剖宫产术中持续输注去氧肾上腺素预防腰硬联合麻醉引起的低血压量效关系

Dose-effect relationship of continuous infusion of phenylephrine during cesarean section to prevent hypotension of women caused by combined spinal-epidural anesthesia

目的:探讨剖宫产术中持续输注去氧肾上腺素预防腰硬联合麻醉引起低血压的效果,并分析其量效关系。方法:选取2018年10月-2021年2月在本院择期行剖宫产手术的足月孕妇150例,随机数表法分为6组各25例;均在蛛网膜下腔注射10 mg比重布比卡因及5μg舒芬太尼麻醉,随后对6组分别静脉输注去氧肾上腺素2μg、4μg、6μg、8μg、10μg、12μg,并分别记为PE2组、PE4组、PE6组、PE8组、PE10组、PE12组,均用生理盐水稀释至5 ml,胎儿娩出时停止输注。在麻醉期间持续观察、记录产妇心率、血压、产妇不良反应及胎儿脐动脉血气分析结果,孕妇收缩压恢复至基础值及以上则视为治疗低血压有效,采用logistic回归分析绘制量效关系曲线,并计算半数有效剂量(ED50)、95%有效剂量(ED_(95)),记录产妇在手术期间第一次低血压时间,低血压治疗情况及术后并发症。结果:6组基础收缩压、首次低血压发生时间、手术时间、术毕尿量、住院时间比较无差异(P>0.05);6组心动过缓、恶心呕吐、寒战发生率比较无著差异(P>0.05),但6组预防低血压有效率随着去氧肾上腺素给药剂量的增加而升高(P<0.05);分析发现,去氧肾上腺素预防腰硬联合麻醉引起低血压ED_(50)(95%CI)为6.3μg(5.0~7.5μg),ED_(95)(95%CI)为12.3μg(10.1~13.7μg);6组胎盘剥离时HR、SBP、CI、SVI、SVV均高于麻醉前、胎儿娩出前、术毕时(P<0.05),但6组间各指标比较无差异;6组新生儿1minApgar评分、5minApgar评分、碱剩余(BE)、乳酸、PH值比较无差异(P>0.05)。结论:去氧肾上腺素在剖宫产中预防腰麻引起低血压的ED50、ED_(95)分别为6.3μg、12.3μg。

Objective:To investigate the effect of continuous infusion of phenylephrine to prevent hypotension of women during cesarean section caused by combined spinal-epidural anesthesia,and to analyze its dose-effect relationship.Methods:A total of 150 pregnant women with full-term who underwent elective cesarean section in hospital were se-lected as the research subjects between October 2018 and February 2021.These women were divided into 6 groups(25 cases in each group)by random number table method.All women had received intrathecal injection of 10mg specific gravity of bupivacaine and 5μg of sufentanil for anesthesia.Then,the women in the group A,in group B,in group C,in group D,in group E,and in group F were given intravenous infusion of 2μg,4μg,6μg,8μg,10μg,and 12μg of phenylephrine diluted with normal saline to 5ml,respectively.The infusion of the women in the six groups was stopped at the delivery of baby.The heart rate,the blood pressure value,the maternal adverse reactions rate,and the results of fetal umbilical artery blood gas analysis of the women in the six groups were observed and recorded during anesthesia.The systolic blood pressure value of the women returning to the basic value and above was considered effec-tive treatment of hypotension.Logistic regression analysis was performed to help draw the dose-effect relationship curve.The median effective dose(ED_(50))and 95%effective dose(ED_(95))were calculated.The first occurrence time ofhypotension during the operation,the treatment of hypotension,and the postoperative complications situations of thewomen in the six groups were recorded.Results:There were no significant differences in the basal systolic blood pres-sure value,the time of first hypotension occurrence,the operation time,the urine volume after operation,and the timeof hospital stay of the women among the six groups(P>0.05).There were no significant differences in the incidencesof bradycardia,nausea and vomiting,and chills of the women among the six groups(P>0.05),but the effective rateof preventing hypotension of the women in group A,in group B,in group C,in group D,in group E,and in group Fhad increased gradually(P<0.05).The analysis showed that the values of EDso(95%CI)and EDs(95%CI)of pheny-lephrine for preventing hypotension of the women caused by the combined epidural during anesthesia were 6.3μg(5.0-7.5μg)and 12.3μg(10.1-13.7μg),respectively.The value of HR,SBP,CI,SVI,or SVV of the women in the sixgroups when the placental separation was significantly higher than those before anesthesia,before delivery,or at theend of operation(P<0.05),but which of the women had no significant differences among the six groups.There wereno significant differences in the lmin Apgar score and 5min Apgar score of the newborns,and the values of buffuer ex-cess(BE),lactic acid,and PH of the women among the six groups(P>0.05).Conclusion:The values of EDso(95%CI)and EDes(95%CI)of phenylephrine for preventing hypotension of the women caused by the combined epidural dur-ing anesthesia are 6.3μg and 12.3μg.