Small bowel and liver pO2 during intravenous vasopressin infusion.

It has been suspected that vasopressin infusion may cause small bowel necrosis and liver ischaemia. In this study a direct method of measuring the oxygen tension of these organs during intravenous vasopressin infusion was used for the first time. Vasopressin in a dose of 2.75 mU/kg/min was infused during a 45 minute period in ten dogs. Both intestinal and liver pO2 decreased to a hypoxic level. This level was observed within a mean time of 25 minutes in both organs. After discontinuing the vasopressin infusion the oxygen tension was noted to return to normal in 45 minutes. It is concluded that vasopressin causes definite ischaemia of the small bowel and the liver parenchyma, and consequently this vasoactive drug should be used with care. The exact time of onset and duration of intestinal hypoxia could be of great value in planning vasopressin induced hypoxia for radioprotection.