🏥 USMLE Exam Prep

A 70-year-old man with end-stage renal disease on hemodialysis presents to the emergency department with muscle weakness and palpitations. His ECG shows peaked T waves and a widened QRS complex. Labs reveal a serum potassium level of 7.2 mEq/L. What is the most appropriate initial pharmacologic intervention to stabilize the cardiac membrane?

A Insulin and glucose
B Calcium gluconate
C Sodium polystyrene sulfonate (Kayexalate)
D Furosemide

✓ Correct Answer: Option B

In hyperkalemia with ECG changes, calcium gluconate is the immediate treatment of choice to stabilize the cardiac membrane and prevent arrhythmias, even though it does not lower serum potassium levels.

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