氦气对自主呼吸患者和插管机械通气患者缓解气道阻塞均安全有效,但是它的治疗作用还未充分揭示,氦气没有支气管扩张或抗炎作用,但它的密度比氮气和氧气低,因而可降低气道阻力。氦气还通过减少雷诺氏数使气道中的湍流区变成层流区,进一步降低气道阻力。气道阻力下降使呼吸作功减少。本文报道了用氦氧混合气(heliox)治疗急性重症哮喘的临床观察。 Helium is safe and effective in relieving airway obstruction in patients with spontaneous breathing and intubated mechanical ventilation. However, the therapeutic effect of helium has not been fully revealed. Helium has no bronchodilation or anti-inflammatory effect, but its density is lower than that of nitrogen and oxygen, Thus reducing airway resistance. Helium also further reduces airway resistance by reducing the Raynaud’s number by turning the turbulence zone in the airway into a laminar flow zone. Reduced airway resistance reduces breathing work. This article reports the clinical observation of heliox in the treatment of acute severe asthma.