The effect of dobutamine on hepatic blood flow and oxygen supply-uptake ratio during enflurane nitrous oxide anesthesia in humans undergoing liver resection.

Liver surgery is often accompanied by hepatic hypoperfusion and hypoxia, and it is controversial whether catecholamines increase hepatic blood flow and oxygen supply. The effects of 3 micrograms.kg-1.min-1 dobutamine on hepatic circulation and oxygen balance were examined in patients anesthetized with enflurane, nitrous oxide, and oxygen for liver surgery. Dobutamine did not cause a significant increase in hepatic arterial blood flow. However, total hepatic blood flow and portal venous blood flow were increased, resulting in an increase in hepatic oxygen delivery (HDO2). The increase in HDO2 was not associated with an improvement of hepatic oxygen supply-uptake ratio, since hepatic oxygen uptake (HVO2) also increased. After hepatectomy, the increases in portal venous blood flow and HDO2 were not accompanied by an increase in HVO2. The stimulation of hepatocellular oxygen metabolism by dobutamine and depressed responsiveness of adrenoceptors on hepatocytes in which metabolism was already augmented are the likely explanation for the different reactions before and after hepatectomy.