Breathing a mixture of helium and oxygen (He-O2) is beneficial for people suffering acute episodes of asthma, as well as for people with chronic obstructive pulmonary disease (COPD), according to new studies reported Tuesday at the European Respiratory Society meeting in Glasgow, Scotland.

The low density of helium makes the mixture easier to breath, and for oxygen to diffuse throughout the lungs.

Dr. Philippe Sattonnet, of Bel Air Hospital in Metz-Thionville, France, reported the findings of a study evaluating the usefulness of He-O2 for severe exacerbations of asthma treated by mobile emergency units.

The 2-year study included 203 adults who suffered asthma attacks and were given bronchodilator therapy every 20 minutes for an hour. Half were given pure oxygen to breathe, and the remainder received a mixture of 65 percent helium and 35 percent oxygen.

“After one hour, the asthma clinical score was actually the same for the two groups,” Dr. Sattonnet explained in a statement, “but the peak expiratory flow rate (PEFR) was much higher in the subjects on He-O2.”

Fewer than half as many patients in the He-O2 group (8 vs. 20 percent) needed to stay in intensive care for more than 4 days, and the He-O2 patients were seven times less likely to require mechanical ventilation (1 against 7 percent), he added.

“These data support the use of (He-O2) as first line therapy for acute asthma,” the team concludes.

In a separate report, Dr. Liz Laude of Royal Hallamshire Hospital in Sheffield, UK, told the conference that helium-oxygen mixtures can be of benefit in COPD.

Her group’s study was conducted with 82 patients with moderately severe COPD who were each given four gases in randomised order: air with 21 percent oxygen, air with a slightly enriched oxygen content of 28 percent, and two He-O2 mixtures - heliox 21 and heliox 28, in which the nitrogen component of the first two gases was replaced by helium.

Heliox 21 was found to be equivalent to the 28 percent oxygen mixture in improving walking endurance and slightly better at reducing breathlessness after exertion, but “heliox 28 is the hands-down winner,” Laude said.

“It provided an average 64 percent improvement in the distance covered and maintained a better blood oxygen concentration even though the distance walked was greater,” she explained.