摘要目的 探讨全凭七氟烷吸入诱导时小儿喉罩通气道置入所需的呼气末七氟烷最低肺泡有效浓度.方法 全麻下行择期手术患儿27例,ASA Ⅰ或Ⅱ级,年龄3～8岁.吸入8%七氟烷高浓度诱导,睫毛反射消失后调整吸入七氟烷的浓度以达到呼气末浓度的预定值,维持这个预定值10mn后为患儿置人喉罩.置入喉罩即刻以及置入喉罩后的1 min内患儿如果出现咳嗽、肢体运动、下颌松弛困难以致喉罩无法插入,屏气、喉痉挛、低氧血症这其中的任何一项即认为置入喉罩不满意.七氟烷预定浓度根据序贯法确定,初始患儿的呼气末七氟烷浓度为2.0%,若喉罩置入不满意,则下一患儿的七氟烷预定浓度增加0.2%;若喉罩置入满意,则下一患儿的七氟烷预定浓度降低0.2%.结果 患儿满意置入喉罩通气道时的七氟烷MACLMA为(2.01±0.19)%.ED95为2.36%(95%CI 2.15%～4.15%).结论 50%和95%的患儿在呼气末七氟烷浓度分别为2.01%和2.36%时置入喉罩不发生咳嗽、体动及其他气道不良反应.

abstractsObjective To investigate the minimum alveolar concentration (MAC) of sevoflurane required for insertion of laryngeal mask airway (LMA) in anesthetized children. Methods 27 children, aged 3-8, with an ASA physical status Ⅰor Ⅱ, underwent elective surgery under general anesthesia induced by inhalation of 8% sevoflurane in oxygen. After loss of eyelash reflex, the designated end-tidal concentration of sevoflurane remained stable for at least 10 min, and then the LMA was inserted. Each target concentration at the time of insertion was predetermined by the Dixon up-and-down method (with 0.2% as a step size) starting at 2.0% end-tidal concentration of sevoflurane. Successful insertion was defined as excellent inserting condition (fully relaxed jaw, no coughing, and no movement of the limbs, no breath holding, and no laryngospasm). Results The mean MAC of sevoflurane to achieve successful LMA insertion in 50% of children was (2.01±0.19)% ,and the ED95 was 2.36% (95% CI 2.15%-4.15%).Conclusion LMA insertion can be safely accomplished without coughing, moving, or any other airway complications in 50% and 95% of children at 2.01% and 2.36% end-tidal concentrations of sevoflurane.