Maternal hypotension & epidural anesthesia for C-section

关于孕妇在区域麻醉期间的中心血流动力学的数据缺乏。本研究的目的是探讨硬膜外麻醉后心率(HR)、每搏输出量(SV)、全身血管阻力(SVR)和静脉输液对产妇低血压的影响，以及这些变量在整个剖宫产手术中的变化规律。尽管采取了预防措施，但剖宫产区域麻醉期间低血压是很常见的。产妇低血压对胎儿氧合有危险，会引起产妇恶心和呕吐，极端情况下还会对产妇造成危险。静脉输液最常用于预防低血压，但还没有找到最佳的输液量，低血压的发生率差异很大。仅靠液体充其量可以降低38%的低血压发生率。一个基本的实践假设是，区域麻醉导致化学交感神经切除，通过减少静脉回流而导致低血压，而且不会广泛减少。仅靠液体充其量可以降低38%的低血压发生率。一个基本的实践假设是，区域麻醉会导致化学交感神经切除，通过减少静脉回流而导致低血压，而不会显著减少SVR。这一观点是基于非孕妇的SVR平均减少15%(范围高达40%)。但有证据表明，在区域麻醉期间，孕妇的SVR比未怀孕的妇女减少得更多。如果SVR充分降低，仅靠液体不足以增加心输出量以预防低血压。在这种情况下，处理SVR应能更好地预防低血压。确定哪些变量随着时间的推移对低血压模式有显著影响对于指导未来的干预研究是必要的。消除产妇低血压将降低胎儿低氧血症、产妇不适和产妇发病率的风险，同时改善产妇对分娩体验的享受。

Data on central hemodynamics of pregnant women during regional anesthesia is lacking. The purpose of this study is to determine the 1) influence of heart rate (HR), stroke volume (SV), systemic vascular resistance (SVR) and IV fluid administration on maternal hypotension after epidural anesthesia and 2) the pattern of these variables throughout C-section. Despite preventative measures, hypotension during regional anesthesia for cesarean section is common. Maternal hypotension poses a risk to fetal oxygenation, causes maternal nausea and vomiting, and poses maternal danger when extreme. Intravenous fluid is most often used to prevent hypotension, but an optimal volume of fluid has not been found and the incidence of hypotension varies widely. Fluid alone at best reduces the incidence of hypotension at 38%. An underlying practice assumption is that regional anesthesia, which results in a chemical sympathectomy, causes hypotension by reducing venous return and does not significantly reduce widely. Fluid alone at best reduces the incidence of hypotension at 38%. An underlying practice assumption is that regional anesthesia, which results in a chemical sympathectomy, causes hypotension by reducing venous return and does not significantly reduce SVR. This view is based on an average 15% (range up to 40%) reduction in SVR in non-pregnant persons. But there is evidence that SVR is reduced more in pregnant than non-pregnant women during regional anesthesia. If SVR is reduced sufficiently, fluid alone will not increase cardiac output enough to prevent hypotension. In this case, addressing SVR should result in superior prevention of hypotension. Determining which variables have a significant influence on the pattern of hypotension over time is necessary to direct future interventional studies. Elimination of maternal hypotension will reduce the risk of fetal hypoxemia, maternal discomfort, and maternal morbidity while improving maternal enjoyment of the birth experience.