Flashcards in PE/DVT Deck (35)
Sources of Emboli?
upper extremity veins
DVT in legs (90%)
Non blod clot emboli sources?
6 congenital causes of hypercoagulability?
Factor V Leiden mutation***
Prothrombin "G" mutation
Protein C & Protein S deficiency
Antithrombin III deficiency
9 acquired causes of hypercoagulability?
(4 more important)
antiphospholipid antibody syndrome
4+ DVT risk factors are associated with a confirmed DVT rate of ___%;
3 risk factors >> ___%
0 risk factors >> ___%
What factors determine the extent of physiologic consequences of PE?
The size of the embolus
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?
1. increased pulm vasc resistance
2. impaired gas exchange
3. alveolar hyperventilation
4. increased airway resistance (bronchoconstriction)
5. decreased pulm compliance
What causes increase in pulm vasc resistance in PE?
1. Vascular obstruction
2. Neurohumoral agents (serotonin, Endothelin)
What causes impaired gas exchange in PE?
1.Increased alv dead space from vasc obstr (V/Q mismatch)
2. Impaired carbon monoxide transfer (low DLCO) due to loss of gas exchange surface
3. 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?
widened A-a gradient
What causes tachypnea associated with PE?
increased minute ventilation
What causes hypoxia associated with PE?
shunting (if massive PE)
What are the consequences, in terms of circulation + cardiac symptoms, of PE? (6)
Decrease in cardiac output
Pulmonary hypertension and cor pulmonale
Diagnostic Measures for PE
Clinical signs and symptoms
Laboratory data (ABG/BNP/Troponin)
Helical CT (CT Pulmonary angiography)
What happens to the clot (micro path) following PE? Which is most favorable?
1. Fibrinolyis (most favorable outcome)
2. Organization of clot
3. Partial resolution /compensation via opening of arterial, collateral circ, increased alv ventil
Common signs and symptoms in PE
(increase HR/RR; decrease CO2/O2)
Abn lab data in PE?
Widened A-a gradient
Nml or elevated WBC
elevated LDH and bilirubin
EKG findings in PE
Nonspecific ST-T abnormalities
S1Q3T3 – found in a minority of patients***
Chest Radiography in PE (8)
(What's most common?)
Normal CXR (most common)
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
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)
1. 15 sec breath hold to complete test!
2. Better results in patients w/o structural disease
3. 30% observer variability
4. Majority of the scans are indeterminate
What is the "gold standard test" for PE? How will a PE look on this test?
What can establish or exclude the diagnosis of DVT?
Serial noninvasive studies (ultrasound)
Primary diagnostic modality of choice for PE?
Note: If a PE is excluded: provides alternate diagnosis in about 70% of patients
Clinical manifestations of DVT
Swelling of the leg
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)
if sedated or sick:
1. TED hose stockings
2. Intermittent external pneumatic compression of the calf and thigh
How are PE treated?
1. thrombolysis (tPA)
2. radiological intervention (clot disrupted w catheter or embolectomy)
3. surgical (Pulm embolectomy, thromboendarterectomy)
Prognosis, if PE treated?
1. death = uncommon
2. pulm hemodynamics return to nml in 2-8 weeks
3. very fe develop pulm HTN