Pulmonary Embolism Flashcards
What is an embolus?
Blockage of a blood vessel at a site by a solid/liquid/gas distant from its origin
What can make up an embolus?
Thrombus Tumour Air Fat Amniotic fluid
What is the most common origin of a PE?
DVT
What are the risk factors for a PE?
Pregnancy Prolonged immobilisation Contraceptive pill Long travel Obesity Surgery Previous VTE
What is the pathophysiology of a PE?
Right ventricular overload
Respiratory failure
Pulmonary infarction
What causes right ventricular overload?
Pulmonary artery pressure increases - causes RV dilatation + strain
Inotropes released to attempt to maintain BP - causes pulmonary artery vasoconstriction - makes it worse
What causes respiratory failure?
Areas of V/Q mismatch - low RV output
What causes pulmonary infarction?
Small distal emboli may cause alveolar haemorrhage
What are the symptoms of PE?
Dyspnoea
Pleuritic chest pain
Cough +/- haemoptysis
Leg pain - if caused by DVT
What are the signs of PE?
Dyspnoea
Tachycardia
Low BP
Raised JVP
What are differentials for a suspected PE?
Pneumothorax Pneumonia Pleurisy MSK pain MI Pericarditis
What investigations should you do for a suspected PE?
ECG CXR Bloods - FBC, troponin, D dimer ABG CTPA
What would an ABG show with a PE?
Respiratory alkalosis
- hypoxaemia
- hypocapnia
What would a CXR show with a PE?
Commonly = normal
Wedge sign
Knuckle sign
What would an ECG show with a PE?
Sinus tachycardia = common
Right heart strain - T wave inversion in V1-4, II, III, aVF
S1Q3T3
What score system is used for assessing PE risk?
Wells for PE
What are the Wells criteria?
Clinical signs/symptoms PE likely? HR >100 Immobilisation/recent surgery Previous DVT/PE Haemoptysis Malignancy
What does a Well’s score of 0-4 indicate?
PE unlikely
What does a score of 4+ indicate?
PE likely
How do you manage a patient with PE?
Immediate heparinisation
O2
Thrombolysis
How does heparinisation reduce mortality?
Stops thrombus propagation - at source and in lungs
