Spinal anaesthesia: cardiac accelerators: 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 · Spinal anaesthesia: cardiac accelerators

Sample item

A high spinal block causes bradycardia mainly through blockade of which nerves?

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

The answer and the reasoning

C. Cardioaccelerator fibres from T1 to T4

Sympathetic fibres from T1 to T4 supply the heart, and their blockade removes sympathetic tone, leaving unopposed vagal influence. Reduced venous return also triggers the Bezold-Jarisch reflex.

Option by option

  • A. Phrenic nerve

    The phrenic nerve supplies the diaphragm.

  • B. Vagus nerve

    The vagus is not blocked and works unopposed.

  • C. Cardioaccelerator fibres from T1 to T4 (correct)

    Correct. T1 to T4 cardioaccelerators are blocked.

  • D. Stellate ganglion only on the right side

    The stellate ganglion is within the sympathetic chain but not the only cause.

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, Cardioaccelerator fibres from T1 to T4. Sympathetic fibres from T1 to T4 supply the heart, and their blockade removes sympathetic tone, leaving unopposed vagal influence.

Why is "Phrenic nerve" not the answer?

The phrenic nerve supplies the diaphragm.

Why is "Vagus nerve" not the answer?

The vagus is not blocked and works unopposed.

Why is "Stellate ganglion only on the right side" not the answer?

The stellate ganglion is within the sympathetic chain but not the only cause.

What concept does this question test?

It tests Spinal anaesthesia: cardiac accelerators in Anaesthesia. Reduced venous return also triggers the Bezold-Jarisch 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 Spinal anaesthesia: cardiac accelerators?

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.