A 55-year-old male develops acute kidney injury post-cardiac surgery, with creatinine rising from 1.0 to 3.5 mg/dL. He is anuric and hyperkalemic with a potassium level of 6.8 mEq/L and new peaked T-waves on EKG. What is the most appropriate immediate intervention for his hyperkalemia?

✓ Correct Answer: Option A

In severe hyperkalemia with EKG changes, intravenous calcium gluconate is the immediate priority. It stabilizes the cardiac membrane, preventing life-threatening arrhythmias, without lowering serum potassium levels. Other therapies like insulin/dextrose or dialysis will lower potassium.