[Use of helium and oxygen mixtures in status asthmaticus].

Four patients in status asthmaticus and with alveolar hypoventilation were given a helium-oxygen (He-O2) mixture to breathe during 4 hours. Clinical improvement and return to normal of arterial blood gas levels were rapid and dramatic in all patients. The He-O2 mixture, which is a low density gas, causes a reduction in pulmonary resistance and an improvement in overall alveolar ventilation.