Font Size  Pulmonary Embolism  Pulmonary Embolism (PE) Overview
A pulmonary embolism (PE) is a blood clot in the lung. The clot
usually forms in smaller vessels in the leg, pelvis, arms, or
heart, but occasionally the clot can be large. When a clot forms
in the large veins of the legs or arms, it is referred to as a
deep venous thrombosis (DVT). The pulmonary embolism occurs when
part or all of the DVT breaks away and travels through the blood
in the veins and lodges in the lungs.  The clot travels through
the vessels of the lung continuing to reach smaller vessels
until it becomes wedged in a vessel that is too small to allow
it to continue further. The clot blocks all or some of the blood
from traveling to that section of the lung. These blockages
result in areas in the lung were the disruption of blood flow
does no allow the carbon dioxide waste to be delivered to the
air sacs for removal (ventilation). Similarly, since blood is
blocked to certain portions of the lung, oxygen can not be
extracted from the