🏥 USMLE Exam Prep

A 55-year-old man with a history of chronic kidney disease presents with generalized weakness and fatigue. An electrocardiogram (ECG) shows tall, peaked T waves. Laboratory results reveal a serum potassium level of 7.2 mEq/L. What is the most important immediate intervention to stabilize the cardiac membrane?

A Intravenous insulin and dextrose
B Sodium polystyrene sulfonate (Kayexalate)
C Intravenous calcium gluconate
D Intravenous furosemide

✓ Correct Answer: Option C

In severe hyperkalemia with ECG changes (like peaked T waves), intravenous calcium gluconate is the immediate priority. It directly stabilizes the cardiac membrane, reducing the risk of arrhythmias, without lowering serum potassium levels.

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