短时俯卧位机械通气对急性肺损伤病人呼吸功能及血液动力学的影响

Effects of prone position on functional residual capacity,pulmonary gas exchange and hemodynamics in patients with acute lung injury

目的观察短时闯俯卧位机械通气对急性肺损伤病人功能残气量(FRC)、气体交换功能及血液动力学的影响。方法选择机械通气治疗的急性肺损伤病人8例,分别于仰卧位和俯卧位后30min行动脉血气分析,随即采用密闭式氦稀释法测定FRC,持续监测动态胸肺顺应性(Cst)以及血液动力学变化。结果与仰卧位相比,俯卧位后30min病人FRC从(1.4±0.4)L上升至(1.5±0.3)L(P<0.05),动脉血氧分压(PaO2)从(120±28)mmHg增加至(140±24)mmHg(P<0.01),同时肺泡动脉氧分压差减小,氧合指数上升(P<0.05),Csr差异无统计学意义。平均动脉压、中心静脉压、心率等血液动力学指标差异无统计学意义。PaO2与FRC间的相关系数r=0.709(P<0.05)。结论短时间俯卧位可以增加急性肺损伤病人FRC,改善氧合状况,且对血液动力学无明显影响。

Objective To investigate the effects of prone position on functional residual capacity (FRC) , pulmonary gas exchange and hemodynamics in mechanically ventilated patients with acute lung injury (ALI) .Methods Eight patients (6 male, 2 female) aged 29-61 yr who developed ALI with PaO2/FiO2 < 300 complicating acute serious pancreatitis (1 patient), septic shock (2 patients), multiple trauma (3 patients) or major surgery (2 patients) were included in this study. The patients were sedated with fentanyl 0.025-0.10 μg· kg-1·min-1 and midazolam 0.3-0.6 μg·kg-1·min-1 . Mechanical ventilation was facilitated with pipecuronium 0.08-0.10 mg·kg-1 . FRC (using helium dilution technique), airway resistance, dynamic total respiratory system compliance (Ccr), PaO2 , SpO2, PET CO2 , ECG and hemodynamics were measured before and 30 min after the patients were placed in prone position.Results Thirty minutes after the patients were placed in prone position, FRC increased from (1.4±0.4) L to (1.5±0.3) L (P < 0.05), PaO2/FiO2 increased from 215 ± 65 to 248 ± 66 (P < 0.05) , PA-aO2 difference decreased from (283±154)mm Hg to (260±66)mm Hg ( P < 0.05) but there was no significant change in Ccr, PaCO2, MAP, HR and CVP. Conclusion Prone position can increase FRC and improve pulmonary gas exchange in mechanically ventilated patients with ALI without compromising hemodynamics.