Effects of intravenous vasopressin on canine mesenteric arterial blood flow, bowel oxygen consumption, and cardiac output.

The effects of various doses of intravenous vasopressin on mesenteric arterial blood flow, intestinal oxygen consumption, and cardiac output in anesthetized dogs were investigated. Optimal dose rate of intravenous vasopressin was found to be 3.0 mU/kg/min. At this dose rate, mesenteric arterial blood flow, intestinal oxygen consumption, and cardiac output decreased by 57%, 57% and 26%, respectively. Increasing the dose rate to 8.0 mU/kg/min did not offer significant gains. Maximum effect was observed 20 min after the beginning of the infusion. The effects disappeared 10-20 min after the infusion was discontinued, with the exception of superior mesenteric blood flow which showed a rebound increase. We conclude that in the anesthetized dog, intravenous infusions of vasopressin at low dose rates (3.0 mU/kg/min) substantially reduce mesenteric blood flow and intestinal oxygen extraction with moderate reduction of cardiac output. Possible clinical applications of low dose intravenous infusions of vasopressin would include reduction of portal hypertension and bowel protection during radiation therapy.