评估S1运动阻滞以确定用于硬膜外镇痛的安全、可靠的试验剂量。

Evaluation of S1 motor block to determine a safe, reliable test dose for epidural analgesia.

作者信息

Daoud Z, Collis R E, Ateleanu B, Mapleson W W

机构信息

Anaesthetic Department, Memorial Hospital, Darlington DL3 6HX, UK.

出版信息

Br J Anaesth. 2002 Sep;89(3):442-5.

PMID:12402723

Abstract

BACKGROUND

Accidental intrathecal injection of bupivacaine during epidural analgesia in labour remains a hazard, with the potential to cause total spinal anaesthesia and maternal collapse. Sacral block appears early after intrathecal injections compared with epidural ones, and we therefore used SI motor block to determine a safe and reliable test dose for epidural catheter misplacement.

METHODS

Mothers booked for elective Caesarean section were given various intrathecal doses of bupivacaine with fentanyl during routine combined spinal-epidural anaesthesia.

RESULTS

Using sequential allocation we found that the ED50 for SI motor block 10 min after intrathecal injection was bupivacaine 7 mg with fentanyl 14 micrograms (95% CI, 6.2-7.8 mg). We then used intrathecal bupivacaine 13 mg to look for the ED95. We found the calculated ED97.5 to be bupivacaine 9.7 mg with fentanyl 19.4 micrograms (95% CI, 8.7-11.4).

CONCLUSION

We conclude that testing for SI motor block 10 min after epidural injection of bupivacaine 10 mg is a reliable test to detect accidental intrathecal injection in the obstetric population.

摘要

背景

分娩时硬膜外镇痛期间意外鞘内注射布比卡因仍然是一种风险，有可能导致全脊髓麻醉和产妇虚脱。与硬膜外注射相比，鞘内注射后骶部阻滞出现得更早，因此我们使用骶部运动阻滞来确定硬膜外导管误置的安全可靠试验剂量。

方法

计划行择期剖宫产的产妇在常规腰麻-硬膜外联合麻醉期间接受不同鞘内剂量的布比卡因加芬太尼。

结果

采用序贯分配法，我们发现鞘内注射后10分钟产生骶部运动阻滞的半数有效剂量（ED50）为布比卡因7mg加芬太尼14μg（95%可信区间，6.2 - 7.8mg）。然后我们使用13mg鞘内布比卡因来寻找95%有效剂量（ED95）。我们发现计算得出的97.5%有效剂量（ED97.5）为布比卡因9.7mg加芬太尼19.4μg（95%可信区间，8.7 - 11.4）。