Which assessment finding indicates that sodium polystyrene sulfonate is effective?

Sodium polystyrene sulfonate is particularly effective in the treatment of hyperkalemia, which is an elevated level of potassium in the blood. This medication works by binding to potassium in the gastrointestinal tract, allowing it to be excreted from the body. As a result, one of the primary expected outcomes after administering sodium polystyrene sulfonate is a decrease in serum potassium levels. Monitoring for this change is critical in assessing the effectiveness of the treatment, as a decrease signifies that the drug is successfully lowering the potassium concentration in the blood.

While an increase in serum sodium levels could occur as a result of using sodium polystyrene sulfonate, it is not a direct indication of the medication's effectiveness in treating hyperkalemia. An increase in serum calcium levels is not relevant to the action of sodium polystyrene sulfonate, and control of diarrhea does not relate to the effectiveness of this particular treatment, since the primary aim is to manage potassium levels rather than gastrointestinal symptoms.