呼气末正压个体设置优化术中机械通气，减少术后肺不张
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Individual Positive End-expiratory Pressure Settings Optimize Intraoperative Mechanical Ventilation and Reduce Postoperative Atelectasis
背景与目的
建议术中行肺保护性通气，以减少腹部手术后肺部并发症。虽然生理潮气量的保护作用已经确定，但呼气末正压(PEEP)所提供的额外保护作用仍不确定。作者假设低的固定PEEP可能不适合所有的病人，在麻醉期间设置个体化 的PEEP可能改善手术期间和术后的肺功能。
方 法
40例患者在手术室(20例腹腔镜和20例开腹)接受研究。他们进行了择期腹部手术，随机分为常规PEEP组 (4cm H2O)或电阻抗断层成像指导的PEEP组(肺泡复张后应用，同时以尽量减少肺塌陷和肺过度膨胀为目标)。患者在麻醉下拔除气管插管，并且不改变设置好的PEEP或部分激发氧气分压，拔管后行胸部计算机断层扫描。我们的主要目标是识别电阻抗断层成像指导的PEEP值，以获得减少肺塌陷和肺气肿的最佳折衷方案。
结 果
电阻抗断层成像指导的PEEP值在个体间差异显著(中位，12cm H2O;范围6 - 16cm H2O;95% CI, 10—14)。与4 cm H2O PEEP值的组相比，随机选择电阻抗断层成像指导PEEP值的患者术后肺不张较少(肺组织肿块相比6.2±4.1 vs. 10.8± 7.1%);P = 0.017)，术中驱动压力较低(术中驱动压力平均值为8.0 ±1.7 vs. 11.6± 3.8 cm H2O;P < 0.001)。术中电阻抗断层成像引导的PEEP臂氧合更好(腹腔镜组435 ±62 vs 266 ±76 mmHg;P < 0.001)，同时表现出等效的血流动力学(术中平均动脉压为80±14 mmHg vs. 78 ±15 mmHg;P = 0.821)。
结 论
在腹部手术麻醉期间，接受保护性潮气量的患者对PEEP的要求差别很大。个体化的PEEP设置可以减少术后肺不张(ct测量)，同时改善术中氧合作用和驱动压力，副作用最小。
原始文献摘要
Sérgio M. Pereira, M.D.; Mauro R. Tucci, M.D., Ph.D.; Caio C. A. Morais, P.T., M.Sc.; Claudia M. Simões, M.D., Ph.D.; Bruno F. F. Tonelotto, M.D.; Michel S. Pompeo, M.D.; Fernando U. Kay, M.D., Ph.D.; Paolo Pelosi, M.D., F.E.R.S.; Joaquim E. Vieira, M.D., Ph.D.; Marcelo B. P. Amato, M.D., Ph.D. Anesthesiology. 2018; 129(6):1070-1081. doi: 10.1097/ALN.0000000000002435
Background: Intraoperative lung-protective ventilation has been recommended to reduce postoperative pulmonary complications after abdominal surgery. Although the protective role of a more physiologic tidal volume has been established, the added protection afforded by positive end-expiratory pressure (PEEP) remains uncertain. The authors hypothesized that a low fixed PEEP might not fit all patients and that an individually titrated PEEP during anesthesia might improve lung function during and after surgery.
Methods: Forty patients were studied in the operating room (20 laparoscopic and 20 open-abdominal). They underwent elective abdominal surgery and were randomized to institutional PEEP (4 cm H2O) or electrical impedance tomography guided PEEP (applied after recruitment maneuvers and targeted at minimizing lung collapse and hyperdistension, simultaneously). Patients were extubated without changing selected PEEP or fractional inspired oxygen tension while under anesthesia and submitted to chest computed tomography after extubation. Our primary goal was to individually identify the electrical impedance tomography guided PEEP value producing the best compromise of lung collapse and hyperdistention.
Results: Electrical impedance tomography guided PEEP varied markedly across individuals (median, 12 cm H2O; range, 6 to 16 cm H2O; 95% CI, 10 14). Compared with PEEP of 4 cm H2O, patients randomized to the electrical impedance tomography guided strategy had less postoperative atelectasis (6.2 4.1 vs. 10.8 7.1% of lung tissue mass; P = 0.017) and lower intraoperative driving pressures (mean values during surgery of 8.0 1.7 vs. 11.6 3.8 cm H2O; P < 0.001). The electrical impedance tomography guided PEEP arm had higher intraoperative oxygenation (435 62 vs. 266 76 mmHg for laparoscopic group; P < 0.001), while presenting equivalent hemodynamics (mean arterial pressure during surgery of 80 14 vs. 78 15 mmHg; P = 0.821).
Conclusions: PEEP requirements vary widely among patients receiving protective tidal volumes during anesthesia for abdominal surgery. Individualized PEEP settings could reduce postoperative atelectasis (measured by computed tomography) while improving intraoperative oxygenation and driving pressures, causing minimum side effects.
麻醉学文献进展分享
贵州医科大学高鸿教授课题组
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