静脉推注去氧肾上腺素预防剖宫产腰硬联合麻醉后低血压90%有效剂量及其对母婴影响

Determination of 90%effective dose prophylactic bolus dose of phenylephrine to prevent hypotension during cesarean delivery under combined spinal and epidural anesthesia and effects on mothers and infants

目的通过序贯分析法确定剖宫产腰硬联合麻醉后静脉推注去氧肾上腺素使90%产妇不发生低血压的剂量。方法根据Biased Coin up‑down序贯法依次对40例择期行剖宫产的产妇进行前瞻性双盲序贯研究。蛛网膜下腔注射0.75%罗哌卡因10.5 mg和芬太尼10µg复合硬膜外注射2%利多卡因5 ml后,观察产妇对不同去氧肾上腺素剂量的反应。主要观察指标为胎儿娩出前维持产妇SBP不低于基础值80%所使用去氧肾上腺素的剂量。次要观察指标包括头晕、胸闷、恶心、呕吐、心动过缓、补救性使用去氧肾上腺素、追加阿托品、继发性高血压的发生情况、去氧肾上腺素总量、最高麻醉阻滞平面、脐带动脉和静脉血血气分析、新生儿1 min Apgar评分、新生儿5 min Apgar评分。应用Isotonic回归分析估计90%有效剂量(90%effective dose,ED90)及其95%CI。结果腰硬联合麻醉后静脉预推注去氧肾上腺素预防产妇低血压的ED90剂量为116.5µg(95%CI 114.44~135.33µg)。产妇的低血压发生率为15%,其他低血压相关不良反应发生率也很低。新生儿的脐静脉和脐动脉血气分析结果无明显异常,新生儿1 min、5 min Apgar评分均为10(10,10)分。结论静脉单次预推注去氧肾上腺素120µg能有效预防腰硬联合麻醉后产妇低血压的发生,新生儿结局良好。

Objective To determine the dose of phenylephrine through intravenous bolus to prevent hypotension in 90%of pregnant women during cesarean delivery under combined spinal and epidural anesthesia by the sequential analysis method.Methods This was a prospective,double‑blinded,and sequential study.A total of 40 pregnant women who were scheduled for cesarean delivery were enrolled and the Biased Coin up‑down method was used.The women were injected into the subarachnoid space with 0.75%of ropivacaine(10.5 mg)and fentanyl(10µg),in addition to epidural injection of 2%lidocaine(5 ml).The effects of different doses of phenylephrine on the women were observed.The primary outcome was the dose of phenylephrine to maintain the systolic blood pressure(SBP)above 80%of the baseline before delivery.The secondary outcomes included dizziness,breathlessness,nausea,vomiting,bradycardia,rescue use of atropine and phenylephrine,secondary hypertension,the total dose of phenylephrine,the highest plane of sensory nerve block,the results of umbilical arterial and venous blood gas analysis,and 1‑min and 5‑min Apgar scores.The 90%effective dose(ED90)and 95%confidence intervals(CI)were estimated using the isotonic regression methods.Results The ED90 of phenylephrine through intravenous bolus to prevent hypotension in pregnant women under combined spinal and epidural anesthesia was 116.5µg(95%CI 114.44‒135.33µg).The incidence of maternal hypotension was 15%,with low incidences of hypotension related adverse reactions.The data about blood gas analysis of the neonatal umbilical vein and artery were normal,while 1 min and 5 min Apgar scores were both 10(10,10).Conclusions A single intravenous bolus of phenylephrine at 120µg can effectively prevent hypotension after combined spinal and epidural anesthesia,with good neonatal outcomes.