Q: Please comment on the use of vasopressin and epinephrine in current advanced cardiac life support (ACLS) protocols. Based on recent studies, is there any evidence that one is more efficacious than the other?
—Andrew Obermeier, PA-C, Venice, Fla.
A: This past summer, the American Heart Association, the American College of Cardiology, and the European Society of Cardiology (AHA/ACC/ESC) released the 2006 Guidelines for the Management of Patients with Ventricular Arrhythmias and the Prevention of Sudden Cardiac Death (Circulation. 2006;114:1088-1132). The guidelines offer vasopressin as an alternative to epinephrine in pulseless ventricular fibrillation (VF) and pulseless ventricular tachycardia (VT). The evidence for superiority is not clearly established between epinephrine and vasopressin.
A literature review reveals that the overall end point of survival to hospital discharge has not shown any difference in the use of vasopressin or epinephrine when administered during CPR for VF/VT. While efficacy and safety have been demonstrated with both medications, there are still inadequate data to evaluate comparison efficacy. Numerous studies have been completed, but no clear answer has been reached. There are many complex confounding factors, such as the length of asphyxia, the underlying degree of ischemia during CPR, the underlying cause of VF/VT, and the inability to perform against placebo-controlled studies.
Vasopressin has a longer half-life. It is administered once as a dose of 40 units IV, whereas epinephrine 1 mg IV is administered every three to five minutes. For further discussion, see N Engl J Med. 2004;350:105-113 and Crit Care Med. 2002;30(4 Suppl):S157-S161.
—Debra Kleinschmidt, PhD, PA (98-4)