Pulmonary Embolus Flashcards
Define pulmonary embolus
- Obstruction of pulmonary arterial bed by a dislodged thrombus or heart valve vegetation
- Serious and potentially fatal condition
Where do PE’s usually arise from?
- Arise from:
A. Thrombus in venous circulation
B. Thrombus from right side of heart - > 90% originate from clots in deep veins of lower extremities
- Approx. 50-70% of symptomatic PE’s have LE DVT when diagnosed
Where else can PEs arise from?
- Air embolus from central lines
- Amniotic fluid from active labor
- Fat embolus from femur fracture
what is Virchow’s Triad? What are its components?
3 categories of factors that are thought to contribute to thrombosis:
A. Hypercoagulability
B. Hemodynamic changes (stasis, turbulence)
C. Endothelial injury/dysfunction
What risk factors are asst. with pulmonary embolism?
1. Surgical procedure A. Ortho, pelvic, abdominal 2. Cancer 3. Oral contraceptives 4. Pregnancy 5. Bedrest (prolonged nonactivity) 6. Prior Hx DVT or PE
What causes a thrombus to dislodge?
- Trauma
- Intravascular pressure changes
- Change in peripheral blood flow
What is the pathophys of PE?
- Starts with (Virchow’s Triad):
Vascular wall damage
or Venostasis or Hypercoaguability - Thrombus dislodges
- Embolus →right side of heart → pulmonary artery
- Embolus occludes pulmonary arterial vessel
What happens when an embolus occludes the pulmonary arterial vessel?
- Prevents alveoli from producing sufficient surfactant
- Alveoli collapse
- Atelectasis develops
What are the symptoms of PE?
- Nonspecific
- Pleuritic chest pain
- Dyspnea
- Apprehension
- Cough
- Hemoptysis
What are the signs of PE?
- Tachycardia
- Tachypnea
- Rales
- Low grade fever
- ↓ PaO2
- Loud S2
- +/- LE edema
- S3 or S4 gallop
What are the ABG results in PE?
Resp alkalosis secondary to hyperventilation
What are the EKG results in PE?
- Sinus tachycardia
- Non specific ST-T wave abnormalities
- S1Q3T3
A. Seen in < 20% patients
What is the D-dimer test?
degradation product of fibrin
What are the D-dimer results in PE?
- ↑ in presence of thrombus
- Sensitivity 95-97%, specificity 45%
- Can be used as a screen to R/O thrombosis
- > 250 ng/mL D-Dimer Units (DDU)
- > 0.5 mcg/mL Fibrinogen Equivalent Units (FEU)
What are the CXR results in PE?
1. May be normal (most commonly) or show non-specific abnormalities A. Atelectasis B. Prominent PA C. Elevated hemidiaphragm D. May show Hampton's hump
What is a ventilation/perfusion scan and when is it indicated?
- Demonstrates perfusion defect with normal ventilation
2. Done if contraindication to CT contrast dye or CT not available
What is the initial test for identifying a PE?
Spiral CT, noninvasive
What is the definitive test for PE?
- Pulmonary CT angiogram
A. Rarely used unless non-invasive testing leaves uncertainty of diagnosis
What are the treatment goals in PE?
- Maintain adequate cardiovascular & pulm function during resolution of obstruction
- Prevent recurrence of emboli
What are the anticoagulation treatment options for PE?
Recurrent PE requires life long anticoagulation
- LMW heparin
A. Enoxaparin (Lovenox) SQ q 12h x 5+ days
B. Fondaparinux (Arixtra) SQ qd x 5+ days
C. Rivaroxaban (Xarelto) PO bid x 21 days
D. Dalteparin (Fragmin) SQ qd-bid x 5+ days
AND - Start warfarin (Coumadin) 2-10 mg qd
A. Maintain INR 2.0-3.0 (goal 2.5)
What are SpO2 goals for PE treatment?
Oxygen therapy to maintain SaO2 > 90%
What is Inferior IVC Filter? When is it indicated?
- Indicated in patients who are at high risk of recurrence or when anticoagulants are a major contraindication
- Filters blood returning to heart & lungs
What are the anticoagulation guidelines for PE?
- 3 mo of anticoagulation after first episode provoked by surgery or a transient nonsurgical risk factor
- 6-12 mo for unprovoked episode w/low to moderate risk of bleeding (3 mo if high risk of bleeding)
How is PE prevented in high risk pts?
- For high risk patients:
A. Early ambulation
Intermittent pneumatic compression stockings
B. Low molecular weight heparin or low dose heparin
