Special anaesthesia: renal failure: 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 · Special anaesthesia: renal failure

Sample item

Why must serum potassium be checked before giving suxamethonium to a patient with chronic renal failure?

AIt raises potassium by 0.5 to 1 mEq/L and could precipitate arrhythmia if already highBIt causes renal failureCIt lowers potassiumDIt is excreted unchanged by the kidney

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

The answer and the reasoning

A. It raises potassium by 0.5 to 1 mEq/L and could precipitate arrhythmia if already high

Suxamethonium raises potassium by about 0.5 mEq/L in normal patients, and this may be dangerous when baseline potassium is high. It is not contraindicated if potassium is normal, because its breakdown is by plasma cholinesterase.

Option by option

A. It raises potassium by 0.5 to 1 mEq/L and could precipitate arrhythmia if already high (correct)
Correct. Baseline hyperkalaemia matters.
B. It causes renal failure
It does not cause renal failure.
C. It lowers potassium
It does not lower potassium.
D. It is excreted unchanged by the kidney
It is hydrolysed by cholinesterase.

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 A, It raises potassium by 0.5 to 1 mEq/L and could precipitate arrhythmia if already high. Suxamethonium raises potassium by about 0.

Why is "It causes renal failure" not the answer?

It does not cause renal failure.

Why is "It lowers potassium" not the answer?

It does not lower potassium.

Why is "It is excreted unchanged by the kidney" not the answer?

It is hydrolysed by cholinesterase.

What concept does this question test?

It tests Special anaesthesia: renal failure in Anaesthesia. 5 mEq/L in normal patients, and this may be dangerous when baseline potassium is high. It is not contraindicated if potassium is normal, because its breakdown is by plasma cholinesterase.

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 Special anaesthesia: renal failure?

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.