轻比重左旋布比卡因用于老年患者单侧腰椎麻醉的最低有效剂量

目的 探讨轻比重左旋布比卡因(LB)用于老年患者单侧腰椎麻醉的最低有效剂量.方法 25例择期下肢手术老年患者,采用上下序贯法,第1例蛛网膜下隙给予的0.25%LB轻比重液7.50 mg,以后每例根据上一例阻滞平面情况确定其剂量,如果上一例阻滞平面低于胸10(T10)则增加LB 0.25 mg,如果上一例阻滞平面不低于T10则减少LB 0.25 mg,用Dixon-Massey公式计算最低有效剂量.结果 依据Dixon-Massey公式计算的0.25%轻比重LB用于老年单侧下肢手术患者腰麻的最低有效剂量为6.67 mg(95%可信区间6.43～7.25);所有病例麻醉效果优良;双下肢改良Bromage评分,健侧肢体均为0～1分,而患侧肢体均为2～3分;麻醉期间低血压2例,无其他不良反应.结论 0.25%轻比重LB用于老年下肢手术患者腰椎麻醉的最低有效剂量为6.67 mg.

The minimal local analgesic dose of hypobaric levobupivacaine in elderly patients undergoing spinal anesthesia during unilateral lower limb surgery

Objective To determine the minimal local analgesic dose (MLAD) of hypobaric levobupivacaine in elderly patients undergoing spinal anesthesia during lower limb surgery. Methods A total of 25 patients underwent spinal anesthesia with hypobaric levobupivacaine during lower limb surgery. The initial dose of levobupivaeaine was 7.50 mg for the first patient. The dose for next patient was added by 0.25 mg if the level of sensory block was lower than that of T10, conversely the dose was subtracted by 0.25 mg. The MLAD of hypobaric levobupivacaine was calculated with up-and-down sequential experiment according to Dixon-Messay method. Results The MLAD of hypobaric levobupivacaine were 6.67 mg (95% confidence interval: 6.34-7.25). The anesthesia effects of all patients were good. The degree of motor blockade of the healthy leg was less than another leg.The intraoperative and postoperative complications rates associated with spinal anesthesia were low.Conclusions The MLAD of hypobaric levobupivacaine is 6.67 mg in elderly patients undergoing spinal anesthesia during unilateral lower limb surgery.