The effects of helium-hyperoxia on 6-min walking distance in COPD : A randomized, controlled trial

Background We hypothesized that breathing helium-hyperoxia (HeO 2 ) would significantly improve 6-min walking test (6MWT) distance in COPD subjects. Methods This was a blinded, randomized crossover study. At visit 1, we assessed pulmonary function, exercise capacity, and 6MWT distance. Visits 2 and 3 consisted of four 6MWTs in which the following different inspired gases were used: room air (RA) by mask; 100% O 2 by mask (mask O 2 ); 100% O 2 by nasal prongs (nasal O 2 ); and 70% He/30% O 2 by mask (HeO 2 ). Walking distance, shortness of breath, leg fatigue, O 2 saturation, and heart rate (HR) were assessed. Results Sixteen COPD subjects participated (mean FEV 1 /FVC ratio [± SD], 48 ± 8%; mean FEV 1 , 55 ± 13% predicted). Subjects walked farther when breathing HeO 2 (564 m) compared to RA (497 m; p 2 (520 m; p 2 (528 m; p 2 , there was no increase in shortness of breath or leg fatigue. There was desaturation when breathing RA (8%; p 2 (5%; p 2 (3%; difference not significant) and mask O 2 (0%; difference not significant). There were no significant differences in HR in the four 6MWTs. Conclusions The use of HeO 2 increased 6MWT distance in COPD subjects more than either mask O 2 or nasal O 2 compared to RA. The increased walking distance was not associated with increased shortness of breath or leg fatigue. The results suggest that clinical benefit would be obtained by administering HeO 2 during exercise, which may have significant clinical implications for the management of COPD patients.