Effect of maternal hypothermic cardiopulmonary bypass on fetal homodynamic and carbohydrate metabolism / 中华胸心血管外科杂志

ABSTRACT

Objective To evaluate effects of maternal hypothermic cardiopulmonary bypass on fetal homodynamic and carbohydrate metabolism. Methods Twenty pregnant sheep were divided into four groups randomly control group(n=5),normothermic group (35-36℃)(n=5), mild hypothermic group(32-34℃)(n=5) and moderate hypothermic group (28-31℃)(n=5).Thoracotomy was performed without CPB in the control group. Routine CPB was established with different temperature in other three groups. The temperature of normothermic group was kept normal; the left two groups were cooled down to the set point of temperature and then rewarmed back to normal level. Fetal and maternal temperatures, heart rate,mean blood pressure(BP), pulse index (PI) of fetal umbilical artery (UA) and internal carotid artery (CA) were evaluated at cooling and rewarming stages. Biochemical indicators including blood glucose and lactic acid were also measured at the same time. Results There are no differences in mesn BP of ewas and fetal lambs between the different groups (P＞0.05). CA PI value of mild hypothermic group and moderate hypothermic group were significantly higher than those of control group and normothermic group (P＜0.05). There was no difference of UA PI in the four groups, but PI increased following the prolonged duration of CPB. There was no difference change of blood glucose in the four group of fetus, which was significantly lower than the ewe groups. An upward trend of fetal blood lactic acid with time was observed in three CPB groups. The whole level of fetal blood lactic acid was much higher than that of maternal blood of lactic acid. Conclusion Cooling of maternal bypsss decreases fetal heart rate significantly,and fetal heart rate recovered to base line following rewarming phase. There was no signicant effect of CPB on fetal mean BP. However, CPB impacted on the blood flow of fetal brain and umbilical artey. Hypothermia CPB can increase fetal blood glucose and blood lactic acid dramatically.