In hyperkalemia, which is used to stabilize the cardiac membrane?

• A. Insulin with glucose
• B. Calcium chloride or calcium gluconate
• C. Albuterol
• D. Sodium bicarbonate

Answer: (B)

When potassium is elevated, the heart’s cells become more excitable and conduction can become erratic. The immediate goal is to stabilize the cardiac membrane to prevent dangerous arrhythmias. Calcium does this by raising the threshold potential of cardiac myocytes, making it harder for cells to depolarize in the face of high extracellular potassium. This stabilizing effect happens within minutes and protects the heart while other measures lower or shift potassium, such as insulin with glucose, beta-agonists, or bicarbonate. Importantly, calcium does not reduce the potassium level itself; it simply protects the heart from the current high potassium while you use other therapies to reduce potassium or remove it from the body. In practice, calcium is given IV as calcium gluconate or calcium chloride to provide rapid membrane stabilization.