昂丹司琼减少腰麻剖宫产术中低⾎压发⽣的最⼩有效剂量：随机对 照优势试验
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Minimal effective weight-based dosing of ondansetron to reduce hypotension in cesarean section under spinal anesthesia: a randomized controlled superiority trial
背景与目的
腰麻后可发⽣Bezold–Jarisch反射，引起⾎管扩张和静脉回流减少，导致⼼动过缓和低⾎压。已知影响Bezold–Jarisch反射的因素之⼀是5-羟⾊胺。昂丹司琼是⼀种5-羟⾊胺受体阻断剂，通过阻断5-羟⾊胺的作⽤抑制静脉扩张。有研究发现，腰麻前给予⼀定剂量的昂丹司琼可减少术中低⾎压发⽣，但所有这些研究都使⽤了固定剂量的昂丹司琼，尚⽆报道昂丹司琼按体重给药可减少低⾎压发⽣。本研究旨在确定昂丹司琼根据患者体重给药以减少腰麻剖宫产术中低⾎压发⽣的最佳剂量。
方 法
本研究为前瞻、三盲、平⾏、随机对照试验。228例产妇腰麻前5min随机静脉注射⽣理盐⽔（NS组）、 0.05 mg/kg 昂丹司琼（O1组）或0.1 mg/kg 昂丹司琼（O2组）。⽐较三组间低⾎压发⽣率、平均动脉⾎压、⼼率、⾎管升压素使⽤量和失⾎量，并评估产妇和新⽣⼉并发症。采⽤⼴义估计⽅程法⽐较⾎压和⼼率的变化。
结 果
13例患者因未进⾏⼲预（n=12）和违反试验⽅案（n=1）被排除。215例患者进⾏意向性治疗分析。NS组（n = 72）、O1组（n=71）和O2组（n=72）的低⾎压发⽣率分别为81.9%、84.5%和73.6%（P=0.23）。O1组产前低⾎压发作次数（腰麻后前14min）显著⾼于NS组（5 vs 2, P = 0.02）。三组患者整个⼿术过程中的总体⼼率⽆差异。三组患者的麻⻩碱使⽤量和失⾎量相似。O2组胃复安使⽤量显著低于NS组（2.8% vs 16.7%, P = 0.01）。产妇或新⽣⼉⽆严重不良反应发⽣。
结 论
本研究中，腰麻前静脉注射昂丹司琼0.05 mg/kg或0.1 mg/kg 并不能减少低⾎压的发⽣率。
原始文献摘要
Oof uvong M,Kunapaisal T,Karnjanawanichkul O,et
al.Minimal effective weight-based dosing of ondansetron to reduce hypotension in cesarean section under spinal anesthesia: a randomized controlled superiority trial[J].BMC Anesthesiology,2018,18(1):105-114.
Background: The weight-based dosing of ondansetron to reduce hypotension has never been investigated. The aim of this study is to determine the optimal dose of ondansetron required based on the patient's weight to reduce hypotension f ollowing spinal anesthesia for cesarean section.
Methods: In this prospective, triple-blinded, parallel group,
randomized controlled trial, a total of 228 pregnant women were randomized to receive either normal saline (group NS) or ondansetron 0.05 mg/kg (group O1) or ondansetron 0.1 mg/kg (group O2) intravenously 5 min bef ore induction of spinal anesthesia. The incidence of hypotension, mean arterial pressure, heart rate, vasopressor requirements, and blood loss between the three groups were compared.Maternal and neonatal complications were also assessed. Changes in blood pressure and heart rate were compared using the generalized estimating equations method.
Results: Thirteen patients were excluded f rom the analysis because of no intervention (n = 12) and protocol violation (n = 1). Two hundred and fif teen patients remained f or the intention-to-treat analysis. The incidence of hypotension in groups NS (n = 72), O1 (n = 71), and O2 (n = 72) were 81.9%, 84.5%, and 73.6%, respectively (P = 0.23). The episodes of hypotension bef ore delivery (first 14 min af ter spinal
anesthesia) were significantly higher in group O1 compared to NS (5 vs 2, P = 0.02). The overall heart rates throughout the operations were not diff erent among the three groups. The ephedrine requirements and amount of blood loss were also similar among the three groups. The metoclopramide requirement was significantly lower in group O2 compared to group NS (2.8% vs 16.7%, P = 0.01).There were no serious adverse events in terms of maternal or neonatal complications.
Conclusions: Ondansetron 0.05 mg/kg or 0.1 mg/kg administered before spinal anesthesia did not reduce the incidence of hypotension in this study.
麻醉学文献进展分享
贵州医科大学高鸿教授课题组
编辑：李华宇 审校：代东君