Effects of Dopamine on the Portal Circulation After Therapeutic Hepatic Artery Ligation

Abstract

Comment At first glance this article appears as a rather arcane investigation of limited clinical practicality for the anesthesiologist. Actually the is not the case. Cannulation and ligation of the hepatic artery of man are commonly employed when dealing with either primary hepatic tumors or secondary metastatic tumors to the liver. In massive trauma to the liver, the hepatic artery can be tied off and survival of the organ occur. The human liver is a remarkable organ in that if it is basically free of diffuse or hepatocellular disease, it can survive with its arterial blood supply ligated. Sole reliance on portal venous flow allows the liver to survive, but it must be stated that that survival is marginal particularly early after hepatic arterial ligation. Since most tumors of the liver seem to have blood supply derived more from hepatic arterial than from portal venous sources, hepatic arterial ligation is a worthwhile clinical entity. However, if there is some mechanism by which portal flow can be pharmacologically increased, hepatic function is then better ensured. In the past, glucagon had been advocated as a compound increasing hepatic portal venous flow after hepatic arterial ligation, but the results were equivocal at best. The present article indicates that portal venous flow can be increased as high as 50% by dopamine concentrations given intravenously which do not increase systemic blood pressure. Unfortunately these studies are done postoperatively rather than in-traoperatively. It would be advantageous as anesthesiologists to be able to acutely increase blood flow to the liver by amplifying portal venous flow. Future studies should tell us whether dopamine can do this on an acute basis. Somewhat parenthetically, it is unfortunate in this article that anesthetic techniques were not mentioned nor were techniques used to sedate the patients and keep them pain free in the postoperative era. Certainly most pharmacologic interventions with potent anesthetic drugs seriously alter hepatic blood flow and are an important variable. Burnell R. Brown, Jr., M.D., Ph.D., F.F.A.R.C.S.