The use of oxygen in the palliation of breathlessness. A report of the expert working group of the...

The use of oxygen in the palliation ofbreathlessness. A report of the expert workinggroup of the scientific committee of the associationof palliative medicine

Sara Bootha,*, Heather Andersonb, Maelie Swannickc, Rosemary Waded,Suzanne Kitee, Miriam Johnsonf

aOncology Centre, Box 193, Addenbrooke’s Hospital, Hills Road, Cambridge CB2 2QQ, UKbWythenshawe Hospital, Southmore Road, Manchester M23 9LT, UKcNightingale McMillan Unit, 117A London Road, Derby DE1 2QS, UKdWest Suffolk Hospital, Hardwick Lane, Bury St. Edmunds IP33 2QY, UKeLeeds General Infirmary, Great George Street, Leeds LS1 3EX, UKfSt. Catherine’s Hospice, Scarborough, YO12 6TB, UK

Accepted 21 August 2003

Summary Dyspnoea is a common, distressing symptom and difficult to control withmedical treatment. The role of oxygen in reducing the severity of the symptoms andimproving quality of life is still unclear. A working party of the Association of PalliativeMedicine Science Committee set out to examine the evidence concerning the use ofoxygen for the palliation of breathlessness in COPD, advanced cancer and chronicheart failure and to make recommendations for clinicians working in palliative care.There were very few randomised controlled trails available for any of theseconditions. There was no evidence available for heart failure, very little foradvanced cancer and although there were a number of trails on the use of oxygen inCOPD very few, until recently, used reduction of breathlessness as an outcomemeasure. Recommendations are made on the basis of the evidence available andexpert opinion such as the Royal College of Physicians report on the use of domiciliaryoxygen. Oxygen use has to be tailored to the individual and a formal assessment madeof its efficacy for reducing breathlessness and improving quality of life for thatperson.& 2003 Elsevier Ltd. All rights reserved.

KEYWORDS

Dyspnoea;

Cancer;

Heart failure;

COPD;

Palliation;

Oxygen

Introduction

Breathlessness remains an enigma.1 It is a dominantsymptom in the advanced stages of many disordersincluding cancer, cardio-respiratory and neurologi-cal disease. Clinicians are often unable to control

breathlessness effectively2 in contrast with malig-nant pain management where it is now possible tooffer relief for most patients with oral pharmaco-logical therapy alone even in advanced disease. Intheir last year of life as many as 94% patients withchronic lung disease, 78% of those with lung cancer3

and more than 50% of patients with heart disease4

will experience breathlessness. Its prevalence isincreasing in the population as a whole for a

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*Corresponding author.E-mail address: [email protected] (S. Booth).

0954-6111/$ - see front matter & 2003 Elsevier Ltd. All rights reserved.doi:10.1016/j.rmed.2003.08.008

Respiratory Medicine (2004) 98, 66–77

number of reasons, paradoxically, for example,because of the success of the secondary preventionof the complications of myocardial infarction5

which delay but do not prevent the onset of heartfailure and breathlessness. Breathlessness is aproblem that is reaching epidemic proportions.6,7

It is clear that a unitary theory of the causationof breathlessness is inadequateFit is not simply adisorder of the heart and lungs either singly or incombination. It is a complex multisystem disorderwith evidence of neurohormonal abnormalities,peripheral and respiratory muscle dysfunction;and a whole host of other changes outside thecardio-respiratory system.

There is continuing controversy about the placeof oxygen in palliative care. In the early palliativecare literature, it is generally stated that oxygentherapy can do more harm than good if theequipment comes between patient and family inthe late stages of an illness. There was, andremains, a concern that patients can becomedependent on oxygen, not wishing it to be removedeven when they are clearly dying and whenpharmacological therapy could offer some reliefin the form of sedation.

Domiciliary oxygen is expensive.8 In the Cam-bridgeshire area alone (population 775,000) nearly14 million pounds was spent on oxygen concentra-tors in 2000, a rise from 11 million in 1996. It isimportant that clinicians are able to target thisdrug at the right patients as oxygen can haveadverse effects (Appendix A) as well as benefits forpatients’ and families’ quality of life.

This working party set out to examine theevidence available for the use of oxygen in thepalliation of breathlessness in chronic obstructivepulmonary disease (COPD), advanced cancer andcardiac failure. We did not consider neurologicaldisease, interstitial lung disease or acute exacer-bations of heart failure or COPD. Oxygen is one partof a complete palliative care treatment strate-gyFother appropriate medical and surgical inter-ventions, the management of psychological andsocial concerns and support of the family and othercarers are also essential to produce the bestsymptom relief possible. These aspects of careare not further mentioned as the remit of thisgroup was to assess the evidence available on theuse of oxygen in the palliation of breathlessnessand make recommendations (even where goodevidence was scarce) to guide palliative careclinicians in the use of oxygen for the palliation ofbreathlessness.

We were asked to consider only randomisedcontrolled trials (RCT)9 and the search strategyused is set out in each section. The evidence for

each patient group is summarised and then generalclinical recommendations are made from ourfindings and expert clinical opinion.10,11

Definitions10

Short-burst oxygen therapy: Intermittent use ofoxygen for relief of breathlessness, before exerciseor for recovery after exercise.

Ambulatory oxygen therapy: Provision of oxygentherapy during exercise and/or the activities ofdaily living.

Long-term oxygen therapy (LTOT): Provision ofoxygen therapy at home on a continuous and long-term basis, ideally for at least 15 h daily, includingtime spent asleep. In COPD, it is prescribed withinspecific guidelines to prolong survival.

Background

Participants with COPD in trials of oxygen use canbe divided into four groups: those with acuteexacerbations, at rest, during exercise or on long-term oxygen therapy. The British Thoracic Society(BTS) guidelines recommend the use of long-termoxygen therapy in specific patients to improvesurvival rather than palliation, as it reducessecondary polycythemia, prevents progression ofpulmonary hypertension and improves neuropsy-chological health. At rest the BTS COPD guidelines11

state ‘‘Short bursts of oxygen from a cylinder via afacemask are widely prescribed to relieve breath-lessness. There are no data to support or refute thispracticey’’ The guidelines also state that goodevidence to support the use of ambulatory oxygenis also lacking.

Dyspnoea is a common symptom in patients withadvanced cancer and generally has a mixedaetiology.12 Oxygen is commonly used in thepalliation of breathlessness without clear evidenceof its efficacy.

The mechanisms behind the sensation of breath-lessness in chronic heart failure (CHF) are notclear and are thought to be multifactorial. Inaddition to a variable amount of pulmonaryoedema, there is an abnormal ventilatory responseto exercise and carbon dioxide production resultingin an increased ventilatory dead space. Otherfactors may include increased arterial chemore-ceptor sensitivity and abnormal skeletal musclewith enhanced muscle ergoreflex activity thatfurther stimulates ventilation and sympatheticactivity.

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The use of oxygen in the palliation of breathlessness 67

Method

Search strategies

A search was undertaken focused on Medline,EMBASE and the Cochrane Library limited to humanstudies from 1966 (1975 for heart failure). Forsubjects with COPD the keywords of oxygen,oxygen therapy, COPD, chronic obstructive airwaysdisease, breathlessness and dyspnoea weresearched in various combinations. The referencesof relevant papers were then hand searchedtogether with Chest, Thorax and The AmericanJournal of Respiratory and Critical Care Medicinefrom 1970. For subjects with cancer the keywordsof oxygen, oxygen therapy, cancer, neoplasm andbreathlessness/dyspnoea were searched in variouscombinations. The references of relevant paperswere then hand searched. For subjects with heartfailure the search words were CHF, oxygen therapyand breathlessness. All studies, which recordedwhen breathlessness was cited as a reason to stopan exercise regimen, were also reviewed.

Outcome measures

A reduction in breathlessness as measured with aspecific tool or scale. In the studies found, thesewere often simple visual analogue scales (VASs) orthe Borg scale.13

Results

Patients with COPD

There were no large RCTs found. The trials includedin this review were small controlled trials eithersingle or double blind. A crossover design was usedin all trials except those of long-term oxygen. Manystudies14 measured physiological variables andendurance whilst using oxygen but did not assessdyspnoea. The results are shown in table formdivided into three categories of trial participantsFat rest, exercise and long-term oxygen therapyat rest.

Oxygen therapy at rest: Only five papers werefound where oxygen therapy was given to patientswith COPD at rest and these are summarised inTable 1.

Oxygen therapy and exercise (ambulatory andshort-burst oxygen): Exercise tests used includedtreadmill, cycle, 6min or endurance walks; oftentwo types of exercise were used in each study.Oxygen therapy is given during exercise unless

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Table

1Su

mmaryofstudiesusingoxyge

ntherapyforbreathlessness

inpatients

withCOPDat

rest.

Study

Methods

No.

Mean

baseline

oxyge

nleve

lsIntervention

Comparison

Outcome

Maineffect

Liss

and

Grant1

5Singleblind

crossove

rtrial

8Pa

O27.07

kPa

2an

d4l/min

oxyge

nwithor

withoutLidoca

ine

2an

d4l/min

compressedairall

vianasal

cannulae

Chan

gein

VAS

Nosign

ifica

ntdifference

.Lidoca

ineincreasesdyspnoea

Kollefan

dJohnson16

Singleblind

crossove

rtrial

9Pa

O26.67

kPa

Tran

strach

eal

oxyge

nat

2an

d4l/min

withan

dwithoutLidoca

ine

Tran

strach

eal

airat

2an

d4l/min

Chan

gein

VAS

Sign

ifica

ntlymore

breathless

onhighflow

oxyge

nan

dair.

WithLidoca

inenodifference

Swinburn

etal.1

7Double

blind

randomised

crossove

rtrial

12Pa

O26.71

kPa

andSaO285

%28

%oxyge

nvia

mask

Compressedairvia

mask

Chan

gein

VAS

Sign

ifica

ntim

prove

menton

oxyge

n

Booth

etal.1

8Singleblind

crossove

rtrial

13Ran

ge80

–99

%SaO2

Oxyge

nat

4l/min

vianasal

cannulae

Air

at4l/min

via

nasal

cannulae

Chan

gein

VAS

andBorg

scale

Improve

mentonairan

doxyge

nan

dnosign

ifica

nt

difference

betw

eenthetw

oga

ses

O’Donnell

etal.1

9Baselinetest

pre-

exe

rcisetrial

11Pa

O26.93

kPa

60%oxyge

nusing

mouth

piece

21%oxyge

nusing

mouth

piece

Chan

gein

Borg

Nodifference

inreported

dyspnoea

68 S. Booth et al.

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PRES

S

Table 2 Summary of studies using oxygen therapy for breathlessness in patients with COPD before, during and after exercise.

Study Methods No. Mean baselineoxygen

Intervention Comparison Outcome Main effect

Woodcocket al.20

Double blind RCT 10 PaO2 rest9.65 kPa andexercise8.19 KPa

Oxygen carried bysubject or assistant

Compressed airboth via nasalcannulae

Change in VAS Slower increase in dyspnoeaand increased endurance

Waterhouseand Howard21

Single blind RCT 20 PaO2 onexercise8.9 kPa

Oxygen 2 and 4 l/min via nasalcannulae

Compressed air vianasal cannulae androom air

Change in VAS Reduced dyspnoea on oxygen

Swinburnet al.22

Double blind RCT 5 SaO2 93% restand 86% onexercise

Oxygen 60% viamouth piece

Room air via mouthpiece

Change in VAS Increased endurance, samedyspnoea

Evans et al.23 Single blind RCT 19 PaO2 rest8.05 kPa

Oxygen afterexercise via mask

Compressed air viamask and room air

Change in VAS Shorter recovery time withoxygen

Davidsonet al.24

Double blind RCT 17 PaO2 8.60 KPa,SaO2 94% atrest and 87.5%on exercise

Oxygen subjectschoice of mask/nasal cannulae

Compressed airgiven as oxygen

Change in VAS Slower increase in dyspnoeaand increased endurance

Lane et al.25 Single blind non-randomizedcrossover trial

9 PaO2 8.92 kPaat rest

Oxygen to maintainoxygen saturationvia mouth piece



McKeon et al.26 Double blind RCT 21 PaO2 8.85 kPaand SaO2 92%rest and 83%exercise

Portable oxygen at4 l/min via nasalcannulae


Change in VAS Slower increase in dyspnoeaon oxygen

McKeon et al.27 Double blind RCT 20 PaO2 7.73 kPaand SaO2 91%rest and 83%after exercise

Oxygen beforeexercise via nasalcannulae

Compressed airbefore exercise vianasal cannulae

Change in VAS No difference

Leach et al.28 Single blind RCT 20 PaO2 8.74 kPaat rest and7.82 KPa afterexercise

Oxygen at 2, 4 and6 l/min via mask

Compressed air 4 lvia mask


Dean et al.29 Double blind RCT 12 PaO2 9.47 kPaat rest and8.4 kPa afterexercise

40% oxygen viamouth piece

Compressed air viamouth piece

Change in Borg Increased endurance untillimited by the same dyspnoea

Dewan andBell30

Single blind RCT 10 SaO2

maintained atHigh and low flowtranstracheal

High and low flowair through nasal

Change in Borgscale

High flow greater dyspnoeaand increased endurance

Theuse

ofoxyge

nin

thepallia

tionofbreathlessn

ess

69

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PRES

S

Table 2 (continued)



92% and 98% oxygen therapy cannulaeRoberts et al.31 Non-blind RCT 15 PaO2 6.98 kPa

and lowestSaO2 74.6%

On demand oxygendelivery systemusing nasalcannulae

Continuous oxygenvia nasal cannulaeand room air

Change in VAS Less dyspnoea on bothmethods of giving oxygen

O’Donnellet al.32

Double blind RCT 11 PaO2 9.87 kPaand SaO2 90%


21% oxygen viamouth piece

Change in Borgscale

No change in dyspnoea butincreased endurance

Marques-Magallaneset al.33

Single blind RCT 18 PaO2 6.8 kPa Oxygen 40% afterexercise via mask

Compressed air viamask and room air

Change in VAS No reduction in dyspnoea

Revill et al.34 Single blind RCT 10 SaO2 92% atrest and 80%on exercise

Oxygen 2 l/min vianasal cannulae

Sham oxygen vianasal cannulae androom air

Change in Borgscale

No change in dyspnoea butincreased endurance

Killen andCorris35

Single blind RCT 18 SaO2 94% atrest and o90%on exercise

Oxygen 2 l/min viaface mask beforeand after exercise

Compressed air viaface mask


Knebel et al.36 Double blind RCT 31 SaO2 97% atrest and 90%on exercise

Oxygen at 4 l/minvia nasal cannulae


Change in VAS No reduction in dyspnoea

Somfay et al.37 Single blind RCT 10 SaO2 95.7% atrest and 92%on exercise

Oxygen at 30%, 50%,75% and 100% viamouth piece

Compressed air viamouth piece

Change inmodified Borg

Oxygen dose-dependentreduction in dyspnoea

Jolly et al.38 Double blind RCT 20 PaO248 kPa atrest and onexercise twogroupsSaO2o90% and490%

Oxygen 6, 9 and12 l/min via nasalcannulae

Compressed air vianasal cannulae

Change in Borgscale

Oxygen reduced dyspnoea indesaturation and non-desaturation groups

Maltais et al.39 Double blind RCT 14 PaO2 11.3 kPaat rest and9.33 kPa onexercise

Oxygen via mouthpiece (FIO2¼ 0.75)


Change in Borgscale

Reduced dyspnoea on oxygen

O’Donnellet al.19

Double blind RCT 11 PaO2 6.93 kPaat rest and6.13 kPa afterexercise



Change in Borgscale

Increased endurance untillimited by the same dyspnoea

Eaton et al.40 Double blind RCTover 12 weeks

50 At rest PaO2

9.2 kPa andSaO2 94% and

Oxygen 4 l/minduring exercise vianasal cannulae

Compressed air 4 l/min during exercisevia nasal cannulae

Change inchronicrespiratory

Reduced dyspnoea on oxygen

70

S.Booth

etal.

ARTIC

LEIN

PRES

S

Table 3 Summary of studies using oxygen therapy in the long term for breathlessness in patients with COPD.


Intervention Comparison Outcome Main effects

McDonaldet al.41

Single blind randomisedcrossover trial over 12weeks

26 PaO2 9.2 kPaand SaO2 94%

Oxygen 4 l/min vianasal cannulae

Compressed air vianasal cannulaeduring exercise

Change in Borg No significant change indyspnoea

Rooyackerset al.42

Randomised controlledtrial over 10 weeks notblind

24 PaO2 10 kPa atrest and7.3 kPa at peakexercise

Oxygen 4 l/minduring exercise

Room air duringexercise 10 weeks

Change in Borgand chronicrespiratorydiseasequestionnaire

Rehabilitationprogramme improveddyspnoea, no increasedbenefit fromsupplemental oxygen

Garrod et al.43 Single blind randomisedcontrolled trial over 6weeks

22 At rest PaO2

8.5 kPa andSaO2 92.3%,SaO2 82% onexercise


Compressed air 6weeks duringexercise via nasalcannulae

Change in Borg Small decrease indyspnoea

Eaton et al.40 Double blind RCT over 12weeks

50 At rest PaO2

9.2 kPa andSaO2 94% andSaO2 82% afterexercise


Compressed air 4 l/min during exercisevia nasal cannulae

Change inchronicrespiratorydiseasequestionnaire

Small decrease indyspnoea

Theuse

ofoxyge

nin

thepallia

tionofbreathlessn

ess

71

otherwise stated. Twenty-two papers were foundand the results are summarised in Table 2.

Long-term oxygen therapy (LTOT): Trials of LTOTtend to use quality of life measures as opposed tomeasurements of breathlessness and only threehave been included using our criteria. The aim ofLTOT is to prolong survival not to palliate dyspnoeabut where dyspnoea was assessed it was importantto see the effect. The trials are summarised inTable 3.

Patients with cancer

There were no large RCTs found. Two of the trialsincluded in this review were small controlled trialswith a crossover design and one an ‘N of 1’ study.The results for patients with advanced cancer areshown in Table 4. The patients in the trials hadadvanced cancer with either primary or secondarydisease in the thorax. Most, but not all had lungcancer.

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Table 4 Summary of studies using oxygen therapy for breathlessness in patients with advanced cancer.

Study Methods No. Meanbaselineoxygen


Brueraet al.44

N of 1 doubleblind crossovertrial

1 SaO2 84% Oxygen at5 l/min for5min at restvia mask

Compressedair at 5 l/minvia mask

Change inVAS

Less breathless onoxygen

Brueraet al.45

Double blindcrossover trial

14 o90%SaO2

Oxygen at5 l/min for5min at restvia mask

Compressedair at 5 l/minvia mask

Change inVAS

Less breathless onoxygen

Boothet al.18

Single blindcrossover trial

38 Between80% and99% SaO2

Oxygen at4 l/min for15min at restvia nasalcannulae

Compressedair at 4 l/minvia nasalcannulae

Change inVAS andBorg scale

Improvement withair and oxygen andno significantdifference betweenthe two gases

Table 5 Summary of the available evidence on the use of oxygen in chronic heart failure.

Study Method No./NYHAgrade

Comparison Outcome Main effect

Moore et al.46 Double blind RTBicycle ergometerexercise test

7/II 5/III 21%, 30% and50% oxygenvia amouthpiece

Change perceivedexertion (Borgscale) anddyspnoea (VAS)

Mean SaO2 unchangedduring exercise on airDyspnoea reduced with50% oxygen

Restricket al.47

Double blind RT6min walks,oxygen carried bysubject orassistant.Endurance walks,oxygen carried bysubject

12/III Air andoxygen at 2and 4 l/minvia nasalcannulae

Change inbreathlessness asrated on amodified Borgscale and VAS

Mean SaO2 fell onexercise on air Nochange in distancewalked or Borg or VASscores with oxygen

Russell et al.48 Double blind RT.Bicycle ergometerexercise test

16/II–III 21% and 60%oxygen via amouthpiece

Stated reason forstopping exercise

Mean SaO2 unchangedduring exercise on air13 subjects stoppedexercising complainingof fatigue and threebecause of dyspnoea

72 S. Booth et al.

Patients with heart failure

There were no large randomised controlled studiesfound. There were no studies specifically looking atthe effects of oxygen on reducing the sensation ofbreathlessness in severe heart failure.

There were two small studies which included VASscore and/or Borg scale for breathlessness as one ofthe study end-points and one study recordeddyspnoea as a reason patients gave for stoppingexercise schedules. The studies are discussed belowand summarised in Table 5.

Moore et al.46 found that during bicycle ergometerexercise testing with oxygen-enriched air, there was asignificant increase in arterial oxygen saturation. Inaddition, total exercise duration was prolonged,carbon dioxide production was reduced. Whenbreathing 50% oxygen, perceived exertion rated (Borgscore) was significantly reduced and subjectivedyspnoea scores rated lower on a VAS. Inhaling 30%oxygen produced values intermediate between airand 50% oxygen. Restrick et al.47 and Russell et al.48

did not confirm this. Restrick, in a double-blind studyof 12 subjects with heart failure (New York HeartAssociation (NYHA) class III) found that although 2 and4 l/min ambulatory oxygen increased resting arterialoxygen saturation compared with air, there was nosignificant difference in distance walked or perceivedbreathlessness on a Borg or VAS. In this study, patientswere required to carry their own portable oxygencylinders: this would have increased workload incompromised patients. Russell et al. failed to showany reduction in minute ventilation or functionalbenefit with higher oxygen concentrations. The studyunfortunately did not look at the subjective assess-ment of breathlessness although the authors didcomment on the number of patients who stopped dueto breathlessness or fatigue. All patients had thesame reason for stopping during exercise tests,breathing either concentration of oxygen. In bothMoore and Russell’s studies, the mean arterial oxygensaturation did not fall during exercise on air incontrast to Restrick’s study where the mean oxygensaturation fell significantly. In response to Russell’sstudy, Abinader and Sharif49 noted that the effect ofincreased oxygen concentration in patients withheart failure is variable. They commented that theconcentration of 60% inspired oxygen was probablytoo high leading to an increase in systemic vascularresistance and also suggested that the exerciseprogramme may have been too strenuous for thosewith severe heart failure. They also raised the pointthat none of Russell’s subjects desaturated onexercise and suggested that it is those patients withheart failure who desaturate on exercise that benefitmost from oxygen.

Chua et al.50 investigated the contribution of theperipheral chemoreceptors to ventilation and alsothe effects of their suppression on exercisetolerance in patients with mild to moderate heartfailure. In the course of this study, an increase inexercise tolerance and a decrease in dyspnoea wasnoted when the participants were breathing 100%oxygenFbut as a descriptive study this was notincluded in our review of evidence.

Summary of evidence in patients with COPD

(1) There is evidence for and against using oxygenfor palliation of breathlessness at rest.

(2) The majority of studies using oxygen duringexercise show that patients experience lessbreathlessness at equivalent level of exercisewhen compared to air.

(3) There is no evidence that pre-oxygenationreduces breathlessness during exercise.

(4) There is recent evidence that using oxygen mayspeed recovery from breathlessness, givenbefore or after exercise.35

(5) A recent study suggests that the effect ofambulatory oxygen on quality of life over alonger-term cannot be predicted from patients’baseline characteristics or their acute/short-term response to oxygen therapy.40 Even whenthey experienced acute/short-term response tooxygen therapy, a significant proportion ofpatients will not continue to use ambulatoryoxygen at home because of poor tolerability.

It is important to note that all these trials hadsmall numbers of subjects. In most papers theinvestigators remark on the markedly differentresponses from one patient to another.

Summary of evidence in patients with cancer

Oxygen may be helpful for the palliation ofbreathlessness in some patients with advancedcancer but at the present time there is littleevidence to enable clinicians to predict whichpatients will obtain benefit. Some form of formalclinical assessment like an ‘N of 1’ trial, isnecessary to determine its usefulness for eachindividual.

Summary of evidence in patients with heartfailure

There is insufficient evidence currently availablefor the use of oxygen for breathlessness in thesepatients. Most patients included in the reviewed

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studies had stable mild to moderate heart failure(NYHA II–III) and it is difficult to extrapolate theseresults to patients with severe (NYHA IV) CHF, or tothose with unstable disease.

Conclusion

It is clear both from the work of this group and theRCP working party,10 that further research isneeded to enable palliative care clinicians toprescribe this potentially useful therapeutic toolmore effectively. This paper reviews the evidenceconcerning oxygen treatment alone. In the trialspresented here patients were stable and receivingother standard treatments. Oxygen therapy is not acomplete answer to the palliation of breathlessnessin these groups of patients.

When the literature as a whole is reviewed, thereis evidence that oxygen can have a useful role inthe palliation of this symptom18,45 in selectedpatients with advanced cancer and COPD.43 InCHF the absolute lack of evidence is a barrier toany certainty. The clinical recommendations for theuse of oxygen in palliative care below are based onthe findings of our review in conjunction with thewider body of expert clinical opinion.10,11,51

Key recommendations

Basic principles of oxygen therapy inpalliative care

* Oxygen therapy may be one part of the palliativeor supportive care of patients with cancer, COPDand chronic cardiac failure, never a completetreatment in itself.

* The adverse effects of oxygen therapy need tobe part of the assessment for oxygen therapy foreach individual (set out in Appendix A).

* Oxygen therapy in palliative care is morecomplex than the simple correction of hypox-aemia.

* Only in exceptional circumstances should oxygenbe instigated as a long-term option for contin-uous use, by a physician, without some formalassessment of its efficacy for breathlessness, orquality of life, for that patient. Such assessmentis probably most usefully done in the home overa pre-determined period of time.

* The assessment method used before an indivi-dual is prescribed oxygen therapy needs to betailored for each person and the way in whichoxygen is to be used. Formal exercise testing(as set out in Appendix C) may not be the

most appropriate or most accurate way ofassessing the need for oxygen for a particularpatient. Clinical judgement and consultationwith the patient are the foundations of palliativecare as improved quality of life is the centralaim.

* The treatment strategy, including the use ofoxygen, may change quite rapidly in advancedcancer and needs frequent reassessment andadjustment as necessary.

* LTOT for chronic respiratory illness should onlybe instigated by a respiratory physician.

Recommendations for clinical practice

Oxygen therapy at rest

Patients with COPD and advanced cancerOxygen therapy at rest should only be prescribed asa long-term option for use during most hours of theday after careful assessment of the severity ofbreathlessness and quality of life over a predeter-mined time by patients using simple diaries andappropriate scoring systems. An ‘n of 1’ trial, usingthe principles described by Bruera,44 may be thesimplest way of doing this (see Appendix B).Patients who benefit from oxygen and com-pressed air should be given whichever gas is mostappropriate.

Patients with chronic heart failureThere is no evidence to suggest that the use ofoxygen therapy at rest is useful in patients withCHF. An individual trial may be indicated if thepatient is hypoxaemic.

Short-burst oxygen therapy

Short-burst oxygen therapy and short-term oxygentherapy is recommended for patients with ad-vanced cancer for the relief of breathlessness.The RCP working party stated that ‘‘despiteextensive prescription of short-burst oxygen ther-apy, there is no adequate evidence available forfirm recommendationsyit may be prescribed forepisodic breathlessness not relieved by othertreatments in patients with severe COPDyheartfailure and in palliative care’’.

There is some evidence from Booth et al.18 thatoxygen and air can help to relieve breathlessness atrest and whilst this study did not demonstrate asignificant difference between oxygen and air theimprovements in dyspnoea were greater withoxygen than with air. The work of Killen and

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74 S. Booth et al.

Corris35 indicates that short-burst oxygen therapybefore or after exertion in patients with COPD canreduce the severity of dyspnoea on exertion.Patients with advanced cancer, who are breathlesswithout a remediable cause, have a short prognosis(months rather than years). Most are treated inoncology outpatients or hospice units where it maybe difficult to do formal exercise testing as aroutine. Whilst there is a clear need for moreresearch evidence, it is acceptable to provideshort-burst oxygen therapy for patients withbreathlessness on exertion after a formal, butsimple test of its efficacy in that individual.52

Ambulatory oxygen therapy

Patients with COPD and advanced cancerAmbulatory oxygen therapy is appropriate for manypatients with COPD and breathlessness who desa-turate on exercise, and this condition should beactively sought using simple exercise testing andoximetry. In the RCP report, ambulatory oxygen isrecommended10 for patients who, desaturate atleast 4% below 90% on a baseline walk breathing airand/or there is an improvement of 10% in walkingdistance or breathlessness scores with supplemen-tal oxygen or experience a sustained improvementin their breathlessness on using it. Assessing theimpact of oxygen over a period of time on apatient’s quality of life at home, by means ofsimple standardised tools may give a more accuratepicture of its importance to an individual as arecent study by Eaton et al. demonstrated.Although some patients gained acute (measuredby an exercise test) and short-term (assessed by theChronic Respiratory questionnaire) benefit fromoxygen therapy this was not necessarily sustainedover a 12 week period. In addition, 14(41%) ofacute or short-term responders did not want tocontinue oxygen after the trialF11 of these citingpoor acceptability. It is not possible to determinewhich patients will benefit from oxygen from theirbaseline characteristics. Some sort of formalassessment is needed. A recent retrospective studyin patients with COPD suggested that a baselineresting arterial oxygen saturation below 95% maypredict the need for ambulatory oxygen53 but theresults of this study need further careful prospec-tive research. At the moment, for patients withadvanced cancer a documented improvement inbreathlessness on exertion when using oxygen or asimple ‘N of 1’ trial would give sufficient evidencefor the prescription of ambulatory oxygen in thisgroup.

Patients with chronic heart failureThere is little evidence to support any recommen-dations for patients with CHF but patients who aretroubled by breathlessness and who are willing touse oxygen should have a formal trial of its efficacyat rest and on exercise. The RCP report does notrecommend ambulatory oxygen therapy for pa-tients with CHF.

Appendix A. Adverse effects of oxygentherapy

(1) Restriction of activities.(2) Oxygen apparatus is cumbersome and for an

already disabled patient may act as a disincentiveto going out and living as normally as possible.

(3) Impaired communication between patient andfamily.

(4) If patients become psychologically dependenton oxygen they may attend too much on themechanics of having their oxygen therapy.Some will not even remove their mask for evena minute and conversation with is impeded.They may even become frightened when thereis any interruption in the oxygen supply andrefuse to go out without a continuous supplyfrom a cylinder. This may have a deleteriousimpact on quality of life.

(5) Fire hazard: Oxygen promotes combustion.Patients who smoke during oxygen therapyare in great danger of facial burns and somefatalities have been reported.

(6) Hypercapnic respiratory failure: The dangers ofoxygen therapy in those patients with Type IIrespiratory failure are well known.

(7) Withdrawing oxygen: Once oxygen has beengiven to a patient it is often difficult to stop itsuse even when it is on longer relieving breath-lessness or being used appropriately.

(8) The cost of oxygen: Oxygen is not cheap andshould be used appropriately rather thanuniversally.

(9) Humidification of oxygen in LTOT is usuallyunnecessary as this is done adequately by thepatient’s own upper respiratory tract. Humidi-fiers tend to be noisy, bulky and often ineffectivebut may be necessary for a specific problem.

Appendix B. Formal testing to assesspatients for oxygen at rest

(1) At present there is no agreed testing proce-dure.

(2) Formal assessment of fan or oxygen shouldinclude rating scales to assess breathlessnessbefore and after the intervention.

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(3) Formal assessment of oxygen therapy shouldinclude the use of oximetry to establish foreach individual whether there is a link betweenhypoxaemia and breathlessness.

(4) Formal assessment of oxygen therapy shouldestablish whether there is a difference for anindividual between the response to oxygen atrest and on exercise.

(5) The rating scale should be appropriate both tothe patient group and the parameter tested.For example, VASs are useful for breathlessnessin any condition but can only assess thesymptom itself at a particular period of time,rather than its impact on quality of life. It maybe more appropriate to measure quality of lifeif assessing the benefits of oxygen for a patientat homeFthey can then choose to use it mostappropriately for their circumstances.

(6) An ‘N of 1’ trial may be helpful.44

Appendix C. Formal exercise testing toassess patients for ambulatory oxygentesting

(1) Choose a validated exercise test such as theshuttle walking test.51

(2) The patient should have at least one formalpractice test, as there is a learning effect.

(3) Just before starting the test, measure thepatient’s SaO2 whilst they breathe room air andask the patient to assess their current level ofbreathlessness using a VAS.

(4) Carry out the test with oxygen or air (thepatient should not know which they are receiv-ing) and measure saturation and breathlessnesson a VAS as soon after the patient stops as youcan. It is possible to measure saturation andpulse rate continuously with some oximeters.

(5) Repeat the test after a rest period (2 h plus) oron another day using oxygen or air from aportable cylinder carried by the patient. Theoxygen and air administration should becarried out as a double-blind procedureand the patient should not be told theirsaturation results until after both have beencompleted.

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