罗哌卡因在小儿上肢骨折手术中的半数有效浓度

EC50 of Ropivacaine in Supracondylar Fractures of Humerus in Children

目的测定罗哌卡因用于超声引导下腋路臂丛神经阻滞时的半数有效浓度(EC 50),为学龄前儿童臂丛神经阻滞提供罗哌卡因浓度选择的理论依据。方法选择3~6岁拟行肱骨髁上骨折手术的患儿25例,ASAⅠ~Ⅱ级,所有患儿均采用全身麻醉复合臂丛神经阻滞下完成。全身麻醉诱导后,在超声引导下行腋路臂丛神经阻滞,定位成功后给予罗哌卡因1ml/㎏。采用Dixon序贯法进行试验,患儿接受罗哌卡因的起始浓度为0.2%,若前一例患儿切皮后有体动反应或平均动脉压(MAP)和(或)心率(HR)与切皮前相比升高>20%,则下一例患儿应用高一级浓度;若前一例患儿切皮后无体动反应或MAP和(或)HR与切皮前相比升高<20%,则下一例患儿应用低一级浓度,试验剂量的浓度序列级别为0.025%。数据采集后使用Probit概率单位回归法计算EC 50及其95%CI。结果在25例参与研究的患儿中,运用Probit概率单位回归法计算,罗哌卡因行腋路臂丛神经阻滞的EC 50为0.128%(95%CI:0.111%~0.142%)。结论序贯法计算得出,在全身麻醉下联合腋路臂丛神经阻滞行肱骨髁上骨折手术的罗哌卡因EC 50为0.128%。

Objective To determine the EC 50 of ropivacaine in ultrasound-guided axillary brachial plexus block in pre-school age children.Methods Twenty five children(ASAⅠ-Ⅱ)aged 3-6 years who were scheduled for upper extremity surgery were enrolled.All the children were performed under general anesthesia combined with brachial plexus block.Axillary brachial plexus block was guided by ultrasound after anesthesia induction,and ropivacaine was given 1ml/kg after localization.The Dixon′s up-and-down sequential allocation was used for determining the concentration of ropivacaine.The test initial concentration of ropivacaine was 0.2%.When a patient showed an increase of either heart rate or mean arterial blood pressure(MAP)>20%by the analgesic response of the initial skin incision,the concentration of ropivacaine given to the next patient was increased(positive response).In the absence of either heart rate or MAP increasing>20%by the analgesic response of the previous patient to the initial skin incision,the concentration of ropivacaine given to the next patient was decreased(negative response).The test interval concentration was set at 0.025%.The EC 50 and 95%CI of ropivacaine in axillary brachial plexus block was calculated with the probit probability unit regression method.Results The EC 50 of ropivacaine in axillary brachial plexus block was 0.128%(95%CI:0.111%-0.142%).Conclusion The EC 50 of ropivacaine for general anesthesia combined axillary brachial plexus block in supracondylar fractures of humerus in children was 0.128%.