Respiratory physiology and ventilation: 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 · Respiratory physiology and ventilation: curriculum recognition

Sample item

A paralysed patient receives a tidal volume of 400 mL, with a plateau pressure of 25 cmH2O and PEEP of 5 cmH2O. What is the static compliance?

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

The answer and the reasoning

B. 20 mL/cmH2O

Static compliance is the tidal volume divided by the plateau pressure minus PEEP, which is 400 / (25 - 5) = 20 mL per cmH2O. Forgetting to subtract PEEP gives a falsely low value. Normal values in ventilated adults are higher, so this indicates stiff lungs.

Option by option

  • A. 80 mL/cmH2O

    This divides by the PEEP alone and is meaningless here.

  • B. 20 mL/cmH2O (correct)

    Correct. 400 divided by the driving pressure of 20 gives 20.

  • C. 16 mL/cmH2O

    This divides by the plateau pressure alone and ignores PEEP.

  • D. 13 mL/cmH2O

    This divides by 30, adding PEEP to the plateau pressure.

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, 20 mL/cmH2O. Static compliance is the tidal volume divided by the plateau pressure minus PEEP, which is 400 / (25 - 5) = 20 mL per cmH2O.

Why is "80 mL/cmH2O" not the answer?

This divides by the PEEP alone and is meaningless here.

Why is "16 mL/cmH2O" not the answer?

This divides by the plateau pressure alone and ignores PEEP.

Why is "13 mL/cmH2O" not the answer?

This divides by 30, adding PEEP to the plateau pressure.

What concept does this question test?

It tests Respiratory physiology and ventilation: curriculum recognition in Anaesthesia. Forgetting to subtract PEEP gives a falsely low value. Normal values in ventilated adults are higher, so this indicates stiff lungs.

How hard is this question?

We tag it as a multi-step question: it asks you to combine more than one idea. 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 Respiratory physiology and ventilation: 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.