A 58-year-old man with a history of hypertension and diabetes mellitus presents to the emergency department in cardiac arrest. Cardiopulmonary resuscitation (CPR) is initiated immediately. After 2 minutes of high-quality chest compressions and ventilation, the cardiac monitor shows a rhythm of coarse ventricular fibrillation (VF). The defibrillator is charged and a shock is delivered. After the shock, the rhythm changes to pulseless electrical activity (PEA). What is the most appropriate next step in the management of this patient?