[Effects of dopamine and dobutamine on hepatic circulation and metabolism in hemorrhagic hypotensive pigs].

Effects of dopamine and dobutamine in a dose of 5, 10 or 20 micrograms.kg-1.min-1 on hepatic blood flow and hepatic metabolism were studied in normotensive and hemorrhagic hypotensive (MAP 50mmHg) pigs during 1 MAC enflurane anesthesia. PaCO2 was maintained within a physiological range (30-35mmHg) by controlled ventilation. Portal venous blood flow and hepatic arterial blood flow were measured by ultrasonic blood flowmetry. Hepatic oxygen supply and consumption were calculated from blood flows and oxygen contents. Each dose of dopamine and dobutamine did not change significantly MAP and cardiac output in both normotensive and hypotensive pigs. In the normotensive state, dopamine increased significantly total hepatic blood flow and hepatic oxygen supply, by raising portal venous blood flow, but dobutamine did not increase them. Also in the hemorrhagic hypotensive state, dopamine increased significantly total hepatic blood flow and hepatic oxygen supply by increasing both portal venous blood flow and hepatic arterial blood flow, but dobutamine did not produce similar increase. On the other hand, there was no significant change in hepatic oxygen consumption in both normotensive and hypotensive pigs by dopamine and dobutamine administration. These results suggest that dopamine is superior to dobutamine for hepatic circulation and hepatic metabolism especially in the hemorrhagic hypotensive state.