A 72-year-old man with known CKD G4 (eGFR 22) is admitted with a serum potassium of 6.8 mEq/L. ECG shows peaked T waves and widened QRS complexes. Which is the FIRST intervention to perform?
- A IV insulin + 50% dextrose
- B IV calcium gluconate 10 mL of 10% solution over 2–3 minutes ✓
- C Sodium bicarbonate IV infusion
- D Kayexalate (sodium polystyrene sulphonate) enema
Correct answer: B. IV calcium gluconate 10 mL of 10% solution over 2–3 minutes
Explanation
In hyperkalaemia with ECG changes (peaked T waves, QRS widening), the priority is membrane stabilisation to prevent fatal arrhythmias. IV calcium gluconate acts within minutes to antagonise the cardiac membrane effects of hyperkalaemia by raising the threshold potential. This does not lower potassium but protects the heart while potassium-lowering measures are initiated. Insulin-dextrose and bicarbonate shift potassium into cells (onset 15–30 minutes). Kayexalate removes potassium over hours and is not appropriate for emergency cardiac protection.
Reference: Harrison's Principles of Internal Medicine, 21st ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.