Session 5- Pulmonary Embolism Flashcards
where do pulmonary emboli most commonly originate
deep veins of the lower limb, pelvis or abdomen
what factors predispose to venous thromboembolism
endothelial injury
stasis
hypercoagulable state
consequences of PE- heart, lungs, perfusion
hypoxaemia due to V/Q mismatch
obstruction to the pulmonary circulation causes a rise in pulmonary artery pressure; with a large obstruction this can cause right ventricular strain/failure and a drop in CO evidenced by sinus tachycardia- Inotropes are also released which cause vasoconstriction which further exacerbates the issue further restricting the flow of blood out of the pulmonary artery
the poorly perfused part of the lung may undergo infarction but usually does not do so because the bronchial arteries provide an alternative blood supply and airways continue to supply to lung tissue
what is FES
fat embolism syndrome
-when fat emboli dont resolve
consist of a triad
-petechial rash, decreased level of consciousness and SOB
how do amniotic fluid emboli present
sudden prodound and unexpected matenal collapse associated with hypotension hypoxaemia and DIC
risk factors for PE
Immobilty malignancy recent long distance travel pregnancy obesity recent surgery HRT oral contraceptives
symptoms of PE
pleuritic chest pain
dizziness
syncope
low grade fever
clinical findings that confirm a PE
detection of embolism on CTPA ABG -resp alkalosis -low po2 -low pCO2 -elevated pH
a normal paO2 does elimate a PE
d dimers
what is used to prevent clot propagation
LMWH - low molecular weight heparin
it stops thrombus propagation in the pulmonary arteries and allows the bodys fibrinolytic system to lyse the clot
stops thrombus propagation at the embolitic source and reduces the frequency of further pulmonary embolism
signs of PE
tachycardia
tachypnoea
lowe extremity oedema
antithrombin III deficiency
no antithrombin which breaks down ckots through inhibiting thrombin
factor V leiden mutation
resistance to activated protein C is the most common risk factpr for DVT/PE in european descent
how can PE lead to resp failure
due to areas of ventilation perfusion mismatch
low right ventricle output
shunt with patent foramen ovale
how does PE lead to pulmonary infarction
small distal emboli may create areas of alveolar haemorrage
resulting in haemoptysis, pleuritis and small pleural effusion
classic ECG in PE
deep s wave in lead 1
q wave in lead 3
inverted t wave in lead 3
