机械通气是一种生命支持手段，其时间延长或缩短均会给患者带来不利影响，因此当患者原发病因去除时应尽早撤离呼吸机。撤机过程可引起一系列心血管及呼吸系统的病理生理变化，患者的心功能或容量状态可能是导致撤机成败的重要因素。脑钠肽（ BNP）是近年来得到广泛研究的心脏标志物，它能较好地反映心功能状态，是诊断心力衰竭的可靠指标。因此，BNP可能在一定程度上对指导成功撤机提供新思路。“,”Mechanical ventilation is a kind of life support method ,it may be harmful to patients whether it is prolonged or shortened from appropriate time.Therefore patients should be weaned from mechanical ven-tilation as soon as their primary etiology is removed .Weaning process can cause a series of pathophysiological change of the cardiovascular and respiratory system,and cardiac function and volume status may be important factors for the weaning outcome.Brain natriuretic peptide(BNP) is a sort of cardiac biomarker being widely investigated recently,it can well reflect status of cardiac function of patients,and is a reliable index of heart failure diagnosis.Thus BNP may supply a new strategy of guiding successful weaning.