Background: Helium-hyperoxia (HH) reduces dyspnea and increases exercise tolerance in patients with COPD. We investigated whether breathing HH would allow patients to perform a greater intensity of exercise and improve the benefits of a pulmonary rehabilitation program.
Methods: Thirty-eight nonhypoxemic patients with COPD (FEV(1)=47 +/- 17%(pred)) were randomized to rehabilitation breathing HH (60:40 He:O(2); n = 19) or air (n = 19). Patients cycled for 30 min, 3 days/week for 6 weeks breathing the assigned gas. Exercise intensity was prescribed from baseline, gas-specific, incremental exercise tests and was advanced as tolerated. The primary outcome was exercise tolerance assessed as a change in constant-load exercise time (CLT) following rehabilitation. Secondary outcomes were changes in exertional symptoms, health related quality of life (as assessed by the Short-form 36 and St George respiratory questionnaires), and peak oxygen consumption during an incremental exercise test.
Results: The HH group had a greater change in CLT following rehabilitation compared to the air group (9.5 +/- 9.1 vs 4.3 +/- 6.3 min, p < 0.05). At an exercise isotime, dyspnea was significantly reduced in both groups, while leg discomfort only decreased in the HH group. The changes in exertional symptoms and peak oxygen consumption were not different between groups. Health-related quality of life significantly improved in both groups; however, the change in St. George respiratory questionnaire total score was greater with HH (-7.6 +/- 6.4 vs -3.6 +/- 5.6, p < 0.05). During rehabilitation, the HH group achieved a higher exercise intensity and training duration throughout the program (p < 0.05).
Conclusions: Breathing HH during pulmonary rehabilitation increases the intensity and duration of exercise training that can be performed and results in greater improvements in CLT for patients with COPD.
Trial registration: ClinicalTrials.gov NCT00406705.