PE Flashcards
what is a pulmonary embolism
obstruction of pulmonary artery secondary to blood clot
what is a thromboembolis
a blood clot on the move
what is Venous thromboembolic disease (VTE)
2 manifestations of the same disease
how do PEs cause ventilation perfusion mismatch (V/Q mismatch)?
blood cannot get to the lungs to pick up oxygen, so the alveoli has fresh air that isnt reaching the blood
how do PEs cause ventilation perfusion mismatch (V/Q mismatch)?
blood cannot get to the lungs to pick up oxygen, so the alveoli has fresh air that isnt reaching the blood
physiologic response to V/Q mismatch
hyperventilation which causes respiratory alkalosis
possible consequence of thromboembolus in ASD
- it bypasses the RV and goes to the L side into aorta and into brain causing an embolic stroke
phrase to describe factors that lead to DVT/PEs
virchows triad
Virchows triad
- Intimal damage/endothelial injury
- hemodynamic changes/stasis
- hypercoagulability (cancer, factor deficiency, pregnancy, etc)
pulmonary vasculature occlusion results in ____ and subsequent ____
results in hypoxemia and subsequent pulmonary vasoconstriction
pulmonary vasculature occlusion results in ____ and subsequent ____
results in hypoxemia and subsequent pulmonary vasoconstriction
what is the classic triad of PEs that is rare
sudden dyspnea
pleuritic chest pain
hemoptysis
most common sign of PE on physical exam
tachypnea
lung exam with PE
usually normal but rales may be heard
sx of DVT
calf or thigh pain, redness, tenderness or swelling
3 common signs of PE on physical exam
tachypnea
tachycardia
low grade fever
what is D-dimer? when is it used?
- product of fibrin degradation after clot is broken down
- used to exclude PE in when probability of PE is low (negative result r/o thrombosis)
what happens if d-dimer is positive?
get a chest scan
classic finding of PE on an EKG
S1Q3T3
wide deep S in Lead I, Q wave and T wave inversion in Lead III
seen in less than 20% of PEs
test that is useful in patients who cannot have contrast or radiation exposure (pregnancy)
V/Q scans
what was the old “gold standard” imaging for PE? which imaging is now first line diagnostic imaging
- Pulmonary angiography was old gold standard
- First line CT pulmonary angiography (CTPA)
which imaging is used mostly for therapeutic intervention and pre-operative evaluation of pulmonary arteries
pulmonary angiography
preferred way to determine if PE is likely is via…
PERC rule
when is wells criteria typically used
more subtle presentation or if you can’t PERC out
how does the PERC rule work
if all 8 things apply then there is only 1% chance of VTE at 45 days. if ANY of the statements do NOT apply to the patient then you cannot perc out
try to list all 8 things in PERC rule
dont need to memorize for exam but helps with knowing general PE signs.
- under 50 yo
- HR under 100
- O2 sat over 95
- no prior DVT or PE
- no trauma or surgery in past 4 wks
- no hemoptysis
- no exogenous estrogen
- no clinical signs of DVT
what score is considered PE unlikely via modified wells criteria & traditional wells
- modified is no more than 4
- traditional– under 2 is “low”, over 6 is high
3 signs of poor prognosis
- RV dysfunction on US
- elevated biomarkers (BNP, NT-proBNP, troponin)
- shock
who is IVC filter indicated for (2)
- For patient w/ PE or DVT + high bleeding risk
- recurrent PE despite anticoag
PE unlikely, now what should you order
get D-dimer
PE unlikely + D-dimer over 500, now what?
get CTPA
if CTPA is positive, what does this mean?
PE confirmed
if CTPA is positive, what does this mean?
PE confirmed
initial management if patient has stable PE
- can give O2
- start IV
initial tx if unstable hypotension & if resp. support needed
- Hypotension: IV fluids < 1 L & early pressor support (NE)
- Resp. support: oxygen
anticoag preferred in pregnancy or malignancy or liver dz
LMWH (enoxaparin) 1-2x daily SQ
oral anticoag option
factor Xa inhibitors (rivaroxaban or apixaban)
anticoag used if unstable, severe renal failure (CrCl under 30), extensive clot burden, obesity or edema
IV UFH
what is the aPTT target with IV UFH
1.5-2.5
4 anticoags for if there is hx of /e/o HIT
fondaparinux
agatroban
danaparoid
bilvalirudin
if there is very large PE or very unstable pt, expert consult with possiblity for what 3 interventions?
- thrombolytic therapy– alteplase
- catheter directed thrombus removal
- embolectomy
the last ditch effort in treating PE requires expert consultation to consider what?
ECMO (extracorporeal membrane oxygenation)
typical long term anticoags (5)
- factor Xa in. (rivaro- or apixaban)
- direct thrombin inhibitors (dabigatran)– needs heparin at start
- warfarn
- enoxaparin (LMWH)
- fondaparinux (subQ factor Xa inhibitor)
typical long term anticoags (5)
- factor Xa in. (rivaro- or apixaban)
- direct thrombin inhibitors (dabigatran)– needs heparin at start
- warfarn
- enoxaparin (LMWH)
- fondaparinux (subQ factor Xa inhibitor)
typically we transition enoxaparin or IV UFH to what 3 meds (except in pregnancy)
- warfarin
- xa inhibitor (rivaro or apixaban)
- direct thrombin inhibitor (dabigatran)
