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

Objective To determine the median effective dose (ED50) for motor block after intrathecal bupivacaine and ievobupivacaine and define their motor-blocking 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/m2/ undergoing elective gynecological surgery under combined 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 ED50for motor block was 6.04 mg for bupivacaine (95% CI 5.30-6.93 mg), 9.55 mg for levobupivacaine (95% CI 8.62-10.97 mg) (P <0.01). The relative motor blocking potency ratio was levobupivacaine/bupivacalne 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.

The potencies for motor block after intrathecal bupivacaine and levobupivacaine