A nurse is caring for a client who has acute kidney injury. The client's arterial blood gases are: pH: 7.26, PaCO_2: 30 mm Hg, HCO_3: 14 mEq/L. Which of the following acid-base imbalances should the nurse identify the client is experiencing?

Choice A rationale Metabolic alkalosis is characterized by a high pH (normal range 7.35-7.45), indicating alkalinity, and a high HCO_3- (normal range 22-26 mEq/L), indicating a primary metabolic disturbance. The client's pH of 7.26 is acidic, and the HCO_3- of 14 mEq/L is low, which contradicts the parameters for metabolic alkalosis. Choice B rationale Metabolic acidosis is defined by a low pH (7.26, acidic) and a low HCO_3- (14 mEq/L). Acute kidney injury often leads to this imbalance because the kidneys are unable to excrete hydrogen ions (H+) and reabsorb or generate bicarbonate (HCO_3-), resulting in a net accumulation of acid in the body. The low PaCO_2 (30 mm Hg, normal range 35-45 mm Hg) indicates a compensatory hyperventilation. Choice C rationale Respiratory acidosis is marked by a low pH and a high PaCO_2 (partial pressure of carbon dioxide), reflecting impaired CO_2 excretion by the lungs. The client's PaCO_2 (30 mm Hg) is low, not high, ruling out a primary respiratory acidosis. HCO_3- levels are not the primary disturbance in this case. Choice D rationale Respiratory alkalosis is characterized by a high pH and a low PaCO_2. The client's pH (7.26) is low (acidic), not high, which immediately rules out respiratory alkalosis as the primary imbalance. The low PaCO_2 in this scenario is a compensatory mechanism for the metabolic problem.