Intraoperative hemodynamic investigations during portacaval shunt.

We studied the hemodynamics of hepatic blood flow before and after creation of portacaval shunts in 28 patients. Electromagnetic flow recordings were used to measure hepatic arterial flow (HAF) and portal venous flow (PVF) with respect to total hepatic blood flow (THBF). No correlation between PVF and portal pressure was found, but PVF was directly related to liver function. The concept that patients with low PVF tolerate shunts better (with respect to postoperative course and encephalopathy) than those with high PVF was not supported. Our investigations suggest the existence of a compensatory mechanism that tends to maintain THBF by increasing HAF following creation of a shunt. This compensatory increase occurs only in those patients with good liver function and normal or enlarged livers.