剖宫产术硬膜外5mL生理盐水容量扩张下鞘内注射等比重布比卡因ED_(50)的测定

Determination of ED_(50) of Lntrathecal Isobaric Bupivacaine with Epidural Capacity Expansion by 5mL Normal Saline in Cesarean Section

目的测定剖宫产术硬膜外5m L生理盐水容量扩张下鞘内注射等比重布比卡因的半数有效量（ED_（50））值。方法择期剖宫产术孕妇84例行腰硬联合麻醉,根据随机分组情况鞘内注入等比重布比卡因7、8、9、10、11、12和13mg（n=12）,在硬膜外腔置入导管之后以0.5m L/s的速度注入生理盐水5m L。注入生理盐水后15min内双侧痛觉消失平面到达T6且感觉阻滞Hollmen分级至少2级被认定为诱导成功。诱导成功并且手术当中硬膜外没有追加任何局部麻醉药物被认定为手术成功。采用logistic回归分析测量布比卡因的ED_（50）值。结果诱导成功的布比卡因ED_（50）值为8.961mg（95%CI：8.083~9.839）,手术成功的布比卡因ED_（50）值为9.351mg（95%CI：8.915~9.787）。随着鞘内注射布比卡因的量增加,麻醉平面上升到T6节段所需的时间缩短,差异有统计学意义（P〈0.05）,各组诱导和手术成功的例数增加。各组术中最大血压下降百分比、去氧肾上腺素的用量以及恶心呕吐的发生差异无统计学意义（P〉0.05）。结论剖宫产术硬膜外5m L生理盐水容量扩张下鞘内注射等比重布比卡因诱导成功的ED_（50）值为8.961mg,手术成功的ED_（50）值为9.351mg。

Objective Determination of half effective dose（ EDs0 ） value of intrathecal isobaric bupivacaine with epidural capacity expansion by 5mL normal saline in caesarean section. Methods 84 elective caesarean pregnant women with combined spinal epidural anesthesia, received intrathecal injection of 7,8,9,10,11,12 and 13mg（ n = 12 ） bupivacaine according to the silu- ation of random grouping and were transfused 5mL normal saline at the rate of 0. 5mL/s after implantation of catheter in the epi- dural space. Induction success was identified when bilateral pain vanishing level reached T6 and sensory block Hollmen grade of at least 2. Induction success and operation without any additional local anesthetic drugs in epidural space were identified as operation success. Logistic regression analysis was used to measure the EDs0 value of bupivacaine. Results The ED50 values of cases with induction success was 8. 961mg（95% CI：8. 083 -9. 839）, and the values of ED 50 was 9.351 mg（95 % CI：8.915 9. 787 ）in cases with operation success. With the increase in the amount of intrathecal bupivacaine, time for the level of anesthesia rising to T6 segment decreased （P 〈 0. 05 ）, and cases with induction success or operation success in each group increased. Differences of groups in maximum blood pressure drop percentage, phenylephrine dosage and nausea and vomiting were not statistically signifi- cant. Conclusion The ED50 value of intrathecal isobaric bubivacaine with epidural capacity expansion by 5mL normal saline in cesarean section in cases with induction success was 8. 961mg, and the ED 50 value in cases with operation success was 9.351 mg.