Airway anatomy, equipment, and airway management: curriculum recognition: 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 · Airway anatomy, equipment, and airway management: curriculum recognition

Sample item

A laryngeal papilloma is to be excised with a laser under general anaesthesia. Which approach reduces the risk of an airway fire?

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

The answer and the reasoning

C. Lowest tolerated oxygen fraction, diluted with air, with no nitrous oxide

A fire needs fuel, an ignition source and an oxidiser. Oxygen and nitrous oxide both support combustion, so the lowest tolerable oxygen fraction, diluted with air or helium, is used. A laser-resistant tube with a saline-filled cuff is used to protect the fuel.

Option by option

  • A. Nitrous oxide in oxygen as the carrier gas

    Nitrous oxide supports combustion as oxygen does.

  • B. Pure oxygen to prevent desaturation during apnoea

    Pure oxygen strongly supports combustion and raises fire risk.

  • C. Lowest tolerated oxygen fraction, diluted with air, with no nitrous oxide (correct)

    Correct. Lowering the oxidiser concentration reduces the chance and severity of fire.

  • D. Unprotected PVC tube with an air-filled cuff

    A standard PVC tube is flammable and is an unsafe fuel source in a laser field.

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 C, Lowest tolerated oxygen fraction, diluted with air, with no nitrous oxide. A fire needs fuel, an ignition source and an oxidiser.

Why is "Nitrous oxide in oxygen as the carrier gas" not the answer?

Nitrous oxide supports combustion as oxygen does.

Why is "Pure oxygen to prevent desaturation during apnoea" not the answer?

Pure oxygen strongly supports combustion and raises fire risk.

Why is "Unprotected PVC tube with an air-filled cuff" not the answer?

A standard PVC tube is flammable and is an unsafe fuel source in a laser field.

What concept does this question test?

It tests Airway anatomy, equipment, and airway management: curriculum recognition in Anaesthesia. Oxygen and nitrous oxide both support combustion, so the lowest tolerable oxygen fraction, diluted with air or helium, is used. A laser-resistant tube with a saline-filled cuff is used to protect the fuel.

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 Airway anatomy, equipment, and airway management: curriculum recognition?

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.