A mixture of helium and oxygen is less dense than room air. This property allows the gas to flow with less turbulence past airway narrowings, thereby decreasing airway resistance and increasing the volume of gas exchange. Previous studies demonstrated that airway obstruction that is manifested by stridor was present in 92% of patients requiring reintubation. Eight pediatric patients with burns in whom postextubation stridor or retractions unresponsive to racemic epinephrine developed, were treated with "heliox" (helium and oxygen) for 28 +/- 5 hours with an initial helium concentration between 50% and 70%. Of the eight patients treated with heliox, only two experienced respiratory distress and required reintubation. Both patients had stridor for a longer time before the initiation of heliox therapy compared with those patients who did not require reintubation. After initiation of heliox therapy, patients experienced a significant decrease in respiratory distress scores (6.8 +/- 0.7 vs 2.0 +/- 0.7). Heliox was able to relieve persistent stridor and thereby aid in the prevention of respiratory distress and reintubation.