Abstract
The purpose of this study was to investigate whether helium-hyperoxia (HeHOx) would allow greater tolerance to maximal and sub-maximal exercise compared to HOx on isolation in hypoxemic COPD patients under long-term O2 therapy (LTOT).
On a double-blind study, 24 GOLD IV males (FEV1=35.2±10.1% pred, Pa,O2=56.2±7.5 mmHg) were submitted to incremental and constant-load cycling at 70–80% peak work rate while breathing HOx (60% N2, 40% O2) or HeHOx (60% He, 40% O2).
HeHOx improved resting airflow obstruction and lung hyperinflation in all but 2 patients (p<0.05). Peak work rate and time to exercise intolerance were higher with HeHOx than HOx in 17/24 (70.8%) and 14/21 (66.6%) patients, respectively (p<0.05). End-expiratory lung volumes were lower with He-HOx despite a higher ventilatory response (p<0.05). He-HOx speeded on-exercise O2 uptake kinetics by ∼ 30%, especially in more disabled and hyperinflated patients. Fat-free mass was the only independent predictor of higher peak work rate with He-HOx (r2=0.66; p<0.001); in contrast, none of the resting characteristics or exercise responses were related to improvements in time to exercise intolerance (p>0.05).
Helium is a valuable ergogenic aid when added to HOx for most LTOT-dependent patients with advanced COPD.
- Chronic obstructive pulmonary disease
- chronic respiratory failure
- exercise testing
- helium
- hyperoxia
- long-term oxygen therapy
- ERS