What is the MOST appropriate initial treatment for a patient with symptomatic hyperkalemia?

The most appropriate initial treatment for a patient with symptomatic hyperkalemia is calcium chloride. This is because calcium plays a critical role in stabilizing cardiac membranes and counteracting the effects of elevated potassium levels on the heart. In cases of hyperkalemia, potassium raises the risk of cardiac arrhythmias. Administering calcium chloride can quickly help to protect the heart from these dangerous effects by stabilizing the myocardial membranes, making it an immediate priority in acute management.

While glucose and insulin can effectively lower serum potassium levels over time, they do not provide immediate protection against potential cardiac complications. Hyperventilation and sodium bicarbonate may also contribute to potassium movement into cells, but their effects are generally slower and not an adequate substitute for the immediate cardioprotective effects of calcium chloride. Therefore, the initial approach must prioritize cardiac safety, which makes calcium chloride the most appropriate choice in this scenario.