Effects of incremental infusion rates of vasopressin (1.2, 2.4 and 4.8 units/hour) on renal blood flow (RBF), glomerular filtration rate (GFR), renal oxygen consumption (RVO
) and renal oxygen extraction (RO
Ex) in post-cardiac surgery patients. Vasopressin causes a constriction of renal efferent arterioles with a decrease in RBF and an increase in GFR and RVO2.Vasopressin impairs the renal oxygen demand/supply relationship as reflected by the increase in RO2 Ex. From  with permission.