应用序贯法研究超声引导腘窝坐骨神经阻滞的有效剂量

ED50 and ED95 of 0.5% ropivacaine for ultrasound-guided popliteal sciatic nerve block in patients using up-and-down method

目的确定0.5%罗哌卡因用于超声引导腘窝坐骨神经阻滞时的半数有效剂量(ED50)和95%有效剂量(ED95)。方法选择拟行外踝关节或跟骨手术患者45例,在超声引导下行腘窝坐骨神经阻滞,定位成功后注入0.5%罗哌卡因。采用Dixon序贯法进行试验,0.5%罗哌卡因起始容量为30 m L,若完全阻滞,则下一例减少3 m L;若不完全阻滞,则下一例增加3 m L。注射后在30 min内每5 min评估胫神经和腓总神经的感觉和运动阻滞情况。采用Probit概率单位回归法计算ED50和ED95。结果 0.5%罗哌卡因在超声引导下腘窝入路坐骨神经阻滞的概率单位模型为Probit(P)=-1.877+1.184(ln剂量),ED50和ED95分别为4.88 m L和19.56 m L。胫神经的感觉阻滞完全例数为30例,占66.7%;腓总神经的感觉阻滞完全例数为39例,占86.7%,差异具有统计学意义(χ2=5.031,P=0.025)。胫神经的运动阻滞完全例数为32例,占71.1%;腓总神经的运动阻滞完全例数为39例,占86.7%,差异无统计学意义(χ2=3.269,P=0.071)。结论应用序贯法研究超声引导下腘窝坐骨神经阻滞0.5%罗哌卡因的ED50和ED95分别为4.88 m L和19.56 m L,在外踝关节或跟骨手术中具有较好临床应用效果。

Objective To determine the ED50（50% effective dose） and ED95（95% effective dose） of 0.5% ropivacaine for ultrasound-guided popliteal sciatic nerve block in patients. Methods 45 patients were recruited to accept the uitrasound-guided popliteal sciatic nerve block for calcaneus and lateral ankle surgery. The up-and-down method was used to determine the ED50 and ED95. The starting dose of 0.5% ropivacaine was set at 30 mL, which was decreased by 3 mL for secondary patients if the block was successful and increased by 3 mL for secondary patients if the block was failed. Probit Regression Model were established to calculate the ED50 and ED95. After the injection of local anaesthetic, the degree of sensory and motor blockade of the tibial and common peroneal nerves was assessed every 5 minutes for 30 minutes. Results The Probit model for 0.5% ropivacaine for ultrasound-guided popliteal sciatic nerve block was Probit（P）=-1.877＋1.184 （In doze）. The ED50 and ED95 were 4.88 mL and 19.56 mL. The success rates of sensory blockade for the tibial nerve and common peroneal nerve were 66.7%（30 cases） and 86.7%（ 39 cases）, respectively, with statistically significant difference （ χ2 =5.031, P=0.025）. The success rates of motor blockade of these two nerves were 71.1% （32 cases） and 86.7% （39 cases）, respectively, without statistically difference significant （ χ2 = 3.269, P = 0.071）. Conclusion ED50 and ED95 of 0.5% ropivacaine for ultrasound-guided popliteal sciatic nerve block in patients using the up-and-down method are 4.88 mL and 19.56 mL, which is very useful for calcaneus and lateral ankle surgery.