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NEW Added to close a syllabus gap — resuscitation and emergency medicine is its own top-level syllabus section.

Resuscitation: BLS & ALS

The algorithm split by rhythm, the reversible causes, drug doses, and what changes in the special circumstances you will be asked about.

The algorithm

Shockable — VF / pulseless VTNon-shockable — PEA / asystole
First actionShock immediately, then resume CPR for 2 minCPR 2 min; adrenaline as soon as access is obtained
Adrenaline1 mg after the 3rd shock, then every 3–5 min (alternate cycles)1 mg immediately, then every 3–5 min
Amiodarone300 mg after the 3rd shock; further 150 mg after the 5thNot indicated
Energy150–200 J biphasic, then 150–360 J
  • Compressions: depth 5–6 cm, rate 100–120/min, ratio 30:2 until the airway is secured, then continuous compressions with 10 breaths/min.
  • Minimise interruptions — pre-charge the defibrillator and pause for under 5 seconds.
  • Paediatric differs: 5 rescue breaths first, ratio 15:2 (2 rescuers), defibrillation 4 J/kg, adrenaline 10 µg/kg.
  • Neonatal differs again: ratio 3:1, start in air.

Reversible causes — 4 Hs and 4 Ts

4 Hs4 Ts
Hypoxia
Hypovolaemia
Hyper/hypokalaemia & metabolic
Hypothermia
Tension pneumothorax
Tamponade (cardiac)
Toxins
Thrombosis (coronary or pulmonary)
  • Capnography is mandatory once intubated: confirms tube position, gauges CPR quality, and a sudden rise in ETCO₂ suggests ROSC. Persistently <1.3 kPa (10 mmHg) after 20 min is a poor prognostic sign.
  • Ultrasound during the rhythm check helps identify tamponade, hypovolaemia, PE and pneumothorax — without extending the pause.

Special circumstances

  • Anaphylaxis: adrenaline 500 µg IM (0.5 ml of 1:1000); under anaesthesia with IV access, 50 µg IV boluses. Remove the trigger, fluids, then chlorphenamine and hydrocortisone as second line. Mast cell tryptase immediately, at 1–2 h, and a baseline at 24 h.
  • Local anaesthetic toxicity: stop injecting, 100% oxygen, control seizures, 20% lipid emulsion 1.5 ml/kg then 15 ml/kg/h. Avoid lidocaine and vasopressin; use small adrenaline doses. Prolonged resuscitation may be needed.
  • Hyperkalaemia: calcium chloride/gluconate to stabilise the myocardium, insulin-dextrose and salbutamol to shift, dialysis to remove.
  • Hypothermic arrest: "not dead until warm and dead". Withhold drugs below 30 °C; limit to 3 shocks below 30 °C. Rewarm actively, consider ECMO.
  • Pregnancy: manual left uterine displacement, early airway control, and perimortem caesarean section within 5 minutes if no ROSC after 4 minutes — done for the mother's benefit, to relieve aortocaval compression.
  • Massive PE: consider thrombolysis and continue CPR for 60–90 minutes afterwards.

Post-resuscitation care

  • Targeted temperature management — avoid fever, maintain 32–36 °C for at least 24 hours in comatose survivors.
  • Normoxia and normocapnia — titrate FiO₂ to SpO₂ 94–98%; hyperoxia worsens reperfusion injury.
  • Coronary angiography if a cardiac cause is suspected · glycaemic control · seizure treatment · delay prognostication for at least 72 hours.

Guidance follows current ERC/Resuscitation Council principles. Always check the live algorithm before an exam — the details are periodically revised.