Foreign body. Atelectasis is common in children who have inhaled an object, such as a peanut or small toy part, into their lungs. Narrowing of major airways from disease. Chronic infections, including fungal infections, tuberculosis and other diseases, can scar and constrict major airways. Tumor in a major airway.
He'll be placed on blood thinners to break up the clots...which can take from days to weeks. This is also a very dangerous time for him, as a clot could travel and lodge in a coronary artery on his heart, causing a heart attack, or it could travel and lodge in an artery in his brain causing a stroke.
Once the blood begins to clot, you will want to avoid disturbing the clot for 72 hours. Do not rinse your mouth vigorously, do not use a straw, do not smoke, and do not brush your teeth near the extraction point for this period of time. It will also be helpful to avoid strenuous exercise for 24 hours.