Department of Anaesthesia and Intensive Care, The Chinese University of Hong Kong, Prince of Wales Hospital, Shatin, Hong Kong, China.
Curr Opin Anaesthesiol. 2010 Jun;23(3):304-9. doi: 10.1097/ACO.0b013e328337ffc6.
Hypotension during regional anaesthesia for caesarean section remains a common clinical problem, particularly for spinal anaesthesia. The purpose of this review is to evaluate recent research in this area with a focus on English language papers from the past 1-2 years.
Risk factors for hypotension include increased sympathetic tone, increasing age, obesity, higher blocks and higher birthweight, but not multiple gestation. Methods aimed at countering effects of aortocaval compression do not reliably prevent hypotension. Intravenous crystalloid prehydration has poor efficacy, and focus has changed toward cohydration and use of colloids. Phenylephrine is established as a first-line vasopressor, although there are limited data from high-risk patients. Initial phenylephrine bolus dose requirement may be surprisingly large. Phenylephrine infusions can be conveniently titrated to maintain blood pressure and prevent maternal symptoms. Ephedrine crosses the placenta more than phenylephrine and direct fetal effects of ephedrine may explain associated depression of fetal pH and base excess.
Recent research supports decreased use of crystalloid prehydration and ephedrine and increased use of cohydration, colloids, smaller spinal doses and phenylephrine. Further research is required to investigate these techniques in high-risk patients and to evaluate novel monitoring techniques.
剖宫产时的区域麻醉低血压仍然是一个常见的临床问题，尤其是在脊髓麻醉时。本综述的目的是评估该领域的最新研究，重点关注过去 1-2 年的英文文献。
低血压的危险因素包括交感神经张力增加、年龄增长、肥胖、阻滞平面升高和出生体重升高，但多胎妊娠不是危险因素。旨在对抗腔静脉受压影响的方法并不能可靠地预防低血压。静脉晶体预补液效果不佳，关注焦点已转向联合补液和使用胶体。去氧肾上腺素已被确立为一线血管加压药，尽管高危患者的数据有限。去氧肾上腺素初始推注剂量的需求可能大得惊人。去氧肾上腺素输注可方便地滴定以维持血压并预防产妇症状。麻黄碱比去氧肾上腺素更能通过胎盘，麻黄碱对胎儿的直接作用可能解释了其与胎儿 pH 值和碱剩余降低相关。
最近的研究支持减少晶体预补液和使用麻黄碱，增加联合补液、胶体、较小剂量的脊髓麻醉药物和去氧肾上腺素的使用。需要进一步研究以评估高危患者中这些技术，并评估新的监测技术。
