Spinal anaesthesia: 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

Sample item

Profound hypotension after spinal anaesthesia is primarily caused by blockade of which fibres?

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

The answer and the reasoning

A. Preganglionic sympathetic fibres

Spinal local anaesthetic blocks sympathetic outflow, causing arterial and venous vasodilation with reduced venous return. Fluids, vasopressors and positioning are used as appropriate.

Option by option

  • A. Preganglionic sympathetic fibres (correct)

    Correct. Preganglionic sympathetic blockade produces vasodilation.

  • B. Parasympathetic vagal fibres

    Vagal fibres are not blocked by lumbar spinal anaesthesia.

  • C. Somatic motor fibres only

    Motor block does not itself explain the haemodynamic collapse.

  • D. Postganglionic sympathetic fibres

    Postganglionic sympathetic fibres lie outside the neuraxis.

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.

More Anaesthesia questions

Questions about this Anaesthesia question

What is the answer to this Anaesthesia question?

The best answer is A, Preganglionic sympathetic fibres. Spinal local anaesthetic blocks sympathetic outflow, causing arterial and venous vasodilation with reduced venous return.

Why is "Parasympathetic vagal fibres" not the answer?

Vagal fibres are not blocked by lumbar spinal anaesthesia.

Why is "Somatic motor fibres only" not the answer?

Motor block does not itself explain the haemodynamic collapse.

Why is "Postganglionic sympathetic fibres" not the answer?

Postganglionic sympathetic fibres lie outside the neuraxis.

What concept does this question test?

It tests Spinal anaesthesia in Anaesthesia. Fluids, vasopressors and positioning are used as appropriate.

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 Spinal anaesthesia?

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.