Pulmonary embolism (PE) Flashcards
What are the risk factors for a PE?
Anything affecting Virchow’s triad and family history
What is Virchow’s triad?
Venous stasis
Endothelial injury
Hypercoaguability
What factors affect venous stasis and increase the risk of PE?
Immobility (long flight)
Post surgery
Varicose veins
AF
What factors affect endothelial injury and increase the risk of PE?
Smoking
Hypertension
Trauma
Vascular catheters
What factors affect hypercoagulability and increase the risk of PE?
Pregnancy
Obesity
Malignancy
COCP
Antiphospholipid syndrome
Protein C and S deficiency
Factor V Leiden
A DVT embolises and enters the right heart via what vessel?
Inferior vena cava
What does an occlusion of the pulmonary artery small vessels cause?
Increased A-a gradient (alveolar oxygen minus arterial oxygen pressure)
There is ventilation with no perfusion so the V/Q decreases
Results in reactive bronchoconstriction causing increased dyspnoea and smaller airways
A PE increases the pulmonary pressure causing pulmonary hypertension and r___ v______ strain leading to cor pulmonale and right heart failure
right ventricle
What are symptoms of a PE?
Sudden onset of SOB
Pleuritic chest pain
Swollen painful calf (DVT)
History of immobility
Signs of heart failure
What are signs of heart failure?
Hypotension
Tachycardia
Peripheral oedema
What is used to diagnose a PE
Wells score
If 4 or greater than PE likely so perform CTPA (CT pulmonary angiogram)
What is done if the Wells score is lower than 4 (PE assessment)?
D-dimer (is a by-product of the blood clotting and breakdown process, so measures the clot burden. Is sensitive but not specific.)
At what level of D-dimer should a CTPA be performed to check for PE?
500 ng/ml or more
What scan should be given if a CTPA is contraindicated?
V/Q scan
What are ECG characteristics of a PE?
S1Q3T3
S waves are deep in lead I
Q waves v deep in lead III
T waves inverted in lead III
RBBB in V1-3, RSR pattern due to right axis deviation
Sinus tachycardia
