Pulmonary embolism is a common disease. Although the statements differ in different studies, one can assume that in Germany on average about 1 person per 1, 000 inhabitants annually is affected by pulmonary embolism - older people more often than younger. Pulmonary embolism is one of the leading causes of death among hospital patients.
Clogged vessel as a cause
The right heart pumps the oxygenated blood out of the body into the large and small arteries of the pulmonary circulation. In these it is brought to the alveoli, where it is enriched again with oxygen.
Sometimes, however, the blood from the body not only releases carbon dioxide to exhale, but also flushes dangerous particles: mostly blood clots from a thrombosis in the leg veins, but also - much less often - fat, for example, after an operation on the bone, air through a Infusion, bacteria, tumor cells or amniotic fluid, which enters the maternal circulation during birth. These substances can get stuck and clog the corresponding vessel.
If the graft is only in a small artery, this may go unnoticed; if a larger or several vessels are affected, this can lead to a serious, life-threatening clinical picture.
How exactly does the pulmonary embolism develop?
In most people, the pulmonary embolism is caused by a blood clot that has formed in the veins of the pelvis or legs. From these caked blood cells, small particles dissolve and are carried on with the bloodstream. The veins widen initially and finally lead into the portal vein, which leads to the right heart. Only in the lungs branch the vessels again and become ever narrower. Therefore, the particles settle there again and move the vessel.
Once this process has started, the blood builds up, slowing down its flow, which can lead to more and more clots forming in the pulmonary vessels. The right heart has to pump against this suddenly increased pressure and it does not get enough blood in the left heart. This in turn means that on the one hand, the blood pressure drops and the coronary arteries are no longer supplied with enough blood, which reduces the cardiac output, on the other hand, too little oxygen-rich blood reaches the body and organs.
In addition, the body lacks oxygen, as in the lung area behind the closed vessel no more blood passes and thus less surface is available for oxygen exchange.