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

我们研究了山羊离体胎儿在水中的操纵系统，利用膜氧合器建立体外循环。体外循环采用以下两种方法；一种是经脐血管A-V分流术，另一种是经颈血管V-A分流术，在新生儿ECMO中比较流行。在回路中插入透析器和血液过滤器，采用流量自动调节系统等技术改进，延长了存活时间。最长存活时间为34小时。在A-V旁路方法中，心血管动力学非常不稳定，特别是在灌注开始时。在早期病例中，一些胎儿在灌注开始后不久因心血管抑制而猝死。随着宫内插管等技术的改进，使用薄壁导管，缓解了a - v旁路灌注引起的心血管变化，并使生存时间稍长。V-A旁路法不是对胎儿的生理性灌注，从灌注开始心血管动力学稳定，没有发生猝死。尸检时，两种方法和A-V旁路法的动脉导管经常收缩，灌注时的胎儿血管造影也证实了这一点。两种方法的存活时间差异无统计学意义。我们正在寻求通过脐带血管的A-V旁路方法，因为它更能代表胎儿的生理循环。然而，非常严格的控制是必要的，因为这种方法的心血管动力学非常不稳定，特别是在灌注开始时。到目前为止，我们还不能维持胎儿足够长的生命到成熟，但在未来，有可能通过人工子宫（胎盘）来维持胎儿的生命。

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).