俯卧位通气对急性呼吸窘迫综合征患者呼吸力学的影响

Effects of ventilation in prone position on the respiratory mechanics in patients with acute respiratory distress syndrome

目的探讨俯卧位通气对急性呼吸窘迫综合征acuterespiratorydistresssyndrome，ARDS）患者呼吸力学的影响。方法15例ARDS患者，在镇静、不保留自主呼吸情况下持续俯卧位通气2h。观察初始仰卧位、俯卧位1、2h及恢复仰卧位1、2h的氧分压（oxygenpartialpressure，Pa02）、二氧化碳分压（carbondioxidepartialpressure，PaC02）、氧合指数（oxygenationindex，Pa02／Fi02）、呼吸系统阻力（resistanceoftherespiratorysystem，Rrs）、肺阻力（resistanceofthelung，Rlung）、胸壁阻力（resistanceofthechestwall，Rcw）、静态顺应性（staticcompliance，Cstat）、胸壁顺应性（complianceofthechestwall，Ccw）、肺部顺应性（complianceofthelung，Clung）、吸气末跨肺压（end—inspiratorytranspulmonarypressure，Ptp-i）、呼气末跨肺压（end-expiratorytranspulmonarypressure，Ptp-e）、心率（heartrate，HR）、平均动脉压（meanarterialpressure，MAP）、中心静脉压（centralvenouspressures，CVP）、心指数（cardiacindex，CI）。结果与初始仰卧位比较，俯卧位通气能显著提高PaO2、PaO2/FiO2，而且复转为仰位后2h仍维持高于初始仰卧位时的水平。俯卧位后，Rrs、Rlung、Rcw无明显变化；在俯卧位1h，Ccw显著下降；在俯卧位2h时Clung显著改善；在仰卧位1h时Cstat升高；在俯卧位2h，Ptp-i、Ptp-e均升高。此外，俯卧位对血流动力学无明显影响。结论俯卧位通气可以通过提高跨肺压，改善肺顺应性等呼吸力学变化进而改善氧合，同时对血流动力学无不良影响。

Objective To determine the effects of ventilation in prone position on the respiratory mechanics in patients with acute respiratory distress syndrome （ARDS）. Method A total of 15 ARDS patients who underwent mechanical ventilation under anesthesia were placed in prone position for 2 h. Then, they were observed for oxygen partial pressure （PaO2）, carbon dioxide partial pressure （PaCO2）, oxygenation index （PaO2/FiO2）, resistance of the respiratory system （Rrs）, resistance of the lung （Rlung）, resistance of the chest wall （Rcw）, static compliance （Cstat）, compliance of the chest wall（Ccw）,compliance of the lung（Clung）,end-inspiratory transpulmonary pressure （Ptp-i）,end-expiratory cardiac transpulmonary pressure（Ptp-e）, heart rate （HR）,mean arterial pressure （MAP）, central venous pressures （CVP）, and index （CI） were measured and recorded initially in supine position, 1 h and 2 h after being in prone position and 1 h and 2 h after recovery into supine position. Results Patients in prone position presented remarkably increased PaO2 and PaO2/FiO2 compared with those initially in supine position, which remained higher 2 h after being in supine position. No significant change was found in Rrs, Rlung and Rcw and hemodynamics before and after ventilation in prone position. Furthermore, Cow was decreased marked after being in prone position for 1 h; Clung was remarkably improved after being in prone position for 2 h; Cstat was elevated after being in supine position for 1 h; and Ptp-i and Ptp-e were increased significantly after being in prone position for 2 h, compared with those initially in supine position. Conclusions Ventilation in prone position can improve transpuhnonary pressure, lung compliance and pulmonary gasexchange without adverse effects on hemodynamics.