Muscle relaxants: prolonged apnoea after suxamethonium: 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 · Muscle relaxants: prolonged apnoea after suxamethonium

Sample item

A 30-year-old remains flaccid and apnoeic two hours after suxamethonium for appendicectomy. Train-of-four shows no response and he is haemodynamically stable. What is the most appropriate management?

AGive neostigmine to reverse the blockBContinue ventilation with sedation until spontaneous recoveryCGive sugammadexDGive atropine to counter the depolarisation

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

The answer and the reasoning

B. Continue ventilation with sedation until spontaneous recovery

Prolonged suxamethonium block from low or atypical plasma cholinesterase resolves by itself, so the safe course is controlled ventilation with sedation so that the patient is not awake and paralysed. Neostigmine worsens the block, and sugammadex does not bind suxamethonium. Family testing is advised later.

Option by option

A. Give neostigmine to reverse the block
Neostigmine inhibits the remaining cholinesterase and would prolong the block.
B. Continue ventilation with sedation until spontaneous recovery (correct)
Correct. The block wears off spontaneously, so ventilation and sedation are the safe treatment.
C. Give sugammadex
Sugammadex binds steroidal relaxants and has no affinity for suxamethonium.
D. Give atropine to counter the depolarisation
Atropine blocks muscarinic receptors and does nothing at the neuromuscular junction.

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, Continue ventilation with sedation until spontaneous recovery. Prolonged suxamethonium block from low or atypical plasma cholinesterase resolves by itself, so the safe course is controlled ventilation with sedation so that the patient is not awake and paralysed.

Why is "Give neostigmine to reverse the block" not the answer?

Neostigmine inhibits the remaining cholinesterase and would prolong the block.

Why is "Give sugammadex" not the answer?

Sugammadex binds steroidal relaxants and has no affinity for suxamethonium.

Why is "Give atropine to counter the depolarisation" not the answer?

Atropine blocks muscarinic receptors and does nothing at the neuromuscular junction.

What concept does this question test?

It tests Muscle relaxants: prolonged apnoea after suxamethonium in Anaesthesia. Neostigmine worsens the block, and sugammadex does not bind suxamethonium. Family testing is advised later.

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 Muscle relaxants: prolonged apnoea after suxamethonium?

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.