Airway management: high-flow nasal 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 · Airway management: high-flow nasal oxygen

Sample item

How does heated humidified high-flow nasal oxygen improve oxygenation during apnoea or in hypoxaemic respiratory failure?

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

The answer and the reasoning

B. It delivers a set FiO2, flushes pharyngeal dead space and gives low-level positive airway pressure

High flows exceed inspiratory demand, so the delivered fraction is reliable, the pharyngeal dead space is washed out and a modest positive pressure is generated. During apnoea, oxygen is delivered continuously and extends safe apnoea time.

Option by option

  • A. It delivers 100 percent oxygen through a closed circuit with a sealed face mask

    It is an open system with nasal prongs and not a sealed circuit.

  • B. It delivers a set FiO2, flushes pharyngeal dead space and gives low-level positive airway pressure (correct)

    Correct. These are the three recognised mechanisms of benefit.

  • C. It provides pressure-support breaths synchronised with inspiration

    Synchronised pressure-support breaths are given by non-invasive ventilation.

  • D. It replaces ventilation by paralysing the respiratory muscles

    It does not paralyse muscles or replace ventilation.

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 B, It delivers a set FiO2, flushes pharyngeal dead space and gives low-level positive airway pressure. High flows exceed inspiratory demand, so the delivered fraction is reliable, the pharyngeal dead space is washed out and a modest positive pressure is generated.

Why is "It delivers 100 percent oxygen through a closed circuit with a sealed…" not the answer?

It is an open system with nasal prongs and not a sealed circuit.

Why is "It provides pressure-support breaths synchronised with inspiration" not the answer?

Synchronised pressure-support breaths are given by non-invasive ventilation.

Why is "It replaces ventilation by paralysing the respiratory muscles" not the answer?

It does not paralyse muscles or replace ventilation.

What concept does this question test?

It tests Airway management: high-flow nasal oxygen in Anaesthesia. During apnoea, oxygen is delivered continuously and extends safe apnoea time.

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 management: high-flow nasal 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.