Which agent is used for cardiac protection in acute hyperkalemia management?

• A. Calcium gluconate
• B. Sodium bicarbonate
• C. Furosemide
• D. Potassium chloride

Answer: (A)

Calcium gluconate stabilizes the cardiac membrane during acute hyperkalemia. Hyperkalemia makes cardiac cells more excitable and prone to dangerous arrhythmias by lowering the threshold for depolarization. The calcium provided by calcium gluconate raises the threshold and helps restore the difference between the resting membrane potential and the threshold, dampening excitability and protecting the heart even before potassium levels are lowered. This protective effect is immediate, buying time for other treatments that actually lower or redistribute potassium to take effect.

Sodium bicarbonate can help drive potassium into cells and correct acidosis, but it does not provide the same immediate membrane stabilization or rhythm protection. Furosemide increases potassium excretion, which can lower potassium, but its effect is not rapid enough for acute cardiac protection. Potassium chloride would worsen hyperkalemia and is not used in this setting.