COPD USMLE Step 1 Practice Question
A 62-year-old woman with COPD on postoperative day 4 following total hip replacement presents with acute dyspnea, pleuritic chest pain, and tachycardia. Vital signs show HR 112 bpm, BP 138/88 mmHg, RR 22/min, SpO2 88% on room air, and temperature 37.2°C. Chest X-ray reveals a wedge-shaped opacity. D-dimer is elevated at 2.8 µg/mL. She denies leg swelling. Which anatomic site is the most likely source of thromboembolism?
Answer choices
- ALeft atrial appendage
- BPortal venous system
- CDeep veins of the lower extremityCorrect answer
- DPulmonary veins
- ECoronary sinus
- FRight ventricular wall
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