Intravenous and inhalational agents: nitrous oxide and pulmonary hypertension: 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 · Intravenous and inhalational agents: nitrous oxide and pulmonary hypertension

Sample item

Which statement describes the effect of nitrous oxide in a patient with pulmonary hypertension?

AIt has no pulmonary vascular effect and is safeBIt can raise pulmonary vascular resistance, so it is best avoidedCIt dilates pulmonary vessels by releasing nitric oxideDIt lowers pulmonary vascular resistance and is a preferred adjunct

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

The answer and the reasoning

B. It can raise pulmonary vascular resistance, so it is best avoided

Nitrous oxide can increase pulmonary vascular resistance, particularly in patients with pre-existing pulmonary hypertension, and so is usually avoided in them. It is a different molecule from nitric oxide, the inhaled pulmonary vasodilator.

Option by option

A. It has no pulmonary vascular effect and is safe
It has a recognised pulmonary vascular effect in pulmonary hypertension.
B. It can raise pulmonary vascular resistance, so it is best avoided (correct)
Correct. It may increase pulmonary vascular resistance and worsen right heart strain.
C. It dilates pulmonary vessels by releasing nitric oxide
Nitrous oxide is not nitric oxide and does not release it.
D. It lowers pulmonary vascular resistance and is a preferred adjunct
It does not lower pulmonary vascular resistance.

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.

Questions about this Anaesthesia question

What is the answer to this Anaesthesia question?

The best answer is B, It can raise pulmonary vascular resistance, so it is best avoided. Nitrous oxide can increase pulmonary vascular resistance, particularly in patients with pre-existing pulmonary hypertension, and so is usually avoided in them.

Why is "It has no pulmonary vascular effect and is safe" not the answer?

It has a recognised pulmonary vascular effect in pulmonary hypertension.

Why is "It dilates pulmonary vessels by releasing nitric oxide" not the answer?

Nitrous oxide is not nitric oxide and does not release it.

Why is "It lowers pulmonary vascular resistance and is a preferred adjunct" not the answer?

It does not lower pulmonary vascular resistance.

What concept does this question test?

It tests Intravenous and inhalational agents: nitrous oxide and pulmonary hypertension in Anaesthesia. It is a different molecule from nitric oxide, the inhaled pulmonary vasodilator.

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 Intravenous and inhalational agents: nitrous oxide and pulmonary hypertension?

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.