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

During one-lung ventilation, blood flow to the collapsed, non-ventilated lung is partly diverted by a local mechanism that limits the shunt. What is this mechanism?

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

The answer and the reasoning

B. Hypoxic pulmonary vasoconstriction

Low alveolar oxygen tension constricts the pulmonary arterioles supplying that region, diverting blood to better ventilated lung. Volatile agents blunt the response somewhat, and vasodilators abolish it. It is a local response and not a neural reflex.

Option by option

  • A. Hering-Breuer inflation reflex

    The Hering-Breuer reflex inhibits inspiration when the lungs are stretched.

  • B. Hypoxic pulmonary vasoconstriction (correct)

    Correct. Local hypoxia constricts the pulmonary vessels and redirects blood flow.

  • C. Bainbridge reflex

    The Bainbridge reflex raises heart rate when the right atrium is stretched.

  • D. Bezold-Jarisch reflex

    The Bezold-Jarisch reflex causes bradycardia and hypotension through cardiac chemoreceptors.

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, Hypoxic pulmonary vasoconstriction. Low alveolar oxygen tension constricts the pulmonary arterioles supplying that region, diverting blood to better ventilated lung.

Why is "Hering-Breuer inflation reflex" not the answer?

The Hering-Breuer reflex inhibits inspiration when the lungs are stretched.

Why is "Bainbridge reflex" not the answer?

The Bainbridge reflex raises heart rate when the right atrium is stretched.

Why is "Bezold-Jarisch reflex" not the answer?

The Bezold-Jarisch reflex causes bradycardia and hypotension through cardiac chemoreceptors.

What concept does this question test?

It tests Respiratory physiology and ventilation: curriculum recognition in Anaesthesia. Volatile agents blunt the response somewhat, and vasodilators abolish it. It is a local response and not a neural reflex.

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.