Cardiac Arrest Algorithms
The Adult Cardiac Arrest Algorithm organizes the chaos of a code into a repeatable 2-minute cycle. This chapter walks the shockable and non-shockable pathways and the reversible causes you must hunt for.
The 2-minute cycle: shockable and non-shockable pathways
Cardiac arrest care runs in 2-minute cycles of high-quality CPR punctuated by rhythm checks. In the shockable pathway (VF/pVT): shock, immediately resume CPR for 2 minutes, then re-check the rhythm; give epinephrine every 3-5 minutes after the first shock, and add amiodarone or lidocaine for refractory VF/pVT. In the non-shockable pathway (asystole/PEA): do NOT shock; give epinephrine as soon as possible, continue CPR, and re-check the rhythm every 2 minutes. After each shock, resume compressions immediately — do not pause to check a pulse — because a perfusing rhythm often lags behind a successful shock.
The H's and T's — reversible causes
Especially in PEA and asystole, survival hinges on finding and fixing a reversible cause. The H's are hypovolemia, hypoxia, hydrogen ion (acidosis), hypo-/hyperkalemia, and hypothermia. The T's are tension pneumothorax, tamponade (cardiac), toxins, thrombosis of the lungs (pulmonary embolism), and thrombosis of the heart (acute coronary occlusion). Run through this checklist deliberately during CPR — for example, a needle decompression for tension pneumothorax or a fluid bolus for hypovolemia can reverse an arrest that no drug would fix.