Sanuki Takuro, Sugioka Shingo, Hirokane Motoko, Son Hiroki, Uda Rumiko, Akatsuka Masafumi, Kotani Junichiro
Assistant Professor, Department of Anesthesiology, Osaka Dental University, Osaka, Japan.
J Oral Maxillofac Surg. 2010 May;68(5):1038-42. doi: 10.1016/j.joms.2009.12.029. Epub 2010 Mar 12.
The aim of this study was to investigate the influence of mouth opening on oropharyngeal leak pressure, intracuff pressure, and cuff position of the laryngeal mask airway (LMA).
Fifteen patients who were scheduled for elective oral surgery were recruited into this study. A single, experienced LMA user inserted the LMA according to the manufacturer's recommended technique. Oropharyngeal leak pressure, intracuff pressure, and fiberoptic assessment of the LMA position were documented under 3 mouth conditions: neutral position (1.4-cm distance between upper and lower incisors), mouth open (5- to 6-cm distance between upper and lower incisors), and return to the neutral position. Any ventilation difficulties under the 3 mouth conditions were recorded.
Oropharyngeal leak pressure with the mouth open was higher than in the neutral position (P < .001). Compared with the neutral position, intracuff pressure was also higher with the mouth open (P < .001). Both measurement values returned to control levels when the neutral position was once again assumed. The LMA position observed by fiberoptic bronchoscopy was unchanged by mouth opening and was similar in the 3 mouth conditions (P = .998). Although ventilatory difficulties occurred after mouth opening in 8 of 15 patients (P < .001), it did not occur when the neutral position was reassumed.
This study showed that mouth opening led to substantial increases in oropharyngeal leak pressure and intracuff pressure of the LMA, warranting caution because gastric insufflation, sore throat, and ventilation difficulties may occur.
本研究旨在探讨张口对喉罩气道（LMA）的口咽漏气压、套囊内压及套囊位置的影响。
15例择期口腔手术患者纳入本研究。由一位经验丰富的LMA使用者按照制造商推荐的技术插入LMA。记录3种口部状态下的口咽漏气压、套囊内压以及通过纤维支气管镜评估的LMA位置：中立位（上下切牙间距1.4 cm）、张口位（上下切牙间距5至6 cm）及恢复至中立位。记录3种口部状态下出现的任何通气困难情况。
张口时的口咽漏气压高于中立位（P <.001）。与中立位相比，张口时套囊内压也更高（P <.001）。当再次恢复至中立位时，这两个测量值均恢复至对照水平。纤维支气管镜观察到的LMA位置在张口时未发生改变，且在3种口部状态下相似（P =.998）。虽然15例患者中有8例在张口后出现通气困难（P <.001），但恢复至中立位时未出现通气困难。
本研究表明，张口会导致LMA的口咽漏气压和套囊内压大幅升高，鉴于可能发生胃内充气、咽痛及通气困难，需谨慎操作。
