Liver Enzymes and Oxygen Supply During Prolonged Extracorporeal Circulation with Standard Flow Rates

In a random group of 20 dogs undergoing a 3-hour extracorporeal circulation bypass with a standard flow rate of 100 ml/min/kg, a significant relationship was observed between the changes in increased levels of SGOT, SGPT and BSP retention, in decreased levels of liver microsomal enzymes oxidizing chlorpromazine and pethidine and venous pH, pO2. and oxygen saturation and increased levels of venous pCO2. The conclusion was drawn that oxygen supply to the liver, hypercarbia and acidosis during cardiopulmonary bypass are partly responsible for these changes, and that haemolysis, haemo-dilution, anaesthesia and operative trauma also affect the serum enzymes.