Which of the following is the first step in treating hyperkalemia in critically ill patients?

In the management of hyperkalemia, particularly in critically ill patients, the first step typically involves stabilizing the cardiac membrane to prevent life-threatening arrhythmias that can occur due to elevated potassium levels. Administering calcium chloride or calcium gluconate intravenously accomplishes this by competing with potassium at the myocardial cell membrane, thereby reducing the excitability of the myocardium and mitigating the risk of cardiac arrest.

Calcium chloride is often preferred due to its higher elemental calcium content, but calcium gluconate serves the same purpose with a milder side effect profile. This initial step is crucial because hyperkalemia can lead to serious cardiac complications, hence immediate intervention is necessary to protect the heart.

Subsequent treatments for hyperkalemia may include insulin administration, which helps shift potassium back into cells, using albuterol to drive potassium into cells via beta-adrenergic stimulation, or renal replacement therapy such as dialysis to remove excess potassium from the body. However, the immediate priority is to stabilize the heart with calcium before addressing the underlying hyperkalemia with other therapies.