Pulmonary Embolism Flashcards
def
occlusion of pulmonary vessels, most commonly by a thrombus that has traveled to the vascular system from another site
aetiology
thrombus (>95% from DVT of lower limbs & rarely from right atrium in patients with AF)
others include amniotic fluid embolus, air embolus, fat emboli, tumour emboli, mycotic emboli from right-sided endocarditis
what groups are at risk of PE
surgical patients immobility obesity OCP HF malignancy
epi
common especially in hospitalized patients
occur in 10-20% of those with confirmed DVT
history
dependent on size & site of PE
small - asymptomatic
moderate - sudden onset dyspnoea, cough, haemoptysis, pleuritic chest pain
large - all of above plus severe central pleuritic chest pain, shock, collapse, acute RHF, death
multiple small recurrent - symptoms of pulmonary HTN
examination
small -no signs -earliest signs are tachycardia or tachypnoea moderate -tachypnoea, tachycardia, low SaO2 massive -shock, cyanosis, signs of RH strain (raised JVP, left parasternal heave, accentuated S2 HS) multiple recurrent PE -signs of pulmonary HTN -signs of RHF
what scores are used to predict probability of PE
Wells score
Revised Genova Score
what is the Wells score
> 4 high probability
1 clinically suspected DVT (3.0) 2 PE most likely diagnosis (3.0) 3 recent surgery in last 4 wks (1.5) 4 immobilization (1.5) 5 tachycardia (1.5) 6 history of DVT/PE (1.5) 7 haemoptysis (1.0) 8 malignancy (1.0)
what is the revised genova score
> 11 high probability
4-10 intermediate probability
<3 low probability
>65yrs 1 recent surgery (1 month) 2 previous DVT/PE 3 acute malignancy 2 unilateral leg pain 3 haemoptysis 2 HR >75-94/min 3 HR >95/min 5 unilateral leg oedema & tenderness 4
investigations
1 low probability -D-dimer (cross-linked degradation products, highly sensitive but poor specificity) 2 high probability -requires imaging 3 additional initial investigations -bloods (ABG) -ECG (normal, show tachycardia, RAD, RBBB) -CXR to exclude other diagnoses 4 spiral CT pulmonary angiogram -first line investigation of choice -good sensitivity for moderate & large emboli 5 ventilation-perfusion scan -identifies areas of ventilation & perfusion mismatch which would indicate infarcted lung -unsuitable if a preexisting lung disease exists 6 pulmonary angiography -gold standard but rarely used 7 doppler USS of lower limb -for venous thrombosis 8 echo -may show right heart strain
management - primary prevention
graduated pressure stockings & heparin prophylaxis in those at risk (surgery)
rapid mobilisation & adequate rehydration post-surgery
management if haemodynamically stable
o2
anticoagulation with heparin or LMWH heparin
analgesics for pain
management if haemodynamically unstable (massive PE)
resuscitate
o2
IV fluid resuscitation
thrombolysis with tPA if cardiac arrest imminent
what is tpa
tissue plasminogen activator
involved in breakdown of clots
management - surgical or radiological
embolectomy if thrombolysis is contraindicated
IVC filters for recurrent PEs
