Which of the following statements best identifies a known risk factor for pulmonary embolism?

• A. Regular exercise
• B. Recent surgery, immobilization, bed rest, long travel
• C. Birth control only
• D. None of the above

Answer: (B)

Knowing risk factors for a pulmonary embolism is about recognizing situations that promote clot formation and venous pooling. The statement that mentions recent surgery, immobilization, bed rest, and long travel highlights classic scenarios that increase the chance of a clot forming in the veins. After surgery there can be endothelial injury and a temporary rise in clotting tendency; immobilization or bed rest slows blood flow, allowing clots to develop; long periods of sitting during travel also cause venous stasis. Together these elements tie into Virchow’s triad—stasis, endothelial injury, and hypercoagulability—which explains why these factors raise PE risk. Regular exercise reduces risk rather than increases it, and while birth control can raise risk in some individuals, it’s not the sole factor, so it doesn’t cover all known contributors. None of the above would be correct because these factors are indeed established risk factors.