A 58-year-old man collapses in a shopping mall. Bystanders initiate CPR immediately. On arrival of the emergency medical services at 4 minutes, the patient is found to be in ventricular fibrillation on the monitor. After 2 minutes of high-quality CPR and one defibrillation attempt (200 J biphasic), the rhythm remains VF. What is the most appropriate next step in the management of this patient?

Explanation

## Management of Refractory Ventricular Fibrillation **Key Point:** In VF that persists after the first defibrillation attempt, vasopressor therapy (epinephrine) should be administered during CPR, followed by defibrillation attempts every 2 minutes. **High-Yield:** According to the 2020 American Heart Association Guidelines for CPR and Emergency Cardiovascular Care, the recommended approach for persistent VF is: 1. Continue high-quality CPR 2. Administer epinephrine 1 mg IV/IO as soon as possible (ideally during the first 2 minutes of resuscitation) 3. Repeat epinephrine every 3–5 minutes 4. Attempt defibrillation every 2 minutes **Clinical Pearl:** Epinephrine improves coronary and cerebral perfusion pressure during CPR, increasing the likelihood of return of spontaneous circulation (ROSC) in refractory VF. The drug should be given early and repeated at regular intervals. **Mnemonic:** **ACLS VF Algorithm** — After first shock fails: **A**dminister epinephrine, **C**ontinue CPR, **L**ook for reversible causes, **S**hock again at 2 minutes. ### Timing and Dosing | Intervention | Timing | Dose | | --- | --- | --- | | First defibrillation | Immediately | 120–200 J biphasic | | Epinephrine | After 1st failed shock | 1 mg IV/IO | | Repeat epinephrine | Every 3–5 minutes | 1 mg IV/IO | | Amiodarone | After 2nd or 3rd shock | 300 mg IV/IO | | Defibrillation attempts | Every 2 minutes | Same energy | **Tip:** In this scenario, the patient is at 4 minutes with one failed defibrillation. Epinephrine should be given immediately during ongoing CPR, not delayed further.