Department of Anesthesia, Hangzhou City Linping District Maternal and Child Care Hospital, Hangzhou, China.
Department of Anesthesia, Jiaxing University Affiliated Women and Children Hospital, Jiaxing, China.
BMC Pregnancy Childbirth. 2023 Dec 6;23(1):840. doi: 10.1186/s12884-023-06165-5.
Prior studies have shown that, when administered as an intravenous bolus to prevent uterine atony, prophylactic phenylephrine infusion increased the dose requirement of oxytocin and second-line uterotonics. For the prevention of uterine atony, oxytocin should be delivered by continuous infusion. Here, we aimed to determine the ED50 and ED90 parameters (the effective doses for 50 and 90% patients without uterine atony) of oxytocin for co-infusion with prophylactic phenylephrine during cesarean delivery.
In this prospective randomized double-blinded dose-finding study, one hundred patients were divided into four groups to receive 2.5, 5.0, 7.5, or 10 IU/h oxytocin infusion, after the umbilical cord was clamped during the study period. The uterine tone was evaluated and defined as either adequate or inadequate. Probit regression analysis was applied to calculate the ED50 and ED90 of oxytocin infusion. Uterine tone, the percentage of patients who needed additional oxytocin bolus, second-line uterotonics, side effects, estimated blood loss, and neonatal outcomes were monitored.
The estimated ED50 and ED90 values of the oxytocin infusion doses for the prevention of uterine atony were 1.9 IU/h (95% CI -4.6-3.8) IU/h and 9.3 IU/h (95% CI 7.3-16.2) IU/h, respectively. Across groups, there was a significant linear trend between the infusion dose and the percentage of patients who required additional oxytocin (p-value = 0.002). No differences were observed in the incidence of side effects and neonatal outcomes.
Under the conditions of this study, the ED90 of oxytocin infusion for the prevention of uterine atony was 9.3 IU/h, which is higher than the current recommendation. This finding is helpful for clinical practice, because of the routine use of phenylephrine in cesarean delivery. Further studies are needed to determine the appropriate initial bolus of oxytocin after neonatal delivery.
The study was registered on the Chinese Clinical Trial Register (register no. ChiCTR2200059556 ).
先前的研究表明，在静脉推注以预防子宫收缩乏力时，预防性苯肾上腺素输注会增加催产素和二线子宫收缩剂的剂量需求。对于预防子宫收缩乏力，应通过连续输注催产素。在这里，我们旨在确定在剖宫产期间与预防性苯肾上腺素联合使用时催产素的 ED50 和 ED90 参数（无子宫收缩乏力的 50%和 90%患者的有效剂量）。
在这项前瞻性随机双盲剂量探索研究中，在研究期间脐带夹闭后，将 100 名患者分为四组，分别接受 2.5、5.0、7.5 或 10 IU/h 催产素输注。评估子宫张力并定义为适当或不适当。应用概率回归分析计算催产素输注的 ED50 和 ED90。监测子宫张力、需要额外催产素推注的患者百分比、二线子宫收缩剂、副作用、估计失血量和新生儿结局。
预防子宫收缩乏力的催产素输注剂量的估计 ED50 和 ED90 值分别为 1.9 IU/h（95%CI -4.6-3.8）IU/h 和 9.3 IU/h（95%CI 7.3-16.2）IU/h。在各组之间，输注剂量与需要额外催产素的患者百分比之间存在显著的线性趋势（p 值=0.002）。副作用和新生儿结局的发生率无差异。
在本研究条件下，预防子宫收缩乏力的催产素输注 ED90 为 9.3 IU/h，高于目前的推荐值。这一发现有助于临床实践，因为苯肾上腺素在剖宫产中常规使用。需要进一步的研究来确定新生儿分娩后催产素的适当初始推注量。
该研究在中国临床试验注册中心（注册号 ChiCTR2200059556）注册。
