Effect of vasopressin on the mixing of portal venous blood in awake man.

Abstract

Transumbilical portal venous catheterization was performed in 11 patients for diagnostic selective portography. By use of a multiple-catheter technique, the effects of intravenous infusion of [8-lysine]vasopressin on portal venous mixing of tributary flows was measured by simultaneous blood sampling from the left and right portal branch, taking advantage of the oxygen saturation difference between splenic and superior mesenteric venous blood and also by infusion of 133Xe into one of the portal tributaries. Slight signs of incomplete portal mixing were observed at rest in eight of nine patients. During vasopressin infusion, the heterogeneity of oxygen saturation and xenon activity in the portal branches increased significantly. There was also a significant average shift of splenic venous blood toward the left portal branch with, in some patients, only splenic blood in this branch. Streamlining thus was a dynamic phenomenon related to the reduced and altered portal venous flow pattern. This must be considered during flow measurements, and might also have pathophysiological significance in liver diseases.