Hyperkalaemia Management — FRCA Final MCQ

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EasyIntensive Care MedicineHyperkalaemia ManagementFRCA Final

A 58-year-old man has a serum potassium concentration of 6.8 mmol/L post-operatively. His ECG shows tall, tented T waves with widening of the QRS complexes, and his capillary blood glucose is 8.0 mmol/L. He receives 30 mL of calcium gluconate 10% intravenously over 10 minutes with continuous ECG monitoring. Which is the most appropriate primary treatment to shift potassium into cells?

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Correct answer: D — Intravenous soluble insulin 10 units with glucose 25 g

The correct answer is D. Calcium stabilises the myocardium but does not reduce serum potassium, so potassium-lowering treatment must follow immediately. Soluble insulin stimulates cellular Na+/K+-ATPase activity, producing a reliable intracellular potassium shift; the standard regimen is 10 units with 25 g glucose intravenously. Potassium begins to fall within approximately 10–20 minutes and the effect peaks at 30–60 minutes. Capillary glucose requires prolonged monitoring because hypoglycaemia may be delayed. Nebulised salbutamol also shifts potassium intracellularly but has a variable response and is an adjunct rather than reliable sole therapy. Sodium bicarbonate is not routine redistribution therapy and is reserved mainly for significant metabolic acidosis. Calcium resonium and furosemide remove potassium from the body rather than shifting it into cells, and neither provides sufficiently reliable immediate redistribution in this emergency.

Reference: Norfolk and Norwich University Hospitals NHS Foundation Trust. A Clinical Guideline for the Management of Hyperkalaemia in Adults, sections 3.2–3.3. Approved August 2024; next review August 2027. https://www.nnuh.nhs.uk/publication/download/hyperkalaemia-in-adults-jcg0020-v6/