Background: The aim of this study was to examine patterns of domestic activity and ambulatory oxygen usage in patients with chronic obstructive pulmonary disease (COPD) in their domestic environment.
Methods: 20 patients (14 male), mean (SD) age 73.4 (6.8) yrs, FEV1 1.0 (0.5) l with stable COPD were recruited after completing a 7-week pulmonary rehabilitation programme. Patients were either hypoxic at rest or desaturated on exercise. Patients were randomised to an 8-week, double blind, placebo controlled trial of cylinder oxygen versus cylinder air. Total domestic physical activity and health-related quality of life measures were recorded pre and post intervention.
Results: There were no significant changes in domestic activity or HRQL measures after the intervention for either cylinder oxygen or cylinder air except for a worsening of the CRQ dyspnoea domain on cylinder air. There was a significant increase in mean duration (min per day) of cylinder use (p < 0.05) between weeks 1 vs. 7 and 1 vs. 8 for the oxygen group. However when comparing the two groups together there was no between group differences in cylinder use or time spent outside the home. Over the 8 weeks the majority of patients were using the cylinders in the home rather than outside, however the number of times patients reported using the cylinders outside the home increased over the 8 weeks for the oxygen group.
Conclusion: In the short term, ambulatory oxygen therapy is not associated with improvements in physical activity, HRQL or time spent away from home. However the use of cylinder oxygen increased over the 8 weeks compared to cylinder air. Patients need time to learn how to use oxygen and ambulatory oxygen appears to enhance activities rather than increase them.
Editor's Comment. This is a small study highlighting some peripheral issues associated with prescribing supplemental oxygen to patients with COPD. The need for additional oxygen was based on demonstrated hypoxemia at rest or exercise-related desaturation. Patients were randomized to receive oxygen or air at 2 L/min from color-coded but otherwise identical cylinders. Neither group showed any improvement in the measured outcomes of level of activity or HRQL, but there was a significant increase in cylinder use by weeks 7 and 8 in the oxygen group. Earlier studies have produced equivocal results and multiple opposing factors are potentially present. The negatives consist of the inconveniences related to the equipment (size, weight, and the need for replacement) as well as social aspects associated with a reluctance to use this equipment in public. The benefits, on the other hand, may need time to be recognized and were not readily evident even after 8 weeks of use. Importantly, the long-term benefits of oxygen supplementation in those with only exercise-induced desaturation remain unproven. As a footnote, this article shows an unusually high number of proofreading errors-this is a reflection of shortened publication cycles and is yet another issue to contend with as the rush to disseminate data becomes a full stampede.