小儿异氟醚麻醉喉罩通气道拔除时最低肺泡有效浓度的临床研究

Minimum Alveolar Concentration of lsoflurane Anesthesia when Removing Laryngeal Mask Air-way in Peaditrics

【目的】观察喉罩通气道拔除时异氟醚的最低肺泡有效浓度。[方法]42例择期行整形手术患儿，高流量吸入异氟烷、60％氧化亚氮诱导并维持麻醉，手术结束后停止吸入氧化亚氮，并维持设定的异氟醚浓度15min后拔除喉罩。根据Dixon序贯法确定喉罩拔除时的异氟烷浓度，每0．1％异氟烷为1个增减单位。患儿未出现咳嗽、牙关紧闭、体动、屏气及喉痉挛则认为拔除喉罩平稳。【结果】50％及95％小儿平稳拔除喉罩时呼气末异氟烷浓度（即EC50及EC95）分别为1．44％及1．65％。【结论】2～6岁患儿喉罩满意拔除时呼气末异氟烷EC50和EC95值分别为1．44％和1．65％。

[Objective] To observe the minimum alveolar concentration of isoflurane when removing laryn- geal mask airway（LMA）. [Methods]Forty two cases of selective plastic surgery children received high-flow inhalation of isoflurane induced by 60% nitrous oxide and the maintenance of anesthesia. After surgery, the former isoflurane continued for 15min, and nitrous oxide inhalation was ceased and I.MA was removed. The concentration of isoflurane was determined by Dixon sequential method when removing LMA. Each 0. 1 sevoflurane served as an increase or decrease unit. If children had no cough, lockjaw, body movement, breath and throat spasms, LMA was removed smoothly. [Results]When LMA was removed smoothly, the end-tidal isoflurane concentration of 50% and 95% of the children （EC50 and EC95） were 1.24% and 1.45%, respectively. [Conclusion]The children with 2-6 years old have satisfactory LMA removal. The end-tidal sevoflu-rane （EC50 and EC95） values are 1.44% and 1.65%, respectively.