Oxygen compared to air during exercise training in COPD with exercise-induced desaturation.

Abstract

Almost half the patients referred to pulmonary rehabilitation with chronic obstructive pulmonary disease (COPD) desaturate during exercise. Although oxygen supplementation may ameliorate oxygen desaturation, the effects on outcomes of exercise training have not been rigorously evaluated. The study aimed to determine whether supplemental oxygen during exercise training was more effective than medical air in improving exercise capacity and health-related quality of life in people with COPD.People with COPD who demonstrated oxygen desaturation <90% during the six-minute walk test were recruited to this multi-centre trial with randomisation (independent, concealed allocation) to either an Oxygen Group or Air Group, blinding (participants, exercise trainers and European Respiratory Journal assessors) and intention-to-treat analysis. Both groups received the respective gas from concentrators via nasal prongs at five litres/min during exercise training consisting of treadmill and cycle exercise, three times/week for eight weeks. Primary outcomes were the endurance shuttle walk test (ESWT) and Chronic Respiratory Disease Questionnaire total score (CRQ-Total).111 participants (60 males), mean (sd) age 69 (7) years, with moderate to severe COPD were recruited and 97 completed (Oxygen Group n=52; Air Group n=45). At the end of the 8-week training there were no between-group differences in change in ESWT (mean difference [95% Confidence Interval] 15 s [-106-136] or change in CRQ-Total (0.0 points [-0.3-0.3]). Within-group changes at end-training were significant for ESWT and CRQ-Total (all p<0.01).Exercise capacity and health-related quality of life improved in both groups, with no greater benefit from training with supplemental oxygen than medical air.