A 60-year-old patient with end-stage renal disease on hemodialysis misses two sessions and presents with weakness and palpitations. ECG shows wide QRS complexes and peaked T waves. Serum potassium is 7.5 mEq/L. What is the immediate first-line intervention to stabilize the cardiac membrane?
✓ Correct Answer: Option A
Intravenous calcium gluconate (or calcium chloride) immediately stabilizes the cardiac membrane by antagonizing the cardiotoxic effects of hyperkalemia. It does not lower serum potassium but protects the heart from arrhythmias.