From the Department of Anesthesiology and Critical Care, Medical Center (JH, HP, JS, WB, HB, SS, AS) and Faculty of Medicine, University of Freiburg, Freiburg, Germany (JH, HP, JS, WB, HB, SS, AS).
Eur J Anaesthesiol. 2021 Feb 1;38(2):146-156. doi: 10.1097/EJA.0000000000001269.
The success of ventilation with a laryngeal mask depends crucially on the seal between the mask and the periglottic tissue. Increasing the laryngeal mask's cuff volume is known to reduce oral air leakage but may lead to gastric insufflation.
We hypothesised that a lower cuff pressure would result in less gastric insufflation. We sought to compare gastric insufflation with laryngeal mask cuff pressures of 20 cmH2O (CP20) and 60 cmH2O (CP60) during increasing peak airway pressures in a randomised controlled double-blind cross-over study. We also evaluated the incidence of gastric insufflation at the recommended peak airway pressure of 20 cmH2O or less and during both intermittent positive airway pressure and continuous positive airway pressure.
After obtaining ethics approval and written informed consent, 184 patients ventilated via laryngeal mask received a stepwise increase in peak airway pressure from 15 to 30 cmH2O with CP20 and CP60 in turn. Gastric insufflation was determined via real-time ultrasound and measurement of the cross-sectional area of the gastric antrum. The primary endpoint was the incidence of gastric insufflation at the different laryngeal mask cuff pressures.
Data from 164 patients were analysed. Gastric insufflation occurred less frequently at CP20 compared with CP60 (P < 0.0001). Gastric insufflation was detected in 35% of cases with CP20 and in 48% with CP60 at a peak airway pressure of 20 cmH2O or less. Gastric insufflation occurred more often during continuous than during intermittent positive airway pressures (P < 0.01).
A laryngeal mask cuff pressure of 20 cmH2O may reduce the risk of gastric insufflation during mechanical ventilation. Surprisingly, peak airway pressure of 20 cmH2O or less may already induce significant gastric insufflation. Continuous positive airway pressure should be avoided due to an increased risk of gastric insufflation.
The study was registered in the German Clinical Trials Register (DRKS00010583) https://www.drks.de.
喉罩通气的成功在很大程度上取决于喉罩与会厌周围组织之间的密封。增加喉罩套囊的容积已知可以减少口腔漏气，但可能导致胃充气。
我们假设较低的套囊压力会导致更少的胃充气。我们旨在比较在递增的气道峰压下，喉罩套囊压力为 20cmH2O（CP20）和 60cmH2O（CP60）时的胃充气情况。我们还评估了在推荐的气道峰压 20cmH2O 或更低以及在间歇正压通气和持续正压通气时胃充气的发生率。
在获得伦理批准和书面知情同意后，184 名通过喉罩通气的患者接受了逐步递增的气道峰压从 15 至 30cmH2O 的递增，同时分别使用 CP20 和 CP60。胃充气通过实时超声和测量胃窦横截面积来确定。主要终点是不同喉罩套囊压力下胃充气的发生率。
对 164 名患者的数据进行了分析。CP20 时胃充气的发生率低于 CP60（P<0.0001）。在气道峰压为 20cmH2O 或更低时，CP20 组中胃充气的发生率为 35%，CP60 组中为 48%。在持续正压通气时，胃充气比间歇正压通气更常见（P<0.01）。
喉罩套囊压力为 20cmH2O 可能会降低机械通气时胃充气的风险。令人惊讶的是，气道峰压为 20cmH2O 或更低时可能已经引起了明显的胃充气。由于胃充气的风险增加，应避免使用持续正压通气。
该研究在德国临床试验注册处（DRKS00010583）进行了注册，https://www.drks.de。
