Trauma and burns: compartment pressure threshold: practice question

A General Surgery 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.

Try it

General Surgery · Trauma and burns: compartment pressure threshold

Sample item

A man with a tibial fracture has a tense swollen calf and pain on passive stretch. His diastolic blood pressure is 70 mmHg and the measured compartment pressure is 55 mmHg. What is the interpretation and action?

ACompartment pressure below 60 mmHg is normal, so give analgesia and elevateBPerfusion pressure of 125 mmHg is adequate, so observeCFasciotomy is delayed until pulses disappearDPerfusion pressure of 15 mmHg is below the 30 mmHg threshold, so fasciotomy is indicated

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

The answer and the reasoning

D. Perfusion pressure of 15 mmHg is below the 30 mmHg threshold, so fasciotomy is indicated

Compartment perfusion pressure is the diastolic pressure minus the compartment pressure. A difference below 30 mmHg threatens muscle and nerve perfusion and indicates fasciotomy, together with clinical findings. Loss of pulses is a late sign.

Option by option

A. Compartment pressure below 60 mmHg is normal, so give analgesia and elevate
Normal compartment pressure is about 0 to 10 mmHg, so 55 mmHg is markedly raised.
B. Perfusion pressure of 125 mmHg is adequate, so observe
The perfusion pressure is calculated as the difference, not the sum, of the two pressures.
C. Fasciotomy is delayed until pulses disappear
Waiting for pulse loss allows irreversible muscle and nerve ischaemia.
D. Perfusion pressure of 15 mmHg is below the 30 mmHg threshold, so fasciotomy is indicated (correct)
Correct. The difference of 15 mmHg is below 30 mmHg, which is the usual threshold for fasciotomy.

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 General Surgery question

What is the answer to this General Surgery question?

The best answer is D, Perfusion pressure of 15 mmHg is below the 30 mmHg threshold, so fasciotomy is indicated. Compartment perfusion pressure is the diastolic pressure minus the compartment pressure.

Why is "Compartment pressure below 60 mmHg is normal, so give analgesia and e…" not the answer?

Normal compartment pressure is about 0 to 10 mmHg, so 55 mmHg is markedly raised.

Why is "Perfusion pressure of 125 mmHg is adequate, so observe" not the answer?

The perfusion pressure is calculated as the difference, not the sum, of the two pressures.

Why is "Fasciotomy is delayed until pulses disappear" not the answer?

Waiting for pulse loss allows irreversible muscle and nerve ischaemia.

What concept does this question test?

It tests Trauma and burns: compartment pressure threshold in General Surgery. A difference below 30 mmHg threatens muscle and nerve perfusion and indicates fasciotomy, together with clinical findings. Loss of pulses is a late sign.

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 Trauma and burns: compartment pressure threshold?

Learn classic signs and eponyms alongside what they diagnose. Then use the flashcards and the other General Surgery 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.