A pulmonary embolism happens when a blood clot, usually from a deep vein in the leg, breaks off and lodges in the lung arteries. It blocks blood flow through the lung and strains the right side of the heart, and a large clot can cause sudden collapse.
Key symptoms
- Sudden shortness of breath
- Sharp chest pain that is worse on breathing in
- Cough, sometimes with blood
- Lightheadedness or fainting
- A swollen, painful leg from the original clot
What you find on exam
- Fast breathing and fast heart rate
- Low oxygen saturation
- Low blood pressure in a massive embolism
- Leg swelling, tenderness or warmth
- Raised jugular venous pressure with right heart strain
Tests
- Clinical probability with the Wells score or PERC rule
- D-dimer if probability is low; a normal result helps rule it out
- CT pulmonary angiogram to confirm; V/Q scan if CT contrast cannot be given
- ECG, troponin and BNP to look for right heart strain
- Bedside echocardiogram in an unstable patient
Treatment basics
- Oxygen and close monitoring
- Start anticoagulation promptly, such as heparin, enoxaparin or apixaban
- Massive embolism with shock: systemic thrombolysis such as alteplase
- Catheter or surgical clot removal if thrombolysis is not possible or fails
- Continue anticoagulation for at least 3 months
Red flags
- Low blood pressure or fainting
- Saturation falling despite oxygen
- Signs of right heart strain or cardiac arrest
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Sources: NASEMSO National Model EMS Clinical Guidelines; NCCPA PANCE Content Blueprint; NBOME COMLEX-USA clinical presentations. Written by Making Synapses. Making Synapses is not affiliated with these organizations.