Pulmonary Embolism (Thromboembolism)
A pulmonary embolism occurs when an artery in the lung becomes obstructed, usually by a clot, or embolus. Most often, the clot forms in a deep vein of the leg or pelvic area and a piece breaks away, traveling through the venous system and heart and into the lungs. Less commonly, the obstruction may be due to a globule of fat that enters the bloodstream following a fracture.
Symptoms and complications vary depending on the site of the obstruction and the extent of impaired lung function. Chest pain, breathlessness, and shallow breathing are typical early signs, combined sometimes with lightheadedness and agitation or restlessness. Life-threatening deterioration is signaled by worsening pain, especially when coughing or taking a deep breath; blood-streaked sputum; a rapid heartbeat; heavy perspiration; and the onset of shock.
Many conditions promote the development of a pulmonary embolism, including heart failure, stroke, obesity, thrombophlebitis, and leg or hip fractures. Prolonged bed rest, especially after surgery, increases the risk, as does use of birth control pills by women who smoke or have a history of phlebitis or other clotting disorders.
Pulmonary hypertension, increased blood pressure in the lung, is a potential complication, especially if the embolism blocks blood flow to 30 percent or more of a lung. A deadly complication is pulmonary infarction, in which part of the lung dies and is replaced with scar tissue. Fortunately, this does not happen often because clots begin to dissolve, or lyse, almost immediately after reaching the lungs.
About 500,000 Americans suffer pulmonary embolisms each year, with a mortality rate of about 10 percent. Before age 45, the condition is somewhat more common in women, but after that age, the incidence is about equally divided between the sexes. Diagnostic Studies and Procedures If a doctor suspects a pulmonary embolism, an immediate chest X-ray and lung scan will be ordered. A pulmonary angiogram, an X-ray of the lungs' blood vessels after injection of an opaque dye, will provide a definitive diagnosis. Doppler ultrasound, a test that uses high-frequency sound waves to study blood flow, also may be performed to locate the clot.
Medical Treatments
An individual experiencing a massive pulmonary embolism is hospitalized and immediately placed in an intensive care unit where procedures are started to improve heart and lung function. Supplemental oxygen will be given to compensate for temporary reduction in lung function, and analgesics offered if pain is severe. When medical measures appear to be inadequate, emergency surgery may be considered to remove the obstructed portion of the lung.
Treatment concentrates on dissolving the blood clot and preventing the formation of new ones. Unless there are complications such as bleeding or a stroke, clot-dissolving (thrombolytic) drugs, such as streptokinase or tissue plasminogen activator (TPA), may be administered. To prevent new clots from forming, anticoagulant drugs such as intravenous heparin, perhaps combined with warfarin, may be given.
Complications, such as pulmonary hypertension and cardiac arrhythmias, are also treated with drugs. Antibiotics are prescribed if the embolus has resulted in a bacterial infection.
Alternative Therapies
Physical Therapy. Prolonged bed rest can lead to sluggish circulation and a pooling of blood in the legs, thus increasing the risk of clots. Early ambulation to increase circulation following surgery, a fracture, childbirth, or a serious illness is an important preventive measure. Even if a person cannot get up, a physical therapist can teach the patient ankle and leg movements and other exercises that can be done in bed. Patients who are unable to move themselves can benefit from passive exercises in which a caregiver physically moves their limbs.
Self-Treatment
As noted, regular exercise can help prevent clots from forming in the legs and elsewhere. Cycling is an especially good activity to promote leg circulation; so is walking. If your job involves sitting for long periods, get up and walk about every hour or so. Between walks, elevate your feet and legs by placing them on a stool under your desk. Interrupt long auto trips by stopping every hour or two for a brief walk, even if it means getting off a major highway. Similarly, during a long plane trip, take regular strolls in the aisle.
If you have varicose veins, talk to your doctor about prescription elastic stockings to help improve circulation.
If you have a history of thrombophlebitis or another condition that increases the risk of a pulmonary embolism, you may be instructed to lake a daily aspirin to help prevent the formation of blood clots.
Other Causes of Lung Obstructions
An air bubble that enters the bloodstream during intravenous therapy or a transfusion can travel to the lungs and disrupt blood flow. Disorders to be ruled out in a diagnosis include septic shock, pericarditis, heart attack, congestive heart failure, and pneumonia, all of which produce symptoms similar to those of a pulmonary embolism.