When stimulating adult pigs with
ventricular fibrillation or postcountershock pulseless electrical activity for
cardiopulmonary resuscitation,
vasopressin improved vital organ blood flow, cerebral
oxygen delivery, ability to be resuscitated, and neurologic recovery better than
epinephrine. In pediatric preparations with
asphyxia,
epinephrine was superior to
vasopressin, whereas in both pediatric pigs with
ventricular fibrillation and adult porcine models with
asphyxia, combinations of
vasopressin and
epinephrine proved to be highly effective. This may suggest that a different efficiency of vasopressors in pediatric vs. adult preparations and different effects of dysrhythmic vs. asphyxial
cardiac arrest on vasopressor efficiency may be of significant importance. Whether these theories can be extrapolated to humans is unknown at this time. In patients who experienced out-of-hospital
ventricular fibrillation, a larger proportion of patients treated with
vasopressin survived 24 hrs compared with patients treated with
epinephrine; during in-hospital
cardiopulmonary resuscitation, comparable short-term survival was found in groups treated with either
vasopressin or
epinephrine. Currently, a large trial comprising patients who experience
out-of-hospital cardiac arrest and who are treated with
vasopressin vs.
epinephrine is ongoing in Germany, Austria, and Switzerland. The new
cardiopulmonary resuscitation guidelines of both the American Heart Association and the European
Resuscitation Council consider 40 units of
vasopressin intravenously and 1 mg of
epinephrine intravenously equally effective for the treatment of adult patients with
ventricular fibrillation; however, because of a lack of clinical data, no recommendation for
vasopressin has been made for adult patients with
asystole and pulseless electrical activity or for pediatric patients.