Adult patients with vasopressor-requiring, inhospital cardiac arrest, i.e., with asystole, pulseless electrical activity, or ventricular fibrillation/pulseless ventricular tachycardia not responsive to two attempts at defibrillation. Patients have already participated in 2 prior RCTs (references 3 and 4). Thus, the below-provided Eligibility Criteria are the Criteria already employed by the prior RCTs.