Tourniquet Time Limits — FRCA Final MCQ

Instant feedback + full explanation. One question, done properly.

EasyAnaesthetic Equipment & SafetyTourniquet Time LimitsFRCA Final

A 67-year-old man undergoes elective total knee replacement using a pneumatic thigh tourniquet. In routine practice, what is the generally accepted maximum duration of continuous lower-limb tourniquet inflation before it should be deflated to permit reperfusion?

Educational content. Not a substitute for clinical judgement or local policy.

Reveal the answer and explanation

Correct answer: B — 120 minutes

The correct answer is B: 120 minutes. Continuous lower-limb tourniquet inflation should generally be limited to 2 hours. Prolonged arterial occlusion depletes cellular ATP and causes progressive muscle and nerve ischaemia; subsequent deflation releases lactate, carbon dioxide, potassium and other metabolites into the circulation and may produce hypotension, acidosis or arrhythmia. If continued tourniquet use is unavoidable, it should be deflated to permit reperfusion, with UK NHS guidance specifying at least 10 minutes after 2 hours. Sixty or 90 minutes may be chosen as shorter local targets but are not the generally accepted maximum. Inflation for 150 or 180 minutes without reperfusion exposes the limb to an avoidably greater risk of ischaemic muscle injury, neuropraxia, rhabdomyolysis and irreversible microvascular damage.

Reference: Recommendations and Protocols for the Safe Use of Tourniquets in Upper- and Lower-Extremity Surgeries, 2025. https://pubmed.ncbi.nlm.nih.gov/40740594/