Internal Medicine
Collapse After Knee Replacement: High-Risk Pulmonary Embolism
Presentation
A 64-year-old woman presents 6 days after total knee arthroplasty with the sudden onset of severe dyspnea and a witnessed syncopal episode. She appears anxious and diaphoretic, with cool extremities and distended neck veins. She has not been taking her prescribed chemoprophylaxis because it "upset her stomach."
T 37.0 C, HR 128, BP 82/54 mmHg, RR 30, SpO2 86% on room air
↻ Bedside echo shows a severely dilated, hypokinetic right ventricle with septal flattening and a preserved apex (McConnell sign). IV unfractionated heparin is started. Repeat BP is 80/50 mmHg despite a fluid bolus.
Given her presentation and hemodynamics, what is the most appropriate immediate step to confirm the suspected diagnosis?