利用胎羊体外循环模型观察胎盘功能及胎心功能变化 ,研究胎羊体外循环建立方法和存在问题.结果显示直接肺动脉插管较经右室流出道肺动脉插管出血少.表明胎羊保温、胎盘保护和防止术中出血及子宫收缩是实验成功的关键.“,”To study the placental and fetal heart function, cardiopulmonary bypass was established in fetal lambs and the different methods of cannulation were applied. The results showed that the direct pulmonary artery cannulating was more reliable than pulmonary artery cannulating through right ventricular outflow tract .Besides, the warming of the fetal lamb, avoiding of uterine contraction, umbilical cord twist and bleeding during operation should be also emphasized.