目的　探讨根据动态肺压力 容积曲线低位转折点压力 (Pinf)选择急性呼吸窘迫综合征 (ARDS)患者最佳呼气末正压 (PEEP)的可行性。方法　以 8例早期ARDS患者为研究对象 ,测定动态肺压力 容积曲线及Pinfd。采用低流速法测定准静态肺压力 容积曲线 ,并确定静态肺压力 容积曲线低位转折点压力 (Pinfs)。调整PEEP水平 ,观察患者血流动力学、肺机械力学和氧代谢的变化。结果　当PEEP从Pinfd - 6cmH2 O水平增加到Pinfd +6cmH2 O时 ,动脉血氧分压、动脉血氧饱和度、气道平均压和气道峰压均显著增加。与Pinfd +6cmH2 O比较 ,Pinfd - 4cmH2 O时的动态肺顺应性显著增高。Pinfd +6cmH2 O时的心脏指数有降低趋势 ,Pinfd - 4cmH2 O时的氧输送有升高趋势。当Pinfd为 (1 2 .8± 3 .2 )cmH2 O ,Pinfs为 (1 1 .0± 3 .2 )cmH2 O ,两者具有正相关性 (r =0 .99,P <0 .0 5)。回归方程为Pinfd =1 .66+1 .0 1×Pinfs。结论　当ARDS患者行机械通气治疗时 ,Pinfd - 4cmH2 O或Pinfs - 2cmH2 O为最佳PEEP ,可获得最大氧输送。 Objective To investigate the feasibility of selecting the optimal positive end-expiratory pressure (PEEP) in patients with acute respiratory distress syndrome (ARDS) based on the low pulmonary pressure-volume curve (Pinf). Methods Eight patients with early stage ARDS were selected as experimental subjects. Dynamic pulmonary pressure volume curve and Pinfd were measured. Quasi-static lung pressure-volume curves were measured using a low flow rate method and the Pinfold pressure (Pinfs) of the static lung pressure-volume curve was determined. PEEP was adjusted to observe the changes of hemodynamics, lung mechanics and oxygen metabolism. Results When PEEP increased from Pinfd - 6cmH2O to Pinfd + 6cmH2O, arterial partial pressure of oxygen, arterial oxygen saturation, mean airway pressure and peak airway pressure were significantly increased. Compared with Pinfd + 6cmH2O, dynamic lung compliance was significantly increased at Pinfd - 4cmH2O. The cardiac index of Pinfd + 6cmH 2 O decreased and the oxygen transport increased with Pinfd - 4cmH 2 O. When Pinfd was (122.8 ± 3.2) cmH2O and Pinfs was (110 ± 3.2) cmH2O, there was a positive correlation between them (r = 0.99, P <0.05 ). The regression equation is Pinfd = 1 .66 + 1 .0 1 × Pinfs. Conclusions Pinfd - 4cmH 2 O or Pinfs - 2cmH 2 O is the best PEEP for ARDS patients and the maximal oxygen delivery is obtained.