麻醉诱导时呼气末正压对面罩通气过程中胃进气的影响
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Effect of positive end-expiratory pressure on gastric insufflation during induction of anaesthesia when using pressure-controlled ventilation via a face mask: A randomised controlled trial
背景与目的
麻醉诱导期间面罩通气（FMV）与胃内气体进入相关，可能导致返流及误吸。研究表明治疗阻塞性睡眠呼吸暂停综合征(OSAS)和胃食管反流病时，持续正压通气（CPAP）可增加下段食管括约肌 (LES) 压力来减少胃反流。本研究假设麻醉诱导过程中，在CPAP预充氧后应用呼气末正压（PEEP）行面罩通气可以减少胃内气体注入的风险。本研究主要目：（1）比较麻醉诱导后固定PEEP水平或零PEEP（ZEEP）时FMV胃内充气的发生率。（2）研究有无PEEP的FMV对上食管括约肌（UES）、食管中断和下食管括约肌（LES）压力的影响。
方 法
本研究为单中心、随机对照试验，共纳入30例健康志愿者。麻醉诱导后，在不使用或使用CPAP 10 cmH2O的情况下进行预充氧，然后使用ZEEP或PEEP 10 cmH2O进行压力控制的FMV。在预充氧吸气期间，呼吸停止期间和面罩通气过程中每一个PEEP水平下的2~3个呼吸周期间，测量上食管括约肌（UES）、食管体和下食管括约肌（LES）的压力。食管体的压力为从UES下缘至LES上缘的平均压力。
结 果
与ZEEP组相比，PEEP组中与PIP相关的胃内气体注入的发生率更高。在15 cmH2O或以下的PIP时，两组均未发生胃内气体注入。在PIP为 30 cmH2O时，PEEP组15例中有13例、ZEEP组15例中有5例出现胃内气体注入。两组麻醉诱导后的UES压力均显著降低，自主呼吸停止后UES压力进一步降低。麻醉或PIP水平均不会显著影响食管体压力。从自主呼吸到开始预充氧，PEEP组的LES压力明显增加，而ZEEP组没有显著差异。麻醉诱导后，各组的平均LES压力显著降低。
结 论
随着PEEP的增加，试验水平的PEEP在FMV期间促进胃充气。这一结果表明，在FMV麻醉诱导后应谨慎使用PEEP，而使用CPAP是安全的。
原始文献摘要
Cajander P, Edmark L, Ahlstrand R, Magnuson A, de Leon A；Effect of positive end-expiratory pressure on gastric insufflation during induction of anaesthesia when using pressure-controlled ventilation via a face mask: A randomised controlled trial.Eur J Anaesthesiol. 2019 Sep; 36(9):625-632. doi: 10.1097/EJA.0000000000001016.
BACKGROUND:Face mask ventilation (FMV) during induction of anaesthesia is associated with risk of gastric insufflation that may lead to gastric regurgitation and pulmonary aspiration. A continuous positive airway pressure (CPAP) has been shown to reduce gastric regurgitation. We therefore hypothesised that CPAP followed by FMV with positive end-expiratory pressure (PEEP) during induction of anaesthesia would reduce the risk of gastric insufflation.
OBJECTIVE:The primary aim was to compare the incidence of gastric insufflation during FMV with a fixed PEEP level or zero PEEP (ZEEP) after anaesthesia induction. A secondary aim was to investigate the effects of FMV with or without PEEP on upper oesophageal sphincter (UES), oesophageal body and lower oesophageal sphincter (LES) pressures.
DESIGN:A randomised controlled trial.
SETTING:Single centre, Department of Anaesthesia and Intensive Care, Örebro University Hospital, Sweden.
PARTICIPANTS:Thirty healthy volunteers.
INTERVENTIONS:Pre-oxygenation without or with CPAP 10 cmH2O, followed by pressure-controlled FMV with either ZEEP or PEEP 10 cmH2O after anaesthesia induction.
MAIN OUTCOME MEASURES:A combined impedance/manometry catheter was used to detect the presence of gas and to measure oesophageal pressures. The primary outcome measure was the cumulative incidence of gastric insufflation, defined as a sudden anterograde increase in impedance of more than 1 kΩ over the LES. Secondary outcome measures were UES, oesophageal body and LES pressures.
RESULTS:The cumulative incidence of gastric insufflation related to peak inspiratory pressure (PIP), was significantly higher in the PEEP group compared with the ZEEP group (log-rank test P < 0.01). When PIP reached 30 cmH2O, 13 out of 15 in the PEEP group compared with five out of 15 had shown gastric insufflation. There was a significant reduction of oesophageal sphincter pressures within groups comparing pre-oxygenation to after anaesthesia induction, but there were no significant differences in oesophageal sphincter pressures related to the level of PEEP.
CONCLUSION:Contrary to the primary hypothesis, with increasing PIP the tested PEEP level did not protect against but facilitated gastric insufflation during FMV. This result suggests that PEEP should be used with caution after anaesthesia induction during FMV, whereas CPAP during pre-oxygenation seems to be safe.
麻醉学文献进展分享
贵州医科大学高鸿教授课题组
翻译：王贵龙 编辑：何幼芹 审校：王贵龙