Objective: To discuss the difference of vital capacity ( VC), expiratory reserve volume ( ERV) and inspiratory capacity ( IC) in chronic obstructive pulmonary disease ( COPD) patients and the normal subjects after breathing helium-oxygen mixtures ( heliox). 目的探讨慢性阻塞性肺病(COPD)患者呼吸氦氧混合气(He-O2)后肺活量(VC)及其组成补呼气容积(ERV)和深吸气量(IC)的变化与健康人的差异。