A nurse is reviewing the arterial blood gas results of a client with the following values: pH 7.51, HCO3 33 mEq/L, and PaCO2 45 mm Hg. Based on these results, which acid-base imbalance should the nurse identify, and what is the most appropriate initial nursing action?

Choice A rationale Metabolic acidosis is identified by a pH below 7.35 and a bicarbonate level below 22 mEq/L. The patient's pH is 7.51, which indicates alkalosis, and the bicarbonate is 33 mEq/L, which is high. These values do not support a diagnosis of acidosis. Administering sodium bicarbonate would be contraindicated as it would further increase the pH and bicarbonate levels, worsening the alkalotic state. Therefore, this choice is incorrect based on the provided laboratory data. Choice B rationale The pH of 7.51 is above the normal range of 7.35 to 7.45, indicating alkalosis. The HCO3 of 33 mEq/L is above the normal range of 22 to 26 mEq/L, which identifies the cause as metabolic. The PaCO2 of 45 mm Hg is at the high end of the normal range of 35 to 45 mm Hg, suggesting a compensatory respiratory effort. In metabolic alkalosis, the nurse must monitor the respiratory rate because the body slows breathing to retain carbon dioxide. Choice C rationale Respiratory alkalosis is characterized by a pH above 7.45 and a PaCO2 below 35 mm Hg. While the patient's pH of 7.51 indicates alkalosis, the PaCO2 is 45 mm Hg, which is not low. The high bicarbonate level indicates a metabolic rather than a respiratory origin. While sedatives might be used for hyperventilation in respiratory alkalosis, they are not the appropriate initial action for this patient's metabolic imbalance. The primary focus must be on the metabolic cause. Choice D rationale Respiratory acidosis is defined by a pH below 7.35 and a PaCO2 above 45 mm Hg. The patient's values show a high pH of 7.51 and a normal PaCO2 of 45 mm Hg, which completely contradicts this diagnosis. Preparing for intubation is an extreme intervention that is not supported by these arterial blood gas results. The values clearly point to a metabolic alkalotic state rather than a respiratory acidotic state requiring immediate mechanical ventilation or invasive airway management.