背景:仰卧位与死产有关,可能继发于下腔静脉压迫,心输出量(CO)和子宫胎盘灌注减少。怀孕期间俯卧位影响的证据尚不清楚。本研究旨在确定产妇俯卧位对产妇血流动力学和胎儿心率的影响。与左侧位置相比。
方法:21名妊娠28周的妇女每5分钟接受非侵入性CO监测(猎豹),并在左外侧(20分钟)进行连续胎心率监测(MONICA),俯卧(30分钟),其次是左外侧(20分钟)。通过问卷调查评估焦虑和舒适度。回归分析(根据时间调整)比较了不同位置之间的变量。从初步研究中得出的信息用于现有的孕妇循环数学模型中,以确定下腔静脉阻塞是否可以解释观察到的影响。此外,进行范围审查以确定报告的临床,孕妇俯卧位的血流动力学和胎儿影响;如果研究报告了临床结局或影响或孕妇在怀孕期间俯卧位,则纳入研究。研究记录按出版物类型分组,以便于数据综合和批判性分析。在有足够研究的地方进行荟萃分析。
结果:俯卧位产妇血压(BP)和总血管阻力(TVR)升高(sBP109vs104mmHg,p=0.03;dBP74vs.67mmHg,p=0.003;TVR1302对1075达因。s-1cm-5,p=0.03)。俯卧位中的CO减少(5.7对7.1mL/分钟,p=0.003)。胎儿心率,变异性和减速率没有改变。然而,俯卧位的胎儿加速度较少(86%vs95%,p=0.03)。手术后焦虑减轻,与之前相比(p=0.002),尽管舒适度略有下降(p=0.04)。该模型预测,如果下腔静脉闭塞发生,sBP,DBP和CO通常会降低。然而,TVR保持相对一致,这意味着当闭塞发生时,MAP和CO以相似的速率降低。范围审查发现,来自47名孕妇和胎儿的结局包括妊娠期间俯卧位的病例报告,总体上是有利的。三项调查俯卧位对母体血流动力学影响的前瞻性研究的荟萃分析发现sBP和母体心率增加,但对呼吸频率没有影响,氧饱和度或基线胎儿心率(尽管研究之间存在显著异质性).
结论:俯卧位与CO降低相关,但对胎儿健康的影响不确定。CO的下降可能是由于腔内压缩,由计算模型支持。需要进一步的工作来优化怀孕中俯卧位的安全性。
背景:该试验已在clinicaltrials.gov(NCT04586283)注册。
Supine sleep position is associated with stillbirth, likely secondary to inferior vena cava compression, and a reduction in cardiac output (CO) and uteroplacental perfusion. Evidence for the effects of prone position in pregnancy is less clear. This study aimed to determine the effect maternal prone position on maternal haemodynamics and fetal heart rate, compared with left lateral position.
Twenty-one women >28 weeks\' gestation underwent non-invasive CO monitoring (Cheetah) every 5 minutes and continuous fetal heart rate monitoring (MONICA) in left lateral (20 minutes), prone (30 minutes), followed by left lateral (20 minutes). Anxiety and comfort were assessed by questionnaires. Regression analyses (adjusted for time) compared variables between positions. The information derived from the primary study was used in an existing mathematical model of maternal circulation in pregnancy, to determine whether occlusion of the inferior vena cava could account for the observed effects. In addition, a scoping
review was performed to identify reported clinical, haemodynamic and fetal effects of maternal prone position; studies were included if they reported clinical outcomes or effects or maternal prone position in pregnancy. Study records were grouped by publication type for ease of data synthesis and critical analysis. Meta-analysis was performed where there were sufficient studies.
Maternal blood pressure (BP) and total vascular resistance (TVR) were increased in prone (sBP 109 vs 104 mmHg, p = 0.03; dBP 74 vs 67 mmHg, p = 0.003; TVR 1302 vs 1075 dyne.s-1cm-5, p = 0.03). CO was reduced in prone (5.7 vs 7.1 mL/minute, p = 0.003). Fetal heart rate, variability and decelerations were unaltered. However, fetal accelerations were less common in prone position (86% vs 95%, p = 0.03). Anxiety was reduced after the procedure, compared to beforehand (p = 0.002), despite a marginal decline in comfort (p = 0.04).The model predicted that if occlusion of the inferior vena cava occurred, the sBP, dBP and CO would generally decrease. However, the TVR remained relatively consistent, which implies that the MAP and CO decrease at a similar rate when occlusion occurs. The scoping
review found that maternal and fetal outcomes from 47 included case reports of prone positioning during pregnancy were generally favourable. Meta-analysis of three prospective studies investigating maternal haemodynamic effects of prone position found an increase in sBP and maternal heart rate, but no effect on respiratory rate, oxygen saturation or baseline fetal heart rate (though there was significant heterogeneity between studies).
Prone position was associated with a reduction in CO but an uncertain effect on fetal wellbeing. The decline in CO may be due to caval compression, as supported by the computational model. Further work is needed to optimise the safety of prone positioning in pregnancy.
This trial was registered at clinicaltrials.gov (NCT04586283).