Analysis of factors affecting placental transfer of anesthetic drugs and umbilical circulation with the delivered human-placenta perfusion model.

人胎盘灌注研究之所以没有完成，主要有两个原因：(1)可用的胎盘数量较少；(2)其有效性太短，无法完成预定的方案。虽然我们将通过改进我们的方法继续进行胎盘模型研究，但我们在项目期间得出了以下两个发现。各种麻醉剂在几种胎盘灌注液中的溶解度。挥发性麻醉剂在血浆代用品、白蛋白溶液、脂肪乳剂、全氟化学乳剂（FC-43）和水溶液中的溶解度（液/气分配系数；lambda）。在除FC-43外的所有溶液中，λ值的数量级为氟烷>安氟烷>异氟烷>七氟烷，而四种麻醉剂的λ值几乎相同，均为5.5。建立了顶空进样法测定异丙酚的方法。剖宫产过程中胎盘氧向胎儿输送的改善。(1)剖宫产术前采用100%吸氧七氟醚麻醉，可改善胎儿供氧，无严重胎儿抑郁、子宫舒张时间延长、出血量增加。(2)脊髓麻醉前给予5%麦芽糖醋酸化林格液可增加胎儿氧合，增加母婴血红蛋白解离曲线P50的差异（预防胎儿酸中毒）。

The human-placenta perfusion study has not been completed because of two reasons : (1)only a small number of placenta were available, (2)its valiability was too short to finish the secheduled protocol. Although we will continue to do this placental model study by improving our methodology, the following two findings were driven out in our project term.1. The solubilities of various anesthetic agents into several placental perfusion solutions.The solubilities (liquid/gas partition coefficient ; lambda) of volatile anesthetics in plasma substitutes, albumin solution, fat emulsions, perfluorochemical emulsion (FC-43), and aqueous solutions. The order of magnititude of lambda value was halothane>enflurane>isoflurane>sevoflurane in all solutions except FC-43, while lambda values in four anesthetics were almost the same at 5.5. The determination method for propofol was established by using head space sampling.2. The improvement of placental oxygen transfer to the fetus during cesarean delivery.(1)Use of sevoflurane anesthesia with 100% oxygen before cesarean section was proved to improve oxygen delivery to fetus without severe fetal depression, prolonged uterine relaxation and increased blood loss.(2)5% maltose-acetated Ringer solution prior to spinal anesthesia was proved to increase fetal oxygenation with increasing the difference of P50 in hemoglobin dissociation curve between mother and baby (prevention of fetal acidosis).