A drug use evaluation (DUE) of an institution's ACLS medication administration records yields the following data:
* Rate of amiodarone use in patients with asystole = 30%
* Rate of amiodarone use in patients with ventricular fibrillation = 90%
* Rate of epinephrine use in patients with pulseless electrical activity (PEA) = 98%
* Rate of vasopressin use in patients with pulseless ventricular tachycardia = 50% Which of the following treatments should be targeted for intervention?