Wahlen B M, Heinrichs W, Latorre F
Clinic of Anaesthesiology, Johannes Gutenberg University, Mainz, Germany.
Paediatr Anaesth. 2004 Apr;14(4):313-7. doi: 10.1046/j.1460-9592.2003.01213.x.
The objective of the present study was to evaluate the prelaryngeal position of the laryngeal mask airway (LMA(TM)) in children, and to determine the influence of mask positioning on gastric insufflation and oropharyngeal air leakage.
A total of 100 children, 3-11 years old, scheduled for surgical procedures in the supine position under general anaesthesia were studied. After clinically satisfactory LMA placement, tidal volumes were increased stepwise until air entered the stomach, airway pressure exceeded 30 cmH(2)O, or air leakage from the mask seal prevented further increases in tidal volume. LMA position in relation to the laryngeal entrance was verified using a flexible bronchoscope.
The insertion of the LMA with a clinically satisfactory position was achieved in all patients at the first attempt. Gastric air insufflation occurred in five of 49 patients with malpositioned LMA. No incident of gastric air insufflation was observed in 51 patients with correctly positioned LMA. The minimum inspiratory pressure leading to mask leakage was 17 cmH(2)O for incorrectly positioned LMA, and 25 cmH(2)O for correctly positioned LMA. Clinically unrecognized LMA malposition was associated with a significantly increased incidence of either oropharyngeal leakage (r = 0.59; P = 0.0001) or gastric insufflation (r = 0.25; P = 0.01).
Clinically undetected LMA malpositioning is a significant risk factor for gastric air insufflation in children between 3 and 11 years, undergoing positive pressure ventilation, especially at inspiratory airway pressures above 17 cmH(2)O.
本研究的目的是评估儿童喉罩气道（LMA™）在喉前的位置，并确定面罩位置对胃充气和口咽漏气的影响。
对100例年龄在3至11岁、计划在全身麻醉下仰卧位进行手术的儿童进行研究。在临床上LMA放置满意后，逐步增加潮气量，直到空气进入胃内、气道压力超过30 cmH₂O，或面罩密封处漏气阻止潮气量进一步增加。使用柔性支气管镜确认LMA相对于喉入口的位置。
所有患者首次尝试时均成功插入位置临床满意的LMA。49例LMA位置不当的患者中有5例发生胃内空气充气。51例LMA位置正确的患者未观察到胃内空气充气事件。LMA位置不当导致面罩漏气的最小吸气压力为17 cmH₂O，位置正确的为25 cmH₂O。临床上未识别的LMA位置不当与口咽漏气（r = 0.59；P = 0.0001）或胃充气（r = 0.25；P = 0.01）的发生率显著增加相关。
对于3至11岁接受正压通气的儿童，临床上未检测到的LMA位置不当是胃内空气充气的重要危险因素，尤其是在吸气气道压力高于17 cmH₂O时。
