The experimental and clinical study of heliox in treating bronchial asthma

Objective: To evaluate the effects of breathing helium-oxygen(heliox: 79% He-21% O2) on bronchial asthma by way of experimental and clinical observations.

Methods: Six mongrel dogs were randomly inspired air or heliox after dripping 2% methacholine in its' tracheas controlled by 900C ventilator. During the experimental course, respiratory mechanical limits, hemodynamic index and blood gas values were observed. Eight asthmatic patients inspired heliox with assisted respirator of recycle-used helium, and the data of pulmonary function tests, arterial blood gas values of patients were recorded.

Results: The results demonstrated that heliox could reduce airway resistance, airway pressure and work of breathing, improve lung effective compliance, but had no effects on pulmonary circulation and systemic circulation. Heliox could ameliorate oxygen diffusion and CO2 eliminating, but the duration was very short after stopping breathing heliox. The assisted respirator of recycle-used helium could save helium distinctively, and the clinical application demonstrated that the instrument may be useful for pulmonary obstructive diseases.

Conclusions: Heliox can reduce airway pressure, ameliorate oxygen diffusion and CO2 eliminating, so breathing heliox might be one of effective ways for asthmatic patients.