From the Department of Anesthesiology, The First College of Clinical Medical Science, China Three Gorges University, Yichang, China.
Anesth Analg. 2014 Apr;118(4):863-8. doi: 10.1213/ANE.0000000000000147.
In this study, we sought to determine the median effective dose (ED50) for motor block of intrathecally administered plain bupivacaine in adults (20-80 years) and to assess the effect of age on ED50 required for motor block.
This study was performed in 129 adult patients undergoing transurethral, urological, or lower limb surgery under combined spinal and epidural anesthesia. Patients were stratified according to age as follows: 20 to 30, 31 to 40, 41 to 50, 51 to 60, 61 to 70, and 71 to 80 years. The spinal component of the anesthetic was established by bolus administration of up-and-down doses of 0.75% plain bupivacaine, determined by Dixon's method. The degree of motor block after intrathecal administration of each dose was evaluated by the modified Bromage and hip motor function score. The ED50 values were estimated from the up-and-down sequences using the method of Dixon and Massey and logistic regression. Other end points were included on the basis of sensory block level, duration of motor blockade, hypotension, and vasopressor requirements.
ED50 for motor block using intrathecal bupivacaine was 10.22 mg (95% confidence interval [CI], 9.96-10.49 mg) in 20- to 30-, 9.52 mg (95% CI, 9.02-10.07 mg) in 31- to 40-, 8.37 mg (95% CI, 7.56-9.26 mg) in 41- to 50-, 7.30 mg (95% CI, 6.84-7.79 mg) in 51 to 60, 6.55 mg (95% CI, 6.01-7.13 mg) in 61- to 70-, and 5.78 mg (95% CI, 5.01-6.67 mg) in 71- to 80-year-old patients. The maximum cephalic analgesic level was L1-L2 level at 5 minutes and T10-L1 at 10 minutes after administration of intrathecal plain bupivacaine in the 6 age groups. There was a significant difference in the duration of motor blockade among groups.
The ED50 for motor block of intrathecally administered plain bupivacaine decreased steeply with advancing age.
本研究旨在确定椎管内给予布比卡因时成人（20-80 岁）运动阻滞的中效剂量（ED50），并评估年龄对运动阻滞所需 ED50 的影响。
本研究纳入 129 例行椎管内-硬膜外联合麻醉下经尿道、泌尿科或下肢手术的成年患者。患者按年龄分层如下：20-30 岁、31-40 岁、41-50 岁、51-60 岁、61-70 岁和 71-80 岁。通过 Dixon 法确定 0.75%布比卡因的上下剂量递增法建立椎管内麻醉的脊髓成分。通过改良 Bromage 和髋关节运动功能评分评估每次剂量椎管内给药后的运动阻滞程度。ED50 值使用 Dixon 和 Massey 方法的上下序列法和逻辑回归法从上下序列中估算。还根据感觉阻滞水平、运动阻滞持续时间、低血压和血管加压药需求纳入其他终点。
20-30 岁组椎管内布比卡因运动阻滞的 ED50 为 10.22mg（95%置信区间[CI]，9.96-10.49mg），31-40 岁组为 9.52mg（95%CI，9.02-10.07mg），41-50 岁组为 8.37mg（95%CI，7.56-9.26mg），51-60 岁组为 7.30mg（95%CI，6.84-7.79mg），61-70 岁组为 6.55mg（95%CI，6.01-7.13mg），71-80 岁组为 5.78mg（95%CI，5.01-6.67mg）。椎管内给予布比卡因后 5 分钟时最高头部镇痛水平为 L1-L2 水平，10 分钟时为 T10-L1 水平。6 个年龄组之间的运动阻滞持续时间存在显著差异。
椎管内给予布比卡因时运动阻滞的 ED50 随年龄的增长急剧下降。
