Why do blood clots form in hospital patients or patients who are on bed rest? Is there a chemical ch

Sacha Prashad

UCLA

Susan, FR

Why do blood clots form in hospital patients or patients who are on bed rest? Is there a chemical change?

Sacha Prashad
HHMI Gilliam Fellow,
UCLA
The formation of blood clots is the body’s natural way to stop bleeding. When vessels are damaged and break, clots form through a process called the coagulation cascade. Patients who remain bedridden for long periods, or who may be immobile for extended periods of time (such as during a long plane ride), are at risk for the formation of clots inside their blood vessels.

Normally, blood constantly flows through vessels with the help of body movement and muscle contraction, which squeeze veins and promote blood flow. However, blood can pool in the legs during long periods of immobility. Pooling of the blood can lead to the accumulation of clotting factors and the formation of a clot inside a vessel. Clot formation inside vessels is dangerous because the clots can break off and, for example, go to the lungs, leading to pulmonary embolism, a blockage of an artery in the lung.