Effect of vasopressin on regional splanchnic blood flows in conscious man

In 11 conscious normovolaemic patients with acute or chronic pancreatitis the effect of a continuous intravenous infusion of lysine-8-vasopressin, 5 IU/70 kg b.w./20 min on the portal and the hepatic venous blood flows was studied by using multiple portal catheters, oxygen saturation measurements and an indicator dilution technique with continuous infusion of 133Xe into the portal vein or its tributaries. During vasopressin infusion the total hepatic blood flow, estimated by the Bradley technique with indocyanine green dye, was reduced to 61% of the value at rest. Owing to the simultaneously occurring streamlining of the portal venous flow with incomplete mixing of indicator and blood, the portal and hepatic venous blood flows could be measured in only 3 of 9 patients. The reduction in the portal venous blood flow during vasopressin infusion was more marked than the decrease of the total hepatic flow, corresponding to a calculated increase of the hepatic arterial flow of 50%. Total splanchnic oxygen uptake and extrahepatic splanchnic oxygen uptake were unchanged during and after infusion of vasopressin. Thus, changes in splandhnic blood flow could be estimated from changes in arteriovenous oxygen differences. Also by this method a more pronounced reduction in the portal venous than of the hepatic venous blood flow was observed. The decrease during vasopressin infusion of the superior mesenteric venous flow was more marked than that of the splenic vein. The splanchnic circulatory changes may be different for other doses of vasopressin and in cirrhotic patients with higher hepatic arterial blood flow fractions.