A pulmonary embolism (PE) is a blood clot in the lung. It usually comes from smaller vessels in the leg, pelvis, arms, or heart. When a clot forms in the legs or arms, it is referred to as a deep venous thrombosis (DVT).
The clot travels through the vessels of the lung continuing to reach smaller vessels until it becomes wedged in a vessel that is too small to allow it to continue farther. The clot gets wedged and prevents any further blood from traveling to that section of the lung. When no blood reaches a section of the lung, that portion of the lung suffers an infarct, meaning it dies because no blood or oxygen is reaching it. This is referred to as a pulmonary (or lung) infarct.
Several factors can make someone more likely to develop a blood clot that can eventually break loose and travel to the lung.
• Immobilization: A stroke, broken bone, or spinal cord injury can result in confinement to bed so that clot formation can occur in either the arms or legs.
• Travel: Prolonged travel, such as sitting in an airplane or a long car trip, allows the blood to sit in the legs and increases the risk of clot formation.
• Recent surgery
• Trauma or injury (especially to the legs)
• Heart disease (such as an irregular heartbeat)
• Previous history of blood clot in the legs (DVT) or PE
• Conditions that increase clotting of the blood
Not all PEs exhibit the same signs and symptoms, but certain symptoms may indicate that a PE has occurred.
The following signs and symptoms may occur (in the order they are typically seen):
• Chest pain: Pain is very sharp and stabbing in nature, has a sudden onset, and is worse when taking a deep breath (referred to as pleuritic chest pain).
• Shortness of breath
• Anxiety or apprehension
• Cough: Usually, this cough is dry, but it may be associated with blood.
• Passing out
* Doctors may suspect a blood clot if any of these symptoms occur in someone who has or recently had a swollen or painful arm or leg or who has any of the risk factors.
When you go to a hospital’s emergency department or your doctor’s office with chest pain or other symptoms that may suggest a PE, remember that the diagnosis has not yet been confirmed, and therefore not all treatment will occur from the beginning of an evaluation.
If you have chest pain, you will be placed on a heart monitor, and usually an IV will be inserted.
Some people with PE are critically ill. They have severe shortness of breath, low blood pressure, and low oxygen concentrations. Much more aggressive treatment is undertaken to support or elevate the blood pressure and increase the oxygen in the blood.
The following treatments are the most frequently used for PEs:
• Oxygen can be given in several ways. One is through tubing that is inserted at the tip of the nostrils, called a nasal cannula.
• If you have severely low oxygen levels, you will be given a higher flow of oxygen through a mask.
• You may be so sick that you require ventilator treatment. A large tube is placed into your trachea (windpipe) and connected to a ventilator (breathing machine), which assists or does the breathing for you. If a ventilator is required, you will usually be sedated so that you are not aware, which also helps to ease your breathing and make it effortless.
• Blood-thinning medication is given through your IV, injected in the skin directly, and also taken by mouth.
• Heparin is usually the first medication given. This is given in an IV and works to stop further clot formation from occurring. It is administered continuously through the IV.
• Another medication is called enoxaparin (Lovenox), or a low molecular weight heparin. This medication is given subcutaneously, or just under the skin. It only has to be given every 12 hours, but it does require an injection each time. The current trend is to use low molecular weight heparin for the treatment of PE.
• The oral blood-thinning medication called warfarin (Coumadin) is usually given shortly after the heparin or a low molecular weight heparin is started. The medications are continued until blood tests show that the warfarin is adequately thinning the blood. Once this is shown, then the heparin or enoxaparin is stopped, and the warfarin is continued as an outpatient.
• Blood pressure elevators are IV medications given to critically ill people with low blood pressures. The most commonly used medication is dopamine (Intropin). It works to elevate the blood pressure into an acceptable range.
• “Clot buster” medications (also called thrombolytics) are given to those who are critically ill. The purpose is to break up the clot that is blocking the blood vessel in the lung. These medications are used only in those with massive PE, blood pressure collapse, or severely low oxygen that does not respond to treatment. Examples of these medications are reteplase (Retavase), TPA, streptokinase, and urokinase.