0.5%罗哌卡因用于超声引导经臀下入路坐骨神经阻滞的半数有效剂量

Fifty percent effective dosage of 0.5% ropivacaine for ultrasound guided subgluteal sciatic nerve blocking in elderly patients undergoing ankylosis arthrolysis of knee joint

目的 本研究旨在探讨0.5%罗哌卡因用于超声引导经臀下入路坐骨神经阻滞的半数有效剂量.方法 选取坐骨神经阻滞下行关节僵直手法松解术的老年患者21例,其中,男性9例,女性12例,患者年龄65-79岁,体质量60~90 kg,ASAⅠ-Ⅲ级,在超声引导下行经臀下入路坐骨神经阻滞,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20 mL,若阻滞效果完全,则下1例减少2 mL;若阻滞不完全,则下1例增加容量2 mL.采用Probit概率单位回归法计算超声引导臀下入路坐骨神经阻滞时,0.5%罗哌卡因的半数有效剂量及其95%可信区间.结果 行膝关节僵直松解术老年患者经超声引导臀下入路坐骨神经阻滞时,0.5%罗哌卡因的半数有效剂量及其95%可信区间为14.5（12.5-15.6）mL.结论 0.5%罗哌卡因在超声引导下老年膝关节僵直松解术患者经臀下入路坐骨神经阻滞的半数有效剂量为14.5 mL.

Objective To determine the 50% effective dosage of 0. 5% ropivacaine for ultrasound guided subgluteal sciatic nerve blocking in elderly patients undergoing ankylosis arthrolysis of knee joint. Methods Twenty-one ASA Ⅰ - Ⅲ elderly patients of both sexes, aged 65 - 79 year weighing 60 - 90 kg were recruited to receive ultrasound guided sciatic nerve blocking by means of subgluteal approach for ankylosis arthrolysis of knee joint. The volume of 0. 5% ropivacaine was injected in each patient was based on modified Dixon＇s up-and-down method. The initial volume was 20 mL and each time the volume increased/decreased by 2 mL, The 50% effective dose and 95% confidence interval （95% CI） of 0. 5% ropivacaine were calculated by using Probit Regression method. Results The median effective dosage of 0. 5% ropivacaine for elderly patients undergoing ankylosis arthrolysis of knee joint by using of ultrasound guided sciatic nerve block with subgluteal approach is 14.5 mL （95% confidence interval 12. 5 - 15.6 mL）. Conclusion The 50% effective dosage of 0. 5% ropivacaine for ultrasound guided subgluteal sciatic nerve block in elderly patients undergoing ankylosis arthrolysis of knee joint was 14. 5 mL.