Helium-Oxygen Mixture Eases Breathing in Infants With RSV-Related Bronchiolitis

[Anil Tuladhar]

Inhalation of a helium-oxygen mixture (heliox) decreases accessory respiratory muscles in young infants with acute bronchiolitis due to respiratory syncytial virus infection, "even for those born prematurely," according to a report in the March issue of Chest.

"In this study, we showed that heliox decreased some of the respiratory symptoms of acute severe viral bronchiolitis in young infants, particularly those related to obstruction and work of breathing," Dr. Gilles Cambonie told Reuters Health.

Dr. Cambonie from Arnaud de Villeneuve Hospital, Montpellier, France and colleagues compared the outcomes after treatment with either heliox or an air-oxygen mixture (airox) for 1 hour under an oxyhood in 20 infants less than 3 months of age who were admitted to the pediatric intensive care unit with moderate-to-severe RSV bronchiolitis.

One infant in the airox group was excluded because of an oxygen hemoglobin saturation <90% that persisted despite the maximum 40% FIO2 authorized under the trial protocol.

Modified Wood clinical asthma scores improved between baseline and 60 minutes only in infants treated with heliox, the team reports, with a decrease of 2.35 points compared with 0.05 in the airox group. This improvement was associated with significantly decreased accessory muscle use and less expiratory wheezing.

Cerebral scores, a component of the Wood clinical asthma score, also improved more in the heliox group, the investigators say, but there were no differences between the treatments in inspiratory breath sounds or cyanosis.

Five premature infants treated with heliox had comparable improvements in clinical asthma scores, the results indicate.

After 1 hour, the rate of successful weaning at the first attempt was higher in the airox group (7/9 infants) than in the heliox group (4/10 infants), the researchers note, and the mean duration of gas mixture administration was higher in the heliox group (13.0 hours) than in the airox group (3.6 hours).

One infant in each group required intubation for respiratory failure.

"This study confirmed previous works and added originality in the design (double blind) and distribution of the gas (with an oxyhood)," Dr. Cambonie commented. "Nevertheless, this is not a clear demonstration of the usefulness of heliox in this situation, particularly to avoid intubation or to reduce the length of stay in the ICU."

"For cost reasons, some infants with particularly high risk of severe bronchiolitis could be a specific target to demonstrate risk/benefits of this treatment," Dr. Cambonie added. "This could be investigated in future studies, as might other strategies aimed at reducing the risk of intubation in these patients."

Chest. 2006;129:676-682