What is pulmonary embolism?
Blood clots may migrate along with blood flow from various parts of the body to the lungs and block the blood vessels of the lungs. This condition is known as pulmonary embolism. When only small clots reach the blood vessels of the lungs, only a small portion of the blood vessels of the lung is blocked and may not cause any problem. But when large clots or multiple clots migrate to the lungs and block major blood vessels of the lung or multiple blood vessels, it can cause significant problems. Lack of blood flow to regions of the lung cause wastage of air breathed in, which goes back without being utilized for oxygenating the blood. Hence the oxygen level in the blood falls, causing breathlessness and bluish discoloration of the skin in extreme cases. Blockage of parts of the blood circulation to the lung causes an increase in the blood pressure in the remain blood vessels. High blood pressure in the blood vessels of the lung leads to failure of the right ventricle (lower muscular chamber of the heart) which pumps blood into the lungs. When sufficient quantity of blood cannot be pumped to the lungs, the blood returning to the left atrium (upper chamber of the heart) also decreases, which in turn leads to lower volume of blood pumped into the rest of the body. This causes a fall in the blood pressure of the rest of the body. The individual feels dizziness and may faint in severe cases. It can be seen that massive pulmonary embolism is a life threatening situation demanding immediate medical attention.