Early effects of total hepatectomy on haemodynamic state and organ uptake of catecholamines in the pig

In a previous study, we showed that plasma concentrations of catecholamines were increased during the an hepatic phase in pigs. In this study, we investigated if a constant depth of anaesthesia would prevent these changes and, if not, if the changes were caused by impaired extraction of catecholamines. We measured arterial and venous pressures, heart rate and cardiac output in 10 anaesthetized pigs. Hepatic arterial and portal venous flows were measured. Blood for measurement of catecholamines was sampled from carotid and pulmonary arteries and portal, hepatic and renal veins. After a 2-h observation period, the liver was removed and the circulation reconstituted. Measurements were made and samples obtained for another 2 h. Catecholamine concentrations increased 2-10-fold after hepatectomy. Before hepatectomy, noradrenaline was extracted by the lung (mean extraction ratio 23 (SEM 8)%) and the liver (30 (11)%); after hepatectomy, there was extraction by the kidney (24 (12)%) but extraction by the lung (29 (8)%) was unchanged. Before hepatectomy, adrenaline was extracted predominantly by the kidney (73 (5)%) and the liver (70 (6)%), with minimal extraction by the lung; after hepatectomy, extraction by the lung increased (25 (4)%) and decreased slightly in the kidney (56 (6)%). While mean arterial pressure did not change, heart rate increased by approximately 50% and cardiac index declined (ns) within 2 h after hepatectomy. There was a sharp increase in pulmonary vascular resistance after removal of the liver and changes correlated with increases in arterial plasma concentrations of catecholamines.