A 48-year-old patient with CKD stage 4 (eGFR 22) presents with ECG changes: peaked T waves, widened QRS, PR prolongation. Potassium is 7.2 mEq/L. Bicarbonate is 14 mEq/L. Which is the FIRST therapeutic step to administer?
- A Sodium polystyrene sulphonate (Kayexalate) orally
- B Intravenous sodium bicarbonate
- C IV calcium gluconate (10 mL of 10% solution over 2–3 minutes) ✓
- D Urgent haemodialysis
Explanation
In hyperkalaemia with ECG changes (peaked T waves, wide QRS, PR prolongation), the first priority is cardiac membrane stabilisation with intravenous calcium gluconate (10 mL of 10% solution IV over 2–3 min), which raises the membrane threshold potential and counteracts hyperkalaemia-induced depolarisation. Effect begins within 1–3 minutes. Calcium does not lower potassium levels but protects the heart. Subsequent steps include insulin + dextrose, sodium bicarbonate (if acidosis coexists), salbutamol nebulization (to shift K+ intracellularly) and haemodialysis for definitive removal.
Reference: Harrison's Principles of Internal Medicine, 21st ed.
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