The clot can then dislodge from where it first forms and travel in the blood stream to lodge in one of the pulmonary arteries, the arteries that send blood to the lungs.

A major pulmonary embolism can be fatal. If you think you may have a pulmonary embolism, go to the nearest emergency department or dial triple zero (000) to call an ambulance.

Pulmonary embolism symptoms

Most people with pulmonary embolism have some symptoms, but they can be mild.

Symptoms can include:

• breathlessness, particularly if new or sudden
• rapid breathing
• chest pain
• cough, or coughing up some blood
• fainting
• low blood pressure
• fast or irregular heart beat

Other symptoms include:

• swelling of one or both legs, usually in the calf
• clammy skin
• fever and sweating
• feeling lightheaded or dizzy

Pulmonary embolism risk factors

You are at higher than usual risk of a pulmonary embolism if you haven’t been moving for long periods such as extended travel or being in hospital.

You are also at a higher than usual risk if:

• you smoke
• you use the oral contraceptive pill or hormone replacement therapy, or smoke and take either of those medicines
• you are or have recently been pregnant or overweight
• you have had major surgery
• you have been badly injured
• you've had chemotherapy
• you have a severe illnesses such as heart disease, cancer or respiratory failure
• thrombophilia, a condition in which the blood clots easily
• you have varicose veins

Pulmonary embolism diagnosis

If your doctor thinks you may have a pulmonary embolism, they will talk to you and examine you.

You will be asked to have some tests, such as:

• blood tests
• electrocardiogram (ECG)
• imaging such as a chest x-ray, CT scan, ultrasound or one known as a ventilation-perfusion scan, which measures both air flow and blood flow in your lungs

If you are low risk of having a pulmonary embolism, you may not need extra scans. The Royal Australian and New Zealand College of Radiologists recommend that if your doctor suspects you have a pulmonary embolism, you should ask about the most appropriate test for diagnosis. For further information, visit the Choosing Wisely Australia website.

Complications of pulmonary embolism

A small pulmonary embolism might cause few problems. But a large pulmonary embolism is serious, and can cause heart problems, lung problems or even sudden death.

About a 1 in 3 people who have a pulmonary embolism have another one later.

Pulmonary embolism treatments

Emergency treatment of pulmonary embolism involves:

• oxygen through a mask
• anticoagulant medicines to dissolve blood clots
• surgery to remove a clot (in very serious cases)

Pulmonary embolism prevention

If you are at risk of having a pulmonary embolism, you should not smoke. You will learn what medicines to avoid, and you may need medicine to thin the blood. A few people are advised to have surgery to put a small filter in the main vein in the abdomen, in an effort to catch clots before they reach the lungs.

If you are having surgery, your doctors and nurses will reduce your risk of having a pulmonary embolism by:

• keeping you in hospital for as short a time as possible
• offering medicine, compression stockings and perhaps a machine that pumps the leg muscles while a person is unable to walk, to prevent blood clots forming in the legs of patients following surgery