Local and regional anaesthesia: unilateral epidural block: 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 · Local and regional anaesthesia: unilateral epidural block

Sample item

Twenty minutes after an epidural top-up in labour through a catheter threaded 8 cm into the space, analgesia is absent on the right but good on the left. What is the best action?

AReplace it with a single-shot spinal at onceBDouble the concentration through the same catheter without moving itCAdvance the catheter a further 2 cmDWithdraw the catheter 1 to 2 cm and give another bolus

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

The answer and the reasoning

D. Withdraw the catheter 1 to 2 cm and give another bolus

A catheter threaded too far can pass out through an intervertebral foramen or lie to one side, giving a unilateral block. Withdrawing it a short distance so that less lies in the space and re-dosing usually fixes this. The catheter is replaced if this fails.

Option by option

A. Replace it with a single-shot spinal at once
A spinal on top of a failing epidural is unnecessary and risks an excessive block.
B. Double the concentration through the same catheter without moving it
A stronger dose through a misplaced catheter increases the risk of toxicity without curing the unevenness.
C. Advance the catheter a further 2 cm
Advancing it further makes the one-sided position worse.
D. Withdraw the catheter 1 to 2 cm and give another bolus (correct)
Correct. Withdrawing a deep catheter by 1 to 2 cm usually restores a bilateral block.

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 D, Withdraw the catheter 1 to 2 cm and give another bolus. A catheter threaded too far can pass out through an intervertebral foramen or lie to one side, giving a unilateral block.

Why is "Replace it with a single-shot spinal at once" not the answer?

A spinal on top of a failing epidural is unnecessary and risks an excessive block.

Why is "Double the concentration through the same catheter without moving it" not the answer?

A stronger dose through a misplaced catheter increases the risk of toxicity without curing the unevenness.

Why is "Advance the catheter a further 2 cm" not the answer?

Advancing it further makes the one-sided position worse.

What concept does this question test?

It tests Local and regional anaesthesia: unilateral epidural block in Anaesthesia. Withdrawing it a short distance so that less lies in the space and re-dosing usually fixes this. The catheter is replaced if this fails.

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 Local and regional anaesthesia: unilateral epidural block?

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.