Which factor most contributed to this patient's risk of pulmonary embolism following a recent eight-hour flight?

Which factor most contributed to this patient's risk of pulmonary embolism following a recent eight-hour flight?

• A. Dehydration
• B. Age
• C. Recent long flight
• D. Smoking

Answer: (C)

Prolonged immobility during travel leads to venous stasis in the legs, which is a primary driver of pulmonary embolism. When you sit for many hours, the calf muscles aren’t contracting to push blood back toward the heart, so blood pools in the deep veins of the legs. This stagnant flow makes clot formation more likely, and pieces of those clots can travel to the lungs and cause a pulmonary embolism. In this scenario, the recent eight-hour flight best explains the increased risk because it directly represents a period of extended inactivity that promotes clot formation. Dehydration can contribute by thickening the blood somewhat, but it doesn’t explain the timing as strongly as the long flight. Age and smoking are general risk factors, but the acute factor most linked to the event here is the prolonged flight itself.

Prolonged immobility during travel leads to venous stasis in the legs, which is a primary driver of pulmonary embolism. When you sit for many hours, the calf muscles aren’t contracting to push blood back toward the heart, so blood pools in the deep veins of the legs. This stagnant flow makes clot formation more likely, and pieces of those clots can travel to the lungs and cause a pulmonary embolism. In this scenario, the recent eight-hour flight best explains the increased risk because it directly represents a period of extended inactivity that promotes clot formation. Dehydration can contribute by thickening the blood somewhat, but it doesn’t explain the timing as strongly as the long flight. Age and smoking are general risk factors, but the acute factor most linked to the event here is the prolonged flight itself.