摘要：
目的 测定右美托咪定(dexmedetomidine,Dex)滴鼻用于患儿面罩吸入麻醉诱导前镇静的ED50,比较幼儿、学龄前和学龄患儿ED50的差异. 方法 选择ASA分级Ⅰ、Ⅱ级接受面罩吸入麻醉诱导的患儿,按年龄分为幼儿组(1～3岁)、学龄前组(4～6岁)和学龄组(7～12岁),每组预计35例.每组均在麻醉前1h经鼻滴入Dex,起始剂量为2μg/kg,按改良序贯法进行调整,根据上一例患儿面罩吸入诱导时的镇静满意程度,下一例患儿增加或减少0.25 μg/kg.镇静效果以面罩接受程度四分法进行评估,1～2分为镇静不满意,3～4分为镇静满意.用概率单位回归分析法计算出Dex满意镇静的ED50及相应的95％置信区间(95％CI). 结果 幼儿组、学龄前组和学龄组实际所需例数分别为31、28和30.幼儿组、学龄前组和学龄组Dex滴鼻镇静的ED50和95％CI分别为1.94(1.72～2.18)、1.61(1.41～1.82) μg/kg和1.30(1.13～1.47) μg/kg,3组间比较,差异有统计学意义(P＜0.05). 结论 随着患儿年龄的增加,面罩吸入麻醉诱导前所需Dex滴鼻镇静的ED50减小.%Objective To determine the ED50 of intranasal dexmedetomidine(Dex) sedation for acceptance of mask inhalation anesthesia induction in children,and to compare the difference of ED50 among infants,preschool and school-age children.Methods ASA physical status Ⅰ or Ⅱ children,scheduled for mask inhalation anesthesia induction,were allocated into 3 groups according to age:infant group(1-3 y),preschool group(4-6 y) and school-age group(7-12 y),and the case number expectation for each group is 35.Every child was titrated Dex into nostril 1 h before inhalational induction,and the initial dose of Dex was set at 2 μg/kg.Using the modified Dixon's up-and-down method depending on the sedation effect of the previous child,the dose of Dex in the next child was increased or decreased by 0.25 μg/kg.The tolerant degree of face mask was evaluated using a different 4-point scale.1-2 scores were considered as unsatisfactory and 3-4 scores were considered as satisfactory.Probit analysis was used for calculating ED5o and 95％ confidence interval (CI) of intranasal Dex sedation.Results 31,28 and 30 cases were practically used in infant group,preschool group and school-age group,respectively.The ED50 of Dex for intranasal sedation was 1.94 μg/kg in infant group (95％CI:1.72-2.18 μg/kg),1.61 μg/kg in preschool group (95％CI:1.41-1.82 μg/kg),and 1.30 μg/kg in school-age group (95％CI:1.13-1.47 μg/kg),respectively.The ED50 among the three groups have significant difference (P＜0.05).Conclusions The ED50 of Dex required for intranasal sedation before mask inhalation anesthesia induction is decreased followed by the increase of age in children.
