A nurse is caring for a client who has chronic kidney failure. The client's ABG values are pH 7.12 (7.35 to 7.45), HCO3 20 mEq/L (21 to 28 mEq/L), PaO2 90 mm Hg (80 to 100 mm Hg), and PaCO2 40 mm Hg (35 to 45 mm Hg). Which of the following acid-base imbalances should the nurse identify?

A. Metabolic acidosis is indicated by a low pH (7.12) and low bicarbonate (HCO₃ 20 mEq/L). In chronic kidney failure, the kidneys are unable to excrete acids, leading to this condition. B. Metabolic alkalosis would show a high pH and high HCO₃, which is not present here. C. Respiratory acidosis typically presents with elevated PaCO₂ and low pH, but the PaCO₂ is normal in this case. D. Respiratory alkalosis would present with high pH and low PaCO₂, which are not found in these results.