Small bowel and liver pO2 during vasopressin infusion into the superior mesenteric artery

In an earlier study we found that intravenous vasopressin infusion caused a profound decrease in intestinal and liver pO2. As vasopressin has been reported to be more effective when infused directly into the superior mesenteric artery, we have now studied the effects of this type of administration. Intestinal pO2 and pCO2 and liver pO2 were continuously recorded using a silicone elastomer tube as a tonometer. Vasopressin was infused in a dose of 2.75 mU/kg/min in twelve dogs for 45 minutes. Intestinal tissue pO2 decreased during 45 minute infusion period from 35 +/- 0.9 mmHg to 19 +/- 0.7 mmHg (p less than 0.001) and liver pO2 from 38 +/- 1.9 mmHg to 19 +/- 1.1 mmHg (p less than 0.005). Both values obtained in this study did not differ from those noted when the same dose of vasopressin was administered intravenously.