Rationale The acute effect of supplemental oxygen on exertion is well documented although its use in PR has not yet been clearly established. Two small studies have previously shown no benefit; this may have been due to study power or methodology. Our study investigated whether ambulatory oxygen provides additional benefit to patients undergoing PR who meet the 2006 UK Department of Health criteria for ambulatory oxygen use.
Methods A single blind (researcher) randomised controlled trial compared the effect of a 6 week PR programme either with or without ambulatory oxygen. The study was powered to show an 80% difference between groups. Eligible patients were those who desaturated on baseline exercise testing by >4% to <90% and whose exercise tolerance improved by >10% with ambulatory oxygen. Outcome measures included the Endurance Shuttle Walk Test (ESWT) and the self report Chronic Respiratory Questionnaire (CRQ-SR).
Results Between September 2007 and June 2009 62 patients consented; one patient withdrew choosing to use ambulatory oxygen, ten dropped out of PR. The majority of subjects had Chronic Obstructive Pulmonary Disease; eight had another chronic respiratory condition. Groups were similar at baseline except for weight and BMI (higher in the room air (RA) group). A far greater improvement in ESWT was found in the oxygen group (p=0.000) (Abstract S71 Table 1). When the acute effect of oxygen is excluded the oxygen group improved by 75% more than the RA group; this did not meet statistical significance since the study was powered to show an 80% improvement. The oxygen group gained improvements in three CRQ-SR domains (emotion, fatigue and mastery) above the minimally clinically important difference (MCID) but this was not the case for the RA group; the difference between groups for these domains also reached the MCID. Improvements in the dyspnoea domain were similar between groups, although the oxygen group walked 490 m (122%) further.
Conclusion For patients who desaturate and with an acute positive response to oxygen, ambulatory oxygen significantly enhances the effect of PR.
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Funding This study was supported by a £15000 British Lung Foundation grant.
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