A nurse is reviewing the arterial blood gas values of a client who has chronic kidney disease. Which of the following sets of values should the nurse expect?

Choice A rationale The values indicate a high pH above the normal range of 7.35 to 7.45 and a low bicarbonate level below 22 to 28 mEq/L. This signifies a state of partially compensated respiratory alkalosis rather than a metabolic issue. Chronic kidney disease typically results in acid accumulation because the kidneys cannot excrete hydrogen ions or regenerate bicarbonate effectively. Therefore, an alkalotic pH of 7.50 is physiologically inconsistent with the expected metabolic acidosis seen in renal failure. Choice B rationale These values show a significantly elevated pH and an elevated bicarbonate level, which characterizes metabolic alkalosis. In chronic kidney disease, the nephrons lose the ability to manage electrolyte balance, leading to the retention of metabolic acids like phosphates and sulfates. A pH of 7.55 and bicarbonate of 30 mEq/L would indicate an excess of base or loss of acid, which is the opposite of the clinical presentation expected for a patient with end-stage renal impairment. Choice C rationale This set of values represents metabolic acidosis with partial respiratory compensation, which is the hallmark of chronic kidney disease. The pH is below 7.35, and the bicarbonate is significantly lower than the normal 22 to 28 mEq/L range. The low PaCO2 reflects the lungs attempting to blow off carbon dioxide to raise the pH. Since the kidneys fail to excrete metabolic acids and produce bicarbonate, this acidic state is the most accurate clinical expectation. Choice D rationale These results indicate respiratory acidosis because the pH is low while the PaCO2 is elevated above the normal 35 to 45 mm Hg range. While the pH is acidic, the cause is clearly pulmonary rather than renal. In chronic kidney disease, the primary imbalance is metabolic. An elevated PaCO2 of 50 mm Hg suggests hypoventilation or obstructive lung disease, which does not align with the typical compensatory hyperpnea usually observed when the body reacts to renal-induced metabolic acidosis.