Establishment of intra-water Management of Gaat Fetus. (Extracorporeal Circulation using Membrane Oxygenator)

本研究探讨了山羊离体胎儿在水中的操作系统，建立了膜式氧合器体外循环。一种是经脐血管行动静脉转流术，另一种是经宫颈血管行动静脉转流术，通过在管路中插入透析器和血液过滤器，采用自动调节系统，流速使存活时间延长。最长存活时间为34小时。在A-V转流方法中，心血管动力学非常不稳定，尤其是在灌注开始时。在早期病例中，一些fefuse在灌注开始后不久由于心血管抑制而突然死亡。随着宫内插管等技术的改进，使用薄壁导管，缓解了动静脉旁路灌注引起的心血管变化，存活时间稍长。在不是胎儿生理灌注的V-A旁路方法中，心血管动力学从灌注开始就稳定，没有猝死。尸检时，两种方法及A-V转流法均存在动脉导管狭窄，胎儿血管造影也证实了这一点，两种方法的存活时间无显著性差异。我们正在寻求通过脐血管的A-V旁路方法，因为它代表了更生理的胎儿循环。然而，非常严格的控制是必要的，因为用这种方法，心血管动力学是非常不稳定的，特别是在灌注开始时。目前，我们不能维持胎儿生命足够长的成熟，但在未来，它可能会维持胎儿的生命与人工子宫（胎盘）。

We have investigated the manipulating system of isolated goat fetuses in water, establishing extracorporeal circulation using membrane oxygenator.Extracorporeal circulation was performed by two methods as follows; one method was A-V bypass through umbilical vessels, and the other was V-A bypass through cervical vessels, which is popular in neonatal ECMO.Technical improvements such as insertion of dializer and blood filter into the circuit and adoption of autoregulation system of flow rate made the survival time longer. The longest survial time was 34 hours.In A-V bypass method,cardiovascular dynamics are very labile especially at the beginning of the perfusion. In early cases, some fefuses ended with sudden death shortly after perfusion started due to cardiovascular depression. With technical improvement such as in-utero canulation, using thin wall catheter, eased cardiovascular change due to A-V bypass perfusion, and survival length was a little longer by this modification.In V-A bypass method, which is not a physiological perfusion to fetuses, cardiovascular dynamics are stable from the beginning of the perfusion and there was no sudden death.At autopsy, ductus arteriosus often constricted in both methods and in A-V Bypass method this was also proved by fetal angiography during perfusion.There existed no significant difference in the survival time of the two methods. We are pursuing A-V bypass method through umbilical vessels because it represents more physiological fetal circulation. However, very strict control is necessary because with this methos cardiovascular dynamics is very labile especially at the beginning of perfusion.Hitherto, we cannot sustain fetal life long enough for maturation, but in future, it may be possible to sustain fetal life with artificial uterus(placenta).