Special anaesthesia: hyperbaric oxygen: practice question

A Anaesthesia 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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Anaesthesia · Special anaesthesia: hyperbaric oxygen

Sample item

What is the elimination half-life of carboxyhaemoglobin when the patient breathes 100% oxygen at normal atmospheric pressure?

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

The answer and the reasoning

A. About 60 to 90 minutes

The half-life of COHb is about 4 to 6 hours in room air, around 60 to 90 minutes on 100% oxygen and about 20 to 30 minutes in hyperbaric oxygen at 3 atmospheres.

Option by option

  • A. About 60 to 90 minutes (correct)

    Correct. 100% oxygen shortens it to about 1 hour.

  • B. About 24 hours

    24 hours is far too long.

  • C. About 10 minutes

    10 minutes is shorter than hyperbaric values.

  • D. About 5 hours

    5 hours is the half-life on room air.

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 Anaesthesia question

What is the answer to this Anaesthesia question?

The best answer is A, About 60 to 90 minutes. The half-life of COHb is about 4 to 6 hours in room air, around 60 to 90 minutes on 100% oxygen and about 20 to 30 minutes in hyperbaric oxygen at 3 atmospheres.

Why is "About 24 hours" not the answer?

24 hours is far too long.

Why is "About 10 minutes" not the answer?

10 minutes is shorter than hyperbaric values.

Why is "About 5 hours" not the answer?

5 hours is the half-life on room air.

What concept does this question test?

It tests Special anaesthesia: hyperbaric oxygen in Anaesthesia. The correct option holds because: Correct. 100% oxygen shortens it to about 1 hour.

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 Special anaesthesia: hyperbaric oxygen?

Make a table of each agent, its key advantage and its main side effect. Then use the flashcards and the other Anaesthesia 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.