Which assessment finding indicates to a nurse that a sodium polystyrene sulfonate enema is effective?

The effectiveness of a sodium polystyrene sulfonate enema is primarily evaluated by its ability to lower serum potassium levels in patients who are experiencing hyperkalemia. Sodium polystyrene sulfonate works by exchanging sodium ions for potassium ions in the intestines, facilitating the excretion of potassium through the bowel. Therefore, a return of serum potassium to the normal range directly indicates that the treatment is effectively reducing elevated potassium levels in the patient’s bloodstream.

In this context, while soft stools may be an outcome of the enema, they do not specifically indicate the efficacy of sodium polystyrene sulfonate in lowering potassium. Normal blood pressure and lower levels of markers for dehydration might be important physiological parameters, but they are not direct measures of the drug’s effectiveness. The primary goal of administering this medication is to manage hyperkalemia, making the normalization of serum potassium the most relevant assessment finding in determining the treatment's success.