Maternal hypotension & epidural anesthesia for C-section

孕妇在区域麻醉期间的中心血流动力学数据缺乏。本研究的目的是确定1)心率（HR）、脑卒中量（SV）、全身血管阻力（SVR）和静脉输液对硬膜外麻醉后产妇低血压的影响，以及2)这些变量在剖宫产过程中的模式。尽管有预防措施，剖宫产术中区域麻醉期间低血压是常见的。产妇低血压对胎儿氧合有危险，引起产妇恶心和呕吐，严重时对产妇有危险。静脉输液是预防低血压最常用的方法，但目前还没有找到最佳的输液量，因此低血压的发生率差别很大。单独服用液体最多能减少38%的低血压发生率。一个潜在的实践假设是，区域麻醉导致化学交感神经切除术，通过减少静脉回流而引起低血压，而不是明显地广泛减少。单独服用液体最多能减少38%的低血压发生率。一个潜在的实践假设是，区域麻醉导致化学交感神经切除术，通过减少静脉回流导致低血压，并没有显著降低SVR。这一观点是基于非怀孕者SVR平均降低15%（范围高达40%）。但有证据表明，在区域麻醉中，孕妇的SVR比非孕妇降低得更多。如果SVR降低到一定程度，单靠输液不足以增加心输出量以预防低血压。在这种情况下，处理SVR应该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的模式有重大影响，这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，同时提高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.