目的比较俯卧位机械通气(PPV) 与仰卧位机械通气(SPV)对急性呼吸窘迫 综合征(ARDS)患者呼吸参数指标、血液流 动力学和胸部CT影像学的影响。方法 采 用简单随机抽签法将90例ARDS患者分为 PPV组(n=45)和SPV组(n=45)，采取不同体 位进行机械通气，分别于机械通气前、 机械通气1h、机械通气2h检测血气指标 [pH、动脉血氧分压(PaO2)、动脉二氧化 碳分压(PaCO2)及氧合指数(PaO2/FiO2)]、 血液流动学指标[心率(HR)、平均动脉 压(MAP)]，并于机械通气前及机械通气 48h后行CT检查，定量分析全肺平均CT值 (CTmean)。结果 两组机械通气后PaO2、 PaO2/FiO2均呈升高趋势(P<0.05)，且PPV 组在机械通气1h、机械通气2h的PaO2、 PaO2/FiO2均明显高于SPV组(P<0.05)；两 组不同时间点pH、PaCO2比较差异无统计 学意义(P>0.05)。两组机械通气前后HR、 MAP比较差异均无统计学意义(P>0.05)。 机械通气48h后，两组CTmean较机械通气 前均明显减小，且PPV组显著小于SPV组， 差异均有统计学意义(P<0.05)。结论 PPV 可显著改善ARDS患者动脉氧合状况及肺部 CT值，且对血液流动学无明显影响。

Objective To compare the effect of prone position ventilation (PPV) and supine position ventilation (SPV) on respiratory parameters, hemodynamics and chest CT imaging in patients with acute respiratory distress syndrome (ARDS). Methods 90 patients with ARDS were randomly divided into PPV group (n=45) and SPV group (n=45). They were given mechanical ventilation at different positions. The blood gas indexes [pH, arterial partial pressure of oxygen (PaO2), arterial partial pressure of carbon dioxide(PaCO2) and oxygenation index (PaO2/FiO2)] and hemodynamic indexes [heart rate (HR), mean arterial pressure (MAP)] were detected before mechanical ventilation, after 1h and 2h of mechanical ventilation. CT examination was performed before mechanical ventilation and after 48h of mechanical ventilation. The average CT value (CT mean) of the whole lung was analyzed quantitatively. Results PaO2 and PaO2/FiO2 in the two groups increased after mechanical ventilation(P<0.05). The PaO2 and PaO2/FiO2 in PPV group after 1h and 2h of mechanical ventilation were significantly higher than those in SPV group (P<0.05). There was no significant difference in PaO2 or PaO2/FiO2 between the two groups at different time points (P>0.05). There was no significant difference in HR or MAP between the two groups before and after mechanical ventilation (P>0.05). The CT mean in the two groups decreased significantly after mechanical ventilation, and it of PPV group was significantly smaller than that of SPV group(P<0.05). Conclusion PPV can significantly improve the arterial oxygenation and lung CT value in patients with ARDS, without obvious effect on hemodynamics.