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

本实验对体外循环中山羊胎儿体外循环的操作系统进行了研究，采用膜式氧合器建立体外循环。体外循环采用两种方法，一种是经脐血管的动静脉转流法，另一种是新生儿体外循环术中普遍采用的经颈部血管的动静脉转流法。技术改进包括在电路中插入分流器和血液过滤器，并采用流量自动调节系统，延长了存活期。最长存活时间为34小时。在房室转流术中，心血管动力学非常不稳定，特别是在灌流开始时。在早期病例中，由于心血管抑制，一些发热在开始灌流后不久以猝死告终。随着技术的改进，如宫内插管，使用薄壁导管，缓解了A-V旁路灌注引起的心血管改变，延长了存活时间。V-A旁路方法不是对胎儿进行生理性灌流，心血管动力学从灌流开始就稳定，没有猝死。尸检时，两种方法和A-V旁路方法的动脉导管经常收缩，这一点在灌流过程中也得到了胎儿血管造影的证实。两种方法的存活时间没有显著差异。我们正在寻求通过脐血管的房室旁路方法，因为它代表了更多的生理性胎儿循环。然而，非常严格的控制是必要的，因为在这种方法下，心血管动力学非常不稳定，特别是在灌流开始时。到目前为止，我们不能维持胎儿的生命足够长的成熟，但在未来，它可能维持人工子宫(胎盘)的胎儿生命。

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).