Pulmonary embolism occurs when a blood clot that forms in a leg or the pelvis breaks free and travels to the lungs, where it can cause a blockage in an artery. These types of clots can be fatal and cause more than 100,000 hospitalizations in the United States each year.
Identifying the symptoms of pulmonary embolism is not only critical for health care providers; it is also essential knowledge for patients. Symptoms include:
- Sudden chest pain
- Difficulty breathing
- Cough with blood
- Lightheadedness and fainting
- Excessive sweating
- Bluish tint to skin
- Anxiety
There are several identified risk factors associated with pulmonary embolisms. Patients should always be made aware of them and they include:
- Recent surgery
- Long periods of immobility (such as bed rest because of an illness)
- Cancer
- Heart problems
- Older age
- Taking oral contraceptives
- Previous stroke or heart attack
A recent study by Swiss physicians identified 10 risk factors that indicated a greater risk of short-term death (within 30 days). These risk factors include: an age of 70 years or older; a history of cancer, heart failure, chronic lung disease or chronic kidney disease; cardiovascular disease; altered mental status; high pulse rate; low systolic blood pressure; and reduced oxygen saturation in arterial blood.
Even with known risk factors, pulmonary embolism can be difficult to diagnose because the symptoms are broad and resemble those of other diseases. Results of the patient's history and physical examination are very important. Some other tests that may be beneficial include:
- Chest x-rays
- Electrocardiogram
- Arterial blood gases—measurement of oxygen and carbon dioxide levels in the blood
- D-dimer assay—a blood test for evidence of blood clots
- Ultrasound of the legs—sound wave images to detect blood clots in the veins
- Spiral computed tomography—detailed computerized x-ray imaging
- Lung scan—test of blood flow through the lungs
- Pulmonary arteriogram—injections to show the arteries in the lungs to detect blood clots
Immediate treatment usually includes giving injectable anticoagulants (blood thinners)—such as heparin, followed by warfarin (an anticoagulant taken by mouth)—to stabilize the clot, prevent additional clots, and restore normal blood flow in the lungs. Oxygen and sedatives may be given to make the patient more comfortable. If the clot is large, thrombolytic ("clot busting") drugs may be needed to remove it. Patients without any of the newly identified high risk factors are considered to be at low risk for short-term death and should be eligible for outpatient treatment.
The recent study by the Swiss physicians is notable because a risk score can be calculated quickly and reliably with clinical data easily obtained in the initial history review and physical examination, which had previously been difficult.
Patients with high risk factors for pulmonary embolism should visit their doctor immediately and begin a prescribed treatment regimen. The recent study has shown that patients at low risk and those who begin early treatment can not only reduce fatality rates but may also reduce healthcare costs in the United States by $91 million annually.
Sources: American Heart Association; National Heart, Lung, and Blood Institute