High-Yield Emergency Medicine and ACLS for Medical Exams

Emergency questions test whether you act in the right order. The correct answer is often not the most sophisticated treatment but the most urgent one. This guide summarises resuscitation and emergency algorithms as published by the major resuscitation councils, for exam revision. It does not replace an accredited life support course.

ABCDE: the universal first step

Exam rule: fix problems as you find them, and reassess after every intervention. If the airway is compromised, nothing else comes first.

Adult cardiac arrest

Core principles

• Confirm arrest, call for help, start high-quality CPR: compression depth about 5–6 cm, rate 100–120 per minute, full recoil, minimal interruptions, 30:2 until an advanced airway is placed.
• Attach a defibrillator and assess the rhythm as soon as possible.

Shockable rhythms: VF and pulseless VT

1. Deliver one shock, then immediately resume CPR for two minutes.
2. Reassess the rhythm; shock again if still shockable.
3. Adrenaline 1 mg IV/IO after the third shock in UK and European guidance (American guidance gives it after the second shock), then every 3–5 minutes.
4. Amiodarone 300 mg after the third shock; a further 150 mg after the fifth (lidocaine is an alternative in some guidance).

Non-shockable rhythms: asystole and PEA

1. CPR.
2. Adrenaline 1 mg IV/IO as soon as access is obtained, then every 3–5 minutes.
3. Search for and treat reversible causes.

Reversible causes

After return of spontaneous circulation

ABCDE reassessment, 12-lead ECG, target normal oxygen and carbon dioxide, maintain blood pressure, consider urgent coronary angiography if a cardiac cause is likely, control temperature (avoid fever), and treat seizures.

Peri-arrest arrhythmias

Tachycardia with a pulse

Trap: adenosine is avoided in severe asthma; verapamil is an alternative in some guidance.

Bradycardia

If adverse features (shock, syncope, ischaemia, heart failure): atropine 500 micrograms IV (UK/Europe) or 1 mg (US), repeated to a maximum; if ineffective, transcutaneous pacing or drugs such as isoprenaline or adrenaline infusion, then expert help. Risk of asystole (recent asystole, Mobitz II, complete heart block with broad QRS, ventricular pauses over 3 seconds) needs transvenous pacing.

Anaphylaxis

• Recognition: sudden airway, breathing or circulation problems, usually with skin or mucosal changes, after a trigger (food, drug, sting).
• First line: intramuscular adrenaline into the anterolateral thigh. Adult dose 500 micrograms (0.5 mL of 1 mg/mL); smaller doses for children by age. Repeat after about 5 minutes if needed.
• Supportive: lie flat (sit up if breathing difficulty), high-flow oxygen, IV fluid bolus.
• Refractory: after two doses of IM adrenaline with ongoing problems, get expert help for an adrenaline infusion.
• After: observe for biphasic reactions, measure mast cell tryptase, refer to allergy services, provide adrenaline auto-injectors.

Trap: antihistamines and steroids are not life-saving first-line treatment.

Shock

Trauma

• Catastrophic haemorrhage first (direct pressure, tourniquet), then airway with cervical spine protection, breathing, circulation.
• Haemorrhagic shock: limit crystalloid, give blood products early, tranexamic acid early in major bleeding, and arrange haemorrhage control (surgery or interventional radiology).
• Life-threatening chest injuries: tension pneumothorax, open pneumothorax, massive haemothorax, flail chest, cardiac tamponade.
• Head injury: GCS assessment; CT head criteria include GCS below 13 at first assessment, suspected open or depressed skull fracture, signs of basal skull fracture, post-traumatic seizure, focal neurology, more than one episode of vomiting, and anticoagulant use.

Stroke

• Recognise: sudden facial droop, arm weakness, speech disturbance; exclude hypoglycaemia.
• Imaging: urgent non-contrast CT to exclude haemorrhage.
• Ischaemic stroke: thrombolysis within the licensed time window if criteria are met; mechanical thrombectomy for large-vessel occlusion in selected patients within guideline time windows; aspirin after haemorrhage is excluded (delayed 24 hours after thrombolysis).
• Haemorrhagic stroke: reverse anticoagulation, manage blood pressure, neurosurgical input.
• TIA: aspirin and urgent specialist assessment.

Other emergencies at a glance

Paediatric resuscitation pointers

• Most paediatric arrests are respiratory in origin: open the airway and give five rescue breaths first.
• Compression-to-breath ratio 15:2 for healthcare providers.
• Doses are weight-based; adrenaline 10 micrograms/kg.

Common exam traps

• Choosing investigations before airway or breathing interventions.
• Delaying defibrillation in VF to give drugs.
• Giving adrenaline in anaphylaxis intravenously as a first step outside monitored settings, or using the wrong concentration.
• Treating unstable tachycardia with drugs instead of synchronised cardioversion.
• Thrombolysing a stroke without excluding haemorrhage.
• Ordering a chest X-ray in tension pneumothorax before decompression.

How to revise

Say the algorithms aloud and draw them from memory until they are automatic. Then practise "next step" questions under time pressure. MediFlow Exam Prep includes emergency medicine and resuscitation questions with explanations. Pair this guide with high-yield cardiology and high-yield respiratory medicine.

Summary

• ABCDE, fix as you go, reassess.
• Shockable rhythms: shock early, CPR, adrenaline and amiodarone at the right point.
• Non-shockable: CPR, early adrenaline, four Hs and four Ts.
• Anaphylaxis: intramuscular adrenaline first.
• Unstable arrhythmia: electricity, not drugs.