The nurse is caring for a client. Complete the following sentence by using the lists of options. The client is most likely experiencing _____ due to _____ .

Rationale for correct choices • Pulmonary embolism: The client exhibits sudden onset of dyspnea, chest discomfort, tachypnea, hypoxemia (oxygen saturation 92% on 2 L O₂), and appears in respiratory distress, all of which are classic signs of a pulmonary embolism. Postoperative orthopedic patients, especially after hip arthroplasty, are at high risk due to immobility, venous stasis, and hypercoagulability. • Recent surgery: The client’s recent total hip arthroplasty increases the risk of thromboembolic events. Surgical procedures, particularly major orthopedic surgeries, create a hypercoagulable state and contribute to venous stasis, which can precipitate a pulmonary embolism. Rationale for incorrect choices • Pneumothorax: Pneumothorax typically presents with unilateral chest pain, sudden shortness of breath, and decreased or absent breath sounds on one side. The client’s crackles are bilateral and S3/S4 heart sounds are present, which are not consistent with pneumothorax. • Pneumonia: Although the client has fever and crackles, the sudden onset of symptoms and acute respiratory distress are more consistent with pulmonary embolism rather than pneumonia, which usually develops gradually. Additionally, the timing shortly after surgery favors a thromboembolic event over an infectious process. • Tobacco use: The client reports no history of tobacco use, making this an irrelevant risk factor for the current acute episode. • Activity level: While immobility can contribute to thrombus formation, the client ambulated with assistance earlier, and the more significant risk factor remains recent surgery, which directly predisposes to pulmonary embolism.