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Compartment Pressure Threshold Fasciotomy — FRCA Final MCQ

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ModerateTrauma & Emergency AnaesthesiaCompartment Pressure Threshold FasciotomyFRCA Final

A 58-year-old man undergoes emergency fasciotomy for acute compartment syndrome of the right leg. Compartment pressures were 55 mmHg pre-operatively. What is the critical threshold for compartment pressure that mandates surgical decompression?

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Correct answer: E — Absolute pressure >30 mmHg OR within 30 mmHg of diastolic blood pressure

The threshold for fasciotomy is either: (1) absolute compartment pressure >30 mmHg, OR (2) delta pressure (diastolic BP – compartment pressure) <30 mmHg. The delta pressure method is preferred as it accounts for the patient's perfusion status. For example: a compartment pressure of 35 mmHg may be tolerated if the diastolic BP is 90 mmHg (delta = 55), but dangerous if diastolic is 55 mmHg (delta = 20). Time to fasciotomy correlates directly with outcome: delays >6 hours from symptom onset significantly worsen prognosis.

Reference: BOAST – 2014 – Acute compartment syndrome; NICE – 2020 – NG37 Fractures