孕羊深低温体外循环对胎羊温度和血流动力学及血气的影响

Effect of maternal deep hypothermic cardiopulmonary bypass onfetal lamb temperature, hemodynamics and blood gas

目的探讨孕羊深低温体外循环(CPB)对胎羊温度、血流动力学和血气的影响。方法5头健康怀孕山羊常规建立CPB,转流降温、复温各1 h。监测孕羊和胎羊的温度、心率、平均动脉压、血气值。结果孕羊最低温度(17．4±1．5)℃,胎羊最低温度(24．6±1．5)℃。降温期胎羊温度始终高于孕羊温度,复温期孕羊-胎羊温差逆转,转流结束胎羊温度低于孕羊温度。降温期胎羊心率逐渐减慢,复温期不能恢复正常心率。低温转流15 min,胎羊pH值从转流开始的7．30± 0．03降到7．17±0．07(P<0．05)、PO_2从转流开始的(32．5±4．0)mmHg(1 mmHg=0．133 kPa)降到(17．5±3．0)mm Hg(P<0．05),PCO_2从转流开始的(44．8±2．2)mm Hg升到(56．8±5．1)mm Hg(P<0．05),BE值从转流开始的(-3．2±0．6)升到(-5．7±1．3)(P<0．05),此后血气值进一步恶化,复温阶段胎羊血气值也没有好转。CPB结束胎羊存活率为60％。结论孕羊深低温CPB 影响胎盘的热交换和气体交换功能,对胎羊存活不利。

Objective To evaluate fetal-maternal temperature relationship and fetal cardiovascular and metabolic response during maternal deep hypothermic cardiopulmonary bypass （CPB） in pregnant ewes. Methods Deep hypothermic CPB was instituted in 5 pregnant ewes and lasted 2 h. Fetal and maternal temperature, heart rate, blood pressure and blood gases were evaluated at cooling and warming. Results The deepest temperature of pregnant ewes was （17.4 ± 1.5） ℃ and deepest temperature of fetal lambs was （24.6 ± 1.5） ℃. Fetal temperature was always higher than maternal temperature during cooling. The gradient was inverted during warming. The hypothermic CPB was associated with fetal bradycardia which couldn＇ t recover during warming. Fetal lambs＇ pH values were decreased from 7.30± 0.03 at the beginning of CPB to 7.17± 0.07 at CPB 15 min （P〈0.05）, PO2 reduced from （32.5± 4.0） mm Hg to （17.5±3.0） mm Hg （P〈0.05）, PCO2 increased from （44.8± 2.2） mm Hg to （56.8± 5.1） mm Hg （ P 〈 0.05）, and BE increased from - 3.2 ± 0.6 to - 5.7 ± 1.3 （ P 〈 0.05）. The mortality of fetal lamb was 4096. Conclusion Deep maternal hypothermic CPB was associated with reduction of placental thermal and respiratory functions and threatens fetal lamb survival. Pregnancy;