Paediatric emergencies: carbon monoxide poisoning: practice question

A Pediatrics question in the style of the NEET PG paper. Answer it first, then read why the right option is right and why each of the others is wrong.

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Pediatrics · Paediatric emergencies: carbon monoxide poisoning

Sample item

A 6-year-old is rescued from a closed room where a charcoal stove burned overnight. She is drowsy with headache and vomiting, and a pulse oximeter reads 99 percent on room air. Which is the most appropriate immediate treatment?

Original practice item, not a recalled exam question. Nothing here is recorded.

The answer and the reasoning

D. 100 percent oxygen through a non-rebreathing mask

Carbon monoxide binds haemoglobin with high affinity, and standard pulse oximeters misread carboxyhaemoglobin as oxyhaemoglobin, so the saturation looks normal. Treatment is 100 percent oxygen, which shortens the half-life of carboxyhaemoglobin, with hyperbaric oxygen for severe cases.

Option by option

  • A. Intravenous methylene blue

    Methylene blue treats methaemoglobinaemia and is not an antidote for carbon monoxide.

  • B. Observation on room air since saturation is normal

    Normal oximetry does not exclude carbon monoxide poisoning, and observation on room air delays treatment.

  • C. Intravenous hydroxocobalamin

    Hydroxocobalamin is the antidote for cyanide poisoning.

  • D. 100 percent oxygen through a non-rebreathing mask (correct)

    Correct. High-concentration oxygen displaces carbon monoxide faster, and the oximeter reading is falsely reassuring.

Source note: Original NextPrep sample item — pending expert review. This item is original practice material awaiting independent expert review, so confirm important facts in a standard textbook.

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Questions about this Pediatrics question

What is the answer to this Pediatrics question?

The best answer is D, 100 percent oxygen through a non-rebreathing mask. Carbon monoxide binds haemoglobin with high affinity, and standard pulse oximeters misread carboxyhaemoglobin as oxyhaemoglobin, so the saturation looks normal.

Why is "Intravenous methylene blue" not the answer?

Methylene blue treats methaemoglobinaemia and is not an antidote for carbon monoxide.

Why is "Observation on room air since saturation is normal" not the answer?

Normal oximetry does not exclude carbon monoxide poisoning, and observation on room air delays treatment.

Why is "Intravenous hydroxocobalamin" not the answer?

Hydroxocobalamin is the antidote for cyanide poisoning.

What concept does this question test?

It tests Paediatric emergencies: carbon monoxide poisoning in Pediatrics. Treatment is 100 percent oxygen, which shortens the half-life of carboxyhaemoglobin, with hyperbaric oxygen for severe cases.

How hard is this question?

We tag it as an application question: it asks you to use a fact on a patient or a finding. The tag is our own editorial judgement, not an official difficulty rating, so read the reason for every option, not only the answer.

How should I study Paediatric emergencies: carbon monoxide poisoning?

Memorise milestones and the vaccine schedule as tables and revise them often. Then use the flashcards and the other Pediatrics questions on this site to test what stuck.

Is this a real NEET PG question?

No. It is an original practice item (editorial status: sample, version 1). NextPrep does not publish recalled or leaked questions, and independent faculty review of this item has not been completed yet, so confirm important facts in a standard textbook.