Pulmonary Embolism Flashcards
In what situation should a pulmonary embolism always be considered?
Sudden collapse 1-2 weeks after surgery
What is the mechansim of a pulmonary embolism?
A venous thrombi, usually from a DVT, passes into the pulmonary circulation and blocks blood flow to the lungs. The source is often occult.
What are the risk factors for a pulmonary embolism?
- Malignancy
- Myeloproliferative disorder
- Anti-phospholipid syndrome
- Surgery
- Immobility
- Active inflammation
- Pregnancy
- Combined OCP or HRT
- Previous thromboembolism
- Inherited thrombophilia
What surgery in particular increases the risk of a pulmonary embolism?
Pelvic and lower limb surgery
What are the symptoms of pulmonary embolism?
- Acute dyspnoea
- Pleuritic chest pain
- Haemoptysis
- Syncope
What are the examination signs of a pulmonary embolism?
- Hypotension
- Tachycardia
- Gallop rhythm
- Increased JVP
- Loud P2
- Right ventricular heave
- Pleural rub
- Tachypnoea
- Cyanosis
- AF
What makes PE following surgery far less common?
Thromboprophylaxis
Why might pulmonary embolism be hard to identify?
- It may occur with no predisposing factors
- Breathlessness may be the only sign
How might multiple small pulmonary emboli present?
Much less dramatically, with pleuritic chest pain, haemoptysis, and gradually increasing breathlessness
What might help the diagnosis of pulmonary emboli?
Looking for a source of emboli, especially DVT - is the leg swollen?
How is risk stratified in suspected pulmonary embolism?
Based upon clinical features, using Wells score
What investigations should be done in a patient with suspected pulmonary embolism?
- U&E, FBC, and baseline clotting
- ECG
- D-dimer
- CXR
- ABG
- CT pulmonary angiography
What might the ECG show in a patient with pulmonary embolism?
Commonly normal or shows sinus tachycardia, but might show;
- Right ventricular strain pattern in V1-V3
- Right axis deviation
- Right bundle branch block
- AF
- Deep S waves in I
- Q waves in III
- Inverted T waves in III
What might the chest x-ray show in pulmonary embolism?
Often normal, but may show;
- Decreased vascular markings
- Small pleural effusion
- Wedge-shaped area of infarction
- Atelectasis
What might the ABG show in pulmonary embolism?
Hyperventilation and poor gas exchange leads to decreased PaO2, decreased PaCO2, and increased pH
What is the use of D-dimer?
In a low-probability patient, a negative D-dimer effectively excludes PE
What is the problem with D-dimer?
It has low specificity, and might be increased in thrombosis, inflammation, post-operatively, and in infection
What is the advantage of CTPA?
It is sensitive and specific
What can be used if a CTPA scan is unavailable?
V/Q scan
How is a large pulmonary embolism managed?
- Oxygen if hypoxic, 10-15L/min
- Morphine 5-10mg IV with anti-emetic if patient is in pain or very distressed
- IV access and start LMWH
- If hypotension, give 500mL IV fluid bolus and get ICU input
How should pulmonary embolism be managed if the patient is haemodynamically stable?
If persistent decreased BP, consider vasopressors, e.g. dobutamine or noradrenaline. Aim for systolic BP >90mmHg
How should pulmonary embolism be managed if the patient is haemodynamically unstable?
Consider thrombolysis (alteplase 10mg IB bolus, and then IVI 90mg/2h)
What long-term treatment is required for pulmonary embolism?
Long-term anticoagulation using DOAC or warfarin
Give four examples of underlying causes of pulmonary embolism
- Thrombophilia
- SLE
- Polycythaemia
- Malignancy
How should malignancy be checked for in a patient who has had a pulmonary embolism?
- Careful history
- Full physical examination
- CXR
- FBC
- LFT
- Calcium
- Urianalysis
- Consider CT abdomen/pelvis and mammogram
How long should a patient be on long-term anticoagulation following a pulmonary embolism?
If obvious remedial cause, 3 months. Otherwise, continue for 3-6 months, or longer if recurrent emboli or underlying malignancy
