Regional 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 · Regional anaesthesia

Sample item

A patient with severe COPD is scheduled for shoulder surgery. Why is an interscalene brachial plexus block relatively undesirable in this patient?

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

The answer and the reasoning

D. It almost always blocks the ipsilateral phrenic nerve and reduces diaphragmatic function

At the interscalene level the phrenic nerve lies on the anterior scalene muscle close to the injected local anaesthetic, so ipsilateral hemidiaphragmatic paresis is very common. A healthy patient tolerates this, but a patient with severe lung disease may become dyspnoeic. Alternative blocks or lower volumes are chosen.

Option by option

  • A. It causes high spinal block

    High spinal block would be a rare event from inadvertent spread or injection, not an expected effect.

  • B. It always causes complete motor block of the legs

    An interscalene block affects the upper limb and does not block the legs.

  • C. It causes bilateral recurrent laryngeal nerve palsy

    Bilateral recurrent laryngeal palsy is not expected with a unilateral interscalene block.

  • D. It almost always blocks the ipsilateral phrenic nerve and reduces diaphragmatic function (correct)

    Correct. Hemidiaphragm paralysis can reduce lung function by a clinically important amount in reserve-limited patients.

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 D, It almost always blocks the ipsilateral phrenic nerve and reduces diaphragmatic function. At the interscalene level the phrenic nerve lies on the anterior scalene muscle close to the injected local anaesthetic, so ipsilateral hemidiaphragmatic paresis is very common.

Why is "It causes high spinal block" not the answer?

High spinal block would be a rare event from inadvertent spread or injection, not an expected effect.

Why is "It always causes complete motor block of the legs" not the answer?

An interscalene block affects the upper limb and does not block the legs.

Why is "It causes bilateral recurrent laryngeal nerve palsy" not the answer?

Bilateral recurrent laryngeal palsy is not expected with a unilateral interscalene block.

What concept does this question test?

It tests Regional anaesthesia in Anaesthesia. A healthy patient tolerates this, but a patient with severe lung disease may become dyspnoeic. Alternative blocks or lower volumes are chosen.

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 Regional 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.