Peri-operative characteristics of cerebral oxygen metabolism in patients with encephalopathy after orthotopic liver transplantation

Abstract

To investigate the feature of cerebral oxygen metabolism during peri-operative stage of orthotopic liver transplantation (OLT), in order to identify the difference between the patients with or without complicating encephalopathy after OLT, and the relationship between the cerebral oxygen metabolism and encephalopathy after OLT. Thirty patients undergoing OLT were studied. The patients were divided into two groups according to occurrence or not of encephalopathy after OLT: encephalopathy group and non-encephalopathy group. Blood samples were taken from radial artery and jugular vein simultaneously for blood gas analysis before operation, 25 minutes after onset of anhepatic phase, 30 minutes after graft reperfusion , 3 hours after graft reperfusion , and 24 hours after graft reperfusion. Cerebral arterial oxygen content (CaO(2)), oxygen content of jugular vein blood (CjvO(2)), cerebral arterial-venous oxygen content difference (Ca-jvO(2)), cerebral oxygen extraction ratio (CERO(2)) and cerebral blood flow/cerebral metabolic rate of oxygen ratio (CBF/CMRO(2)) were calculated, and the levels of blood glucose and lactic acid were recorded. There were 11 patients (36.7%) complicated by encephalopathy after OLT. The quantity of red blood cell infusion, blood loss and the dosage of noradrenalin in encephalopathy group were significantly larger compared with non-encephalopathy group. The overall tendency of change in cerebral oxygen metabolism index was about the same for both groups, while CaO(2) and Ca-jvO(2) at 25 minutes after onset of anhepatic phase, 30 minutes after graft reperfusion and 3 hours after graft reperfusion , and CERO(2) at 30 minutes after graft reperfusion and 3 hours after graft reperfusion were significantly decreased compared with those before operation [CaO(2) (ml/L) in encephalopathy group: 132.4 ± 23.5 , 125.9 ± 17.6, 133.4 ± 11.1 vs. 148.5 ± 28.8, in non-encephalopathy group: 135.7 ± 22.4, 130.5 ± 20.0, 139.9 ± 21.2 vs. 148.9 ± 28.2; Ca-jvO(2) (ml/L) in encephalopathy group: 42.9 ± 13.2, 31.4 ± 12.3 , 32.3 ± 6.5 vs. 52.9 ± 23.5, in non-encephalopathy group: 33.0 ± 14.1, 26.6 ± 9.1, 30.6 ± 10.3 vs. 50.2 ± 23.2; CERO(2) in encephalopathy group: (24.9 ± 9.7)%, (24.4 ± 5.5)% vs. (35.4 ± 11.5)%, in non-encephalopathy group: (20.6 ± 7.3)%, (21.9 ± 7.0)% vs. (33.4 ± 13.1)%, all P < 0.05], and they returned to the levels before operation at 24 hours after graft reperfusion. Jugular venous oxygen saturation (SjvO(2)) and CBF/CMRO(2) ratio were significantly increased at 30 minutes after graft reperfusion and 3 hours after graft reperfusion compared with the levels before operation [SjvO(2) in encephalopathy group: 0.838 ± 0.105, 0.835 ± 0.065 vs. 0.709 ± 0.125, in non-encephalopathy group: 0.854 ± 0.074, 0.824 ± 0.074 vs. 0.713 ± 0.138; CBF/CMRO(2) ratio in encephalopathy group: 37.8 ± 16.6, 31.9 ± 6.8 vs. 20.9 ± 6.7 , in non-encephalopathy group: 37.8 ± 14.1, 35.7 ± 13.7 vs. 24.3 ± 14.0, all P <0.05], and they returned to the levels before operation at 24 hours after graft reperfusion. The overall tendency of change in blood glucose and lactic acid was about the same in both groups, while the levels of blood glucose increased significantly from anhepatic phase to 24 hours after graft reperfusion compared with the levels before operation , and the levels of lactic acid increased significantly from anhepatic phase to 3 hours after graft reperfusion compared with the levels before operation and returned to the levels before operation at 24 hours after graft reperfusion. There are significant changes in the features of cerebral oxygen metabolism during OLT, but there is no difference between encephalopathy group and non-encephalopathy group. The occurrence of encephalopathy can be attributed to many factors, so the prevention and treatment should be comprehensive considered.