American Medical Association Family Medical Guide - American Medical Association [361]
Any blockage of blood flow to the lungs can lead to heart failure (see page 570). If a large pulmonary embolism causes the circulatory system to stop functioning, death usually occurs within minutes.
Diagnosis
Anything that predisposes you to deep vein thrombosis also increases your risk of pulmonary embolism. See your doctor if you have symptoms of either disorder, especially if you have recently been confined to bed. Your doctor will examine you and may order a chest X-ray and an electrocardiogram (ECG; see page 559) to determine whether your heart, especially the right side, is under strain. To confirm the diagnosis, the doctor may order a radionuclide scan (see page 114) or CT scan (see page 112) of the lungs. If any doubt remains, he or she may order a pulmonary angiogram to examine arteries in the lungs. A pulmonary angiogram is the same as a coronary angiogram (see page 561), except that it examines the arteries in the lungs instead of in the heart.
Treatment
If you have a pulmonary embolism, you will need to be hospitalized for treatment with anticoagulants (blood thinners) and possibly thrombolytic drugs (clot busters). Heparin, an anticoagulant, helps prevent more blood clots from forming in your lungs and veins. The drug is infused directly into a vein. Occasionally, thrombolytic drugs such as streptokinase or tPA (tissue plasminogen activator) are used to help dissolve blood clots in the lungs. Because treatment with the combination of thrombolytic and anticoagulant drugs carries a risk of internal bleeding, your doctor will closely monitor the ability of your blood to clot normally.
Pulmonary Angiogram
A pulmonary angiogram, also called a pulmonary arteriogram, allows doctors to examine the pulmonary arteries on film. A catheter (a thin, flexible tube) is usually inserted into a large vein in the groin area and threaded up through the heart to the pulmonary artery (the main artery in the lungs). A contrast medium (dye) is injected through the catheter into the pulmonary artery, and a series of rapid-sequence X-rays (like a movie) of the artery and its smaller branches is taken. The arteries are clearly visible, allowing the doctor to detect any blood clots in the blood vessels.
Pulmonary embolism
Part of a blood clot in a deep vein in the leg may break off. When carried along in the bloodstream, the fragment (embolus) can travel to the lungs and block blood flow, causing a pulmonary embolism, which starves the area of the lung beyond the blockage.
An embolism may damage part of the lung, but a person almost always recovers with treatment that prevents another embolism from forming. The doctor will prescribe an anticoagulant to help prevent the formation of more blood clots, thereby reducing the risk of another embolism.
If an embolism is severe, immediate emergency medical treatment is required. The blockage will probably need to be removed surgically. If a person survives the critical first few days after a massive pulmonary embolism, he or she has a good chance of long-term recovery. The chances of recovery are even better if the source of the embolism, usually deep vein thrombosis (see page 605), is detected and treated successfully.
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Blood Disorders
Blood has two basic components: blood cells and plasma (the fluid in which blood cells are suspended). Most blood cells are red blood cells, or erythrocytes, which carry oxygen from the lungs to the rest of the body. Red blood cells contain a protein called hemoglobin, which combines with oxygen in the lungs and delivers it to tissues as blood circulates through the body. Red blood cells also return some of the waste product carbon dioxide from the tissues to the lungs, where it is exhaled and eliminated