A nurse is reviewing the laboratory values of a client who has respiratory acidosis. Which of the following findings should the nurse expect?

Choice A reason: A pH of 7.45 is within the normal range (7.35-7.45) and indicates no acidosis. Respiratory acidosis results from CO2 retention, lowering pH below 7.35 due to hypoventilation. This normal pH value does not reflect the acid-base imbalance expected in respiratory acidosis. Choice B reason: Potassium 3.3 mEq/L indicates hypokalemia, not directly related to respiratory acidosis. Respiratory acidosis may cause hyperkalemia due to hydrogen ion buffering, shifting potassium out of cells. This low potassium level is not a typical finding in respiratory acidosis scenarios. Choice C reason: PaCO2 of 50 mmHg (normal 35-45 mmHg) indicates CO2 retention, the hallmark of respiratory acidosis. Hypoventilation, often from lung disease or airway obstruction, elevates PaCO2, lowering blood pH below 7.35, confirming the acid-base imbalance expected in this condition. Choice D reason: HCO3- of 30 mEq/L (normal 22-26 mEq/L) suggests metabolic compensation for chronic respiratory acidosis but is not the primary finding. Respiratory acidosis is defined by elevated PaCO2, not HCO3-, which increases later as the kidneys retain bicarbonate to buffer acidity.