Huang Ying-zi, Qiu Hai-bo, Liu Ling, Yang Yi, Yan Yan-li
Department of Critical Care Medicine, Zhong-da Hospital and School of Clinical Medicine, Southeast University, Nanjing 210009, China.
Zhonghua Nei Ke Za Zhi. 2004 Dec;43(12):883-7.
To determine the different effect of prone-position ventilation (PPV) in patients with acute respiratory distress syndrome (ARDS) resulting from a pulmonary cause (ARDSp) and that from an extrapulmonary cause (ARDSexp) on oxygenation, respiratory mechanics and hemodynamics. To determine an appropriate duration of ventilation in the prone position in the two groups.
Nine ARDSp patients and seven ARDSexp patients within 3 days of onset of ARDS were included in this study which were classified as two groups. The patients were placed in prone position for 2 h. The effect of different time (pre-PPV, PPV 0.5 h, PPV 2 h) on oxygenation, respiratory mechanics and hemodynamics were observed. Lung computerized tomography (CT) was obtained in both the supine position and 10 min after prone position.
Compared with pre-PPV, in ARDSp, partial pressure of oxygen in artery (PaO(2))/inhaled oxygen concentration (FiO(2)) was not increased after 0.5 h, and increased only after 2 h in the prone position (130.6 +/- 36.2 to 165.1 +/- 72.3, P < 0.05). But in ARDSexp, PaO(2)/FiO(2) was significantly increased after 0.5 h and 2 h in the prone position (116.5 +/- 55.0 to 163.2 +/- 46.4 and 182.7 +/- 87.7, P < 0.05). After 0.5 h in the prone position the responding ratio of ARDSexp was higher than ARDSp (7/7 vs 1/9, P = 0.0007). After 2 h, no significant difference of responding ratio was found between the two groups (6/7 vs 6/9, P = 0.392). The changes of the PaO(2) were similar to the PaO(2)/FiO(2). The PaCO(2) and the static respiratory system compliance (Cstrs) did not differ significantly between the prone position and the supine position in the two groups. In ARDSp, the airway resistance was (10.8 +/- 1.4) cm H2O.s(-1).L(-1) in the supine position, and it was significantly decreased after 2 h in the prone position (8.4 +/- 1.8) cm H2O.s(-1).L(-1) (P < 0.05). Chest CT scans of ARDSp and ARDSexp patients showed marked difference.
PPV could be used to improve severe hypoxemia of ARDS. It improved the PaO(2)/FiO(2) ratio rapidly in ARDSexp, but in ARDSp the improvement took a longer time.
确定俯卧位通气（PPV）对肺源性急性呼吸窘迫综合征（ARDSp）和肺外源性急性呼吸窘迫综合征（ARDSexp）患者的氧合、呼吸力学及血流动力学的不同影响。确定两组患者俯卧位通气的合适时长。
本研究纳入发病3天内的9例ARDSp患者和7例ARDSexp患者，分为两组。患者俯卧位通气2小时。观察不同时间点（PPV前、PPV 0.5小时、PPV 2小时）对氧合、呼吸力学及血流动力学的影响。在仰卧位及俯卧位10分钟后行肺部计算机断层扫描（CT）。
与PPV前相比，ARDSp患者在俯卧位0.5小时后动脉血氧分压（PaO₂）/吸入氧浓度（FiO₂）未升高，仅在俯卧位2小时后升高（130.6±36.2至165.1±72.3，P<0.05）。但在ARDSexp患者中，俯卧位0.5小时和2小时后PaO₂/FiO₂均显著升高（116.5±55.0至163.2±46.4和182.7±87.7，P<0.05）。俯卧位0.5小时后ARDSexp患者的反应率高于ARDSp患者（7/7比1/9，P = 0.0007）。2小时后，两组反应率无显著差异（6/7比6/9，P = 0.392）。PaO₂的变化与PaO₂/FiO₂相似。两组患者俯卧位和仰卧位的PaCO₂及静态呼吸系统顺应性（Cstrs）无显著差异。在ARDSp患者中，仰卧位气道阻力为（10.8±1.4）cmH₂O·s⁻¹·L⁻¹，俯卧位2小时后显著降低至（8.4±1.8）cmH₂O·s⁻¹·L⁻¹（P<0.05）。ARDSp和ARDSexp患者的胸部CT扫描显示出明显差异。
PPV可用于改善ARDS的严重低氧血症。它能迅速提高ARDSexp患者的PaO₂/FiO₂比值，但在ARDSp患者中改善所需时间更长。
