Which of the following best describes the risk factors for pulmonary embolism?

• A. Viral infection and dehydration
• B. Recent surgery, immobilization, bed rest, long travel, atrial fibrillation, birth control, and history of DVT
• C. Smoking cessation and exercise
• D. High-fat diet and cholesterol

Answer: (B)

Pulmonary embolism risk is driven by factors that promote blood clot formation and allow clots to travel to the lungs. The best description includes recent surgery or other injuries that damage vessels, immobilization or bed rest that slows blood flow, long periods of sitting (like a long trip), a history of deep vein thrombosis, atrial fibrillation which can produce clots in the heart, and hormonal factors such as birth control that increase clotting tendency. Having had a DVT in the past also signals a higher lifetime risk of future clots. Together, these factors illustrate the situations that push someone toward venous thromboembolism, which can lead to a pulmonary embolism when a clot migrates to the lungs. In contrast, things like a viral infection with dehydration, or lifestyle changes such as quitting smoking and exercising, or a diet high in fat and cholesterol, do not describe the major, direct risk factors for PE.