A 48-year-old man with CKD stage 4 (eGFR 22 mL/min) has serum potassium of 6.8 mEq/L. ECG shows absent P waves, widened QRS, and tall peaked T waves. The first intervention should be:
- A Sodium polystyrene sulfonate (Kayexalate) 30 g orally
- B Intravenous regular insulin with dextrose
- C Intravenous 10% calcium gluconate ✓
- D Hemodialysis
Explanation
In severe hyperkalemia with ECG changes (widened QRS, peaked T waves, absent P waves), the immediate priority is cardiac membrane stabilization using intravenous calcium gluconate (or calcium chloride). Calcium raises the threshold potential, counteracting the depolarizing effect of hyperkalemia. This acts within minutes. Subsequently, measures to shift potassium intracellularly (insulin-dextrose, sodium bicarbonate, beta-agonists) and then eliminate potassium (diuretics, kayexalate, patiromer, dialysis) are instituted. Kayexalate acts over hours and is not the first step.
Reference: Harrison's Principles of Internal Medicine, 21st ed.
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Written and medically reviewed by the StethoPrep medical team.