A pulmonary embolus is a blood clot shooting to the lungs, usually from a clot in the leg veins.
Relationship between knee surgery and pulmonary embolus
During knee surgery it is common for the surgeon to apply a tourniquet to the thigh to diminish bleeding so that the surgeon can work faster, rather than stopping frequently to seal off any bleeders. The tourniquet may obstruct blood flow for an hour or more, and during this time the sluggish blood in the calf may start the clotting process.
After the surgery, and it may be some days after, the clot in the calf veins may break off and shoot up through the large veins and into the heart, from which it may continue to the lungs, where the vessels branch into smaller vessels and the clot may get trapped there.
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