Lung embolism

Pulmonary embolism is a condition that occurs when one or more arteries in your lungs become blocked. In most cases, pulmonary embolism is caused by blood clots that travel to your lungs from another part of your body — most commonly, your legs or your heart. Pulmonary embolism can be life-threatening. About one-third of people with undiagnosed and untreated pulmonary embolism don't survive.

Pulmonary embolism occurs when a clump of material, most often a blood clot, gets wedged into an artery in your lungs. These blood clots most commonly originate in the deep veins of your legs, but they can also come from other parts of your body. This condition is known as deep vein thrombosis (DVT).

Occasionally, other substances can form blockages within the blood vessels inside your lungs. Examples include:

  • Fat from within the marrow of a broken bone
  • Part of a tumor
  • Air bubbles

It's rare to experience a solitary pulmonary embolism. In most cases, multiple clots are involved. The lung tissue served by each blocked artery is robbed of fuel and may die. This makes it more difficult for your lungs to provide oxygen to the rest of your body.

Pulmonary embolism almost always occurs in conjunction with deep vein thrombosis in your legs, or Atrial Fibrillation in your heart.

Typical other organs where this may occur include:

  • Your Brain (“Stroke”)
  • Your heart (Coronary arteries, acute MI)
  • Your Small bowel (“ischemic” or even dead bowel)
  • Your legs and feet arteries (“ischemic” or even dead part of your leg or foot)

The target organ may suffer severe damage and cause a lethal complication if not treated in time. However, not only thromboembolism will cause the obstruction of blood flow in vessels, but any kind of embolism is capable of causing the same problem.

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Common signs and symptoms of a Pulmonary Embolism include:

  • Shortness of breath. This symptom typically appears suddenly, and occurs whether you're active or at rest.
  • Chest pain. You may feel like you're having a heart attack. The pain may become worse when you breathe deeply, cough, eat, bend or stoop. The pain will get worse with exertion but won't go away when you rest.
  • Cough. The cough may produce bloody or blood-streaked sputum.

Other signs and symptoms that can occur with pulmonary embolism include:

  • Wheezing
  • Leg swelling
  • Clammy or bluish-colored skin
  • Excessive sweating
  • Rapid or irregular heartbeat
  • Weak pulse
  • Lightheadedness or fainting

Pulmonary embolism can also lead to pulmonary hypertension, a condition in which the blood pressure in your lungs is too high. When you have obstructions in the arteries inside your lungs, your heart must work harder to push blood through those vessels. This increases the blood pressure within these vessels and can wear out a section of your heart.

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Risk Factors for developing a Pulmonary Embolism

Although anyone can develop blood clots and subsequent pulmonary embolism, certain factors can increase your risk.

Prolonged immobility

Blood clots are more likely to form in your legs during periods of inactivity, such as:

  • Bed rest. Being confined to bed for an extended period after surgery, a heart attack, leg fracture or any serious illness makes you far more vulnerable to blood clots.
  • Long journeys. Sitting in a cramped position during lengthy plane or car trips slows the current of blood flow, which contributes to the formation of clots in your legs.


Older people are at higher risk of developing clots. Factors include:

  • Dehydration. Older people are at higher risk of dehydration, which may thicken the blood and make clots more likely.
  • Medical problems. Older people are also more likely to have medical problems that expose them to independent risk factors for clots — such as joint replacement surgery, cancer or heart disease.

Recent Surgery is one of the leading causes of problem blood clots, especially joint replacements of the hip and knee. During the preparation of the bones for the artificial joints, tissue debris may enter the bloodstream and help cause a clot. Simply being immobile during any type of surgery can lead to the formation of clots. The risk increases with the length of time you are under general anesthesia.

Medical conditions

  • Heart disease. High blood pressure and cardiovascular disease make clot formation more likely.
  • Atrial Fibrillation. All new onset AF should be managed with a blood thinner such as Warfarin (Coumadin) to protect against blood clots that may cause a stroke, Pulmonary embolism (PE), or a clot to other parts of your body. Atrial fibrillation, especially if not controlled, may also cause heart failure.
  • Pregnancy. The weight of the baby pressing on veins in the pelvis can slow blood return from the legs. Clots are more likely to form when blood slows or pools.
  • Cancer. Certain cancers — especially pancreatic, ovarian and lung cancers — can increase levels of substances that help blood clot, and chemotherapy further increases the risk. Women with a history of breast cancer who are taking tamoxifen or raloxifene also are at higher risk of blood clots.


  • Smoking. For reasons that aren't well understood, tobacco use predisposes some people to blood clot formation, especially when combined with other risk factors.
  • Overweight and Obesity. Excess weight increases the risk of blood clots — particularly in women who smoke or have high blood pressure.
  • Supplemental estrogen. The estrogen in birth control pills and in hormone replacement therapy can increase clotting factors in your blood, especially if you smoke or are overweight.

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Diagnosis of a Pulmonary Embolism is made with a variety of tests:

  • Chest X-ray: 
  • Lung scan, also called a ventilation-perfusion scan (V/Q scan), uses small amounts of radioactive material to study airflow (ventilation) and blood flow (perfusion) in your lungs.
  • CT scans
  • Pulmonary angiogram: This test provides a clear picture of the blood flow in the arteries of your lungs. It's the most accurate way to diagnose pulmonary embolism, but because it requires a high degree of skill to administer and carries potentially serious risks, it's usually performed when other tests fail to provide a definitive diagnosis. It also has the advantage of being able to measure the pressure in the right side of your heart.
  • Ultrasound of your legs.
  • Magnetic resonance imaging (MRI)

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Treatment of Pulmonary Embolism


  • Anticoagulants. Heparin works quickly and is usually delivered with a needle. Warfarin (Coumadin) comes in pill form. Both prevent new clots from forming, but it takes a few days before warfarin begins to work. Risks include bleeding gums and easy bruising.
  • Clot dissolvers (thrombolytics). While clots usually dissolve on their own, there are medications that can dissolve clots quickly. Because these clot-busting drugs can cause sudden and severe bleeding, they usually are reserved for life-threatening situations.

Surgical procedures

  • Clot removal. If you have a very large clot in your lung, your doctor may suggest removing it via a thin flexible tube (catheter) threaded through your blood vessels.
  • Vein filter. A catheter can also be used to position a filter in the main vein — called the inferior vena cava — that leads from your legs to the right side of your heart. This filter can block clots from being carried into your lungs. This procedure is typically reserved for people who can't take anticoagulant drugs or when anticoagulant drugs don't work well enough.

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Prevention of Pulmonary Embolism

Preventing clots in the deep veins in your legs (deep vein thrombosis) will help prevent pulmonary embolism. Some prevention measures are used in hospitals. Others are precautions you can take yourself.

Preventive steps in the hospital

  • Heparin or warfarin (Coumadin) therapy. Anticoagulants such as heparin and warfarin are given to people at risk of clots before and after an operation — as well as to people admitted to the hospital with a heart attack, stroke or complications of cancer.
  • Graduated compression stockings. Compression stockings steadily squeeze your legs, helping your veins and leg muscles move blood more efficiently. They offer a safe, simple and inexpensive way to keep blood from stagnating after general surgery.
  • Use of pneumatic compression. This treatment uses thigh-high or calf-high cuffs that automatically inflate with air every few minutes to massage and squeeze the veins in your legs and improve blood flow.
  • Physical activity. Moving as soon as possible after surgery can help prevent pulmonary embolism and hasten recovery overall. This is one of the main reasons your nurse may push you to get up and walk despite pain at the site of your surgical incision.

Preventive steps while traveling
Sitting during a long flight or automobile ride increases your risk of developing blood clots in the veins of your legs. To help prevent a blood clot from forming:

  • Take a walk. Move around the airplane cabin once an hour or so. If you're driving, stop every hour and walk around the car a couple of times. Do a few deep knee bends.
  • Exercise while you sit. Flex, extend and rotate your ankles or press your feet against the seat in front of you, or try rising up and down on your toes. And don't sit with your legs crossed for long periods of time.
  • Wear support stockings. These help promote circulation and fluid movement. What's more, compression stockings no longer look like something your grandmother would wear — they're available in a range of stylish colors and textures. There are even devices, called stocking butlers, to help you put on the stockings.
  • Drink plenty of fluids. Water is the best liquid for preventing dehydration, which can contribute to the development of blood clots. Avoid alcohol, which contributes to fluid loss.

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