A nurse is reviewing the arterial blood gas (ABG) results of a client who the provider suspects has metabolic acidosis. Which of the following results should the nurse expect to see?

Choice A reason: Metabolic acidosis is characterized by a pH below 7.35 due to increased hydrogen ions or decreased bicarbonate. This results from conditions like diarrhea or lactic acid buildup, reducing the blood’s buffering capacity. The kidneys attempt compensation, but low pH is the hallmark, making this the correct choice. Choice B reason: PaO2 below 70 mm Hg indicates hypoxemia, affecting oxygen levels, not acid-base balance. Metabolic acidosis is driven by bicarbonate loss or acid accumulation, not oxygenation. This parameter is irrelevant to confirming metabolic acidosis, making this choice incorrect. Choice C reason: PaCO2 above 45 mm Hg suggests respiratory acidosis, not metabolic acidosis, as it indicates CO2 retention. In metabolic acidosis, PaCO2 may decrease due to compensatory hyperventilation to expel CO2, making this choice incorrect for the expected ABG results. Choice D reason: HCO3 above 26 mEq/L indicates metabolic alkalosis, not acidosis. In metabolic acidosis, HCO3 is typically below 22 mEq/L due to loss (e.g., diarrhea) or acid overload, reducing buffering capacity. This choice is incorrect as it contradicts the condition’s definition.