Researchers at the University of Alberta in Edmonton, Canada have discovered that by combining helium with 40 per cent oxygen allowed patients with chronic obstructive pulmonary disease (COPD) to increase their exercise capacity by an average of 245 per cent. COPD is a disease of the lungs caused by smoking and includes the conditions of emphysema and chronic bronchitis.
This was the first study to demonstrate that helium-hyperoxia (40 per cent oxygen, 60 per cent helium) improves the exercise tolerance of COPD patients to a greater extent than oxygen alone, which is currently used for treating patients with this disorder. People with severe COPD typically struggle for every breath while exercising and any improvements that could be made to their ability to perform exercise could have significant clinical implications.
The results of the study were published recently in the American Journal of Respiratory Critical Care Medicine.
Patients with COPD have difficulty breathing out and often air is trapped in the lungs at the end of each breath; this has been shown to be one of the primary reasons for the shortness of breath experienced by these patients. Combining the helium and hyperoxia slows down the frequency of breathing while making the air easier to breathe. This combined effect reduces the amount of air trapped in the lungs during exercise.
"This means they don't have to work as hard to breathe and they are not so short of breath during exercise, which allows them to do more," said Dr. Neil Eves, lead author on the study. Eves conducted the study for his PhD dissertation at the University of Alberta.
In the study 10 clinically stable men with moderate to severe COPD were each given four different mixes of gases including room air, while they exercised. During each test they were monitored for exercise time, breathing capacity, work of breathing and symptoms of exertion. The best results were achieved with a mix of 40 per cent oxygen and 60 per cent helium.
The helium-hyperoxia mixture improved the exercise tolerance of the patients by 245 per cent compared with air (21 per cent oxygen, 79 per cent nitrogen), by 56 per cent compared with hyperoxia (40 per cent oxygen, 60 per cent nitrogen) and 116 per cent compared with a "normal" oxygen-helium gas (21 per cent oxygen, 79 per cent helium).
"If patients were to breathe helium-hyperoxia in a rehabilitation setting, they could potentially perform a lot more exercise, which may improve their exercise capacity, fitness level and as a result, quality of life," Eves said.