常温和低温心肺转流期间门静脉血流量及氧代谢的变化

The changes of hepatic portal vein blood flow and oxygen metabolism during normothermic or hypothermic cardiopulmonary bypass

目的 研究常温和低温心肺转流 (CPB)期间门静脉血流量 (PBF)和氧代谢的变化。方法 测定 11只杂种犬在常温 (N组 )或低温 (H组 )CPB期间PBF和氧代谢指标。结果 CPB中低温组SpO2 升高 ,PDO2 、PVO2 降低 (P <0 0 5或P <0 0 1) ;常温组PpO2 、PDO2 降低 ,而PERO2 和PBF升高 (P <0 0 5或P <0 0 1)。CPB后两组SaO2 、PaO2 、SpO2 、PpO2 、PBF、PDO2 均有不同程度的降低(P <0 0 5或P <0 0 1) ,而PERO2 明显升高 (P <0 0 1) ,常温组PVO2 减少 (P <0 0 5 )。两组相比 ,CPB中低温组PaO2 、SaO2 、SpO2 高于常温组 ,PVO2 、PERO2 、PBF低于常温组 (P <0 0 5或P <0 0 1)。CPB后低温组SaO2 、PDO2 、PVO2 和PBF都高于常温组 (P <0 0 5 )。结论 常温和低温CPB期间门脉系统都存在氧代谢障碍 ,但常温CPB期间PBF、门脉组织氧利用明显优于低温CPB ,CPB后PBF。

Objective To investigate the changes of hepatic portal vein blood flow(PBF) and oxygen metabolism during normothermic or hypothermic cardiopulmonary bypass(CPB).Methods Eleven dogs were randomly divided into two groups:hypothermic group(group H,n=5) and normothermic group(group N,n=6).Group H was intermittently infused with 4℃ crystalloid cardioplegia solution.Group N continuously received warm oxygenated cardioplegia blood.During CPB,the lowest pharyngonasal temperature was 28-30℃ in group H and 35.3-37.1℃ in group N.Aortic clamping lasted for 60min and CPB lasted for 90min.The cardiac output (CO),PBF,arterial oxygen saturation(SaO 2),arterial oxygen partial pressure(PaO 2),hepatic portal vein oxygen saturation(SpO 2),hepatic portal vein oxygen partial pressure(PpO 2),hepatic portal vein oxygen delivery(PDO 2),hepatic portal vein oxygen consumption(PVO 2) and hepatic portal vein oxygen extraction rate(PERO 2) were monitored before CPB,during CPB 30,90min and at 60min after CPB.Results Compared with those before CPB,the SpO 2 was increased,PDO 2 and PVO 2 were decreased significantly during the hypothermic CPB(P<0.05 or P<0.01).Whereas during the peroid of normothermic CPB,PpO 2 and PDO 2 were decreased,PERO 2 and PBF were increased(P<0.05 or P<0.01).After CPB,the PVO 2 of group N was decreased(P<0.01),SaO 2,PaO 2,SpO 2,PpO 2,PBF and PDO 2 of two groups were decreasde(P<0.05 or P<0.01) and PERO 2 was increased significantly(P<0.01).During CPB,SaO 2,PaO 2 and SpO 2 of group H were higher and PVO 2,PERO 2,PBF were lower than those of group N(P<0.05 or P<0.01).Whereas after CPB,SaO 2,PDO 2,PVO 2 and PBF of group H were higher than those of group N.Conclusion Either normal or hypothermic CPB may result in hepatic portal tissues hypoxia.During CPB under normathermia,the PBF and oxygen uptake are better than those under hypothermia,which is opposite after CPB.