慢性阻塞性肺疾病机械通气治疗中外源性呼气末正压的设置

Proper extrinsic positive end-expiratory pressure during mechanical ventilation in patients with chronic obstructive pulmonary disease

目的探讨适合慢性阻塞性肺疾病(COPD)患者的外源性呼气末正压(PEEPe)的设置范围。方法明确诊断为COPD合并Ⅱ型呼吸衰竭需行机械通气治疗的患者36例,按PEEPe为0时的内源性呼气末正压(PEEPi)的40%(40%PEEPi组)、50%(50%PEEPi组)、60%(60%PEEPi组)、70%(70%PEEPi组)、80%(80%PEEPi组)、90%(90%PEEPi组)和100%(100%PEEPi组)设置PEEPe,监测呼吸力学、血流动力学和动脉血气变化。结果随着PEEPe的升高,呼吸功下降,呼吸机做功升高,60%、70%、80%、90%和100%PEEPi组与基础值的差异均有统计学意义(P值均<0.05)。食管压差随PEEPe的升高而下降,70%、80%、90%和100%PEEPi组与基础值比较差异均有统计学意义(P值均<0.05)。气道峰压、平台压随PEEPe的升高而升高,60%、70%、80%、90%和100%PEEPi组与基础值的差异均有统计学意义(P值均<0.05),100%PEEPi组与60%PEEPi组的差异也有统计学意义(P<0.05)。心输出量和心指数随PEEPe的升高而下降,90%、100%PEEPi组与基础值的差异均有统计学意义(P值均<0.05)。结论将PEEPe设置在PEEPe为0时所测得PEEPi的60%～80%范围内,可减少患者所做呼吸功,提高机械通气效率,改善呼吸系统顺应性,且对循环系统的抑制作用小,是适合COPD患者的PEEPe设置范围。

Objective To discuss the proper range of extrinsic positive end-expiratory pressure （PEEPe） during mechanical ventilation in patients with chronic obstructive pulmonary disease （COPD）. Methods Thirty- six ventilated patients, with confirmed COPD were included in the present study. Dynamic intrinsic positive end-expiratory pressure （ PEEPi）, work of breathing patient （WOBp）, work of breathing ventilation （WOBv）, difference of esophagus pressure （dPes）, tidal volume （Vt）, peak pressure （Ppeak）, plateau pressure （Pplat）, and respiratory system compliance （Ors） were measured by esophagus balloon pressure sensor and flow sensor. Heart rate （HR）, systolic blood pressure（SBP）, diastolic blood pressure（DBP）, cardiac output（CO）, and cardiac index （el） were measured by GE Solar 8000 monitor. All above measurements were repeated with PEEPe set at 0, 40%, 50%, 60%, 70%, 80%, 90% and 100% of PEEPi. Results WOBp decreased as PEEPe increased, and the difference between PEEPe at 60% of PEEPi and baseline was significantly different （all P〈0. 05）. The dPes decreased as PEEPe increased, and the difference between PEEPe at 70% of PEEPi and baseline was significant （all P〈0.05）. Ppeak and Pplat increased with the increase of PEEPe, and significant difference was found between PEEPe at 60% of PEEPi and baseline （all P〈0.05）; besides, the difference between PEEPe at 60% of PEEPi and PEEPe at 100% of PEEPi was also significant （P〈0. 05）. When PEEPe increased, CO and Cl decreased continuously, and there was significant difference between PEEPe at 90% of PEEPi and baseline （both P〈0. 05）. Conclusion PEEPe at 60% - 80% of PEEPi can reduce WOBp and improve Crs. PEEPe at this level has little inhibition on circulation and is the optimal PEEPe for patients with COPD. （Shanghai Med J, 2009, 32.. 125-127）