The Difference between the Changes in Systemic Oxygen Consumption during Orthotopic Liver Transplantation and Those during Extracorporeal Hepatic Resection

Every organ in the body requires oxygen to perform its function. In liver transplantation and extracorporeal hepatic resection, oxygen utilization by the graft or the re-implanted liver is a prerequisite for restoration of liver function. We compared the changes in systemic oxygen consumption in a patient who underwent orthotopic liver transplantation with those in two patients who underwent extracorporeal hepatic resection. The pre-anhepatic systemic oxygen consumption in the patient who underwent orthotopic liver transplantation seemed to be lower than that in the patients who underwent extracorporeal hepatic resection, possibly due to the depressed oxygen utilization which sometimes occurs in cirrhotic patients. The increase in oxygen consumption or the overconsumption of oxygen after reperfusion was more significant in the patient who underwent orthotopic liver transplantation than in the patients who underwent extracorporeal hepatic resection. The possible causes might be the greater hepatic oxygen debt, an associated intestinal oxygen debt, and/or the greater ischemia/reperfusion-induced overproduction of superoxide anion in the patient who underwent orthotopic liver transplantation. The differences between the changes in systemic oxygen consumption during orthotopic liver transplantation and those during extracorporeal hepatic resection further support the usefulness of systemic oxygen consumption to predict the immediate restoration of blood flow and oxygen utilization in the graft or the re-implanted liver. These findings also support the importance of evaluating oxygen consumption to confirm whether the critically ill or unconscious patient can utilize oxygen on demand or not.