膜式氧合器在胎羊体外循环中的运用

目的　为了改进胎羊体外循环技术 ,探讨膜式氧合器在胎羊体外循环中的应用。　方法　将健康怀孕山羊8只 ,采用 Dideco 90 1膜式氧合器和滚轴泵建立胎羊体外循环 ,常温 (37℃ )转流 6 0分钟 ,氧合器内充低氧混合气体 (8%O2 和 92 % N2 ) ,监测胎羊的血压、心率、血气、血清乳酸和胎盘血管阻力。　结果　胎羊体外循环中动脉氧分压 (PO2 )和二氧化碳分压 (PCO2 )维持在宫内生理水平 ,胎羊心搏有力 ,血压正常。但胎羊 p H值缓慢下降 (P<0 .0 5 ) ,血清乳酸值明显增高 (P<0 .0 1) ,胎盘血管阻力显著上升 (P<0 .0 1)。停体外循环后胎羊出现低氧、高碳酸血症和酸中毒。　结论　胎羊体外循环影响胎盘功能 ,膜式氧合器可以代替胎盘气体交换功能 ,体外循环中胎羊生理低水平 PO2 是否适合其需要值得探讨。

The Application of Membrane Oxygenator in Fetal Lamb under Cardiopulmonary Bypass

Objective To study the application of membrane oxygenator in fetal lamb's cardiopulmonary bypass, for improving the technique of fetal cardiopulmonary bypass. Methods Eight ewes underwent fetal normothermic cardiopulmonary bypass with Dideco 901 membrane oxygenator and roller pump for 60 min. The membrane oxygenator was ventilated with mixture gas(8% oxygen and 92% nitrogen). The fetal lamb blood pressure, heart rate, blood gas, serum lactate and placental vascular resistant were monitored during the bypass. Results The arterial oxygen pressure (PO 2) and partial pressure of carbon dioxide(PCO 2) of fetal lamb were maintained in the fetal physiological level during fetal cardiopulmonary bypass. There were no changes at fetal blood pressure ,heart rate, but pH value decreased progressively with which statistical significance appeared at bypass 60 min ( P <0.05). The serum lactate and the placental vascular resistant elevated significantly during the bypass ( P <0.01). After cardiopulmonary bypass, hypoxia, hypercarbia and acidosis appeared in fetal lamb ( P <0.05). Conclusion The fetal lamb cardiopulmonary bypass destroys the placental function. Membrane oxygenator can take the role of placental gas exchanges. It's deserved to study whether the fetal physiological PO 2 fits for fetal lamb during the bypass.