In a patient with refractory ventricular fibrillation during CPR, what is the recommended intravenous epinephrine dosing and timing?

Explanation

## Epinephrine Dosing in Advanced CPR **Key Point:** The standard epinephrine dose during cardiac arrest is 1 mg (1:10,000 solution) administered intravenously as a bolus, repeated every 3–5 minutes as long as the patient remains in a shockable rhythm (VF/pulseless VT) or asystole/pulseless electrical activity (PEA) without return of spontaneous circulation (ROSC). **High-Yield:** Epinephrine is a non-selective α- and β-adrenergic agonist that: - Increases systemic vascular resistance (α-effect) → improves diastolic blood pressure and coronary perfusion pressure. - Increases heart rate and contractility (β-effect) → enhances cardiac output if ROSC is achieved. - The 1 mg IV dose is empirically derived and has been standard in ACLS for decades; higher doses do not improve outcomes and may increase post-resuscitation myocardial dysfunction. **Clinical Pearl:** Epinephrine is given after the **first defibrillation attempt** in VF/pulseless VT, and then every 3–5 minutes thereafter. In asystole or PEA, epinephrine is given as soon as IV access is obtained, then every 3–5 minutes. The timing is synchronized with defibrillation cycles in shockable rhythms. **Mnemonic:** **1-3-5 Rule** — 1 mg epinephrine IV, repeat every 3–5 minutes during cardiac arrest. ## Epinephrine Timing in ACLS Algorithm ```mermaid flowchart TD A[Cardiac Arrest Detected]:::outcome --> B{Shockable Rhythm?}:::decision B -->|Yes: VF/pulseless VT| C[Defibrillate immediately]:::action B -->|No: Asystole/PEA| D[Epinephrine 1 mg IV ASAP]:::action C --> E[Resume CPR 2 minutes]:::action E --> F{Rhythm check}:::decision F -->|Still VF/pulseless VT| G[Defibrillate again]:::action F -->|Asystole/PEA| H[Continue CPR]:::action G --> I[Epinephrine 1 mg IV]:::action H --> I I --> J[Repeat every 3-5 minutes]:::action J --> K{ROSC achieved?}:::decision K -->|Yes| L[Post-resuscitation care]:::outcome K -->|No| F ``` **Dosing Summary:** - **Initial dose:** 1 mg IV bolus - **Repeat dose:** 1 mg IV every 3–5 minutes - **Route:** Intravenous (central line preferred for better perfusion, but peripheral IV acceptable) - **Concentration:** 1:10,000 (0.1 mg/mL) [cite:AHA 2020 Guidelines for CPR and ECC]