Are oxygen-conserving devices effective for correcting exercise hypoxemia?

摘要

Correction of exercise hypoxemia in advanced lung diseases is crucial and often challenging. However, oxygen-conserving devices have been introduced in the market with limited evidence of effectiveness. In the present study the efficacy of 2 oxygen-conserving devices, a pulse demand oxygen delivery (DOD) system and pendant reservoir cannula (PRC), were evaluated in subjects with COPD and interstitial lung disease (ILD). Methods: A cross-sectional, crossover study included 28 COPD and 31 ILD subjects with oxygen desaturation on the 6-min walk test (average SpO2 88%). Each subject underwent 3 walk tests with DOD, PRC, and continuous oxygen flow by standard nasal cannula (CFNC), in random order, taking average SpO2 ≥ 90% as the resaturation criterion. Results: Exercise desaturation was corrected in 79%, 79%, and 86% of COPD subjects with CFNC, DOD, and PRC, respectively, and in 77%, 61%, and 81% of ILD subjects with CFNC, DOD, and PRC, respectively. When compared to CFNC, the oxygen-conserving devices showed similar efficacy, except a lower performance for the DOD in the ILD subjects (P =.01). Conclusions: Although these oxygen-conserving devices corrected exercise hypoxemia in most COPD and ILD subjects, correction was not achieved in about 20% of the severe COPD subjects, regardless of the device, and in nearly 40% of the ILD subjects with the DOD device. These findings underscore that individualized adjustment of oxygen flow is needed for optimal correction of exercise hypoxemia, especially with a DOD in an ILD patient.