妇科手术患者蛛网膜下腔注射布比卡因与左旋布比卡因运动阻滞效应的比较

The potencies for motor block after intrathecal bupivacaine and levobupivacaine

目的比较妇科手术患者蛛网膜下腔注射布比卡因与左旋布比卡因运动阻滞的的效应。方法拟在脊椎．硬膜外联合麻醉下行妇科手术的患者60例，ASAⅠ或Ⅱ级，年龄20～60岁，身高155～170cm，体重指数〈30kg／m^2，随机分为2组（n=30），布比卡因组（B组）：蛛网膜下腔注射等比重0．5％布比卡因；左旋布比卡因组（L组）：蛛网膜下腔注射等比重0．5％左旋布比卡因。采用序贯法进行试验，每组第1例患者局麻药剂量均为5mg，剂量变化梯度为1mg。运动阻滞有效定义为蛛网膜下腔注药结束后20min内双下肢改良Bromage评分均达到3分。若上1例有效，则下1例采用低一级剂量；若无效，则下1例采用高一级剂量。采用概率单位回归法计算两药运动阻滞的半数有效剂量（ED50）及其95％可信区间（95％Cl）。结果布比卡因运动阻滞的ED50及其95％CI为6．04（5．30～6．93）mg，左旋布比卡因运动阻滞的ED50及其95％CI为9．55（8．62～10．97）mg，布比卡因运动阻滞的ED50低于左旋布比卡因（P〈0．01）；左旋布比卡因与布比卡因运动阻滞的效价比及其95％CI为0．63（0．52～0．75）。结论左旋布比卡因蛛网膜下腔麻醉时运动阻滞的效应低于布比卡因。

Objective To determine the median effeetive dose （ED50） for motor block after intratheeal bupivaeaine and levobupivaeaine and define their motor-bloeking potency ratios. Methods In this study ED50 was determined by up-down sequential allocation. Sixty ASA Ⅰ or Ⅱ patients aged 20-60 yr with body mass index 〈 30 kg/m^2 undergoing eleetive gynecological surgery under eombined spinal-epidural anesthesia were randomized into 2 groups receiving intrathecal 0.5 % bupivacaine and levobupivacaine respectively. The initial dose was 5 mg. Each time the dose increased/decreased by 1 mg. Efficacy was determined by the occurrence of maximum motor block （ Bromage scale = 3） in both lower limbs within 20 min after the spinal injection. Results Intrathecal ED50 for motor block was 6.04 mg for bupivaeaine （95% CI 5.30-6.93 mg） , 9.55 mg for levobupivaeaine （95% CI 8.62-10.97 mg） （P 〈 0.01）. The relative motor bloeking poteney ratio was levobupivacaine/bupivacaine 0.63 （95 % CI 0.52-0.75）. Conclusion The potency of intrathecal levobupivacaine is lower than that of bupivacaine for motor block. The ratio is 0.63.