呼气末正压通气对急性呼吸窘迫综合征患者氧利用率的影响

目的探讨呼气末正压通气（PEEP）对急性呼吸窘迫综合征（ARDS）患者氧利用率（O2UC）的影响。方法选择28例ARDS机械通气患者，放置中心静脉导管，依次调节PEEP为0、5、10、15和20cmH2O五种不同压力水平，分别采动静脉血查血气并计算O2UC，记录心率及平均动脉血压（MBP）等变化。同时抽取30例健康人动静脉血（1次）查血气计算O2UC作为对照。结果（1）ARDS患者五种不同水平的PEEP，其O2UC与健康人O2UC相比均明显下降（P〈0．05或P〈0．01）。（2）在PEEP为15cmH2O时，O2UC值显著低于PEEP为0cmH2O时的02UC（P〈0．05）；PEEP为20cmH2O时，O2UC则非常显著地降低（P〈0．01）。PEEP为5、10cmH2O时，O2UC差异无统计学意义（与PEEP为0cmH2O时比较，P〉0．05）。（3）当PEEP在15cmH2O及20cmH2O时，MBP明显下降（P〈0．05或P〈0．01），HR却明显上升（P〈0．05或P〈0．01）。结论过高PFEP会导致ARDS患者氧利用率的进一步下降，不能真正纠正患者体内组织细胞的缺氧状态，必须寻找最佳PEEP，并适当增加血容量及有效心输出量，才能真正改善患者的缺氧状态。

Effect of PEEP on oxygen utilization coefficient in patients with acute respiratory distress syndrome

Objective To observe the effects of positive end-expiratory pressure(PEEP) on oxygen utiliza-tion coefficient in patients with acute respiratory distress syndrome(ARDS). Methods 28 ARDS patients with me-chanical ventilation were studied. Catheter of central vein was laid. Increment levels of PEEP(0,5, 10, 15 and 20cmH2O) were applied sequentially. Hemodynamics and oxygen metabolism parameters were measured and calcula-tion of O2 UC O2 UC = (SaO2 -SvO2.)/SaO2] were carried out respectively. O2 UC in 30 normal subject groups were carried out. Results Arterial oxygen tension(PaO2) increased significantly(P < 0.05) at PEEP 5cmH2O. Oxygen u-tilization coefficient (O2 UC), heart rate(HR) and mean blood pressure (MBP) were not significantly different (P >0.05) at PEEP 10cmH2O. At PEEP 15cmH2 O, O2UC and HR increased significantly (P < 0.05), but M BP reduced obviously(P < 0.05). Conclusions Too high PEEP can result in oxygen utilization coefficient of ARDS patient de-acend furthur, can not really correct oxygen difieiency condition in patients' organization cell. The optimal PEEP should be found, and blood capacity should be appropriately increased.