Clinical effects of heliox administration for acute bronchiolitis in young infants

Objective: To assess the effect of heliox, a helium-oxygen mixture, on respiratory distress symptoms in young,infants. Design: Prospective randomized, double-blind study. Setting: Pediatric ICU (PICU) of a university hospital. Patients: Twenty infants, all < 3 months old, admitted to the PICU with moderate-to-severe acute respiratory syncytial virus bronchiolitis. Interventions: All infants were randomly and blindly assigned to inhale either heliox or an air-oxygen mixture (airox) for 1 h under an oxyhood. Measurements and results: After 1 h, the respiratory distress score was significantly lower in the heliox group compared with the airox group (3.05 vs 5.5, p < 0.01), with a significant reduction in accessory muscles use (p < 0.05) and expiratory wheezing (p < 0.01). In contrast, inspiratory breath sounds and cyanosis did not significantly differ between groups. The ex-premature infants of the heliox group had a higher respiratory distress score at baseline compared with the term infants of this group (5.8 vs 5.2, p < 0.05) and a comparable decrease in the score at 60 min. Conclusions: In young infants, even those born prematurely, heliox breathing induced a rapid reduction in accessory muscles use and expiratory wheezing. Further studies are needed to confirm the decreased respiratory muscle work of breathing during heliox inhalation in this population.