Epinephrine during
cardiopulmonary resuscitation (
CPR) is being discussed controversially due to its beta-receptor mediated adverse effects such as increased myocardial oxygen consumption, ventricular arrhythmias, ventilation-perfusion defect, postresuscitation myocardial
dysfunction, ventricular arrhythmias and
cardiac failure. In the
CPR laboratory simulating adult pigs with
ventricular fibrillation or postcountershock pulseless electrical activity,
vasopressin improved vital organ blood flow, cerebral
oxygen delivery, resuscitability, and neurological recovery better than did
epinephrine. In paediatric preparations with
asphyxia,
epinephrine was superior to
vasopressin, whereas in both paediatric 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 paediatric 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 point in time. In patients with out-of-hospital
ventricular fibrillation, a larger proportion of patients treated with
vasopressin survived 24 h compared with patients treated with
epinephrine; during in-hospital
CPR, comparable short-term survival was found in groups treated with either
vasopressin or
epinephrine. Currently, a large trial of
out-of-hospital cardiac arrest patients being treated with
vasopressin vs.
epinephrine is ongoing in Germany, Austria and Switzerland. The new
CPR guidelines of both the American Heart Association, and European
Resuscitation Council recommend 40 U
vasopressin intravenously, and 1 mg
epinephrine intravenously as equally effective for the treatment of adult patients in
ventricular fibrillation; however, no recommendation for
vasopressin was made to date for adult patients with
asystole and pulseless electrical activity, and paediatrics due to lack of clinical data. When
adrenergic vasopressors were unable to maintain arterial blood pressure in patients with vasodilatory
shock, continuous infusions of
vasopressin ( approximately 0.04 to approximately 0.1 U/min) stabilised cardiocirculatory parameters, and even ensured weaning from
catecholamines.