The nurse is administering sodium polystyrene sulfonate to a client in acute kidney injury (AKI). Which laboratory finding indicates that the medication has been effective?
Glucose [Reference Range: 74 to 106 mg/dL (4.1 to 5.9 mmol/L)]
Hemoglobin (Hgb) [Reference Range:12-16 g/dL (120-160 g/L)]
Potassium (K+) [Reference Range: 3.5 to 5.0 mEq/L (3.5 to 5.0 mmol/L)]
Ammonia [Reference Range: Adult: 10 to 80 Mcg/dL (6 to 47 Mcmol/dL)]
A.
Serum ammonia level of 30 Mcg/dL (17.62 Mcmol /dL).
B.
Serum potassium level of 3.8 mEq/L (3.8 mmol/L).
C.
Serum glucose level of 120 mg/dL (6.7 mmol/L).
D.
Hemoglobin level of 13.5 g/dL (135 g/L).
The Correct answer and Explanation is:
The correct answer is:
B. Serum potassium level of 3.8 mEq/L (3.8 mmol/L).
Explanation:
Sodium polystyrene sulfonate (SPS) is a medication used primarily to treat hyperkalemia, which is an elevated potassium level in the blood. It works by exchanging sodium ions for potassium ions in the gastrointestinal tract, which leads to the excretion of excess potassium through the feces. This makes it an effective treatment for managing high potassium levels, especially in patients with acute kidney injury (AKI) where the kidneys are unable to effectively excrete potassium.
To assess the effectiveness of sodium polystyrene sulfonate in treating hyperkalemia, monitoring the serum potassium level is crucial. The reference range for serum potassium is 3.5 to 5.0 mEq/L (3.5 to 5.0 mmol/L). A decrease in potassium levels towards the lower end of this range indicates that the medication is effectively lowering the potassium concentration in the blood.
In this scenario, a serum potassium level of 3.8 mEq/L (3.8 mmol/L) falls within the normal reference range. This indicates that the sodium polystyrene sulfonate has been effective in reducing the elevated potassium levels, which is the primary goal of this treatment.
The other laboratory values listed do not directly reflect the effectiveness of sodium polystyrene sulfonate:
- A. Serum ammonia level of 30 Mcg/dL (17.62 Mcmol /dL): This value pertains to ammonia levels, which are more relevant to liver function or certain types of metabolic disorders, not potassium regulation.
- C. Serum glucose level of 120 mg/dL (6.7 mmol/L): This value is related to glucose metabolism and does not provide information about potassium levels.
- D. Hemoglobin level of 13.5 g/dL (135 g/L): This value pertains to the oxygen-carrying capacity of the blood and is not indicative of the efficacy of potassium-lowering treatments.
Thus, monitoring the serum potassium level is the most direct and relevant measure of the medication’s effectiveness in this context.