Cardiac Arrest

What Is Cardiac Arrest?

Cardiac arrest is the sudden loss of effective heart function, causing blood flow to stop and the patient to become unresponsive, pulseless, and apneic or agonally breathing. It's classified by the underlying rhythm, which determines treatment: shockable rhythms (ventricular fibrillation and pulseless ventricular tachycardia) respond to defibrillation, while non-shockable rhythms (asystole and pulseless electrical activity) do not and rely instead on high-quality CPR, epinephrine, and identifying/treating reversible causes. Common causes include acute coronary events, severe arrhythmias, respiratory failure leading to hypoxic arrest, drowning, electrocution, trauma, and overdose. Survival depends heavily on the chain of survival — early recognition and 911 activation, immediate high-quality CPR, rapid defibrillation, effective advanced life support, and integrated post-arrest care.

Why Cardiac Arrest Matters on the Fireground

Cardiac arrest is one of the most time-critical emergencies in EMS — survival drops roughly 7-10% for every minute defibrillation is delayed in a shockable rhythm, and brain injury begins within minutes of blood flow stopping. Firefighters are frequently first on scene before an ALS ambulance arrives, making early, high-quality CPR and rapid AED application by the first-arriving crew one of the single biggest factors in whether a patient survives with good neurological outcome.

Relevant NFPA Standards

• AHA Guidelines: Guidelines for Cardiopulmonary Resuscitation and Emergency Cardiovascular Care
• NFPA 455: Standard for Emergency Medical Services (EMS)

Field Procedures & Tactical Steps

1. Confirm unresponsiveness and absence of normal breathing, then begin high-quality chest compressions immediately at a rate of 100–120 per minute.
2. Apply the AED or cardiac monitor as soon as available and follow prompts to analyze rhythm and deliver a shock if indicated.
3. Continue CPR with minimal interruptions, rotating compressors every 2 minutes to maintain compression quality and prevent fatigue.
4. Establish IV/IO access and administer epinephrine and other medications per ACLS protocol while identifying and treating reversible causes.
5. Reassess rhythm and pulse per protocol intervals, and prepare for post-resuscitation care immediately if return of spontaneous circulation occurs.

Common Context & Application

Encountered on scenes ranging from witnessed collapse at home to sudden collapse in public, drowning, overdose, and trauma — often the first fire apparatus on scene begins CPR and applies an AED well before an ALS ambulance arrives, making first-responder BLS care central to the patient's outcome.

Frequently Asked Questions about Cardiac Arrest