不同剂量右美托咪定鼻腔给药对七氟醚抑制患儿喉罩置入反应EC50的影响

Effects of different doses of dexmedetomidine administered intranasally on median effective concentration of sevoflurane inhibiting responses to laryngeal mask airway insertion in pediatric patients

目的 评价不同剂量右美托咪定鼻腔给药对七氟醚抑制患儿喉罩置入反应半数有效呼气末浓度（EC50）的影响.方法 择期全麻手术患儿,性别不限,年龄1～3岁,体重指数20～ 25kg/m2,ASA分级Ⅰ或Ⅱ级,采用随机数字表法分为3组：对照组（C组）、右美托咪定1 μg/kg组（D1组）和右美托咪定2 μg/kg组（D2组）.麻醉诱导前1h时,D1组和D2组分别鼻腔给予右美托咪定1和2 μg/kg（用生理盐水稀释至1 ml）,C组鼻腔给予生理盐水1 ml.鼻腔给药后45～60 min患儿与父母分离,进入手术室.吸入8％七氟醚诱导意识消失后,用改良序贯法确定七氟醚呼气末浓度,起始七氟醚呼气末浓度为2％,根据喉罩置入反应确定下一例患儿的七氟醚呼气末浓度,浓度梯度为0.2％.评价患儿与父母分离时的镇静程度和对喉罩的接受程度,记录镇静满意情况和喉罩接受满意情况.用概率单位法计算七氟醚抑制喉罩置入反应的EC50及其95％可信区间.结果 与C组比较,D1组和D2组镇静满意率和喉罩接受满意率升高（P＜0.05）;与D1组比较,D2组镇静满意率和喉罩接受满意率升高（P＜0.05）.C组、D1组和D2组七氟醚抑制喉罩置入反应的EC50及其95％可信区间为2.03％（1.91％ ～ 2.15％）、1.76％（1.65％ ～ 1.87％）和1.63％（1.53％～ 1.73％）,D1组和D2组EC50均低于C组,D2组EC50低于D1组（P＜0.05）.结论 右美托咪定1和2 μg/kg鼻腔给药可降低七氟醚抑制患儿喉罩置入反应的EC50,2μg/kg效果更佳.

Objective To evaluate the effects of different doses of dexmedetomidine administered intranasally on the median effective concentration （EC50） of sevoflurane inhibiting responses to laryngeal mask airway （LMA） insertion in the pediatric patients.Methods American Society of Anesthesiologists physical status Ⅰ or Ⅱ pediatric patients of both sexes, aged 1-3 yr, with body mass index of 20-25 kg/m2, scheduled for elective surgery under general anesthesia, were randomly divided into 3 groups： control group （group C） , dexmedetomidine 1 μg/kg group （group D1） , and dexmedetomidine 2 μg/kg group （group D2）.In D1 and D2 groups, dexmedetomidine 1 and 2 μg/kg （in 1 ml of normal saline） were administered intranasally at 1 h before induction of anesthesia, respectively.Group C received the equal volume of normal saline administered intranasally.The children were separated from their parents at 45-60 min after intranasal administration and admitted to the operating room.The children inhaled 8% sevoflurane until they lost consciousness.After loss of consciousness, the end-tidal concentration of sevoflurane was determined using the modified Dixon＆#39;s up-and-down method.The initial end-tidal concentration of sevoflurane was set at 2%.The concentration was increased/decreased by 0.2% in the next patient according to the response to LMA insertion.The patient＆#39;s sedation status and with LMA acceptance were evaluated, and the patient＆#39;s satisfaction with sedation and with LMA acceptance was recorded.Probit analysis was used to calculate the EC50 and 95% confidence interval of sevoflurane inhibiting responses to LMA insertion.Results The patient＆#39;s satisfaction with sedation and with LMA acceptance was significantly higher in D1 and D2 groups than in group C, and in group D2 than in group D1 （P〈0.05）.The EC50 （95% confidence interval） of sevoflurane inhibiting responses to LMA insertion was 2.03% （1.91%-2.15%）, 1.76% （1.65%-1.87%） and 1.63% （1.53%-1.73%） in C, D1 and D2 groups, respectively.The EC50 was significantly lower in D1 and D2 groups than in group C, and in group D2 than in group D1 （P〈0.05）.Conclusion Dexmedetomidine 1 and 2 μg/kg administered intranasally can decrease the EC50 of sevoflurane inhibiting responses to LMA insertion in the pediatric patients, and 2 μg/kg produces better efficacy.