🚨 Cardiac Arrest

The sudden cessation of cardiac mechanical activity, confirmed by the absence of signs of circulation. It is a medical emergency requiring immediate recognition and initiation of Advanced Life Support (ALS) to maximise the chance of survival. Reversible causes must be identified and treated.

Unresponsive and not breathing normally (e.g., gasping or agonal breaths). Absence of a palpable pulse. These signs indicate cardiac arrest and necessitate immediate activation of the emergency response system and commencement of chest compressions.

Check for danger, then assess responsiveness and normal breathing. If unresponsive and not breathing normally, shout for help and activate the emergency team. Immediately commence chest compressions and prepare for defibrillation. Do not delay for pulse checks if unsure.

Any patient who becomes unresponsive and stops breathing normally. Deterioration to cardiac arrest from a previously stable state. Failure to achieve ROSC (Return of Spontaneous Circulation) after initial ALS cycles.

No investigations should delay commencement of CPR. During ALS, ECG rhythm analysis is critical for determining defibrillation eligibility. Point-of-care ultrasound (POCUS) can be used to identify reversible causes (e.g., tamponade, massive PE). Blood tests are taken post-ROSC to guide further management.

Start high-quality chest compressions immediately (rate 100-120/min, depth 5-6cm). Deliver rescue breaths (30:2 ratio). Attach a defibrillator as soon as available and perform rhythm analysis. Defibrillate if the rhythm is shockable (VF/pulseless VT). Administer appropriate medications (e.g., adrenaline, amiodarone) as per ALS algorithm. Identify and treat reversible causes (4Hs and 4Ts).

Cardiac arrest is the ultimate medical emergency, requiring immediate activation of the highest level of emergency response. Failure to achieve ROSC after multiple ALS cycles, or recurrent arrest, requires ongoing senior medical and critical care input. Post-ROSC, immediate ICU referral is standard.

Remember the 4Hs (Hypoxia, Hypovolaemia, Hypo/Hyperkalaemia, Hypothermia) and 4Ts (Tension pneumothorax, Tamponade, Toxins, Thrombosis - coronary/pulmonary) as reversible causes. High-quality chest compressions are paramount. Early defibrillation for shockable rhythms significantly improves outcomes. Post-ROSC care is crucial for neurological outcome.