两种胎羊体外循环方式对胎盘功能影响的比较

Placental functions response to two kinds of extracorporeal circulation in fetal lamb

目的比较两种胎羊体外循环方式对胎盘气体交换功能的影响.方法10头胎羊(妊娠120～140d)随机分为胎盘组(n=5)和人工肺组(n=5).胎盘组运用离心泵和胎盘建立体外循环;人工肺组运用离心泵和人工膜肺建立体外循环,转流中旷置胎盘.两组胎羊体外转流30 min.分别于转流前(T0),转流30 min(T1)、转流后1 h(T2)、转流后2 h(T3)记录胎羊平均动脉压、心率和血气值.结果实验过程中两组胎羊平均动脉压和心率之间的差异没有统计学意义.T1和T2期两组胎羊氧分压、二氧化碳分压以及氧饱和度均在生理范围内.T3期两组胎羊pH值、氧分压和氧饱和度下降、二氧化碳分压增高,与T0期差异有显著性(P＜0.05),两组之间总体差异无显著性.两组胎羊碱剩余结果显示进行性偏酸,人工肺组在T2,T3期较胎盘组更加偏酸,两组之间总体差异无有显著性(P＜0.05).结论胎羊体外循环过程中胎盘作为氧合器,胎盘功能良好,但是体外循环对胎盘长期功能存在影响.旷置胎盘、使用人工氧合器并不能减轻体外循环对胎盘功能的影响.

Objective To compare the effects of two kinds of fetal lamb extracorporeal circulation on the placental gasexchange function.Methods Ten fetal lambs of 120 to 140 days of gestation were randomly divided into the placental group （ n= 5） and the oxygenator group （ n = 5）, Fetal bypass was established with centrifugal pump at the placental group, and bypass of oxygenator group was established with centrifugal pump and oxygenator. The bypass lasted for 30 min. The fetal lamb mean arterial pressure, heart rate, blood gas value were recorded at pre- bypass（To）, 30 min bypass（T1）, post-bypass 1 h（T2）, post - bypass 2 h（I3）. Results Mean arterial pressure and heart rate of two groups had no significant difference during the experiment. The value of PO2,PCO2 and SaO2 of two groups were normal at T1 and T2. However, the value of pH,PO2, and SaO2 decreased and PCO2 increased at 1＂3（ P 〈 0.05）. The base deficit of two groups gradually elevated and oxygenator group increased more than placental group （ P 〈 0.05）. Conclusion Placenta can take the role of oxygenator during fetal lamb extracorporeal circulation and work well. But placental functions can not keep longer after bypass. Exclusion of placenta and usage of oxygenator can not protect placental functions.