Heesen M, Rijs K, Hilber N, Ngan Kee W D, Rossaint R, van der Marel C, Klimek M
Department of Anaesthesia, Kantonsspital Baden, Baden, Switzerland.
Department of Anaesthesiology, Erasmus University Medical Centre, Rotterdam, The Netherlands.
Int J Obstet Anesth. 2019 Feb;37:16-28. doi: 10.1016/j.ijoa.2018.10.006. Epub 2018 Oct 19.
Phenylephrine is the preferred vasopressor for the prevention and treatment of spinal anaesthesia-induced hypotension during caesarean section, because studies on low-risk elective patients found it to have a less detrimental effect on umbilical artery pH compared with ephedrine. However, limited data exist from high-risk parturients and parturients with uteroplacental insufficiency.
We systematically searched for randomised, controlled, double-blinded trials of these two vasopressors in high-risk caesarean sections. We applied conventional meta-analysis, trial sequential analysis, computing the required information size that would exclude type I and II errors, contour-enhanced funnel plot testing for publication bias, meta-regression to assess the dose-response relationship, and the Grading of Recommendations Assessment, Development, and Evaluation system (GRADE). The incidence of fetal acidosis (umbilical arterial pH <7.2) was the primary outcome.
Eight trials (712 patients) with low risk of bias were identified. Pooling six studies of patients with preeclampsia and other reasons for fetal compromise, as well as subgroup analysis of the preeclampsia studies, revealed no significant differences in the incidence of fetal acidosis. Trial sequential analysis showed that the required information size was not reached. The funnel plot was not suggestive of publication bias. Meta-regression showed no dose-response relationship. The GRADE score was moderate quality.
Despite several studies and a large number of patients there was insufficient evidence to make a recommendation for choice of vasopressor in high-risk caesarean section. Trials with adequate power to detect differences in the incidence of fetal acidosis between ephedrine and phenylephrine are required to provide evidence-based guidance.
去氧肾上腺素是剖宫产术中预防和治疗腰麻引起的低血压的首选血管升压药，因为对低风险择期手术患者的研究发现，与麻黄碱相比，它对脐动脉pH值的不利影响较小。然而，关于高危产妇和合并子宫胎盘功能不全的产妇的数据有限。
我们系统检索了这两种血管升压药在高危剖宫产术中的随机对照双盲试验。我们应用传统的荟萃分析、试验序贯分析，计算排除I型和II型错误所需的信息量，用等高线增强漏斗图检验发表偏倚，用荟萃回归评估剂量反应关系，以及推荐分级评估、发展和评价系统（GRADE）。胎儿酸中毒（脐动脉pH值<7.2）的发生率是主要结局。
确定了8项偏倚风险较低的试验（712例患者）。汇总6项关于子痫前期和其他胎儿窘迫原因患者的研究，以及对子痫前期研究的亚组分析，结果显示胎儿酸中毒发生率无显著差异。试验序贯分析表明未达到所需的信息量。漏斗图未提示存在发表偏倚。荟萃回归未显示剂量反应关系。GRADE评分为中等质量。
尽管有多项研究且纳入了大量患者，但仍缺乏足够的证据来推荐高危剖宫产术中血管升压药的选择。需要有足够效力来检测麻黄碱和去氧肾上腺素之间胎儿酸中毒发生率差异的试验，以提供循证指导。
