skip to main content

Carbon monoxide poisoning — MCCQE Part 1 MCQ

Instant feedback + full explanation. One question, done properly.

ModeratePoisoning/OverdoseCarbon monoxide poisoningMCCQE Part 1

39-year-old woman presents with headache and nausea in winter. Her family members also feel unwell and carboxyhaemoglobin is elevated. Which of the following is the most appropriate next step?

Educational content. Not a substitute for clinical judgement or local policy.

Reveal the answer and explanation

Correct answer: C — Give high-flow oxygen and assess need for hyperbaric oxygen

Give high-flow oxygen and assess need for hyperbaric oxygen is best because clustered symptoms and elevated COHb indicate carbon monoxide poisoning. Wait for confirmatory testing before any stabilisation is suboptimal because resuscitation and time-critical treatment should not wait when instability is present; Discharge once symptoms temporarily improve is suboptimal because temporary improvement can precede deterioration; Give an adjunctive medication as the sole first-line treatment is suboptimal because adjuncts do not replace definitive stabilisation; Delay escalation until cardiac arrest or respiratory failure occurs is suboptimal because early escalation is central to emergency care. Pulse oximetry can be falsely reassuring.

Reference: Canadian emergency medicine/toxicology guidance