Analysis on minimum alveolar effective concentration of sevoflurane for laryngeal mask airway insertion under general anesthesia in premature infants

目的 确定矫正胎龄小于37周的早产儿全凭吸入诱导时置入喉罩无体动反应的七氟烷最低肺泡有效浓度(MAC).方法 择期行全凭吸入全身麻醉的矫正胎龄小于37周的早产儿21例,ASA分级Ⅰ～Ⅱ级.吸入6％七氟烷进行全身麻醉诱导,至患儿意识消失后,将呼气末七氟烷浓度调整至预定值,维持15 min不变,然后置入喉罩.根据Dixon's上下法进行试验,初始呼气末七氟烷浓度为2％,置入喉罩时发生体动反应,下一例升高一个浓度梯度,置入喉罩时未发生体动反应,下一例降低一个浓度梯度,相邻浓度梯度为0.2％.将体动反应到无体动反应的中点设为平衡点,计算所有平衡点七氟烷浓度的平均值即为MAC.结果 矫正胎龄小于37周的早产儿置入喉罩无体动反应的七氟烷MAC为1.71％.结论 矫正胎龄小于37周的早产儿置入喉罩无体动反应的七氟烷MAC值低于健康儿童的参考值,这可能是归因于早产儿中枢神经系统发育尚不完善.Objective To determine the minimum alveolar concentration(MAC) of sevoflurane without body movement during laryngeal mask airway(LMA)intubation in premature infants less than 37 weeks of corrected gestational age undergoing total inhalation general anesthesia induction.Methods Twenty-one ASA Ⅰ or Ⅱ premature infants less than 37 weeks of corrected gestational age undergoing elective inhalation general anesthesia were enrolled in this study.At first,the general anesthesia induction was started by inhaling 6 ％ sevoflurane.After the premature infant lost consciousness,the end tidal sevoflurane concentration(ET-sev)was adjusted to the predetermined concentration and maintained stable for 15 min.After that,LMA was inserted.The up-anddown sequential allocation was used to determine MAC.The initial ETsev was 2 ％,which was increased or decreased by 1 gradient concentration in the next case according to the LMA insertion body movement response.The adjacent concentration gradient was 0.2％.The midpoint from th body movement response to non-body movement response was set as the balance point and the mean value of the concentrations of sevoflurane at all the balance points were calculated as MAC.Results The end tidal sevoflurane con centration without the body movement responses to LMA insertion was 1.71％.Conclusion The MAC of sevoflurane without the body movement responses to LMA insertion in premature infants less than 37 weeks of corrected gestational age is 1.71％,which is lower than that in the normal children and probably because imperfect central nervous system development in premature infants.中文核心期刊要目总览(PKU)中国科技核心期刊(ISTIC)334678-4679,46834