Objective: To determine the efficacy of a helium-oxygen mixture in children admitted to the pediatric intensive care unit with acute respiratory syncytial virus (RSV) bronchiolitis.
Design: Randomized, double-blind, controlled, crossover study and nonrandomized, prospective study.
Setting: A pediatric intensive care unit in a university hospital.
Patients: Nonintubated children with signs of acute lower respiratory tract infection and a positive rapid immunoassay for RSV admitted to the pediatric intensive care unit.
Interventions: Treatment with either helium-oxygen or air-oxygen was administered in random order for 20 mins. Nonrandomized patients received helium-oxygen as initial therapy.
Measurements and main results: Clinical Asthma Score, respiratory rate, heart rate, and pulse oximetry oxygen saturation values were recorded at baseline (before randomization) and at the end of each 20-min treatment period (helium-oxygen or air-oxygen). Nonrandomized patients were studied 20 mins into helium-oxygen delivery. Eighteen patients were studied, 13 of whom were randomized. Five children with severe bronchiolitis (Clinical Asthma Score of > or =6) were initially given helium-oxygen and scored at 20 mins. Mean Clinical Asthma Score was 3.04 (range 1 to 7.5) in the 13 randomized patients and 4.25 (range 1 to 9) in the 18 patients overall. Clinical Asthma Score decreased in the 13 randomized patients (mean 0.46, p < .05) and in the 18 patients overall (mean 1.23, p < .01) during helium-oxygen delivery. In randomized patients with Clinical Asthma Scores of <6 (n = 12), a positive correlation (rs = .72) was observed between the Clinical Asthma Score at baseline and the change in Clinical Asthma Score during helium-oxygen administration (p = .009). Respiratory rate and heart rate decreased during helium-oxygen treatment but were not statistically significant. No complications occurred during helium-oxygen delivery.
Conclusions: Inhaled helium-oxygen improves the overall respiratory status of children with acute RSV lower respiratory tract infection. In patients with mild-to-moderate bronchiolitis (Clinical Asthma Scores of <6), the beneficial effects of helium-oxygen were most pronounced in children with the greatest degree of respiratory compromise.