Cardiac Arrest Algorithms
The cardiac arrest algorithm is the single most-tested paramedic protocol. Master the shockable/non-shockable fork and the rest of the code writes itself.
EMT · AEMT · Paramedic
High-quality CPR is the foundation
Nothing else works without perfusion. Rate 100–120, depth 2–2.4 inches, full recoil, minimize interruptions to under 10 seconds, rotate compressors every 2 minutes.
Shockable rhythms: VF and pulseless VT
Defibrillate immediately, then 2 minutes of CPR. Epinephrine 1 mg after the second shock, every 3–5 minutes. Amiodarone 300 mg after the third shock (150 mg second dose) or lidocaine 1–1.5 mg/kg.
Non-shockable: PEA and asystole
CPR, epi 1 mg ASAP, then every 3–5 minutes. Hunt reversible causes — the H's and T's — because that's the only path to ROSC.
- Hypovolemia, Hypoxia, Hydrogen ion, Hypo/Hyperkalemia, Hypothermia
- Tension pneumothorax, Tamponade, Toxins, Thrombosis (cardiac/pulmonary)
Airway during arrest
BVM with good technique is fine early. Supraglottic airway is a strong choice; ETI only if it doesn't interrupt compressions. Once secured, ventilate 10/min asynchronous with compressions.
Post-ROSC care
12-lead ECG, treat hypotension (fluids + norepi), target SpO2 92–98% (not 100%), avoid hyperventilation (target ETCO2 35–40), transport to a PCI-capable center if STEMI present or suspected.
Frequently asked
- When do you stop resuscitation in the field?
- Per local protocol — commonly asystole after 20+ minutes of ACLS with no reversible cause identified, or valid DNR. Traumatic arrest with no signs of life may have shorter criteria.
- Is sodium bicarb still given in cardiac arrest?
- Not routinely. Consider for known hyperkalemia, TCA overdose, or prolonged arrest with confirmed severe acidosis.
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