Östberg Erland, Larsson Alexander, Wagner Philippe, Eriksson Staffan, Edmark Lennart
From the Department of Anaesthesia and Intensive Care, and Centre for Clinical Research, Västmanland Hospital Västerås, Sweden; Department of Surgical Sciences, Uppsala University, Uppsala, Sweden (EÖ, AL, LE), Region Västmanland - Uppsala University, Centre for Clinical Research, Västmanland Hospital Västerås, Sweden (PW), and Department of Surgery and Centre for Clinical Research at Västmanland Hospital Västerås, Sweden; Department of Surgical Sciences, Uppsala University, Uppsala, Sweden (SE).
Eur J Anaesthesiol. 2025 Jan 1;42(1):54-63. doi: 10.1097/EJA.0000000000002071. Epub 2024 Oct 3.
Positive end-expiratory pressure (PEEP) is important to increase lung volume and counteract airway closure during anaesthesia, especially in obese patients. However, maintaining PEEP during emergence preoxygenation might increase postoperative atelectasis by allowing susceptible lung areas to be filled with highly absorbable oxygen that gets entrapped when small airways collapse due to the sudden loss of PEEP at extubation.
This study aimed to test the hypothesis that withdrawing PEEP just before emergence preoxygenation would better maintain postoperative oxygenation.
Prospective, randomised controlled trial.
Single centre secondary hospital in Sweden between December 2019 and January 2023.
A total of 60 patients, with body mass index between 35 and 50 kg m -2 , undergoing laparoscopic bariatric surgery.
Intraoperative ventilation was the same for all patients with a fixed PEEP of 12 or 14 cmH 2 O depending on body mass index. No recruitment manoeuvres were used. After surgery, patients were allocated to maintained PEEP or zero PEEP during emergence preoxygenation.
The primary outcome was change in oxygenation from before awakening to 45 min postoperatively as measured by estimated venous admixture calculated from arterial blood gases.
Both groups had impaired oxygenation postoperatively; in the group with PEEP maintained during awakening, estimated venous admixture increased by mean 9.1%, and for the group with zero PEEP during awakening, estimated venous admixture increased by mean 10.6%, difference -1.5% (95% confidence interval -4.6 to 1.7%), P = 0.354. Throughout anaesthesia, both groups exhibited low driving pressures and superior oxygenation compared with the awake state.
Withdrawing PEEP before emergence preoxygenation, did not alter early postoperative oxygenation in obese patients undergoing laparoscopic bariatric surgery. Intraoperative oxygenation was excellent despite using fixed PEEP and no recruitment manoeuvres, but deteriorated after extubation, indicating a need for future studies aimed at improving the emergence procedure.
www.clinicaltrials.gov , NCT04150276.
呼气末正压（PEEP）对于增加肺容积以及在麻醉期间对抗气道闭合非常重要，尤其是在肥胖患者中。然而，在苏醒前预充氧期间维持PEEP可能会增加术后肺不张，因为当拔管时PEEP突然消失导致小气道塌陷时，易损肺区会被高吸收性的氧气填充并被困住。
本研究旨在验证在苏醒前预充氧前撤去PEEP能更好地维持术后氧合的假设。
前瞻性随机对照试验。
2019年12月至2023年1月期间瑞典的一家单中心二级医院。
共有60例体重指数在35至50 kg·m⁻²之间、接受腹腔镜减肥手术的患者。
所有患者术中通气相同，根据体重指数固定PEEP为12或14 cmH₂O。未采用肺复张手法。术后，患者在苏醒前预充氧期间被分配至维持PEEP组或零PEEP组。
主要结局是从苏醒前到术后45分钟的氧合变化，通过根据动脉血气计算的估计静脉血掺杂来衡量。
两组术后氧合均受损；在苏醒期间维持PEEP的组中，估计静脉血掺杂平均增加9.1%，而在苏醒期间零PEEP的组中，估计静脉血掺杂平均增加10.6%，差异为-1.5%（95%置信区间-4.6至1.7%），P = 0.354。在整个麻醉过程中，与清醒状态相比，两组的驱动压均较低且氧合良好。
在苏醒前预充氧前撤去PEEP，并未改变接受腹腔镜减肥手术的肥胖患者术后早期的氧合情况。尽管使用固定PEEP且未采用肺复张手法，但术中氧合良好，但拔管后氧合恶化，这表明未来需要开展旨在改善苏醒过程的研究。
