Exercise tolerance with helium-hyperoxia versus hyperoxia in hypoxaemic patients with COPD

• Autor(a) principal: Queiroga Junior, Fernando [UNIFESP]
• Data de Publicação: 2013
• Outros Autores: Nunes, Marcos [UNIFESP], Meda, Ethiane [UNIFESP], Chiappa, Gaspar [UNIFESP], Machado, Maria Christina [UNIFESP], Nery, Luiz Eduardo [UNIFESP], Neder, Jose Alberto [UNIFESP]
• Tipo de documento: Artigo
• Idioma: eng
• Título da fonte: Repositório Institucional da UNIFESP
• Texto Completo: http://dx.doi.org/10.1183/09031936.00087812; http://repositorio.unifesp.br/handle/11600/36565

The purpose of this study was to investigate whether helium-hyperoxia (HeHOx) would allow greater tolerance to maximal and submaximal exercise compared to hyperoxia (HOx) on isolation in hypoxaemic chronic obstructive pulmonary disease (COPD) patients under long-term oxygen therapy.In a double-blind study, 24 males in the Global Initiative for Chronic Obstructive Lung Disease functional class IV (forced expiratory volume in 1 s 35.2 +/- 10.1% predicted and arterial oxygen tension 56.2 +/- 7.5 mmHg) were submitted to incremental and constant load cycling at 70-80% peak work rate while breathing HOx (60% nitrogen and 40% oxygen) or HeHOx (60% helium and 40% oxygen).HeHOx improved resting airflow obstruction and lung hyperinflation in all but two patients (p<0.05). Peak work rate and time to exercise intolerance were higher with HeHOx than HOx in 17 (70.8%) out of 24 patients and 14 (66.6%) out of 21 patients, respectively (p<0.05). End-expiratory lung volumes were lower with HeHOx, despite a higher ventilatory response (p<0.05). HeHOx speeded on-exercise oxygen uptake kinetics by similar to 30%, especially in more disabled and hyperinflated patients. Fat-free mass was the only independent predictor of higher peak work rate with HeHOx (r(2)=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 long-term oxygen therapy-dependent patients with advanced COPD.