罗比卡因复合舒芬太尼行硬膜外分娩镇痛的最低有效浓度探讨

The study of minimum local analgesic dose of ropivacaine combined with different concentration of sufentanil during epidural analgesia for labour

目的 寻求自第一产程起硬膜外分娩镇痛的最适舒芬太尼浓度，及与之配伍的罗比卡因的浓度和剂量。方法 选择ASA Ⅰ～Ⅱ级，妊娠≥36周，产前无服用镇痛催眠药史的初产妇124例，随机分为四组，Ⅰ组：罗比卡因复合0．2μg／ml舒芬太尼组；Ⅱ组：罗比卡因复合0．4μg／ml舒芬太尼组；Ⅲ组：罗比卡因复合0．6μg／ml舒芬太尼组；Ⅳ组：对照组，单纯使用罗比卡因。宫口开至2～3cm时于L2～3间隙行硬膜外穿刺置管，分别注入15ml罗比卡因与不同浓度的舒芬太尼混合溶液。根据双盲、序贯的方法，以上一产妇的镇痛效果，确定下一例产妇所用的罗比卡因药液浓度，各组初始的罗比卡因浓度均定为0．12％。结果 4例产妇因脐带脱垂、单侧硬膜外阻滞或结果可疑而退出研究，余120例产妇进入分析。各组罗比卡因分娩镇痛的EC50值分别为Ⅰ组；0．074％（95％CI，0．071％～O．078％）；Ⅱ组：0．048％（95％CI，0．041％～0．056％）；Ⅲ组；0．035％（95％CI，0．029％～0．044％）；Ⅳ组：0．111％（95％CI，0．106％～O．116％），各组间差异均有极显著意义（P＜0．01）。结论 硬膜外复合使用舒芬太尼能剂量相关地降低罗比卡因分娩镇痛的最低有效浓度。使用0．2μg／ml和0．4μg／ml的舒芬太尼得到的罗比卡因的最低有效镇痛浓度分别为0．074％和0．048％，两组均可达到满意镇痛。

Objective To determine the effective concentration of epidural sufentanil combined with ropivacaine for analgesia in the first stage of labor. Methods One hundred and twenty-four ASA Ⅰ- Ⅱnulliparous women of 37-42 week gestation, with 2-3 cm cervical dilatation were randomly assigned to four groups. Group 0 serves as control group using plain ropivacaine. The patients in group 1,2 and 3 were given sufentanil 0.2μg/ml ,0.4μg/ml and 0.6μg/ml respectively. Fifteen milliliter of different concentration of sufentanil combined with ropivacaine was given epidurally. The concentration of ropivacaine was determined by the response of the previous parturient to a higher or lower concentration using double-blind, up-and-down sequential allocation. The initial concentration of epidural ropivacaine in each group was 0. 12%. Results Among the 124 parturients recruited, four were excluded from the study because of prolapse of cord, unilateral blockade and uncertain analgesic efficacy. The results showed that the EC50 of epidural ropivacaine for labor analgesia was 0. 074 （95%CI,0. 071%-0. 078%） in group 1, 0. 048 %（95 %CI,0. 041%-0. 056%） in group 2,and 0. 035% （95%CI,0. 029%-0. 044%） in group 3,0. 111% （95%CI,0. 106%-0. 116%） in group 4,Conclusion The addition of sufentanil resulted in dose-dependent reduction in EC50 of ropivacaine during epidural labour analgesia. The minimum effective concentrations of ropivacaine for epidural labor analgesia combined with 0.2μg/ml and 0.4μg/ml sufentanil are 0. 074% and 0. 0480% respectively.