Alpha agonist drug usage during CPR

As a result of many investigations, the role of adrenergic drugs in cardiopulmonary resuscitation (CPR) has been identified, but the choice of drug and drug dosage are yet to be defined. It has been suggested that the successful return of circulation following cardiac arrest is linked with the ability to achieve a diastolic arterial pressure of 30 to 40 mm Hg. Since the turn of this century, the addition of epinephrine to resuscitation procedures has been shown to increase greatly diastolic arterial pressures and resuscitation success. The key to epinephrine's action lies in its alpha agonist properties (which promote peripheral vasoconstriction, leading ultimately to increased coronary perfusion) rather than its direct beta effects (which increase the workload of the fibrillating myocardium). Indeed, pure alpha agonist drugs work as effectively as epinephrine in restoring the circulation, and beta agonists are totally ineffective when used during the arrest period. The hypothesis that pure alpha agonists may be superior to epinephrine during CPR is the subject of current investigations. To date, drug dosage has been largely empirical. During CPR other factors play a role in drug effectiveness, including the injection site, rate of blood flow, and current metabolic status. Because the early use of effective alpha agonists can improve survival, the search for the best drug, via the best route and at the best dosage deserves additional investigation.