Oxygen therapy for non-hypoxaemic chronic obstructive pulmonary disease

Uronis H, McCrory DC, Samsa G, Currow D, Abernethy A

Published Online:

June 15, 2011

People with chronic obstructive pulmonary disease and breathlessness are sometimes prescribed oxygen therapy in an effort to reduce the sensation of breathlessness. However, the use of oxygen to relieve breathlessness in people who do not have reduced levels of oxygen in their blood stream (so called non-hypoxaemic people) remains controversial as not enough is known about its effectiveness. Additionally, oxygen is not without risk, particularly in those who continue to smoke because of the risk of fire, and it is costly over the long term. This review found that oxygen given to relieve symptoms can modestly reduce breathlessness with data collected from 28 trials (of which 18 had data which we could combine in meta-analyses). Given the magnitude of the effects and the variability in the results of the individual studies, further study is warranted before drawing firm conclusions. This type of oxygen therapy is sometimes called 'palliative oxygen', because it is used to make patients feel better rather than to aim to increase life expectancy.

Abstract (click to read)

Background:

Dyspnoea is a common symptom in chronic obstructive pulmonary disease (COPD). People who are hypoxaemic may be given long-term oxygen relief therapy (LTOT) to improve their life expectancy and quality of life. However, the symptomatic benefit of home oxygen therapy in mildly or non-hypoxaemic people with COPD with dyspnoea who do not meet international funding criteria for LTOT (PaO2< 55 mmHg or other special cases) is unknown.

Objectives:

To determine the efficacy of oxygen versus medical air for relief of subjective dyspnoea in mildly or non-hypoxaemic people with COPD who would not otherwise qualify for home oxygen therapy. The main outcome was patient-reported dyspnoea and secondary outcome was exercise tolerance.

Search strategy:

We searched the Cochrane Airways Group Register, Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE and EMBASE, to November 2009, to identify randomised controlled trials. We handsearched reference lists of included articles.

Selection criteria:

We only included randomised controlled trials of oxygen versus medical air in mildly or non-hypoxaemic people with COPD. Two review authors independently assessed articles for inclusion.

Data collection and analysis:

One review author completed data extraction and methodological quality assessment. A second review author then over-read evidence tables to assess for accuracy.

Main results:

Twenty-eight trials on 702 patients met the criteria for inclusion; 18 trials (431 participants) were included in the meta-analysis. Oxygen reduced dyspnoea with a standardised mean difference (SMD) of -0.37 (95% confidence interval (CI) -0.50 to -0.24, P < 0.00001). We observed significant heterogeneity.

Authors' conclusions:

Oxygen can relieve dyspnoea in mildly and non-hypoxaemic people with COPD who would not otherwise qualify for home oxygen therapy. Given the significant heterogeneity among the included studies, clinicians should continue to evaluate patients on an individual basis until supporting data from ongoing, large randomised controlled trials are available.

This record should be cited as:

Uronis H, McCrory DC, Samsa G, Currow D, Abernethy A. Symptomatic oxygen for non-hypoxaemic chronic obstructive pulmonary disease. Cochrane Database of Systematic Reviews 2011, Issue 6. Art. No.: CD006429. DOI: 10.1002/14651858.CD006429.pub2

Assessed as up to date:

November 4, 2009

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Primary Review Group:

Airways Group

Health topics:

Lungs & airways > Chronic obstructive pulmonary disease (stable) > Ventilation & oxygen

Cochrane Summaries^beta

Independent high-quality evidence for health care decision making

Oxygen therapy for non-hypoxaemic chronic obstructive pulmonary disease

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