PE Flashcards
What is a PE?
Blood clot that is lodged in pulmonary artery tree
Increased pulmonary vascular resistance, V/Q mismatch and possibly reduced pulmonary blood flow
What is the most common source of PE?
Proximal leg thrombus
Does a negative doppler US r/o DVT?
No, US is not reliable for calf vein DVTs (low risk for embolizing)
But 15% risk that calf vein DVTs can extend proximally and become dangerous (can serially US for 2 weeks)
When to worry about PE after surgery?
Fever, sudden dyspnea, chest pain or collapse 1-2 WEEKS after surgery
What is Virchow’s triad?
Venous stasis
Endothelial damage
Hypercoagulable state
RFs for venous stasis?
Immobilization
Obesity, CHF
Chronic venous insufficiency
RFs for endothelial cell damage?
Post-op injury
Trauma
RFs for hypercoagulable states?
Malignancy, cancer treatment Exogenous estrogen (OCP, HRT) Pregnancy, post-partum Prior history of DVT, PE, FHx Coagulopathy Increasing age
When to order a d-dimer?
Need to ensure hospital uses 2nd or higher generation assay that has high sensitivity
Test is used for negative predictive value (negative result rules out PE in settings low clinical probability)
Does NOT rule in PE
ABG findings for PE?
Acute respiratory alkalosis
But some patients may have normal acid-base status and may not be hypoxemic or hypocarbic
ECG findings for PE?
SINUS TACHYCARDIA***
RV strain RV hypertrophy RBBB R axis deviation RA hypertrophy
S1Q3T3
CXR findings in PE?
Atelectasis (ischemia leads to dysfunctional Type II alveolar cells, leading to reduced surfactant and lung collapse)
Small pleural effusion
Normal CXR
What are classic but rare CXR findings for PE?
Westermark’s sign (plump proximal arger with distal oligemia)
Hampton’s hump (peripheral pleural based density representing pulmonary infarct)
When is a d-dimer not necessary?
Any prior probability for PE that is NOT low
Why is a leg doppler preferred as initial imaging?
Presence of DVT has same clinical significant as PE because they have the same treatment
When to consider V/Q scan?
Young, healthy females with no history of CHF or lung disease due to lower dose of radiation (decreased risk of breast CA)
How to interpret results of V/Q scan?
Low probability/normal: rules out PE
High probability: most likely means PE present
Intermediate: follow up with CTPA
How to interpret results of CTPA?
Sensitive and specific for PE
How long to serially doppler a leg for a calf vein DVT?
If a calf vein DVT has not extended proximally by 7-10 days in an untreated ambulatory patient, they will not extend after that time
Treatment for PE?
Admit for observation, O2 if hypoxemic or dyspneic, analgesia for chest pain (narcotic or acetaminophen)
Acute anticoagulation: LMWH
Long term anticoagulation: Warfarin (start at the same time as LMWH, overlap for at least 5 days and until INR in target range of 2-3 for at least 2 days)
When to thrombolyse via IV?
Massive PE (hypotension or clinical RH failure) and no contraindications
IV: hastens resolution of PE but may not improve survival and doubles risk of major bleeding
Catheter-directed thrombolysis by interventional radiologist works better than IV therapy, fewer contraindications
Duration of long term anticoagulation?
If reversible cause for PE (surgery, injury, pregnancy, etc.), then warfarin for 3-6 months
Indefinite anticoagulation if ongoing major risk factor (CA, antiphospholipid antibody, etc)
What is Well’s criteria for PE?
3: signs/symptoms of DVT
3: no alternate dx
1. 5: prior PE/DVT
1. 5: immobilization or surgery 100)
1: hemoptysis
1: malignancy
