Effects of supplemental oxygen vs. room air in COPD patients: A randomized placebo-controlled trial

Background: Supplemental oxygen (O 2 ) improves exercise capacity, oxygenation and dyspnea in patients with hypoxemic chronic obstructive pulmonary disease (COPD). Evidence regarding the effect of O 2 in normoxemic COPD patients or comparing its effects in normoxemic and hypoxemic patients is still scarce. Objective: The aim of our study was to investigate the effect of O 2 in patients with (LTOT) and without indication for long term oxygen therapy (nonLTOT). Methods: 124 COPD patients underwent two 6-minute walking tests (day 2+3) after a pretest (day 1). One test was performed using O 2 and the other using compressed room air in randomized order and a single-blinded fashion. Results: O 2 resulted in a significant increase in 6MWD (+26m, p 2 seems to be the individual level of exercise performance (6MWD) at baseline (r=-0.337, p Comparing LTOT- and nonLTOT-patients, we found that LTOT-patients benefit more from O 2 regarding the walking distance (+33m vs. +15m, p 2 -level (+7.0 vs. +3.4 percentage points, p 2 only when suffering from severe airflow obstruction (r=-0.257, p Discussion: O 2 improves 6MWD, oxygenation and dyspnea in normoxemic and hypoxemic COPD-patients. However, these short-term effects were more pronounced in patients with indication for LTOT than in those without. NonLTOT-patients suffering from severe airflow obstruction or severe exercise-induced dyspnea seem to show a relevant benefit from O 2 .