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Calcium Gluconate Mechanism — ESENeph MCQ

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EasyElectrolyte DisordersCalcium Gluconate MechanismESENeph

A 28-year-old man presents with a serum potassium of 7.2 mmol/L. His ECG shows broad QRS complexes and loss of P waves. Intravenous calcium gluconate (10 mL of 10%) is given. What is the mechanism of action of calcium gluconate in hyperkalaemia?

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Correct answer: D — Stabilises the cardiac membrane against arrhythmia without lowering serum potassium

IV Calcium Gluconate (or Calcium Chloride) is the first-line emergency treatment for hyperkalaemia with ECG changes. It acts by directly stabilising the cardiac myocyte membrane, raising the threshold potential and reducing the risk of arrhythmia. Critically, it does NOT lower serum potassium – it only provides temporary cardiac protection (onset 1-3 minutes, duration 30-60 minutes). Potassium-lowering therapies (insulin/dextrose, salbutamol, RRT) must be given concurrently.

Reference: UK Renal Association 2020 – Hyperkalaemia; Resuscitation Council UK