From the Anesthesia Department, National Liver Institute, Menoufia University, Sheeben Elkom City, Egypt.
Exp Clin Transplant. 2021 May;19(5):462-472. doi: 10.6002/ect.2020.0412. Epub 2021 Mar 17.
Prolonged surgical retraction may cause atelectasis. We aimed to recruit collapsed alveoli, stepwise, monitored by lung dynamic compliance and observe effects on arterial oxygenation and systemic and graft hemodynamics. Secondarily, we observed alveolar recruitment effects on postoperative mechanical ventilation, international normalized ratio, and pulmonary complications.
For 58 recipients (1 excluded), randomized with optimal positive end-expiratory pressure (n = 28) versus control (fixed positive end-expiratory pressure, 5 cm H₂O; n = 29), alveolar recruitment was initiated (pressure-controlled ventilation guided by lung dynamic compliance) to identify optimal conditions. Ventilation shifted to volume-control mode with 0.4 fraction of inspired oxygen, 6 mL/kg tidal volume, and 1:2 inspiratory-to-expiratory ratio. Alveolar recruitment was repeated postretraction and at intensive care unit admission. Primary endpoints were changes in lung dynamic compliance, arterial oxygenation, and hemodynamics (cardiac output, invasive arterial and central venous pressures, graft portal and hepatic vein flows). Secondary endpoints were mechanical ventilation period and postoperative international normalized ratio, aspartate/alanine aminotransferases, lactate, and pulmonary complications.
Alveolar recruitment increased positive end-expiratory pressure, lung dynamic compliance, and arterial oxygenation (P < .01) and central venous pressure (P = .004), without effects on corrected flow time (P = .7). Cardiac output and invasive arterial pressure were stable with (P = .11) and without alveolar recruitment (P = .1), as were portal (P = .27) and hepatic vein flow (P = .30). Alveolar recruitment reduced postoperative pulmonary complications (n = 0/28 vs 8/29; P = .001), without reduction in postoperative mechanical ventilation period (P = .08). International normalization ratio, aspartate/alanine aminotransferases, and lactate were not different from control (P > .05).
Stepwise alveolar recruitment identified the optimal positive end-expiratory pressure to improve lung mechanics and oxygenation with minimal hemodynamic changes, without liver graft congestion/dysfunction, and was associated with significant reduction in postoperative pulmonary complications.
长时间的手术牵拉可能导致肺不张。我们旨在逐步募集塌陷肺泡，通过肺动态顺应性监测，并观察其对动脉氧合和全身及移植物血液动力学的影响。其次，我们观察肺泡募集对术后机械通气、国际标准化比值和肺部并发症的影响。
对 58 名受者（1 例排除）进行随机分组，最佳呼气末正压（n=28）与对照组（固定呼气末正压，5cmH₂O；n=29），采用肺动态顺应性指导压力控制通气启动肺泡募集，以确定最佳条件。通气切换至容量控制模式，吸入氧分数为 0.4，潮气量 6mL/kg，吸呼比为 1:2。在牵拉后和入住重症监护病房时重复肺泡募集。主要终点为肺动态顺应性、动脉氧合和血液动力学（心输出量、有创动脉压和中心静脉压、移植物门静脉和肝静脉血流）的变化。次要终点为机械通气时间和术后国际标准化比值、天冬氨酸/丙氨酸转氨酶、乳酸和肺部并发症。
肺泡募集增加呼气末正压、肺动态顺应性和动脉氧合（P<0.01）和中心静脉压（P=0.004），而对校正流量时间无影响（P=0.7）。心输出量和有创动脉压在有（P=0.11）和无（P=0.1）肺泡募集时保持稳定，门静脉（P=0.27）和肝静脉血流（P=0.30）也是如此。肺泡募集减少术后肺部并发症（n=0/28 与 8/29；P=0.001），而术后机械通气时间无差异（P=0.08）。国际标准化比值、天冬氨酸/丙氨酸转氨酶和乳酸与对照组无差异（P>0.05）。
逐步肺泡募集确定了最佳呼气末正压，以改善肺力学和氧合，同时最小化血液动力学变化，无肝移植物淤血/功能障碍，并与术后肺部并发症显著减少相关。
