Pulmonary Embolism USMLE Step 1 Practice Question
A 32-year-old woman on oral contraceptives presents with acute dyspnea and pleuritic chest pain. Vital signs show HR 112 bpm, BP 128/82 mmHg, RR 22/min, SpO2 88% on room air, and temperature 37.2°C. Chest X-ray is normal. Arterial blood gas reveals pH 7.48, PaCO2 32 mmHg, and PaO2 58 mmHg. D-dimer is elevated at 2.1 μg/mL. No unilateral leg swelling is noted. Which diagnostic test is most appropriate next?
Answer choices
- AVentilation-perfusion scan
- BRepeat chest X-ray in 6 hours
- CEchocardiography
- DComputed tomography pulmonary angiographyCorrect answer
- EImpedance plethysmography
- FPlasma prothrombin time (PT/INR)
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