Effects of controlled low central venous pressure on cerebral oxygen metabolism during liver transplantation

Objective To investigate the effects of controlled low central venous pressure (CLCVP) on cerebral oxygen metabolism during orthotopic liver transplantation (OLT),and study the safety of CLCVP in OLT.Method Forty-six patients subject to OLT were randomly divided into CLCVP group (CL group) and CVP group (C group).Blood samples were taken from radial artery and jugular simultaneously for blood gas analysis before operation (T1,baseline),immediately blocking inferior vena and portal vein (T2),30 min after anhepatic phase (T3),30 min after graft reperfusion (T4),2 h after graft reperfusion (T5),and 24 h after graft reperfusion (T6).Cerebral arterial oxygen content (CaO2),jugular oxygen content (CjvO2),cerebral arterial-venous oxygen content difference (Ca-jvO2),cerebral oxygen extraction rate (CERO2),and cerebral blood flow/ cerebral metabolic rate of oxygen (CBF/CMRO2) were calculated by the Fick formulae.Meanwhile,blood samples were taken from jugular simultaneously for serum creatinine (Cr) and urea nitrogen (BUN) a different time points.We also recorded the whole operation time,anhepatic phase time,volume of blood loss and transfusion,and urine volume.Results As compared with C group,CaO2,CjvO2,Ca-jvO2,SjvO2,CERO2 and CBF/CMRO2 in CL group were nearly not changed at different time pioints (P＞0.05),but in the same group,as compared with T1 and T2,the CaO2,CjvO2,Ca-jvO2 and CERO2 in T3,T4 and T5 were decreased significantly (P＜0.05),and the SjvO2 in T3,T4 and T5 was increased remarkably.The operation time and anhepatic phase time had no significant difference in both groups.As compared with C group,the volume of blood loss and transfusion in CL group were decreased (P＜0.05),and the urine volume in CL group CL was increased significantly (P＜0.05).Cr and BUN showed no significant difference in both groups and at the same time points of C group and CL group.Conclusion CLCVP can decrease volume of blood loss and transfusion,increase urine volume during OLT,and it does not change the cerebral oxygen metabolism during OLT. Key words: Liver transplantation;  Controlled low central venous pressure;  Cerebral metabolic rate of oxygen