Epinephrine Dose: Optimal Versus Standard Evaluation Trial

Inclusion Criteria: * Out-of-hospital cardiac arrest treated by paramedics AND * Initial recorded cardiac rhythm of VF or pulseless VT, or, AED shock on first analysis administered or confirmed by paramedics or fire services, AND * Established intravenous vascular access Exclusion Criteria: * Known or apparent age \<18 years * Initial recorded cardiac rhythm of VF or pulseless VT, or, AED shock on first analysis administered or confirmed by paramedics * Cardiac arrest due to an obvious non-cardiac primary cause (e.g. blunt or penetrating trauma, exsanguination, burns, drug overdose, drowning, anaphylaxis, sudden asphyxiation, etc.) * Administration of intramuscular, endotracheal tube, or intraosseous epinephrine * Prisoners or persons in police custody * Known allergy or sensitivity to epinephrine