Department of Anesthesia and Pain Management, Mount Sinai Hospital, University of Toronto, 600 University Avenue, Room 781, Toronto, ON, M5G 1X5, Canada.
Can J Anaesth. 2014 Mar;61(3):242-8. doi: 10.1007/s12630-013-0082-9. Epub 2013 Nov 27.
The purpose of this study was to determine the intravenous dose of carbetocin required to produce effective uterine contraction in 90% of females (ED90) undergoing elective Cesarean delivery (CD) under spinal anesthesia.
We conducted a double-blind dose-finding study of carbetocin. Forty females undergoing elective CD received carbetocin intravenously upon delivery of the fetus. The dose of carbetocin for each patient was determined according to a biased-coin up-and-down sequential allocation scheme designed to cluster doses close to ED90. The initial dose was 10 μg, with increments/decrements of 5 μg. The anesthesiologist, obstetrician, and patient were blinded to the dose. The obstetrician assessed the uterine tone at one-minute intervals for five minutes after carbetocin administration. In case of unsatisfactory tone, additional uterotonics were administered. The primary outcome was requirement for additional intraoperative uterotonics. Secondary outcomes were postoperative requirement for additional uterotonics within 24 hr of delivery, estimated blood loss and side effects.
The ED90 of carbetocin was 14.8 μg (95% confidence interval 13.7 to 15.8). Thirty-seven patients (92.5%) had adequate uterine tone with no requirement of additional intraoperative uterotonics. Two patients (5%) required postoperative uterotonics within 24 hr. The overall mean (SD) estimated blood loss was 786 (403) mL and the overall incidence of hypotension (decrease in systolic blood pressure ≥ 20% baseline) was 37.5%.
Based on our study, the ED90 of carbetocin at elective CD is less than one-fifth the currently recommended dose of 100 μg. This study was registered at clinicaltrials.gov (NCT-01651130).
本研究旨在确定在脊髓麻醉下接受择期剖宫产（CD）的女性中，使 90%的女性（ED90）产生有效子宫收缩所需的卡贝缩宫素静脉剂量。
我们进行了一项卡贝缩宫素的双盲剂量发现研究。40 名接受择期 CD 的女性在胎儿分娩后接受卡贝缩宫素静脉注射。根据旨在将剂量聚集在 ED90 附近的偏置硬币上下序贯分配方案，为每位患者确定卡贝缩宫素的剂量。初始剂量为 10μg，递增/递减 5μg。麻醉师、产科医生和患者均对剂量不知情。产科医生在给予卡贝缩宫素后 1 分钟间隔评估子宫张力 5 分钟。如果子宫张力不理想，则给予额外的子宫收缩剂。主要结局是需要额外的术中子宫收缩剂。次要结局是产后 24 小时内需要额外的子宫收缩剂、估计失血量和副作用。
卡贝缩宫素的 ED90 为 14.8μg（95%置信区间 13.7 至 15.8）。37 名患者（92.5%）子宫张力良好，无需额外的术中子宫收缩剂。2 名患者（5%）在产后 24 小时内需要额外的子宫收缩剂。总平均（SD）估计失血量为 786（403）mL，总体低血压发生率（收缩压下降≥基线的 20%）为 37.5%。
根据我们的研究，择期 CD 时卡贝缩宫素的 ED90 不到目前推荐剂量 100μg 的五分之一。本研究在 clinicaltrials.gov 注册（NCT-01651130）。
