The nurse is assessing a client who has returned from surgery following a thoracotomy. Which finding indicates the client is experiencing adequate gas exchange?

A. The client demonstrates effective coughing and deep breathing exercises: While this indicates the client is participating in lung expansion strategies, it does not directly confirm the adequacy of gas exchange. B. Current arterial blood gas results are a pH 7.30, PaCO₂ 48 mm Hg, HCO₃⁻ 25 mEq/L, and PaO₂ 75 mm Hg: These values indicate respiratory acidosis (low pH and elevated CO₂) with mild hypoxemia (PaO₂ < 80 mm Hg). This ABG profile shows impaired gas exchange and inadequate ventilation postoperatively. C. The client’s heart rate is 82 beats/minute and respiratory rate is 16 breaths/minute: Normal vital signs are encouraging but do not necessarily reflect the effectiveness of gas exchange. A client can have normal rates but still have inadequate oxygenation or ventilation. D. An oxygen saturation reading of 96% is obtained using pulse oximetry: A SpO₂ of 96% indicates effective oxygenation and is a direct, noninvasive measure of gas exchange. It reflects that hemoglobin is adequately saturated with oxygen, supporting the conclusion of sufficient pulmonary function.