Cardiac Arrest on the NREMT
Cardiac arrest management is the most heavily tested clinical topic on the NREMT exam because it is the most critical skill an EMS provider possesses. The difference between a provider who manages cardiac arrest confidently and one who hesitates can be measured in lives saved. This review covers the current American Heart Association algorithms, emphasizing the decision points and priorities that the NREMT is most likely to test.
Cardiac arrest is defined as the absence of effective cardiac activity, confirmed by unresponsiveness, absent breathing (or only agonal gasps), and absent pulse. When you identify cardiac arrest, the sequence is: activate additional resources, begin CPR, and apply the AED or cardiac monitor as soon as available. Every second of delay in initiating CPR reduces the patient's chance of survival.
High-Quality CPR Components
The foundation of cardiac arrest management is high-quality CPR. Every element matters:
- Compression rate: 100 to 120 compressions per minute. Faster than 120 results in inadequate chest recoil and reduced coronary perfusion.
- Compression depth: At least 2 inches (5 cm) but no more than 2.4 inches (6 cm) for adults. Insufficient depth is the most common CPR error.
- Full chest recoil: Allow the chest to return to its normal position between compressions. Leaning on the chest between compressions prevents cardiac filling.
- Minimal interruptions: Chest compression fraction (the percentage of time compressions are being performed) should be at least 80%. Pause only for rhythm checks (no more than 10 seconds) and defibrillation.
- Ventilation ratio: 30 compressions to 2 ventilations for patients without an advanced airway. Each ventilation should be delivered over 1 second with just enough volume to produce visible chest rise. With an advanced airway in place, deliver 1 ventilation every 6 seconds (10 per minute) without pausing compressions.
Shockable vs. Non-Shockable Rhythms
The cardiac arrest algorithm branches based on the rhythm identified:
Shockable rhythms (VF/pulseless VT): Defibrillate immediately, then resume CPR for 2 minutes before the next rhythm check. Administer epinephrine 1 mg IV/IO after the second shock (and every 3 to 5 minutes thereafter). Administer amiodarone 300 mg IV/IO after the third shock (followed by 150 mg for the next dose if needed). Consider reversible causes (Hs and Ts).
Non-shockable rhythms (asystole/PEA): Continue CPR, administer epinephrine 1 mg IV/IO as soon as possible (and every 3 to 5 minutes), and aggressively search for and treat reversible causes. The Hs and Ts mnemonic helps identify treatable causes: Hypovolemia, Hypoxia, Hydrogen ion (acidosis), Hypo/Hyperkalemia, Hypothermia, Tension pneumothorax, Tamponade (cardiac), Toxins, Thrombosis (pulmonary), Thrombosis (coronary).
Post-ROSC Care
When return of spontaneous circulation (ROSC) is achieved (indicated by a palpable pulse, rising ETCO2, or arterial waveform), transition to post-cardiac arrest care. Priorities include maintaining adequate oxygenation (target SpO2 94 to 99%, avoid hyperoxia), supporting blood pressure (target systolic BP above 90), obtaining a 12-lead ECG to identify STEMI, and transporting to a cardiac arrest center if available. Document the time of arrest, the time CPR was initiated, the number of shocks delivered, medications administered, and the time of ROSC.