From the Department of Anesthesia, Antwerp University Hospital, Edegem, Belgium.
Department of Critical Care Medicine, Antwerp University Hospital, Edegem, Belgium.
Anesth Analg. 2023 Oct 1;137(4):841-849. doi: 10.1213/ANE.0000000000006325. Epub 2022 Dec 14.
Increased intra-abdominal pressure during laparoscopy induces atelectasis. Positive end-expiratory pressure (PEEP) can alleviate atelectasis but may cause hyperinflation. Cyclic opening of collapsed alveoli and hyperinflation can lead to ventilator-induced lung injury and postoperative pulmonary complications. We aimed to study the effect of PEEP on atelectasis, lung stress, and hyperinflation during laparoscopy in the head-down (Trendelenburg) position.
An open-label, repeated-measures, interventional, physiological cohort trial was designed. All participants were recruited from a single tertiary Belgian university hospital. Twenty-three nonobese patients scheduled for laparoscopy in the Trendelenburg position were recruited.We applied a decremental PEEP protocol: 15 (high), 10 and 5 (low) cm H 2 O. Atelectasis was studied with the lung ultrasound score, the end-expiratory transpulmonary pressure, the arterial oxygen partial pressure to fraction of inspired oxygen concentration (P ao2 /Fi o2 ) ratio, and the dynamic respiratory system compliance. Global hyperinflation was evaluated by dead space volume, and regional ventilation was evaluated by lung ultrasound. Lung stress was estimated using the transpulmonary driving pressure and dynamic compliance. Data are reported as medians (25th-75th percentile).
At 15, 10, and 5 cm H 2 O PEEP, the respective measurements were: lung ultrasound scores (%) 11 (0-22), 27 (11-39), and 53 (42-61) ( P < .001); end-expiratory transpulmonary pressures (cm H 2 O) 0.9 (-0.6 to 1.7), -0.3 (-2.0 to 0.7), and -1.9 (-4.6 to -0.9) ( P < .001); P ao2 /Fi o2 ratios (mm Hg) 471 (435-538), 458 (410-537), and 431 (358-492) ( P < .001); dynamic respiratory system compliances (mL/cm H 2 O) 32 (26-36), 30 (25-34), and 27 (22-30) ( P < .001); driving pressures (cm H 2 O) 8.2 (7.5-9.5), 9.3 (8.5-11.1), and 11.0 (10.3-12.2) ( P < .001); and alveolar dead space ventilation fractions (%) 10 (9-12), 10 (9-12), and 9 (8-12) ( P = .23). The lung ultrasound score was similar between apical and basal lung regions at each PEEP level ( P = .76, .37, and .76, respectively).
Higher PEEP levels during laparoscopy in the head-down position facilitate lung-protective ventilation. Atelectasis and lung stress are reduced in the absence of global alveolar hyperinflation.
腹腔镜手术期间腹内压升高会导致肺不张。呼气末正压通气（PEEP）可以缓解肺不张，但可能导致过度充气。塌陷肺泡的周期性开放和过度充气可导致呼吸机诱导性肺损伤和术后肺部并发症。我们旨在研究在头低位（Trendelenburg 位）腹腔镜手术中 PEEP 对肺不张、肺应力和过度充气的影响。
设计了一项开放标签、重复测量、干预性、生理队列试验。所有参与者均来自比利时的一家单一的三级大学医院。我们招募了 23 名计划在 Trendelenburg 位接受腹腔镜手术的非肥胖患者。我们应用递减 PEEP 方案：15cmH2O（高）、10cmH2O 和 5cmH2O（低）。应用肺超声评分、呼气末跨肺压、动脉血氧分压与吸入氧浓度比（Pao2/Fi o2）以及动态呼吸系统顺应性研究肺不张。通过死腔量评估整体过度充气，通过肺超声评估区域性通气。使用跨肺驱动压和动态顺应性估计肺应力。数据以中位数（25%至 75%）表示。
在 15、10 和 5cmH2O PEEP 时，相应的测量值分别为：肺超声评分（%）11（0-22）、27（11-39）和 53（42-61）（P<0.001）；呼气末跨肺压（cmH2O）0.9（-0.6 至 1.7）、-0.3（-2.0 至 0.7）和-1.9（-4.6 至-0.9）（P<0.001）；动脉血氧分压与吸入氧浓度比（mmHg）471（435-538）、458（410-537）和 431（358-492）（P<0.001）；动态呼吸系统顺应性（mL/cmH2O）32（26-36）、30（25-34）和 27（22-30）（P<0.001）；驱动压（cmH2O）8.2（7.5-9.5）、9.3（8.5-11.1）和 11.0（10.3-12.2）（P<0.001）；肺泡死腔通气分数（%）10（9-12）、10（9-12）和 9（8-12）（P=0.23）。在每个 PEEP 水平下，肺超声评分在肺尖区和基底区之间相似（P=0.76、0.37 和 0.76）。
头低位腹腔镜手术时较高的 PEEP 水平有助于实施肺保护性通气。在不导致整体肺泡过度充气的情况下，肺不张和肺应力减轻。
