摘要目的确定在慢性阻塞性肺疾病(COPD)患者中应用外源性呼气末正压(PEEPe)的适宜水平,并比较两种选择PEEPe的方法.方法选取气管插管机械通气的COPD患者10例,首先测定PEEPe为0时的静态内源性呼气末正压(表示为PEEPi,stz),再以PEEPi,stz的0%、40%、50%、60%、70%、80%、90%和100%随机设置PEEPe水平,在不同PEEPe水平下分别测定呼吸力学、血流动力学和氧动力学指标.结果当PEEPe水平不高于PEEPi,stz的80%时,各项指标均变化不明显;当PEEPe加至PEEPi,stz 的90%和100%时, 静态内源性呼气末正压、吸气峰压、平台压、肺毛细血管嵌顿压和中心静脉压均显著升高,P均<0.01;心排血量、左室做功指数均显著下降,P均<0.01;氧输送量也明显下降,P均<0.05;当PEEPe加至PEEPi,stz 的100%时,右室做功指数明显下降,P<0.05.结论 PEEPi,stz的80%为可加用PEEPe的上限,两种选择PEEPe的方法结果相同.

abstractsObjective　To choose one optimal extrinsic positive end-expiratory pressure (PEEPe) for ventilated patients with chronic obstructive pulmonary disease (COPD) and to compare two methods for choosing the optimal level of PEEPe.Methods　Ten ventilated patients with COPD were included in the study. First, static intrinsic positive end-expiratory pressure (PEEPi,st) was measured when PEEPe was zero, and the PEEPi,st was called PEEPi,stz. PEEPe at 0%, 40%, 50%, 60%, 70%, 80%, 90% and 100% of PEEPi,stz, respectively, were applied randomly. Respiratory mechanics, hemodynamics, and oxygen dynamics were recorded 30 minutes after the level of PEEPe was changed.Results　When PEEPe was not higher than 80% of PEEPi,stz, no measurement changed significantly. When PEEPe was increased to 90% and 100% of PEEPi,stz, PEEPi,st, peak inspiratory pressure, plateau pressure, pulmonary capillary wedge pressure and central venous pressure increased significantly, P<0.01. Cardiac output and left ventricular work index decreased significantly, P<0.01. Oxygen delivery decreased significantly, P<0.05. When PEEPe was increased to 100% of PEEPi,stz, the right ventricular work index decreased significantly, P<0.05.Conclusion　Eighty percent of PEEPi,stz was the upper limit of PEEPe. The results of the two methods used to set the level of PEEPe were identical.