By David Douglas

Compared to use of oxygen, breathing a helium-hyperoxia mixture increased exercise tolerance considerably in patients with chronic obstructive pulmonary disease, Canadian researchers report in the June issue of Chest.

As lead investigator Dr. Darcy C. Marciniuk told Reuters Health, "the study demonstrates a significant improvement in walking distance in COPD patients from inspiring helium-oxygen."

Dr. Marciniuk of the University of Saskatchewan, Saskatoon and colleagues conducted a blinded randomized study in 16 subjects with COPD and a mean lung function (FEV1) of 55% predicted. Although this group had impaired respiratory function, they were participants in a maintenance exercise program and were well conditioned.

Breathing room air through a mask, the subjects covered a mean of 497 meters in 6 minutes. The corresponding distance with oxygen through a mask was 520 meters, and with nasal oxygen, it was 528 meters.

However, while breathing a mixture of 70% helium and 30% oxygen through a mask, the subjects covered 564 meters and showed no increase in shortness of breath or leg fatigue. They also demonstrated reduced desaturation compared to use of oxygen or room air, the investigators report.

Nevertheless, Dr. Marciniuk pointed out, "While the use of this inspired gas seems encouraging, practical issues such as cost and availability would need still to be investigated and considered."

Furthermore, "the benefits in a population with more severe COPD should be explored. Patients with more severe disease are more significantly disabled, and as such, the benefits might be even more apparent and meaningful in that population."