Although epinephrine is the vasopressor of choice for cardiopulmonary resuscitation (CPR), the prognosis of patients with cardiac arrest who require epinephrine remains extremely poor, regardless of the cumulative epinephrine dose given. Studies of CPR in animals have demonstrated that vasopressin increases blood flow in vital organs, cerebral oxygen delivery, short-term survival, and neurologic outcome, as compared with epinephrine. However, clinical studies of CPR in patients with in-hospital and out-of-hospital cardiac arrest show that the effects of vasopressin and epinephrine are similar, and that there is no benefit of adding vasopressin to epinephrine.
New England Journal of Medicine - Vol. 359, No. 1, July 3, 2008