5bb6\u5ead\n\u65e5\u5316\u7528\u54c1\n\u5bb6\u5c45\u5bb6\u7535\n\u8010\u7528\u54c1\n\u533b\u7597\n\u4fdd\u5065\n\u504f\u5411\u4ef7\u683c\u5347\u7ea7\n\u504f\u5411\u4ef7\u683c\u964d\u7ea7\n7\nCopyright\n\u00a9\n2022\nby\nBoston\nConsulting\nGroup.\nAll\nrights\nreserved.\n\u4e2d\u56fd\u5f53\u524d\u603b\u4eba\u53e3\u768480%\u662f\u7531\u56db\u4e2a\u4e16\u4ee3\u6784\u6210\uff0c\u5176\u4e2dX\u548cY\u4e16\u4ee3\u7684\n\u4eba\u53e3\u6570\u91cf\u548c\u603b\u6536\u5165\u5360\u6bd4\u5747\u6392\u4f4d\u66f4\u9ad8\n\u6765\u6e90\uff1a\u7b2c\u4e03\u6b21\u5168\u56fd\u4eba\u53e3\u666e\u67e5\uff0c\u4e2d\u56fd2021\u7edf\u8ba1\u5e74\u9274\uff1bBCG\u6d88\u8d39\u8005\u6d1e\u5bdf\u667a\u5e93-\u4e2d\u56fd\u672a\u6765\u6d88\u8d39\u8005\u8c03\u7814\uff08\u8c03\u7814\u65f6\u95f42022\u5e7410\u6708\uff0c\u6837\u672c\u91cfN=9,000\uff09\uff1bBCG\u5206\u6790\u3002\n1. \u56db\u4e2a\u4e16\u4ee3\u7684\u6536\u5165\u8d21\u732e\u52a0\u603b=100%\uff0c\u56db\u4e2a\u4e16\u4ee3\u4ee5\u5916\u7684\u4eba\u7fa4\u6536\u5165\u5360\u6bd4\u5c11\uff0c\u4e0d\u7eb3\u5165\u6536\u5165\u5206\u6790\u3002\u6536\u5165\u57fa\u4e8eBCG CCI\u5b9a\u91cf\u8c03\u7814\u95ee\u5377\u7ed3\u679c\u6d4b\u7b97\u30022. \u4ee52023\u5e74\u8bb0\uff0c\u5404\u4e16\u4ee3\u5468\u5c81\u4e3a\uff0c\u5a74\u513f\u6f6e59-73\u5468\u5c81\uff0c\nX\u4e16\u4ee344-58\u5468\u5c81\uff0c Y\u4e16\u4ee329-43\u5468\u5c81\uff0cZ\u4e16\u4ee314-28\u5468\u5c81\u30023. \u672c\u62a5\u544a\u7814\u7a76\u7684Z\u4e16\u4ee3\u4ec5\u9650\u4e8e18\u5c81\u53ca\u4ee5\u4e0a\u3002\n\u6309\u5e74\u9f84\u5206\u56db\u4e2a\u4e16\u4ee3\u7684\u4eba\u53e3\u6570\u91cf\uff0c\u4eba\u53e3\u5360\u6bd4\uff0c\u6536\u5165\u5360\u6bd41\n1.2\u4ebf 8%\n2.5\u4ebf 18%\n3.3\u4ebf 23%\n3.2\u4ebf 22%\n2.3\u4ebf 17%\n1.7\u4ebf 12%\n1949\u5e74\u53ca\u4ee5\u524d -\n1950-1964\u5e74 \u5a74\u513f\u6f6e2\n1965-1979\u5e74 X\u4e16\u4ee32\n1980-1994\u5e74 Y\u4e16\u4ee32\n1995-2009\u5e743 Z\u4e16\u4ee32\n2010\u5e74\u53ca\u4ee5\u540e \u03b1\u4e16\u4ee3\n\u51fa\u751f\u5e74\u4efd \u4e16\u4ee3 \u4eba\u53e3\u6570\u91cf \u4eba\u53e3\u5360\u6bd4\n22%\n34%\n28%\n16%\n\u6536\u5165\u5360\u6bd41\n80%\n\u603b\u4eba\u53e3\n8\nCopyright\n\u00a9\n2022\nby\nBoston\nConsulting\nGroup.\nAll\nrights\nreserved.\n\u56db\u4e2a\u4e16\u4ee3\u7684\u4e2d\u56fd\u6d88\u8d39\u8005\u6210\u957f\u65f6\u671f\u7ecf\u5386\u8fe5\u5f02\uff0c\u4ece\u800c\u5f62\u6210\u4e86\u4e0d\n\u540c\u7684\u7fa4\u4f53\u8bb0\u5fc6\u3001\u4ef7\u503c\u53d6\u5411\u548c\u6d88\u8d39\u504f\u597d\n\u4e16\u4ee3\u5e74\u4efd\u5b9a\u4e49\n\u4e16\u4ee3\u6982\u8ff0\nZ\u4e16\u4ee31\n1995-2009\u5e74\u51fa\u751f\nY\u4e16\u4ee31\n1980-1994\u5e74\u51fa\u751f\nX\u4e16\u4ee31\n1965-1979\u5e74\u51fa\u751f\n\u5a74\u513f\u6f6e1\n1950-1964\u5e74\u51fa\u751f\n1950\n1960\n1965\n1970\n1975\n1980\n1985\n1990\n1995\n2000\n2005\n2010 1955\n1978\u5e74\n\u6539\u9769\n\u5f00\u653e\n\u5f00\u542f\n1964\u5e74\n\u539f\u5b50\u5f39\n\u8bd5\u7206\n\u6210\u529f\n1982\u5e74\n\u8ba1\u5212\n\u751f\u80b2\n\u8fdb\u5165\n\u56fd\u7b56\n1986\u5e74\n\u4e49\u52a1\n\u6559\u80b2\n\u5b9e\u65bd\n1992\u5e74\n\u623f\u6539\n\u5168\u9762\n\u542f\u52a8\n1994\u5e74\n\u63a5\u5165\n\u56fd\u9645\n\u7f51\u7edc\n1949\u5e74\n\u5efa\u56fd\n\u4e4b\u521d\n1959-61\u5e74\n\u4e09\u5e74\n\u81ea\u7136\n\u707e\u5bb3\n1971\u5e74\n\u8ba1\u5212\n\u751f\u80b2\n\u5f00\u59cb\n\u5ba3\u4f20\n2004\u5e74\n\u7b2c\u4e09\u65b9\n\u652f\u4ed8\n\u5de5\u5177\n\u63a8\u51fa\n2011\u5e74\n\u624b\u673a\u7aef\n\u793e\u4ea4\n\u5e94\u7528\n\u63a8\u51fa\n2001\u5e74\n\u52a0\u5165\n\u4e16\u8d38\n\u7ec4\u7ec7\n1999\u5e74\nPC\u7aef\n\u793e\u4ea4\n\u5e94\u7528\n\u63a8\u51fa\n\u5a74\u513f\u6f6e\uff1a\u751f\u4e8e\u7269\u8d28\u76f8\u5bf9\u532e\u4e4f\u7684\n\u65f6\u671f\uff0c\u793e\u4f1a\u548c\u7ecf\u6d4e\u9605\u5386\u4e30\u5bcc\uff0c\n\u5403\u82e6\u8010\u52b3\uff0c\u6709\u6d53\u539a\u7684\u96c6\u4f53\u548c\u5bb6\n\u5ead\u610f\u8bc6\nX\u4e16\u4ee3\uff1a\u6539\u9769\u6d6a\u6f6e\u7684\u4e2d\u575a\u529b\u91cf\uff0c\n\u901a\u8fc7\u5f00\u9614\u773c\u754c\uff0c\u52aa\u529b\u594b\u6597\uff0c\u5b8c\n\u6210\u793e\u4f1a\u548c\u4e2a\u4eba\u7684\u539f\u59cb\u8d22\u5bcc\u79ef\u7d2f\nY\u4e16\u4ee3\uff1a\u7b2c\u4e00\u4ee3\u72ec\u751f\u5b50\u5973\uff0c\u53d7\n\u76ca\u4e8e\u4e49\u52a1\u6559\u80b2\u7684\u666e\u53ca\uff0c\u6210\u957f\u4e8e\nPC\u7aef\u53d1\u5c55\u65f6\u671f\uff0c\u7ecf\u5386\u57ce\u5e02\u5316\u8fc1\n\u5f99\nZ\u4e16\u4ee3\uff1a\u6570\u5b57\u5316\u539f\u4f4f\u6c11\uff0c\u51fa\u751f\u4e8e\n\u5168\u7403\u5316\u7684\u9ad8\u901f\u53d1\u5c55\u65f6\u671f\uff0c\u4e60\u60ef\n\u4e8e\u901a\u8fc7\u624b\u673a\u7aef\u63a5\u6536\u6d77\u91cf\u4fe1\u606f\n2015\n2020\n2017\u5e74\n\u77ed\u89c6\u9891\n\u5e73\u53f0\n\u5174\u8d77\n2014\u5e74\n\u624b\u673a\u7aef\n\u4e0a\u7f51\n\u4eba\u6570\n\u8d85PC\n\u7cbe\u795e\u4e16\u754c\u6269\u5bb9\u7684\u4e00\u4ee3 \u7269\u8d28\u8d22\u5bcc\u79ef\u7d2f\u7684\u4e00\u4ee3\n\u81ea\u6211\u53d1\u5c55\u63d0\u901f\u7684\u4e00\u4ee3 \u575a\u5fcd\u5949\u732e\u7684\u4e00\u4ee3\n\u6765\u6e90\uff1a\u516c\u5f00\u8d44\u6599\uff1bBCG\u5206\u6790\u3002\n1. \u4ee52023\u5e74\u8bb0\uff0c\u5404\u4e16\u4ee3\u5468\u5c81\u4e3a\uff0c\u5a74\u513f\u6f6e59-73\u5468\u5c81\uff0cX\u4e16\u4ee344-58\u5468\u5c81\uff0cY\u4e16\u4ee329-43\u5468\u5c81\uff0cZ\u4e16\u4ee314-28\u5468\u5c81\u3002\n9\nCopyright\n\u00a9\n2022\nby\nBoston\nConsulting\nGroup.\nAll\nrights\nreserved.\n\u6559\u80b2\u80cc\u666f\n\u672c\u79d1\u53ca\u4ee5\u4e0a\u5b66\u5386\uff08\u6307\u65701\uff09\n\u4e2a\u4eba\u6536\u5165\n\u6708\u5747\u7a0e\u540e\u53ef\u652f\u914d\uff08\u6307\u65701\uff09\n\u804c\u4e1a\u80cc\u666f\n\u7ba1\u7406\u6216\u4e13\u4e1a\u5c97\u4f4d\uff08\u6307\u65701\uff09\nZ\u4e16\u4ee3\nY\u4e16\u4ee3\nX\u4e16\u4ee3\n\u5a74\u513f\u6f6e\nZ\u4e16\u4ee3\nY\u4e16\u4ee3\nX\u4e16\u4ee3\n\u5a74\u513f\u6f6e\nX\u4e16\u4ee3\nZ\u4e16\u4ee3\nY\u4e16\u4ee3\n\u5a74\u513f\u6f6e\n\u201cZ\u4e16\u4ee3\u201d\u53d7\u6559\u80b2\u7a0b\u5ea6\u6700\u9ad8\uff0c\u201cX\u4e16\u4ee3\u201d\u804c\u4e1a\u80cc\u666f\u548c\u6536\u5165\u76f8\n\u5bf9\u6700\u9ad8\nZ\u4e16\u4ee3\nX\u4e16\u4ee3\nY\u4e16\u4ee3\n\u5a74\u513f\u6f6e\n\u6765\u6e90\uff1aBCG\u6d88\u8d39\u8005\u6d1e\u5bdf\u667a\u5e93-\u4e2d\u56fd\u672a\u6765\u6d88\u8d39\u8005\u8c03\u7814\uff08\u8c03\u7814\u65f6\u95f42022\u5e7410\u6708\uff0c\u6837\u672c\u91cfN=9,000\uff09\uff1bBCG\u5206\u6790\u3002\n1. \u6307\u6570=\u67d0\u4e2a\u4eba\u7fa4\u7684\u7279\u5f81\u503c\/\u603b\u4f53\u4eba\u7fa4\u7684\u5e73\u5747\u503c*100\u3002\n\u2022 \u53d7\u6559\u80b2\u7a0b\u5ea6\u6700\u9ad8\n\u2022 \u6b63\u7ecf\u5386\u6821\u56ed\u5230\u804c\u573a\u7684\u8f6c\u6362\n\u2022 \u5f00\u59cb\u62e5\u6709\u72ec\u7acb\u6536\u5165\n\u2022 \u53d7\u6559\u80b2\u7a0b\u5ea6\u8f83\u9ad8\n\u2022 \u5360\u636e\u7684\u804c\u4e1a\u5730\u4f4d\u65e5\u76ca\u589e\u9ad8\n\u2022 \u6536\u5165\u968f\u4e4b\u4e0d\u65ad\u589e\u957f\n\u2022 \u53d7\u6559\u80b2\u7a0b\u5ea6\u8f83\u4f4e\n\u2022 \u5360\u636e\u7684\u804c\u4e1a\u5730\u4f4d\u4f9d\u7136\u6700\u9ad8\n\u2022 \u6536\u5165\u6c34\u5e73\u6700\u9ad8\n\u2022 \u53d7\u6559\u80b2\u7a0b\u5ea6\u6700\u4f4e\n\u2022 \u90e8\u5206\u5df2\u7ecf\u8fdb\u5165\u4e86\u9000\u4f11\u72b6\u6001\n\u2022 \u6536\u5165\u6c34\u5e73\u8f83\u9ad8 \u9ad8\n\u4f4e \u9ad8\n\u4f4e \u9ad8\n\u4f4e\n\u5747\u503c\u6c34\u5e73 \u5747\u503c\u6c34\u5e73 \u5747\u503c\u6c34\u5e73\nCopyright\n\u00a9\n2022\nby\nBoston\nConsulting\nGroup.\nAll\nrights\nreserved.\n10\n\u76ee\u5f55\n\u542f\u793a\u672a\u6765\uff1a\u5168\u9762\u770b\u5f85\u5ba2\u7fa4\uff0c\u8ffd\u8e2a\u4e16\u4ee3\u52a8\u9759\n\u4ee3\u9645\u7279\u5f81\uff1a\u65f6\u4ee3\u53d8\u8fc1\u4e0b\u7684\u4ee3\u9645\u9700\u6c42\u548c\u5dee\u5f02\n\u5b8f\u89c2\u80cc\u666f\uff1a\u4e2d\u56fd\u6d88\u8d39\u97e7\u6027\u53ca\u4e16\u4ee3\u4eba\u7fa4\u8fc1\u79fb\n11\nCopyright\n\u00a9\n2022\nby\nBoston\nConsulting\nGroup.\nAll\nrights\nreserved.\nZ\u4e16\u4ee3\uff1a\u5708\u5c42\u521b\u751f\uff0c\u6cbb\u6108\u4eab\u4e50\nY\u4e16\u4ee3\uff1a\u4e13\u4e1a\u52a9\u529b\uff0c\u7701\u65f6\u589e\u6548\nX\u4e16\u4ee3\uff1a\u8eab\u4efd\u793e\u4ea4\uff0c\u54c1\u8d28\u5f70\u663e\n\u5a74\u513f\u6f6e\uff1a\u7ebf\u4e0a\u4e50\u6d3b\uff0c\u4e2d\u5f0f\u517b\u751f\n12\nCopyright\n\u00a9\n2022\nby\nBoston\nConsulting\nGroup.\nAll\nrights\nreserved.\n\u50a8\u84c4\u610f\u613f\n\u4eba\u6570\u5360\u6bd4\u51c0\u503c\uff08\u589e\u52a0%-\u51cf\u5c11%\uff09\n\u6d88\u8d39\u610f\u613f\n\u4eba\u6570\u5360\u6bd4\u51c0\u503c\uff08\u589e\u52a0%-\u51cf\u5c11%\uff09\n\u6295\u8d44\u610f\u613f\n\u4eba\u6570\u5360\u6bd4\u51c0\u503c\uff08\u589e\u52a0%-\u51cf\u5c11%\uff09\nX\u4e16\u4ee3\u672a\u96e8\u7ef8\u7f2a\uff0c\u4e3b\u52a8\u63d0\u9ad8\u6297\u98ce\u9669\u80fd\u529b\uff1bZ\u4e16\u4ee3\u5728\u6709\u9650\u7684\u80fd\u529b\n\u8303\u56f4\u5185\u60f3\u82b1\u5c31\u82b1\n\u6765\u6e90\uff1aBCG\u6d88\u8d39\u8005\u6d1e\u5bdf\u667a\u5e93-\u4e2d\u56fd\u672a\u6765\u6d88\u8d39\u8005\u8c03\u7814\uff08\u8c03\u7814\u65f6\u95f42022\u5e7410\u6708\uff0c\u6837\u672c\u91cfN=9,000\uff09\uff1bBCG\u5206\u6790\u3002\n\u7f29\u51cf\u987a\u5e8f\uff1a\u6295\u8d44>\u50a8\u84c4>\u6d88\u8d39\n\u7f29\u51cf\u987a\u5e8f\uff1a\u6295\u8d44>\u50a8\u84c4>\u6d88\u8d39\n\u7f29\u51cf\u987a\u5e8f\uff1a\u6d88\u8d39>\u6295\u8d44>\u50a8\u84c4\n\u7f29\u51cf\u987a\u5e8f\uff1a\u6295\u8d44>\u6d88\u8d39>\u50a8\u84c4\nZ\u4e16\u4ee3\nX\u4e16\u4ee3\nY\u4e16\u4ee3\n\u5a74\u513f\u6f6e\nZ\u4e16\u4ee3\nY\u4e16\u4ee3\nX\u4e16\u4ee3\n\u5a74\u513f\u6f6e\nZ\u4e16\u4ee3\nX\u4e16\u4ee3\nY\u4e16\u4ee3\n\u5a74\u513f\u6f6e\n\u9ad8\n\u4f4e \u9ad8\n\u4f4e \u9ad8\n\u4f4e\n\u5747\u503c\u6c34\u5e73-6.1% \u5747\u503c\u6c34\u5e73-10.6% \u5747\u503c\u6c34\u5e73-7.5%\nZ\u4e16\u4ee3\nX\u4e16\u4ee3\nY\u4e16\u4ee3\n\u5a74\u513f\u6f6e\n13\nCopyright\n\u00a9\n2022\nby\nBoston\nConsulting\nGroup.\nAll\nrights\nreserved.\nX\u548cY\u4e16\u4ee3\u5728\u5927\u591a\u6570\u54c1\u7c7b\u4e0a\u5e74\u6d88\u8d39\u652f\u51fa\u90fd\u9886\u5148\u4e8e\u5176\u4ed6\u4e24\u4e2a\u4e16\u4ee3\uff0c\n\u662f\u672a\u6765\u6d88\u8d39\u4e3b\u529b\n\u6765\u6e90\uff1aBCG\u6d88\u8d39\u8005\u6d1e\u5bdf\u667a\u5e93-\u4e2d\u56fd\u672a\u6765\u6d88\u8d39\u8005\u8c03\u7814\uff08\u8c03\u7814\u65f6\u95f42022\u5e7410\u6708\uff0c\u6837\u672c\u91cfN=9,000\uff09\uff1bBCG\u5206\u6790\u3002\n1. \u53cd\u6620\u5e74\u4eba\u5747\u54c1\u7c7b\u6d88\u8d39\u91d1\u989d\u7684\u9ad8\u4f4e\uff0c\u6307\u6570=100\u4ee3\u8868\u548c\u603b\u4f53\u5747\u503c\u76f8\u5f53\uff0c\u6307\u6570>100\u4ee3\u8868\u6bd4\u603b\u4f53\u5747\u503c\u9ad8\uff0c\u6307\u6570<100\u4ee3\u8868\u6bd4\u603b\u4f53\u5747\u503c\u4f4e\uff0c\u672a\u6765\u9884\u671f\u57fa\u4e8e\u6d88\u8d39\u8005\u5bf9\u672a\u676512\u4e2a\n\u6708\u7684\u8bc4\u4f30\u30022. Z\u4e16\u4ee3\u8fd8\u672a\u7ecf\u6d4e\u72ec\u7acb\uff0c\u90e8\u5206\u6d88\u8d39\u7531\u7236\u6bcd\u652f\u51fa\u3002\n82\n113 101 98\nZ\u4e16\u4ee32 \u5a74\u513f\u6f6e\nY\u4e16\u4ee3 X\u4e16\u4ee3\n69\n112\n128\n102\nZ\u4e16\u4ee32 Y\u4e16\u4ee3 X\u4e16\u4ee3 \u5a74\u513f\u6f6e\n76\n106\n134\n84\nZ\u4e16\u4ee32 Y\u4e16\u4ee3 \u5a74\u513f\u6f6e\nX\u4e16\u4ee3\n78\n117 117\n82\nX\u4e16\u4ee3\nZ\u4e16\u4ee32 Y\u4e16\u4ee3 \u5a74\u513f\u6f6e\n\u5747\u503c=100\n\u5747\u503c=100\n\u5747\u503c=100\n\u5747\u503c=100\n\u5065\u5eb7\u4e0e\u751f\u6d3b\u65b9\u5f0f\n\u751f\u6d3b\u5fc5\u9700\u578b\u6d88\u8d39\n\u5e73\u4ef7\u4eab\u53d7\u578b\u6d88\u8d39\n\u9ad8\u7aef\u4ea7\u54c1\u548c\u670d\u52a1\n\u5e74\u4eba\u5747\u54c1\u7c7b\u6d88\u8d39\u7684\u672a\u6765\u9884\u671f\uff08\u6307\u65701\uff09\n\u6d88\u8d39\u6700\u9ad8\u7684\u4e24\u7c7b\u4eba\u7fa4\n\u9ad8\u7aef\u4ea7\u54c1\u670d\u52a1\n\u4f11\u95f2\u65c5\u6e38\uff0c\u5962\u4f88\u54c1\uff0c\n\u6c7d\u8f66\uff0c\u9ad8\u7aef\u9910\u996e\n\u65e5\u5e38\u4eab\u53d7\u578b\n\u5916\u51fa\u5c31\u9910\uff0c\u65e0\u9152\u7cbe\u996e\n\u6599\uff0c\u65f6\u5c1a\u4f11\u95f2\u670d\u9970\uff0c\n\u5927\u5c0f\u5bb6\u7535\u5bb6\u5177\u5bb6\u5c45\n\u5065\u5eb7\u4e0e\u751f\u6d3b\u65b9\u5f0f\n\u81b3\u98df\u8425\u517b\u8865\u5145\u5242\uff0c\u5404\n\u7c7b\u6237\u5916\u6d3b\u52a8\uff0c\u8fd0\u52a8\u978b\n\u53ca\u88c5\u5907\uff0c\u533b\u7f8e\uff0c\u4eba\u5bff\n\u53ca\u5065\u5eb7\u9669\n\u751f\u6d3b\u5fc5\u9700\u578b\n\u751f\u9c9c\u98df\u54c1\u53ca\u534a\u6210\u54c1\u3001\n\u5bb6\u6e05\u53ca\u4e2a\u62a4\n14\nCopyright\n\u00a9\n2022\nby\nBoston\nConsulting\nGroup.\nAll\nrights\nreserved.\n\u56db\u4e2a\u4e16\u4ee3\u7684\u5728\u89c2\u5ff5\u548c\u6001\u5ea6\u4e0a\u4e5f\u5b58\u5728\u9c9c\u660e\u5dee\u5f02\n\u751f\u6d3b\u6001\u5ea6 \u6211\u4eab\u53d7\u72ec\u5904\u65f6\u5149\n\u4fdd\u6301\u4e2a\u6027\u5f88\u91cd\u8981\n\u5e0c\u671b\u4ed6\u4eba\u8ba4\u53ef\u6211\u7684\u6210\u529f\n\u4e2d\u5eb8\u6ca1\u4ec0\u4e48\u4e0d\u597d\n\u6211\u5f88\u9700\u8981\u793e\u4ea4\u548c\u5f52\u5c5e\u611f\n\u793e\u4f1a\u89c2\u5ff5 \u6211\u5173\u5fc3\u548c\u8ba8\u8bba\u56fd\u5bb6\u65f6\u4e8b\n\u5e0c\u671b\u4e0e\u4e2d\u56fd\u6587\u5316\u4fdd\u6301\u8fde\u63a5\n\u6211\u559c\u6b22\u9075\u5b88\u89c4\u5219\n\u6d88\u8d39\u7406\u5ff5 \u613f\u610f\u4e3a\u597d\u4f53\u9a8c\u4e0e\u670d\u52a1\u652f\u4ed8\u6ea2\u4ef7\n\u6211\u7ecf\u5e38\u7292\u8d4f\u81ea\u5df1\n\u503e\u5411\u4e8e\u8d2d\u4e70\u540d\u724c\n\u6d88\u8d39\u524d\u6211\u4f1a\u591a\u65b9\u6536\u96c6\u4fe1\u606f\n\u6211\u603b\u662f\u8bd5\u56fe\u5bfb\u627e\u9ad8\u6027\u4ef7\u6bd4\u9009\u62e9\nZ\u4e16\u4ee3 X\u4e16\u4ee3\nY\u4e16\u4ee3 \u5a74\u513f\u6f6e\n\u76f8\u5bf9\u9ad8\u4e8e\u5747\u503c \u76f8\u5bf9\u4f4e\u4e8e\u5747\u503c\n\u6765\u6e90\uff1aBCG\u6d88\u8d39\u8005\u6d1e\u5bdf\u667a\u5e93-\u4e2d\u56fd\u672a\u6765\u6d88\u8d39\u8005\u8c03\u7814\uff08\u8c03\u7814\u65f6\u95f42022\u5e7410\u6708\uff0c\u6837\u672c\u91cfN=9,000\uff09\uff1bBCG\u5206\u6790\u3002\n\u89c2\u5ff5\u6001\u5ea6\u7684\u91cd\u8981\u6027\u6253\u5206\n\u72ec\u7acb\u4e2a\u6027\u3001\u6587\u5316\u81ea\u4fe1\n\u5bf9\u6210\u529f\u7684\u5b9a\u4e49\u591a\u5143\u5316\n\u6ce8\u91cd\u6027\u4ef7\u6bd4\n\u6ce8\u91cd\u793e\u4ea4\u5f52\u5c5e\u548c\u65f6\u4e8b\n\u8ffd\u5bfb\u4f20\u7edf\u610f\u4e49\u7684\u6210\u529f\n\u4ee5\u201c\u540d\u724c\u201d\u7292\u8d4f\u81ea\u5df1\n\u4f20\u7edf\u4fdd\u5b88\u5e76\u575a\u5b88\u89c4\u5219\n\u5728\u95f2\u6687\u4e2d\u63a2\u7d22\u65b0\u7684\u81ea\u6211\n\u4ee5\u201c\u540d\u724c\u201d\u7292\u8d4f\u81ea\u5df1\n\u5c0a\u91cd\u548c\u9075\u5b88\u89c4\u5219\n\u4fe1\u4efb\u4e13\u4e1a\u54c1\u724c\u548c\u670d\u52a1\n\u8ffd\u6c42\u6548\u679c\u4e0e\u6548\u7387\n15\nCopyright\n\u00a9\n2022\nby\nBoston\nConsulting\nGroup.\nAll\nrights\nreserved.\n\u5174\u8da3\u7231\u597d\u65b9\u9762\uff0c\u5404\u4e16\u4ee3\u7684\u7279\u5f81\u4e5f\u5f88\u663e\u8457\n\u6765\u6e90\uff1a\u6d1e\u5bdf\u89c2\u70b9\u6765\u81ea\u5de8\u91cf\u7b97\u6570\u300c\u767e\u5927\u5174\u8da3\u65cf\u7fa4\u300d 2.0 \u6807\u7b7e\u4f53\u7cfb\uff1bBCG\u5206\u6790\u3002\n\u504f\u597d\u7a0b\u5ea6\n\u9ad8\n\u4f4e\n\u65cf\u7fa4\n\u5b85\u821e\u7c89\n\u4e3b\u673a\u73a9\u5bb6\n\u6f2b\u5c55\u96c6\u90ae\u65cf\n\u65b0\u6f6e\u8fd0\u52a8\u7231\u597d\u8005\n\u6570\u7801\u6444\u5f71\u8fbe\u4eba\n\u659c\u6760\u9752\u5e74\n\u624b\u529e\u6536\u85cf\u5bb6\n\u533b\u7f8e\u7231\u597d\u8005\n\u65cf\u7fa4\n\u8dd1\u53cb\n\u623f\u8f66\u65c5\u884c\u515a\n\u91d1\u66f2\u6b4c\u8ff7\n\u4f11\u95f2\u6e38\u620f\u73a9\u5bb6\n\u745c\u4f3d\u7231\u597d\u8005\n\u5bb6\u7535\u53d1\u70e7\u53cb\n\u8ffd\u5267\u8fbe\u4eba\n\u4e50\u56ed\u5de1\u6e38\u5bb6\n\u65cf\u7fa4\n\u996e\u98df\u517b\u751f\u65cf\n\u533b\u4fdd\u89c4\u5212\u5bb6\n\u7a33\u5065\u7406\u8d22\u5bb6\n\u8dd1\u53cb\n\u7530\u56ed\u6d41\u8fde\u5ba2\n\u5bb6\u5ead\u5f71\u97f3\u515a\n\u98ce\u6295\u5192\u9669\u5bb6\n\u5bb6\u7535\u53d1\u70e7\u53cb\n\u65cf\u7fa4\n\u996e\u98df\u517b\u751f\u65cf\n\u533b\u4fdd\u89c4\u5212\u5bb6\n\u7ea2\u8272\u6587\u5316\u7231\u597d\u8005\n\u5e7f\u573a\u821e\u8fbe\u4eba\n\u65f6\u5c1a\u94f6\u53d1\u65cf\n\u65c5\u5c45\u5019\u9e1f\u4e00\u65cf\n\u94c1\u6746\u519b\u8ff7\n\u751f\u6d3b\u653b\u7565\u5927\u5e08\nZ\u4e16\u4ee3\n\u8ffd\u9010\u5708\u5c42\uff0c\u7d27\u8ddf\u6f6e\u6d41\nX\u4e16\u4ee3\n\u63d0\u5347\u5bb6\u5ead\u751f\u6d3b\u54c1\u8d28\nY\u4e16\u4ee3\n\u5927\u4f17\u5a31\u4e50\uff0c\u6cdb\u8fd0\u52a8\n\u5a74\u513f\u6f6e\n\u6000\u65e7\u7ecf\u5178\uff0c\u4e50\u4eab\u5eb7\u517b\n16\nCopyright\n\u00a9\n2022\nby\nBoston\nConsulting\nGroup.\nAll\nrights\nreserved.\n\u201cZ\u4e16\u4ee3\u201d\u7684\u753b\u50cf\n\u89c2\u5ff5\u6001\u5ea6\n\u4e2a\u6027\u5316\u4e0e\u72ec\u7acb\n\u6210\u957f\u4e8e\u7269\u8d28\u751f\u6d3b\u6781\u5927\u4e30\u5bcc\u4e14\n\u4fe1\u606f\u7206\u70b8\u7684\u65f6\u4ee3\uff0c\u5584\u4e8e\u5bf9\u6bd4\n\u548c\u7814\u7a76\uff0c\u4e0d\u76f2\u4ece\n\u591a\u5143\u5316\u7684\u6210\u529f\u5b9a\u4e49\n\u4f5b\u7cfb\u4e2d\u5eb8\u4e0d\u662f\u8eba\u5e73\uff0c\u800c\u662f\u8ba4\n\u4e3a\u6210\u529f\u7684\u5b9a\u4e49\u662f\u591a\u6837\u7684\uff0c\u4e0d\n\u6267\u8457\u4e8e\u4f20\u7edf\u5b9a\u4e49\u7684\u51fa\u7c7b\u62d4\u8403\n\u6587\u5316\u81ea\u4fe1\n\u5728\u6210\u957f\u4e2d\u89c1\u8bc1\u7956\u56fd\u5f3a\u76db\uff0c\u6b23\n\u8d4f\u4e0e\u4e2d\u56fd\u6587\u5316\u5173\u8054\u7684\u4e1c\u897f\uff0c\n\u6301\u7eed\u884d\u751f\u4e9a\u6587\u5316\u548c\u5c0f\u4f17\u5708\u5c42\n\u6d88\u8d39\u9700\u6c421\n\u2022 \u81ea\u6211\u72ec\u7acb\uff1a\u770b\u91cd\u5f70\u663e\u4e2a\u4eba\u54c1\u5473\uff0c\u62d2\u7edd\u5343\u7bc7\u4e00\u5f8b\n\u2022 \u56de\u5f52\u4eab\u4e50\uff1a\u8ffd\u6c42\u653e\u677e\u6cbb\u6108\uff0c\u8fdc\u79bb\u55a7\u56a3\uff0c\u671f\u5f85\u597d\u73a9\u6709\u8da3\n\u2022 \u57fa\u7840\u529f\u80fd\uff1a\u597d\u7684\u6027\u4ef7\u6bd4\u662f\u6807\u914d\uff0c\u540c\u65f6\u8981\u5feb\u6377\uff0c\u53ef\u9760\n\u6765\u6e90\uff1aBCG\u6d88\u8d39\u8005\u6d1e\u5bdf\u667a\u5e93-\u4e2d\u56fd\u672a\u6765\u6d88\u8d39\u8005\u8c03\u7814\uff08\u8c03\u7814\u65f6\u95f42022\u5e7410\u6708\uff0c\u6837\u672c\u91cfN=9,000\uff09\uff1bBCG\u5206\u6790\u3002\n1. \u6d88\u8d39\u9700\u6c42\u4e0b\u65b9\u4e3a\u6807\u51c6\u5316\u7684\u9700\u6c42\u5f97\u5206\uff0c\u4ee5\u7b2c\u4e00\u4e2a\u7ef4\u5ea6\u4e3a\u4f8b\uff0c\u5206\u503c=0\u8bf4\u660e\u4e0e\u603b\u4f53\u4eba\u7fa4\u6c34\u5e73\u76f8\u5f53\uff0c\u5206\u503c>0\u8bf4\u660e\u66f4\u770b\u91cd\u81ea\u6211\u72ec\u7acb\uff0c\u5206\u503c<0\u8bf4\u660e\u66f4\u770b\u91cd\u878d\u5165\u4ed6\u4eba\u3002\n0\u5206\u503c\u7ebf 0\u5206\u503c\u7ebf 0\u5206\u503c\u7ebf\n17\nCopyright\n\u00a9\n2022\nby\nBoston\nConsulting\nGroup.\nAll\nrights\nreserved.\n\u201cZ\u4e16\u4ee3\u201d\uff1a\u5708\u5c42\u521b\u751f\n\u5708\u5c42 \u6d3b\u52a8 \u5708\u5c42\u5185\u7279\u6709\u7684\u8bed\u8a00\u4f53\u7cfb\n\u4f11\u95f2\u6237\u5916\n\u9732\u8425 Glamping\uff0c\u8425\u5730\uff0cBush Craft\uff0c\u6e29\u6807\uff0cR\u503c\u2026\n\u98de\u76d8 \u6781\u9650\u98de\u76d8\uff0c\u8eb2\u907f\u98de\u76d8\uff0c\u957f\u4f20\uff0c\u8bfb\u79d2\uff0c\u76d8\u6743\u4ea4\u6362\u2026\n\u4e13\u4e1a\u6237\u5916\n\u5f92\u6b65 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BCG\u6d88\u8d39\u8005\u6d1e\u5bdf\u667a\u5e93-\u4e2d\u56fd\u672a\u6765\u6d88\u8d39\u8005\u8c03\u7814\uff08\u8c03\u7814\u65f6\u95f42022\u5e7410\u6708\uff0c\u6837\u672c\u91cfN=9,000\uff09\uff1bBCG\u5206\u6790\uff1b\u65b0\u6c27\u300a2021\u533b\u7f8e\u884c\u4e1a\u767d\u76ae\u4e66\u300b\u3002\n\u884d\u751f\u51fa\u4f17\u591a\u7684\u4e9a\u6587\u5316\u5708\u5c42\u53ca\u5176\u72ec\u7279\u7684\u8bed\u8a00\u4f53\u7cfb\n\u201cZ\u4e16\u4ee3\u201d\u4e0d\u4ece\u4f17\uff0c\u7279\u7acb\u72ec\u884c\uff0c\u4e0d\u4f1a\u56e0\u4e3a\u54c1\u724c\u7684\u77e5\u540d\u5ea6\u548c\u5386\u53f2\u800c\u76f2\u76ee\u4fe1\u670d\uff0c\n\u800c\u662f\u559c\u6b22\u6316\u6398\u522b\u4eba\u4e0d\u77e5\u9053\u7684\u5b9d\u85cf\u65b0\u54c1\uff0c\u540c\u65f6\u201cZ\u4e16\u4ee3\u201d\u7684\u5708\u5c42\u611f\u5f3a\uff0c\u4f8b\u5982\n\u7535\u7ade\u5708\u3001\u52a8\u6f2b\u5708\u3001vlog\u5708\u7b49\u7b49\uff0c\u5546\u5bb6\u60f3\u8981\u548c\u4ed6\u4eec\u6c9f\u901a\u9996\u5148\u9700\u8981\u5f15\u8d77\u4ed6\u4eec\u7684\n\u5174\u8da3\uff0c\u800c\u4e0d\u80fd\u76f4\u63a5\u63a8\u9500\uff0c\u4e0e\u4ed6\u4eec\u6240\u5728\u5708\u5c42\u7684\u610f\u89c1\u9886\u8896\u5408\u4f5c\u5f80\u5f80\u53ef\u4ee5\u4e8b\u534a\u529f\n\u500d\u3002\n\u2014\u2014\u90ed\u4eba\u6770\uff0c\u8ffd\u89c5\u79d1\u6280\u4e2d\u56fd\u533a\u526f\u603b\u7ecf\u7406\n\u4f8b\u5982\uff1a\u5e74\u8f7b\u7684\u201cZ\u4e16\u4ee3\u201d\u662f\u533b\u7f8e\u5e02\u573a\u7684\u4e3b\u6d41\u6d88\u8d39\u4eba\u7fa4\uff0c18-25\n\u5c81\u533b\u7f8e\u6d88\u8d39\u8005\u6570\u91cf\u591a\u4e8e\u5176\u4ed6\u4e16\u4ee3\n\u4e2d\u56fd\u533b\u7f8e\u884c\u4e1a\u6700\u660e\u663e\u7684\u8d8b\u52bf\u662f\u4e16\u4ee3\u6269\u5f20\u4e0e\u4e16\u4ee3\u8fc1\u79fb\uff0c\u4e16\u4ee3\u6269\u5f20\u662f\u6307\uff1a\u7531\nZ\u4e16\u4ee3\u5411\u5176\u4ed6\u4e16\u4ee3\u62d3\u5bbd\uff0c\u76ee\u524dY\u4e16\u4ee3\u662f\u6700\u4e3b\u8981\u7684\u533b\u7f8e\u589e\u91cf\u6765\u6e90\u3002\u4e16\u4ee3\u8fc1\u79fb\n\u5219\u6307\uff1a\u4e0d\u540c\u4e16\u4ee3\u5bf9\u4e8e\u533b\u7f8e\u7684\u8bc9\u6c42\u662f\u6d41\u52a8\u7684\uff0c\u968f\u7740\u5e74\u9f84\u548c\u4eba\u751f\u9636\u6bb5\u7684\u5207\u6362\n\u800c\u8f6c\u5411\u65b0\u7684\u9879\u76ee\uff0c\u4f8b\u5982\uff0cZ\u4e16\u4ee3\u9009\u62e9\u8eab\u4f53\u5851\u5f62\u4ee5\u5c3d\u65e9\u83b7\u5f97\u793e\u4f1a\u5173\u7cfb\u5207\u6362\n\u9636\u6bb5\u7684\u5f62\u8c61\u7ea2\u5229\uff0cY\u4e16\u4ee3\u901a\u8fc7\u8f7b\u533b\u7f8e\u5b9e\u73b0\u7701\u65f6\u9ad8\u6548\u7684\u6297\u8870\u9700\u6c42\uff0c\u518d\u5230X\u4e16\n\u4ee3\u5c06\u8138\u90e8\u9879\u76ee\u4f5c\u7528\u4e8e\u5468\u8eab\u7684\u5168\u9762\u8eab\u5f62\u7ba1\u7406\u3002\u56e0\u6b64\uff0c\u672a\u6765\u7684\u533b\u7f8e\u884c\u4e1a\u5c06\u8d70\n\u5411\u66f4\u52a0\u4e13\u4e1a\u5316\u4e0e\u7ec6\u5206\u5316\u3002\n\u2014\u2014\u91d1\u661f\uff0c\u65b0\u6c27\u9996\u5e2d\u6267\u884c\u5b98\nZ\u4e16\u4ee3\u4e5f\u662f\u5ba1\u7f8e\u5148\u950b\uff0c\u5f15\u9886\u591a\u7c7b\u7f8e\u5b66\u76f8\u5173\u7684\u751f\u6d3b\u65b9\u5f0f\n18\nCopyright\n\u00a9\n2022\nby\nBoston\nConsulting\nGroup.\nAll\nrights\nreserved.\n\u201cZ\u4e16\u4ee3\u201d\uff1a\u6cbb\u6108\u4eab\u4e50\n\u5438\u732b\u64b8\u72d7\u662f\u201cZ\u4e16\u4ee3\u201d 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0\u5206\u503c\u7ebf\n20\nCopyright\n\u00a9\n2022\nby\nBoston\nConsulting\nGroup.\nAll\nrights\nreserved.\n\u201cY\u4e16\u4ee3\u201d\uff1a\u4e13\u4e1a\u52a9\u529b\n\u4f5c\u4e3a\u72ec\u751f\u5b50\u5973\u7684\u7b2c\u4e00\u4ee3\uff0c\u5728\u6210\u957f\u4e2d\u901a\u5e38\u51dd\u805a\u4e86\u6574\u4e2a\u5bb6\u5ead\u7684\u8d44\u6e90\u548c\u671f\u671b\uff0c\u4e0d\u754f\u7ade\u4e89\uff0c\u52c7\u4e8e\u7ade\u4e89\u7684\u4e00\u4ee3\u3002\u6709\u660e\n\u786e\u7684\u76ee\u6807\u9a71\u52a8\uff0c\u4e60\u60ef\u501f\u529b\u4e13\u4e1a\u670d\u52a1\u548c\u4ea7\u54c1\u6765\u66f4\u597d\u5730\u5b9e\u73b0\u76ee\u6807\uff0c\u5e76\u4e50\u610f\u4e3a\u4e13\u4e1a\u4ed8\u8d39\n\u5168\u65b9\u4f4d\u57f9\u517b\u4e0b\u4e00\u4ee3\uff0c\u4f18\u9009\u4e13\u4e1a\u65b9\u6848\u63d0\u5347\u9e21\u5a03\u6548\u679c\n\u6765\u6e90\uff1a 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Y\u4e16\u4ee3 X\u4e16\u4ee3 \u5a74\u513f\u6f6e\n1 2\n22\nCopyright\n\u00a9\n2022\nby\nBoston\nConsulting\nGroup.\nAll\nrights\nreserved.\n\u201cX\u4e16\u4ee3\u201d\u7684\u753b\u50cf\n\u89c2\u5ff5\u6001\u5ea6\n\u793e\u4ea4\u878d\u5165\u4e0e\u5f52\u5c5e\n\u5bf9\u878d\u5165\u4ed6\u4eba\u975e\u5e38\u770b\u91cd\uff0c\u4ed6\u4eec\n\u79ef\u6781\u7ef4\u62a4\u793e\u4ea4\u5173\u7cfb\uff0c\u5e0c\u671b\u4ece\n\u4e2d\u83b7\u5f97\u5f52\u5c5e\u611f\u4e0e\u8eab\u4efd\u8ba4\u540c\n\u8ffd\u6c42\u4f20\u7edf\u7684\u6210\u529f\n\u5728\u8d22\u5bcc\u548c\u5730\u4f4d\u4e0a\u62d2\u7edd\u4e2d\u5eb8\uff0c\n\u4e89\u5f97\u4f20\u7edf\u5b9a\u4e49\u7684\u6210\u529f\u662f\u4e00\u79cd\n\u5171\u8bc6\n\u4e0e\u65f6\u4ff1\u8fdb\n\u5e76\u4e0d\u5b88\u65e7\uff0c\u613f\u610f\u63a5\u7eb3\u65b0\u89c2\u5ff5\n\u548c\u65b0\u4e8b\u7269\uff0c\u4ee5\u6b64\u5f70\u663e\u81ea\u8eab\u7684\n\u5f00\u653e\u53ca\u4e0e\u65f6\u4ff1\u8fdb\n\u6d88\u8d39\u9700\u6c421\n\u2022 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0\u5206\u503c\u7ebf\n23\nCopyright\n\u00a9\n2022\nby\nBoston\nConsulting\nGroup.\nAll\nrights\nreserved.\n\u201cX\u4e16\u4ee3\u201d\uff1a\u8eab\u4efd\u793e\u4ea4\n\u201cX\u4e16\u4ee3\u201d\u6ce8\u91cd\u793e\u4ea4\u878d\u5165\uff0c\u8ffd\u5bfb\u5e76\u8ba4\u53ef\u4f20\u7edf\u610f\u4e49\u4e0a\u7684\u6210\u529f\u3002\u548cZ\u4e16\u4ee3\u559c\u7231\u7684\u865a\u62df\u4e16\u754c\u793e\u4ea4\u4e0d\u540c\uff0cX\u4e16\u4ee3\u66f4\u5e0c\n\u671b\u5728\u7ebf\u4e0b\u793e\u4ea4\u4e2d\u5f70\u663e\u8eab\u4efd\uff0c\u5bfb\u6c42\u4e0e\u7fa4\u4f53\u7684\u5339\u914d\uff0c\u4fc3\u8fdb\u793e\u4f1a\u5173\u7cfb\u7684\u7ef4\u62a4\n\u4ee5\u201c\u54c1\u724c\u201d\u7292\u8d4f\u81ea\u5df1\n\u4e2d\u9ad8\u7aef\u793e\u4ea4\u878d\u5165\u573a\u6240\u7684\u4e3b\u529b\u5ba2\u7fa4\n\u6765\u6e90\uff1aBCG\u6d88\u8d39\u8005\u6d1e\u5bdf\u667a\u5e93-\u4e2d\u56fd\u672a\u6765\u6d88\u8d39\u8005\u8c03\u7814\uff08\u8c03\u7814\u65f6\u95f42022\u5e7410\u6708\uff0c\u6837\u672c\u91cfN=9,000\uff09\uff1bBCG\u5206\u6790\u3002\n1. 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55%\n25\nCopyright\n\u00a9\n2022\nby\nBoston\nConsulting\nGroup.\nAll\nrights\nreserved.\n\u201c\u5a74\u513f\u6f6e\u201d\u7684\u753b\u50cf\n\u89c2\u5ff5\u6001\u5ea6\n\u91cd\u62fe\u81ea\u6211\n\u72ec\u5904\u81ea\u8db3\uff0c\u4e0d\u518d\u9700\u8981\u9891\u7e41\u793e\n\u4ea4\u6216\u5411\u4ed6\u4eba\u8bc1\u660e\u81ea\u5df1\uff0c\u800c\u662f\n\u5fe0\u4e8e\u81ea\u6211\u7684\u9700\u8981\n\u6000\u65e7\u4f20\u7edf\n\u8ba4\u77e5\u548c\u884c\u4e3a\u4e60\u60ef\u4ecd\u504f\u5411\u4f20\u7edf\n\u4e0e\u7a33\u59a5\uff0c\u504f\u5411\u505a\u51fa\u81ea\u5df1\u8ba4\u77e5\n\u8303\u56f4\u5185\u7684\u9009\u62e9\n\u5f00\u542f\u659c\u6760\u4eba\u751f\n\u62e5\u6709\u66f4\u591a\u7684\u95f2\u6687\u65f6\u5149\u548c\u66f4\u5c11\n\u7684\u5bb6\u5ead\u8d1f\u62c5\uff0c\u901a\u8fc7\u57f9\u517b\u5174\u8da3\n\u83b7\u5f97\u4e86\u591a\u91cd\u8eab\u4efd\n\u6d88\u8d39\u9700\u6c421\n\u2022 \u81ea\u6211\u72ec\u7acb\uff1a\u72ec\u5904\u81ea\u8db3\uff0c\u770b\u91cd\u81ea\u5df1\u5bf9\u751f\u6d3b\u7684\u638c\u63a7\u611f\n\u2022 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0\u5206\u503c\u7ebf\n26\nCopyright\n\u00a9\n2022\nby\nBoston\nConsulting\nGroup.\nAll\nrights\nreserved.\n\u201c\u5a74\u513f\u6f6e\u201d\uff1a\u7ebf\u4e0a\u4e50\u6d3b\n17%\n2017\n7%\n4%\n48%\n46%\n14%\n9%\n4%\n2018\n724\n23%\n15%\n10%\n5%\n20%\n2020\n21%\n43%\n2021\n13%\n6%\n41%\n17%\n16%\n7%\n\u5a74\u513f\u6f6e\n49%\nY\u4e16\u4ee3\nX\u4e16\u4ee3\n2019\n27%\n\u5176\u4ed6\u5e74\u9f84\u6bb5\nZ\u4e16\u4ee3\n13%\n25%\n833\n779\n932\n983\n\u201c\u5a74\u513f\u6f6e\u201d\u62e5\u6709\u66f4\u591a\u7684\u95f2\u6687\u65f6\u5149\u548c\u66f4\u5c11\u7684\u5bb6\u5ead\u8d1f\u62c5\uff0c\u4ed6\u4eec\u5f00\u59cb\u91cd\u62fe\u81ea\u6211\uff0c\u5e76\u901a\u8fc7\u62e5\u62b1\u4e92\u8054\u7f51\uff0c\u53d1\u5c55\u51fa\u4e0d\u540c\n\u7684\u5174\u8da3\u7231\u597d\uff0c\u5f00\u542f\u62e5\u6709\u591a\u91cd\u8eab\u4efd\u7684\u659c\u6760\u4eba\u751f\uff0c\u5b9e\u73b0\u8001\u6709\u6240\u4e50\u7684\u4eab\u8001\u751f\u6d3b\n\u4e2d\u56fd\u4e92\u8054\u7f51\u793e\u4ea4\u5e73\u53f0\u4f7f\u7528\u8005\u4eba\u6570\u53ca\u5e74\u9f84\u7ed3\u6784\u53d8\u5316\n\uff08\u5355\u4f4d\uff1a\u767e\u4e07\u4eba\uff09\n\u5360\u6bd4\u53d8\u5316\n-7%\n-9%\n+4%\n+9%\n+3%\n\u6765\u6e90\uff1a BCG\u5206\u6790\uff1beMarketer\u5168\u7403\u5e02\u573a\u7814\u7a76\u673a\u6784\u3002\n\u201c\u5a74\u513f\u6f6e\u201d\u6210\u4e3a\u4e92\u8054\u7f51\u7684\u4e3b\u8981\u589e\u91cf\u6765\u6e90\n\u70ed\u95e8\u8001\u5e74KOL \u4f8b: \u6296\u97f3\u5e73\u53f0\u7c89\u4e1d\u6570\uff08\u4e07\uff09 \u5185\u5bb9\u9898\u6750\n\u6211\u662f\u7530\u59e5\u59e5 3633.1 \u65b0\u519c\u6751\u7684\u8da3\u5473\u751f\u6d3b\n\u53ea\u7a7f\u9ad8\u8ddf\u978b\u7684\n\u6c6a\u5976\u5976\n1399.9 \u8001\u5e74\u7684\u6f6e\u6d41\u7a7f\u642d\n\u8001\u996d\u9aa8 1319.0 \u53a8\u827a\u4e0e\u70f9\u996a\u7684\u6280\u5de7\n\u672b\u90a3\u5927\u53d4 1712.7 \u8001\u5e74\u7684\u7cbe\u81f4\u751f\u6d3b\n\u901a\u8fc7\u4e92\u8054\u7f51\u57f9\u517b\u5174\u8da3\uff0c\u5f00\u542f\u659c\u6760\u4eba\u751f\n\u2022 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\u6296\u97f3\u3001\u5feb\u624b\u7b49\u77ed\u89c6\u9891\u5e73\u53f0\u4e0d\u4e4f\u8001\u5e74KOL\uff0c\u4ee5\u94f6\u53d1\u751f\u6d3b\u7684\u65b9\u65b9\u9762\u9762\u4e3a\u9898\n\u6750\uff0c\u62e5\u6709\u4e86\u73b0\u5b9e\u751f\u6d3b\u4e4b\u5916\u7684\u591a\u91cd\u8eab\u4efd\uff0c\u83b7\u5f97\u767e\u4e07\u3001\u5343\u4e07\u7c89\u4e1d\u7684\u559c\u7231\n27\nCopyright\n\u00a9\n2022\nby\nBoston\nConsulting\nGroup.\nAll\nrights\nreserved.\n\u201c\u5a74\u513f\u6f6e\u201d\uff1a\u4e2d\u5f0f\u517b\u751f\n\u89c2\u5ff5\u4f20\u7edf\uff0c\u6ce8\u91cd\u517b\u751f\u7684\u201c\u5a74\u513f\u6f6e\u201d\uff0c\u5bf9\u4fdd\u6301\u957f\u5bff\u548c\u6d3b\u529b\u6000\u6709\u7f8e\u597d\u7684\u613f\u671b\uff0c\u79c9\u6301\u4ee5\u517b\u4e3a\u4e3b\uff0c\u533b\u517b\u7ed3\u5408\u7684\u4e2d\u5f0f\n\u7406\u5ff5\uff0c\u9752\u7750\u836f\u98df\u540c\u6e90\u6982\u5ff5\u7684\u5546\u54c1\n\u6765\u6e90\uff1a 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