Emergency Medicine and Critical Care: Time-Critical Sequences
Emergency and critical care items test structured resuscitation under time pressure: airway, breathing, circulation, disability, exposure, then definitive care. The exam rewards correct sequencing and recognition of the patient who is occultly shocked, and penalises interventions given in the wrong order or at the wrong dose.
Core rules
- Primary survey. Airway with cervical protection, oxygen and ventilation, IV access with fluid resuscitation, neurological status including glucose, and exposure with prevention of hypothermia.
- Shock. Cold peripheries and narrow pulse pressure suggest low output; warm peripheries with wide pulse pressure suggest distributive shock. Lactate and base deficit quantify hypoperfusion; focused ultrasound answers the cause.
- Sepsis. Measure lactate, obtain cultures without delaying treatment, give broad-spectrum antibiotics within 1 hour for septic shock, give 30 mL/kg crystalloid, and start norepinephrine to target mean arterial pressure ≥65 mmHg.
- Cardiac arrest. Shockable rhythms receive immediate defibrillation, then compressions, epinephrine and amiodarone; search for the reversible causes (hypoxia, hypovolaemia, hypothermia, hypo/hyperkalaemia, tamponade, tension pneumothorax, thrombosis, toxins).
- Anaphylaxis. Intramuscular epinephrine 1:1000, 0.3–0.5 mg into the anterolateral thigh, repeated after 5 minutes; antihistamines and corticosteroids are adjuncts only.
Worked example
A 72-year-old woman with fever and confusion has blood pressure 82/50 mmHg, heart rate 118/min, respiratory rate 28/min and lactate 4.2 mmol/L. This is septic shock: infection plus vasopressor-requiring hypotension or lactate >2 mmol/L. Give 30 mL/kg of balanced crystalloid, take blood cultures if this causes no delay, give broad-spectrum antibiotics within 1 hour, start norepinephrine if mean arterial pressure remains below 65 mmHg, obtain source control, and reassess fluid responsiveness rather than repeating boluses reflexively. The reasoning: lactate marks hypoperfusion, antibiotics are the only intervention that alters survival in a time-dependent way, and excess fluid harms patients with cardiac dysfunction.
Traps that cost marks
- Giving intravenous push epinephrine instead of intramuscular injection in anaphylaxis.
- Delaying antibiotics to obtain cultures or imaging in septic shock.
- Infusing large fluid volumes in cardiogenic shock or pulmonary oedema.
- Forgetting to check and treat glucose and to consider thiamine before dextrose in malnourished patients.