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Study for the development of physiological function in extremely immature fetus by using extrauterine fetal incubation system

宫外胎儿孵化系统对极幼胎儿生理功能发育的研究

基本信息

批准号：
04454414
负责人：
KUWABARA Yoshinori
金额：
$ 4.1万
依托单位：
Juntendo University
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (B)
财政年份：
1992
资助国家：
日本
起止时间：
1992 至 1994
项目状态：
已结题

项目摘要

The aim of our was to evidence the physiological mechanisms to regulate blood gas exchange and circulation in extremely premature fetus. The materials we used were premature goat fetuses during extra uterine incubation by using A-V ECMO,the system of which was developed by our group. It was essential to maintain fetal goats in stable condition during extra uterine incubation. Our previous study revealed that extremely premature goat fetus (95 gestational days, 500 gm) could be incubated for 8 days.However it was issued that the goat fetus lapsed into cardiac failure during extra uterine incubation. So in the first year, the purpose of our study was to examine the feasibility of long time extra uterine incubation of premature goat fetuses without cardiac failure. In consequence, long time extrauterine incubation more than 20 days could be achieved by suppression of the fetal movement and swallowing with diazepam and pancronium bromide administered into blood circuit. In the second year, the purpose was to assess the mechanism of distribution of circulation under the fetal hypoxia. In consequence, it was revealed that intra cranial circulation was influenced by hypercapnia rather than by hypoxemia.Because the blood flow volume of the fetal carotid artery was more increased under the normoxemic hypercapnia than under the isocapnic hypoxemia. Dexamethasone was clinically used to make the fetal lung mature, however the pharmacological functions of the dexamethasone for the premature fetuses were not revealed. In the last year the purpose was to assess the influence of the dexamethasone on the fetal central nervous system. Changes of the short term variability (STV) and long term variability (LTV) of the fetal heart rate were observed after dexamethasone injection. STV and LTV were increased after the administration of the dexamethasone. Therefore it was considered that dexamethasone did not suppress the fetal central nervous system during extra uterine incubation.

本研究的目的是探讨极早产儿血气交换和循环的生理调节机制。本研究以本课题组研制的体外循环体外膜肺氧合系统（A-VECMO）进行体外孵育的山羊胎儿为研究对象。山羊胚胎在宫外孵育过程中应保持稳定状态。本实验室前期研究发现极早产山羊胎儿（妊娠95天，体重500克）可在体外培养8天，但在体外培养过程中发生了心力衰竭。因此，在第一年，我们的研究目的是探讨长期子宫外孵育无心力衰竭的早产山羊胎儿的可行性。因此，通过抑制胎动和将地西泮和潘可溴铵经血液循环给药，可以实现超过20天的长时间宫外潜伏。第二年，探讨胎儿缺氧时循环分布的机制。结果表明，高碳酸血症对颅内循环的影响大于低氧血症，因为正常血二氧化碳浓度时胎儿颈动脉血流量比等血二氧化碳浓度时增加。地塞米松在临床上用于促进胎肺成熟，但其对早产儿的药理作用尚不清楚。去年的目的是评估地塞米松对胎儿中枢神经系统的影响。观察注射地塞米松后胎心率短、长时程变异性（STV）的变化。应用地塞米松后，STV和LTV增加。因此，认为地塞米松在宫外孵育期间不会抑制胎儿中枢神经系统。