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Carbon monoxide poisoning — SCE Acute Medicine MCQ

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HardToxicology and OverdoseCarbon monoxide poisoningSCE Acute Medicine

A patient rescued from an enclosed-space fire has soot in the airway, profound lactic acidosis at 14 mmol/L, hypotension and altered consciousness despite high-flow oxygen. What antidote should be considered?

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

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Correct answer: B — Give hydroxocobalamin for suspected smoke-related cyanide toxicity

The best answer is “Give hydroxocobalamin for suspected smoke-related cyanide toxicity”. This is correct because severe lactate elevation, cardiovascular collapse and neurological impairment in an enclosed fire strongly suggest cyanide exposure. Hydroxocobalamin binds cyanide and is compatible with concurrent CO poisoning. Nitrite-induced methaemoglobinaemia can worsen oxygen carriage, and confirmatory assays must not delay treatment.

Reference: Resuscitation Council UK special-circumstances guidance: https://www.resus.org.uk/professional-library/2025-resuscitation-guidelines/special-circumstances-guidelines