Pulmonary Embolism

Pulmonary (lung) embolism occurs when an artery in the lungs gets blocked. The artery is usually blocked by a blood clot that has traveled to the lung from the legs. When a blood clot forms in one part of the body and travels through the blood to another part of the body, it is called an embolism (EM-buhlizm). When an artery of the lung is blocked, there is less oxygen in the blood. This means the heart and lungs must work harder to pump blood.

The embolism could be so small that it blocks only tiny arteries. A small embolus may cause very few symptoms. But an embolus can be large enough to block a larger artery, which could become life-threatening.

The embolism usually comes from veins in the pelvis, hips, or legs. It also can come from the kidneys, arms, or even the right side of the heart.

Signs and Symptoms

Symptoms usually begin suddenly. The most common sign is shortness of breath. Symptoms may include some or all of the following:

  • Pain in the chest (especially when taking a deep breath or with a cough)
  • Coughing up blood (or mucus and blood)
  • Fast heart rate
  • Fast breathing
  • Fever (usually less than 102.0 F)
  • Sweating
  • Blue lips or nail beds
  • Anxiety
  • Light-headedness
  • Low blood pressure

These symptoms also may occur when other breathing or heart problems are present.

Call 911 or call your doctor immediately if you have any of these symptoms.

Risk Factors

Some conditions that lead to higher risk for pulmonary embolism are:

  • Deep vein thrombosis (throm-BOH-sis) (DVT). A thrombosis is a clot that is caught in a vein.
  • Past history of blood clots
  • Family history of blood clots or inherited conditions that increase your risk of blood clotting
  • Obesity
  • Pregnancy or the period of time just after giving birth (postpartum)
  • Cancer, stroke, or congestive heart failure
  • Being unable to move the legs (leg paralysis) or having to stay in bed for a long period of time
  • Surgery within the last 3 months (especially surgery involving the legs, abdomen, or pelvis)
  • Heart rhythm irregularities
  • High blood pressure
  • Not taking blood thinning medicines as prescribed
  • Sitting for a long period of time, such as on car trips or on airplanes
  • Taking birth control pills

Tests for Pulmonary Embolism

If your doctor thinks you may have pulmonary embolism, the following tests may be performed:

Helical (spiral) CT Scan

CT is short for computed tomography (tuh-MOG-ruff-ee). This scan is very similar to a regular CT scan. The name comes from the shape of the x-ray beam that circles around the patient’s body as the table moves. The patient receives an IV with dye (sometimes called “contrast”). This helps the radiologist see the organs more clearly. A spiral CT of the chest is usually done while the patient takes in and holds one deep breath. Pictures are taken faster than with a regular CT scan. This speed allows images to be captured while dye is still in the arteries of the lungs.

Ventilation-Perfusion Lung Scanning (VQ Scan)

This test lets the doctor look at pictures that match the supply of air in the lungs with the blood flow in the lungs.

Pulmonary Angiography

Pulmonary angiography (anj-ee-OGraff-ee) is a surgical test that can show if pulmonary embolism is present. A pulmonary angiogram is done in the radiology department. The radiologist passes a catheter through a vessel in the groin area to the blood vessels in the lung, then dye is passed through the catheter. The dye lets the radiologist see the circulation of blood in the lungs on x-ray.

Other Tests

Other tests that may be performed are:

  • Doppler study
  • CXR (chest x-ray)
  • EKG (electrocardiogram)
  • Echocardiogram
  • Blood tests
  • Tests to measure oxygen in the blood


Anti-coagulation therapy

If pulmonary embolism is suspected, a treatment called anti-coagulation may be started. This is the most common treatment for pulmonary embolism. Anti-coagulation medicines decrease your blood’s ability to clot. These medicines do not dissolve a blood clot that already exists, but help to keep the blood clot from getting bigger. These medicines also help to stop more blood clots from forming. Anti-coagulation medicines are sometimes referred to as blood thinners. Make sure you ask your doctor, nurse, or pharmacist for complete patient information on your blood-thinning medication.


First, you will probably be started on IV (intravenous) heparin (hep-AR-in). IV heparin begins to work quickly to stop more clots from forming. Heparin is given to you through an IV needle, usually in your arm.

When you are receiving heparin, you have an increased risk for bleeding. You need frequent blood tests to check how clotting is affected. The goal is to make your blood less likely to clot without making it too thin. While on this medicine, you might bruise more easily or be more likely to bleed. You will need to hold pressure on the site of blood draws and be careful to prevent bruising and bleeding in other places of your body.


While on heparin, your doctor may start another blood thinner by mouth called warfarin (Coumadin®) Warfarin is the generic name for this drug. Coumadin® is the brand name. Coumadin® is a pill that is taken by mouth. It usually takes a few days before Coumadin® starts to work and to adjust the dose of this medicine. Tests that measure your clotting ability are called the Protime (PT) and INR. They are done frequently until the right dose for you is determined. Most patients begin taking Coumadin® in the hospital and keep taking it after they leave.

Vitamin K from food and dietary supplements can interfere with the blood-thinning effects of Coumadin®. It is important to keep your intake of Vitamin K the same every day. Changing the amount of Vitamin K you get could result in bleeding or an unwanted blood clot.

1.) Eat the same amount of high Vitamin K foods each day.

It is very important to be consistent. For instance, if you eat a half-cup of a high Vitamin K food daily, continue to eat this same amount each day.

High Vitamin K foods (listed with the highest first)

  • Broccoli
  • Brussels sprouts
  • Kale
  • Greens: collard, turnip, beet, mustard, dandelion
  • Green onions or scallions
  • Spinach

2.) Eat about the same amount of medium Vitamin K foods each day.

For example, it would not be wise to eat leaf lettuce at every meal and then stop eating it entirely. It would be better to substitute another medium Vitamin K food from the list below for the leaf lettuce.

Medium Vitamin K foods

(listed with the highest first)

  • Asparagus
  • Black-eyed peas
  • Cabbage or cole slaw
  • Okra
  • Prunes or dried plums
  • Dark green lettuce or salad greens, like Bibb, Boston, leaf lettuce, or endive
  • Parsley
  • Tofu

Dietary Supplements

  • You may take a daily multivitamin. Many contain 25 micrograms of Vitamin K per tablet. If you do take a multivitamin supplement, you must take it every day.
  • Read the label of any dietary supplement. Do not take supplements that contain more than 100 micrograms of Vitamin K per day.
  • Avoid supplements that may affect how your blood clots. These include Vitamin E tablets, ginkgo, and garlic.

While taking Coumadin®:

  • If possible, use an electric shaver instead of a blade razor when you shave.
  • Do not engage in contact sports.
  • Do not drink alcohol while taking anticoagulants.
  • Avoid drinking cranberry juice or eating cranberry products.
  • Anticoagulants may be dangerous in pregnancy. Call your doctor immediately if you are pregnant or think you may be pregnant. If you plan to become pregnant, discuss this with your doctor or health care provider first.

You must take Coumadin® exactly as your doctor prescribes. After you leave the hospital, you will need frequent blood tests to check if the dose needs to be changed.

Tell your doctor right away if you notice any signs or symptoms of bleeding:

  • Easy or unusual bruising
  • Black or dark stools
  • Bloody urine
  • Bleeding gums
  • Nosebleeds
  • Bleeding from a cut that does not stop
  • Headache, dizziness, or weakness
  • Unusual pain or swelling
  • Throwing up blood
  • Falling or hitting your head

When you go to any kind of dentist or doctor, be sure they know that you take Coumadin®. Carry identification that you are on anti-coagulation medicine. Consider wearing a medical alert tag that says you are taking Coumadin®. Tell your doctor when you get sick, get hurt, or get a cut that won’t stop bleeding. Avoid activities and sports that might cause trauma.

Low-Molecular-Weight (LMW) Heparin

This form of heparin is given by injection (shot) under the surface of the skin (subcutaneous). It is usually given 2 times per day. Some common brand names for this type of heparin are Lovenox® and Fragmin®. Some people may be switched to this medicine after a few days of IV heparin. You could also leave the hospital and go home on this medicine. LMWheparin may be given while the warfarin dose is being adjusted. Sometimes, LMWheparin is given in place of warfarin. To learn how to inject LMWheparin, see the UPMC patient education sheet Blood Clot Prevention: Injection. If you are having difficulty with injection of this medicine, ask if you are eligible for home care

After you leave the hospital, anti-coagulation medicine must still be taken to prevent another blood clot from forming. Blood-thinning medicines are usually needed for months to years, depending on your condition. Your doctor will determine how long you need to take anti-coagulation medicines. Do not stop taking blood-thinning medicine without talking to your doctor. Get detailed information from your health care provider about your anti-coagulation medicine.

Thrombolytic Therapy

Sometimes people with pulmonary embolism receive medicines that can dissolve the clot. These “clot busters” are like the ones patients with heart attacks receive. These medicines may be used for patients who have large blood clots and are severely ill when they come to the hospital with a pulmonary embolism.


Surgery may be necessary to remove the blood clot in some situations. This is called an embolectomy (em-buh-LEK-tuh-me).

Inferior Vena Caval Filters

In some situations, the use of anticoagulation medicines is not possible. For some patients, embolism may occur even when they are taking anti-coagulation medicines. For these people, a filter might be recommended. An inferior venal caval filter (sometimes referred to as an “umbrella”) is usually placed in a large vein that returns blood to the heart from the lower half of the body. This filter catches the clots and prevents them from entering the right side of the heart and then traveling to the lungs. This treatment cannot stop other clots from forming.

Additional Supportive Treatments In The Hospital

Persons with pulmonary embolism may also receive treatment with oxygen. Depending on the person’s condition, additional IV therapies and a stay in the ICU (intensive care unit) may be necessary. Some patients need to wear compression stockings.

Reduce Your Risk

A history of having blood clots is one of the main risk factors for developing another clot. If you have had blood clots, a future embolism is often more severe. Take action to reduce your risk. Take anti-coagulation medicine as prescribed with regular blood test monitoring as your doctor orders.

Some ways you can prevent pulmonary embolism are:

  • Stay active and get out of bed as soon as possible after surgery or illness.
  • On long car or plane trips, take breaks and walk at least every 2 hours. If you can’t walk, at least bend, straighten, and stretch your legs and hips.
  • Change positions often.
  • Do leg exercises if you are on bed rest.
  • Wear compression stockings or have compression therapy as advised following surgery.
  • Don’t cross your legs.
  • Take blood-thinning medicines as prescribed.
  • Have regular blood tests if you are on blood-thinning medicines.
  • Know the symptoms and get immediate medical attention if you have any.
  • Don't smoke.

If low-molecular weight heparin is prescribed for you, take it as directed. Heparin may be prescribed following surgery or if you are on bed rest because of illness.

Related UPMC patient education sheets

Additional Resources

                                                                                                                                             Reviewed 2011

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