PE/DVT Flashcards
Sources of Emboli?
pelvic veins
upper extremity veins
DVT in legs (90%)
Non blod clot emboli sources?
Air Tumor Amniotic fluid Talc Fat
Virchow’s Triad
Stasis
Hypercoagulability
Endothelial injury
6 congenital causes of hypercoagulability?
Factor V Leiden mutation*** Prothrombin "G" mutation Protein C & Protein S deficiency Antithrombin III deficiency Dysfibrinogenemia Homocystinemia
9 acquired causes of hypercoagulability?
4 more important
estrogen* pregnancy (hormonal)* malignancy* nephrotic syndrome* thrombocytosis DIC HIT antiphospholipid antibody syndrome PNH
4+ DVT risk factors are associated with a confirmed DVT rate of ___%;
3 risk factors»_space; ___%
0 risk factors»_space; ___%
100
50
11
What factors determine the extent of physiologic consequences of PE?
The size of the embolus
Cardiopulmonary status/reserve
Neurohormonal substances
Compensation by the circulation (due to PE)?
How does this help?
Vasodilatation of uninvolved vasculature –>
- helps to decrease pulm vasc resistance
- improves V/Q in uninvolved areas
- improves overall oxygenation
What are the physiologic consequences of PE?
- increased pulm vasc resistance
- impaired gas exchange
- alveolar hyperventilation
- increased airway resistance (bronchoconstriction)
- decreased pulm compliance
What causes increase in pulm vasc resistance in PE?
- Vascular obstruction
2. Neurohumoral agents (serotonin, Endothelin)
What causes impaired gas exchange in PE?
- Increased alv dead space from vasc obstr (V/Q mismatch)
- Impaired carbon monoxide transfer (low DLCO) due to loss of gas exchange surface
- Right-to-left shunting (in massive PE)
What causes alveolar hyperventilation in PE?
reflex stimulation of irritant receptors
What are possible causes of decreased pulm compliance in PE?
lung edema, lung hemorrhage or loss of surfactant
Gas exchange abnormalities resulting from PE?
hypocapnia
hypoxemia
widened A-a gradient
What causes tachypnea associated with PE?
increased minute ventilation
What causes hypoxia associated with PE?
V/Q mismatch
shunting (if massive PE)
What are the consequences, in terms of circulation + cardiac symptoms, of PE? (6)
Tachycardia Decrease in cardiac output Systemic hypotension Pulmonary hypertension and cor pulmonale Pulmonary infarction Bradycardia (sometimes)
Diagnostic Measures for PE
Clinical signs and symptoms Laboratory data (ABG/BNP/Troponin) EKG CXR V/Q Scan Pulmonary angiography Helical CT (CT Pulmonary angiography)
What happens to the clot (micro path) following PE? Which is most favorable?
- Fibrinolyis (most favorable outcome)
- Organization of clot
- Partial resolution /compensation via opening of arterial, collateral circ, increased alv ventil
Common signs and symptoms in PE
dyspnea pleuritic CP tachypnea tachycardia loud P2
(increase HR/RR; decrease CO2/O2)
Abn lab data in PE?
Widened A-a gradient
Nml or elevated WBC
elevated d-dimer
elevated LDH and bilirubin
EKG findings in PE
Nonspecific ST-T abnormalities
Tachycardia
S1Q3T3 – found in a minority of patients***
Atrial arrhythmias
Chest Radiography in PE (8)
What’s most common?
Normal CXR (most common) Cardiomegaly Hampton’s hump Westermark’s sign Sausage sign Discoid atelectasis Elevated diaphragm Pleural effusion (small when present)
Do we need to learn Well’s criteria?
Previous DVT or PE Immobil/ Surg with in 4 weeks Tachy HR > 100 per minute Cancer Hemoptysis Edema/Symp of DVT Diagnosis other than PE less likely
Why is Lung Scan Interpretation combined with Clinical Assessment ?
high clinical suspicion + high prob V/Q scan = confirms PE
low + low = excludes
V/Q Scanning - Pitfalls: (4)
- 15 sec breath hold to complete test!
- Better results in patients w/o structural disease
- 30% observer variability
- Majority of the scans are indeterminate
What is the “gold standard test” for PE? How will a PE look on this test?
Pulmonary angiography
- filling defect
- cutoff sign
What can establish or exclude the diagnosis of DVT?
Serial noninvasive studies (ultrasound)
Primary diagnostic modality of choice for PE?
helical CT
Note: If a PE is excluded: provides alternate diagnosis in about 70% of patients
Clinical manifestations of DVT
Swelling of the leg Duskiness Homan’s sign - 50:50 Palpable deep thrombi Dilated superficial veins (collaterals) Tender cord in the femoral triangle
Diagnostic Measures for DVT
Ascending contrast venography (invasive)
Real-time (B-mode) ultrasonography (US) ***
Prevention of DVT (Prophylaxis)
normal patients?
sedated/sick?
Early mobilization
if sedated or sick:
- TED hose stockings
- Intermittent external pneumatic compression of the calf and thigh
- anti-coags
How are PE treated?
- thrombolysis (tPA)
- radiological intervention (clot disrupted w catheter or embolectomy)
- surgical (Pulm embolectomy, thromboendarterectomy)
Prognosis, if PE treated?
- death = uncommon
- pulm hemodynamics return to nml in 2-8 weeks
- very fe develop pulm HTN
“triad” associated with fat embolism?
Mental status changes
Thrombocytopenia
Petechiae in the chest and neck
