Why is bicarbonate added to a solution for a person with hyperkalemia?

Bicarbonate is added to a solution for a person with hyperkalemia because it can help facilitate the exchange of hydrogen ions for potassium ions in the extracellular fluid. When bicarbonate is administered, it raises the pH of the blood, making it less acidic. This change in pH can lead to an influx of hydrogen ions into cells, which stimulates the efflux of potassium ions out of the cells. As a result, potassium levels in the blood decrease, which is crucial for treating hyperkalemia—a condition characterized by elevated potassium levels that can lead to serious cardiac issues.

While bicarbonate does have buffering capabilities by neutralizing acidity, in the context of hyperkalemia, its primary role is the ion exchange mechanism described above. The other options relate to different physiological processes that do not directly address the immediate treatment of high potassium levels.