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18 Cards in this Set
- Front
- Back
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what are 2 examples of venous thromboemboli?
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DVT
PE |
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what are some predisposing factors to venous thrombosis?
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-venous statis due to:
immobility post-op orthopedic surgery esp hip and knee obesity -damage to venous endothelium activates coagulation -hypercoagulable state inherited or acquired via neoplasm -use of estrogen/pregnancy -CHF -hx of PE -increased blood viscosity -acquired anticoagulant def. prtein C, S, AT III |
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acquired risk factors
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*explain 25% of all venous thrombi*
-Factor V Leiden activated protein C resistance inherited thrombophillic defect -G20210A mutation in prothrombin gene results in increase in prothrombin levels |
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where do most fatal emboli arise from?
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proximal veins of legs
-iliac -popliteal -femoral |
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what are the hemodynamic consequences of PE?
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decreased SA of Pul. arterial bed
increased resistance increased artery pressure increased RV work-cor pulmonale could result |
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what are the pulmonary consequences of PE?
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transient bronchoconstriction
increased dead space altered V/Q hyperventilation/hypocapnia/hypoxic vasoconstriction loss of surfactant in embolized zones-localized edema |
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what is the key finding to assess the severity of PE?
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pulmonary artery obstruction is secondary to pulmonary arterial mean pressure and right atrial mean pressure
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what is the frequency of pulmoanry infarctions with PE?
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rarely occurs bc of dual blood supplies
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1. what will ECG findings of PE reveal?
2. what will echo findings reveal? |
1. normal sinus tachycardia
ECG done to r/o cardiac causes never rules in PE 2. r/o cardiac causes but if RV heart failure found could point ot PE |
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what is a non-invasive diagnostic test for PE?
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venous ultrasound
-highly accurate for detection of proximal vein thrombosis in symptomatic pts -veins imaged and compressed in real time |
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what is D-dimer?
when is it safe to withhold therapy on a pts with a suspected PE |
d-dimer formed when cross linked fibrin in thrombi is broken down to plasmin
-has high positive predictor value for DVT (this person does not have PE) -high D-dimer=suspicious low d-dimer r/o clot 2. it is safe to withhold therapy in pts w/normal d-dimer and venous ultrasound |
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what is ventilation-perfusion scanning? aka nuclear lung scan
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2 components:
perfusion scan followed by ventilation scan contrasted with krypton or Xenon -normal perfusion scan excludes PE |
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what is the gold standard diagnostic test for PE?
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pulmonary angiography
-invasive |
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what are the benifits of CT scan?
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non-invasive
90% sensative |
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what are the steps done to dx PE
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1. plasma D-dimer
2.ultrasound 3. nuclear lung scan 4. angiogram |
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what are the pharmacologic methods used for PE prevention?
what are the mechanical methods for preventing PE? |
1. low dose Sub-Q heparin
LMWH 2. intermittent pneumatic compression graded compression stockings |
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when are vena cava interruptions used?
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used when anticoagulation cannot be administered
allows for patency of ivc but prevents clots from passing |
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what are the indications for vena cava filters?
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recurent PE despite antcoagulaiton
at risk for PE recurrence high risk pts with large DVT |
