Department of Critical Care Medicine, Zhongda Hospital, School of Medicine, Southeast University, No.87, Dingjiaqiao Road, Gulou District, Nanjing, 210009, Jiangsu, China.
BMC Anesthesiol. 2020 Oct 21;20(1):266. doi: 10.1186/s12871-020-01164-x.
In acute respiratory distress syndrome (ARDS), lung recruitment maneuvers can recruit collapsed alveoli in gravity-dependent lung regions, improving the homogeneity of ventilation distribution. This study used electrical impedance tomography to investigate the physiological effects of different recruitment maneuvers for alveolar recruitment in a pig model of ARDS.
ARDS was induced in ten healthy male pigs with repeated bronchoalveolar lavage until the ratio of arterial partial pressure of oxygen (PaO) of fraction of inspired oxygen (P/F) was < 100 mmHg and remained stable for 30 min (T). ARDS pigs underwent three sequential recruitment maneuvers, including sustained inflation, increments of positive end-expiratory pressure (PEEP), and pressure-controlled ventilation (PCV) applied in random order, with 30 mins at a PEEP of 5 cmHO between maneuvers. Respiratory mechanics, hemodynamics, arterial blood gas, and electrical impedance tomography were recorded at baseline, T, and before and after each recruitment maneuver.
In all ten pigs, ARDS was successfully induced with a mean 2.8 ± 1.03 L bronchoalveolar lavages. PaO, P/F, and compliance were significantly improved after recruitment with sustained inflation, increments of PEEP or PCV (all p < 0.05), and there were no significant differences between maneuvers. Global inhomogeneity index significantly decreased after recruitment with sustained inflation, increments of PEEP, or PCV. There were no significant differences in global inhomogeneity before or after recruitment with the different maneuvers. The decrease in global inhomogeneity index (ΔGI) was significantly greater after recruitment with increments of PEEP compared to sustained inflation (p = 0.023), but there was no significant difference in ΔGI between increments of PEEP and PCV or between sustained inflation and PCV.
Sustained inflation, increments of PEEP, and PCV increased oxygenation, and regional and global compliance of the respiratory system, and decreased inhomogeneous gas distribution in ARDS pigs. Increments of PEEP significantly improved inhomogeneity of the lung compared to sustained inflation, while there was no difference between increments of PEEP and PCV or between sustained inflation and PCV.
在急性呼吸窘迫综合征（ARDS）中，肺复张手法可以使重力依赖区的萎陷肺泡复张，从而改善通气分布的均一性。本研究采用电阻抗断层成像技术（EIT），探讨在 ARDS 猪模型中不同肺复张手法对肺泡复张的生理学影响。
通过反复支气管肺泡灌洗使 10 只健康雄性猪发生 ARDS，直到动脉血氧分压（PaO）与吸入氧分数（P/F）的比值<100mmHg 并稳定 30min（T）。ARDS 猪依次接受持续气道正压通气（CPAP）、递增呼气末正压（PEEP）和压力控制通气（PCV）三种序贯肺复张手法，每次手法之间间隔 30min，PEEP 为 5cmH2O。记录基线、T 以及每次肺复张手法前后的呼吸力学、血流动力学、动脉血气和 EIT 等参数。
所有 10 只猪均成功进行了 2.8±1.03L 的支气管肺泡灌洗，诱导出 ARDS。持续气道正压通气、递增 PEEP 或 PCV 肺复张后，PaO、P/F 和顺应性均显著改善（均 P<0.05），三种手法之间差异无统计学意义。持续气道正压通气、递增 PEEP 或 PCV 肺复张后，全肺不均匀指数（GHI）均显著降低。三种手法之间肺复张前后 GHI 差异无统计学意义。与持续气道正压通气相比，递增 PEEP 肺复张后 GHI 降低更显著（P=0.023），但递增 PEEP 与 PCV 之间或持续气道正压通气与 PCV 之间 GHI 降低差异无统计学意义。
持续气道正压通气、递增 PEEP 和 PCV 增加了 ARDS 猪的氧合、肺的区域性和整体顺应性，并降低了其通气分布的不均匀性。与持续气道正压通气相比，递增 PEEP 显著改善了肺的不均匀性，而递增 PEEP 与 PCV 之间或持续气道正压通气与 PCV 之间差异无统计学意义。
