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Carbon monoxide poisoning — MCCQE Part 1 MCQ

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HardPoisoning/OverdoseCarbon monoxide poisoningMCCQE Part 1

A 36-year-old woman and her child present with headache, nausea and dizziness after using a generator in a garage during a power outage. Pulse oximetry reads 99%, but venous carboxyhaemoglobin is elevated. The child is confused. What is the most appropriate next step in management?

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Correct answer: C — Give high-flow oxygen and consult poison control about hyperbaric therapy criteria

CO poisoning causes tissue hypoxia while standard pulse oximetry may appear normal; high-flow oxygen is immediate treatment, and hyperbaric oxygen is considered for severe features such as neurologic symptoms, pregnancy or high levels. Antibiotics do not address exposure poisoning. Poison control consultation supports local access decisions.

Reference: Ontario Poison Centre carbon monoxide guidance