目的　探讨外源性呼气末正压 (PEEPe)对慢性阻塞性肺疾病 (COPD)患者呼吸功的影响及其机制。方法　选择接受气管插管和机械通气的COPD患者 10例 ,使用BicoreCP 10 0呼吸力学监测仪进行呼吸力学监测。首先测定PEEPe为 0时的动态内源性呼气末正压 (PEEPi) ,再以此值的 0、40 %、6 0 %、80 %和 10 0 %随机设置PEEPe ;在每次改变PEEPe水平 30min后 ,测定呼吸力学及心率、血压、动脉血气。结果　患者的呼吸功、压力时间乘积、食管压差和动态PEEPi在加用PEEPe后即明显降低 ,且随着PEEPe的增加继续下降 (P值均 <0 0 1)。当PEEPe加至PEEPe =0时所测的动态PEEPi的 80 %和 10 0 %时 ,呼吸机做功显著增加 (P值均 <0 0 1)。呼吸功的变化和动态PEEPi的变化呈直线正相关关系 (r=0 6 0 9,P <0 0 1)。结论　PEEPe可降低呼吸功 ,并且是通过降低患者呼气末肺泡与中心气道之间的压力差来降低呼吸功的 Objective To investigate the effect and mechanism of exogenous positive end expiratory pressure (PEEPe) on respiratory work in patients with chronic obstructive pulmonary disease (COPD). Methods Ten COPD patients who received endotracheal intubation and mechanical ventilation were enrolled in this study. Respiratory mechanics monitoring was performed using the BicoreCP 10 0 Respiratory Mechanics Monitor. First of all, the dynamic endogenous positive end expiratory pressure (PEEPi) with PEEPe of 0 was measured, and then PEEPe was set randomly at 0, 40%, 60%, 80% and 100% of this value. After each change of PEEPe level After 30min, measured respiratory mechanics and heart rate, blood pressure, arterial blood gas. Results The patients’ respiratory work, pressure time product, esophageal pressure difference and dynamic PEEPi decreased significantly after PEEPe addition, and continued to decline with the increase of PEEPe (P <0.01). Ventilator work was significantly increased (P <0.01) when PEEPe was increased to 80% and 100% of the dynamic PEEPi measured at PEEPe = 0. There was a linear positive correlation between changes in respiratory work and changes in PEEPi (r = 0 6 0 9, P 0 01). Conclusions PEEPe reduces the work of breathing and decreases the work of breathing by reducing the pressure difference between the patient’s end-expiration alveolus and the central airway