Final answer:
The effectiveness of sodium polystyrene sulfonate in treating hyperkalemia is indicated by a decreased serum potassium level, as the medication facilitates the removal of excess potassium from the body.
Step-by-step explanation:
The student has asked a question related to assessing the effectiveness of sodium polystyrene sulfonate, which is a medication used to treat hyperkalemia by lowering serum potassium levels. The effectiveness of this medication would be indicated by finding decreased serum potassium levels after administration, as the medication works to exchange sodium ions for potassium ions in the intestine, thereby helping to remove excess potassium from the body. Therefore, the correct answer to the question would be a decreased serum potassium level, which is not explicitly listed but is implied as the expected outcome over the other options provided such as increased serum potassium level, decreased bowel movements, elevated blood pressure, and persistent abdominal pain, none of which indicate the effectiveness of sodium polystyrene sulfonate.