VTE Flashcards
T or F. Bronchospasm and wheezing are seldom a part of VTE
F. Because of the products of platelet products
Why does hypoxia occur with VTE?
initially a V/Q mismatch issue
When should anticoagulation therapy be started if VTE is suspected?
before the diagnosis is confirmed.
S1Q3T3 is an ACUTE setting is indicative of what?
pulmonary embolism (chronically think PAH)
What is the mortality rate of diagnosed PE?
Less than 10% but it bumps up to 30% if undiagnosed
90% of VTE originate where?
deep veins in the legs
Talc emboli are common in which patients?
IVDU
How are air emboli prevented?
lie patients flat and somewhat on side (Trendelenburg position) to prevent intrathoracic pressure from dropping to much
What is VIrchow’s triad?
triad for risk of clot formation
- Stasis
- Hypercoagulability
- Endothelial injury
What things promote stasis of blood?
- immobility/bed rest
- anesthesia
- CHF/cor pulmonale
- central venous catheters
What things promote hypercoaguability(genetic)?
- Factor V Leiden
- Prothrombin G20210A
- Protein C and S deficiency
- Antithrombin III deficiency
- Homocystinemia
What things promote hypercoaguability (acquired)?
- estrogen use
- pregnancy (estrogen use and pressure on IVC promotes stasis)
- malignancy
What is a type of malignancy especially associated with DVT?
adenocarcinoma
Diseases with increased hypercoag?
- *-Heparin induced thrombocytopenia
- *-Nephrotic syndrome
- DIC
- Antiphospholipid syndrome
- PNH
What things can cause endothelium injury?
- homocystinemia
- trauma/injury
- malignancy
- autoimmune
How does a pulmonary embolus affect gas exchange?
there is increased alveolar dead space creating a V/Q mismatch and shunting
How does the V/Q mismatch manifest ton testing?
low DLCO
In PE, there is alveolar hyperventilation. Why?
reflex stimulation of J (irritant) receptors
Why is wheezing seen in PE?
there is increased airway resistance due to bronchoconstriction (increased serotonin production locally by the clot)
How is compliance affected by PE?
decreased due to lung edema, lung hemorrhage, or loss of surfactant
How does the circulation compensate?
there is vasodilation of uninvolved vasculature which helps to decrease the increase in PVR and improves V/Q relationship
T or F. A high SaO2 rules out PE
F. This is due to the compensatory effect in pulmonary circulation
But the A-a gradient will be increased
T or F. The A-a gradient is increased in pulmonary embolism
T.
What are the overall respiratory effects of PE?
Tachypnea (increased minute ventilation)
Hypoxemia (V/Q mismatch)
Shunting (in massive PE)
What are the overall gas exchange effects of PE?
-hypocapnia (low PaCO2)
-hypoxemia (low PaO2)
Wide A-a gradient
What are the overall CV effects of PE?
- tachycardia (50%)
- systemic hypotension
- decrease in CO
- Pulmonary HTN and cor pulmonale (possibly infarction)
What is the gold standard of picking of clots in the pulmonary circulation?
pulmonary angiography
What type of CT scan s used for ruling in/out PE?
Helical
What is the most common complaint form a patient with acute PE?
SOB (and tachypnea)
Other common signs of PE?
- dyspnea
- pleuritic pain
- loud P2
Overall signs of PE?
- tachycardia
- tachypnea
- hypocapnia
- hypoxia
How will a CXR show in PE?
Normal or no new changes (pleural effusions rarely)
What kinds of atelectasis may be seen with PE?
Discoid Atelectasis
What is a Hampton’s Hump?
Triangular area of pulmonary infarction on CXR (fairly rare)
What is a Westermark’s Sign?
Complete occlusion of the pulmonary artery with no vascular markings on CXR
What are some common EKG findings of PE?
- Nonspecific ST-T abnormalities
- Tachycardia
- minority S1Q3T3
How are WBC affected by PE?
normal or increased (modest)
T or F. D-dimer will be elevated in PE
T. This is a byproduct of clot dissolution
D-Dimer less than 500 suggest very low probability of PE
Is BNP elevated or lower in PE?
Elevated- release when the ventricles are stressed and expanded
Other things that may be elevated?
- Troponin
- LDH
- Bilirubin
Why is PaCO2 low in PE?
J receptors are activated and blow off more CO2
What are the results of V/Q scan of PE?
Infiniti
What confirms PE?
High clinical suspicion + High Probability V/Q scan
What are the pitfalls of V/Q scanning?
- 15s breath hold need to complete test
- better result if no structural disease existing
- observer variability
The majority of V/Q scans are read as _____
indeterminate
What is the gold standard for PE diagnosis?
Pulmonary angiography
Other techniques for PE diagnosis?
- digital subtraction angiography
- MRI (takes time)
T or F. Normal perfusion scan excludes PE
T.
When can you rule out PE before even running any scans?
if clinical suspicion is low AND D-dimer below 500
How does DVT manifest?
- Swelling of the leg
- Homan’s sign (50:50)
- dilated superficial veins
Why are superficial veins dilated in DVT?
collateral circulation
How is DVT diagnosed (most practical)?
Bilateral lower extremity Doppler exam (B mode ultrasonography) to demonstrate non-compressibility of the veins
How are DVTs prevented?
- early mobilization
- T.E.D. host stockings
- Intermittent compression of the calf and thigh
Drugs for Heparin presentation?
5000 units of Heparin SQ
How are PEs and DVTs treated (same)?
trying to prevent the formation of subsequent clot formation
- Heparin (monitor aPTT)
- then Warfarin (monitor PT)
What needs to be monitored if you give LMW Heparin?
Factor Xa
What is the most common cause of treatment failure in PE?
failure to achieve and maintain therapeutic anticoagulation int he first 24 hrs
When are fat emboli common?
after long bone fractures in the elderly (because marrow is now replaced by fat)
Triad of fat emboli?
- mental status changes
- thrombocytopenia
- Petechiae in the chest and neck
2-3 days after fall
