CPR & Resuscitation Reference

Cardiopulmonary resuscitation (CPR) combined with automated external defibrillation (AED) is the foundational emergency intervention for cardiac arrest — the sudden cessation of effective cardiac output leading to global ischaemia. Cardiac arrest claims approximately 300,000 lives annually in the United States and 420,000 in Europe, with survival rates that remain below 10% for out-of-hospital cardiac arrest (OHCA) despite decades of research. Outcomes are directly tied to the speed and quality of CPR initiation, defibrillation delivery, and return of spontaneous circulation (ROSC). Advanced life support (ALS) protocols — standardised by the International Liaison Committee on Resuscitation (ILCOR) and implemented through national guidelines (Resuscitation Council UK, AHA, ERC) — structure resuscitation into a systematic 2-minute cycle of CPR (compressions:ventilations 30:2) interrupted only for rhythm check and defibrillation attempts. Shockable rhythms (ventricular fibrillation [VF] and pulseless ventricular tachycardia [pVT]) are treated with immediate defibrillation: biphasic defibrillators at 120–200 J (first shock) and 150–360 J (subsequent shocks); monophasic defibrillators at 360 J for all shocks. Non-shockable rhythms (pulseless electrical activity [PEA] and asystole) require continuous CPR with treatment of reversible causes (the '4Hs and 4Ts'). Adrenaline (epinephrine) 1 mg IV is administered every 3–5 minutes in all cardiac arrest rhythms; amiodarone 300 mg IV is given after the third shock in VF/pVT. Post-ROSC care targets: SBP >100 mmHg, SpO₂ 94–98%, PaCO₂ 35–45 mmHg, and targeted temperature management to prevent secondary neurological injury.

1. 1Confirm cardiac arrest: unresponsive, not breathing normally (absent or gasping breaths), no pulse palpable within 10 seconds — call for help, call 999/911, and start CPR immediately; do not delay compressions to look for a pulse for more than 10 seconds.
2. 2Deliver high-quality CPR: position hands on the lower half of the sternum; compress at rate 100–120/min; depth 5–6 cm (2–2.4 inches); allow full chest recoil after each compression; minimise interruptions to compressions (pause <10 seconds for rhythm check only); maintain 30:2 ratio until advanced airway is placed, then continuous compressions at 100–120/min with ventilation every 6 seconds.
3. 3Attach AED/defibrillator as soon as available: analyse rhythm; if VF or pVT is identified, deliver shock immediately (biphasic 120–200 J for first shock); immediately resume CPR after shock without checking pulse; continue 2-minute CPR cycles.
4. 4Secure IV or IO access during CPR; administer adrenaline (epinephrine) 1 mg IV as soon as access is established for non-shockable rhythms (PEA/asystole), or after the 3rd shock in VF/pVT; repeat every 3–5 minutes.
5. 5Administer amiodarone 300 mg IV after the third shock in refractory VF/pVT; a second dose of 150 mg IV may be given after the fifth shock if VF/pVT persists.
6. 6Systematically identify and treat reversible causes during every CPR cycle using the 4Hs and 4Ts mnemonic: Hypoxia — optimise oxygenation; Hypovolaemia — IV fluid bolus; Hyper/Hypokalaemia/metabolic — treat with ECG guidance; Hypothermia — active rewarming; Tension pneumothorax — needle decompression; Tamponade — pericardiocentesis or surgical drainage; Thrombosis (PE or coronary) — thrombolysis or primary PCI/surgical embolectomy; Toxins — specific antidotes.
7. 7After ROSC, initiate post-cardiac arrest care: maintain airway with endotracheal intubation if not already placed; target SpO₂ 94–98% (avoid hyperoxia); maintain SBP >100 mmHg with fluids/vasopressors; target PaCO₂ 35–45 mmHg (avoid hypo- and hypercapnia); 12-lead ECG for STEMI identification and emergency coronary angiography; initiate targeted temperature management (TTM) at 32–36°C if comatose.