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Bipolar TURP Mild Hyponatraemia — FRCA Final MCQ

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ModerateGeneral AnaesthesiaBipolar TURP Mild HyponatraemiaFRCA Final

A 50-year-old man (ASA II) undergoes a transurethral resection of the prostate using bipolar technology with saline irrigation. Thirty minutes into the procedure, his serum sodium is checked and returns as 132 mmol/L (pre-operative 140 mmol/L). He is asymptomatic. What is the appropriate management?

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Correct answer: B — Continue surgery with close monitoring – the drop is modest and he is asymptomatic with bipolar/saline irrigation

With bipolar TURP using 0.9% saline irrigation, dilutional hyponatraemia still occurs from absorption of isotonic saline (fluid overload without the severe hyponatraemia seen with glycine in monopolar TURP). A drop from 140 to 132 mmol/L is modest and the patient is asymptomatic. Surgery can continue with close monitoring: regular sodium checks (every 15-30 minutes), fluid balance assessment, and clinical observation for symptoms (confusion, nausea, visual disturbance). If Na⁺ drops to <125 or symptoms develop, surgery should be concluded. The risk of TURP syndrome (severe hyponatraemic encephalopathy) is largely eliminated by bipolar technology.

Reference: BAUS – 2019 – TURP guidelines; RCOA – 2023 – Urological anaesthesia