Pulmonary embolism

Background

• Only 40% of ambulatory ED pts w/ PE have concomitant DVT
• Hypoxemia is unpredictable
• 97% of pts p/w dyspnea, tachypnea, or pleuritic pain

DIAGNOSIS

• Step 1: What is the clinical probability of PE?

• Wells Score

1. Symptoms of DVT - 3pts
2. No alternative diagnosis better explains the illness - 3pts
3. HR > 100 - 1.5 pts
4. Immobilization within prior 4wks - 1.5pts
5. Prior history of DVT or PE - 1.5pts
6. Active malignancy - 1pt
7. Hemoptysis - 1pt

• Wells Criteria:

1. 0-1 point: Low probability (3.4%)
2. 2-6 points: Moderate probability (27.8%)
3. 7-12 points: High probability (78.4%)

Low Probability

• If low prob and PERC neg then d/c
• If low prob and PERC + then d-dimer

Moderate Probability

• Obtain d-dimer

High Probability

• Consider anticoagulation before imaging!
• CTPA if GFR >60
• V/Q if GFR <60

TREATMENT

• Oxygen
• IVF
  • Give cautiously as incr. RV wall stress may lead to ischemia
• Pressors
  • Nnorepi, epi, or dopa if 1L NS fails to raise BP
• Anticoagulation
  • Indicated for all patients with confirmed PE or high clinical suspicion
  • Risk-benefit: (untreated PE = 30% mortality, major bleeding <3%)
  • Treatment options:
    • SC LMWH - First-line agent for most hemodynamically stable patients
    • IV/SC UFH - Consider only in pts with:
      • Persistent hypotension
      • Increased risk of bleeding
      • Recent sx/trauma
      • Age > 70yrs
      • Concurrent ASA use
      • Renal failure
      • Morbid obesity or anasarca
      • Thrombolysis is being considered
      • Cr clearance < 30ml/min
• Thrombolysis
  • Consider for patients with confirmed PE and shock
  • Can also consider, although controversial, for:
    • Severe hypoxemia
    • Massive embolic burden on CT
    • RV dysfunction
    • Free-floating RA or RV thrombus
    • Patent foramen ovale
  • Absolute contraindications:
    • History of hemorrhagic stroke
    • Active intracranial neoplasm
    • Recent (<2 months) intracranial sx or trauma
    • Active or recent internal bleeding in prior 6 months
  • Relative contraindications:
    • Bleeding diathesis
    • Uncontrolled severe HTN (sys BP >200 or dia BP >110)
    • Nonhemorrhagic stroke within prior 2 months
    • Surgery within the previous 10 days
    • Plt < 100K
    • Associated with intracranial hemorrhage in 3% of patients
    • Mortality benefit has never been shown
    • Consider embolectomy if thrombolytics are contraindicated

• PROB DETERMINATION (BY SX)

1. Atypical
   1. Alt diag as/more likely-->low
   2. Alt diag less likely
      1. No RF --> low
      2. +RF --> intrmte
2. Typical
   1. Alt diag as/more likely
      1. No RF --> low
      2. +RF --> mod
   2. Alt diag less likely
      1. No RF --> mod
      2. +RF --> high
3. Severe
   1. Alt diag as/more likely->mod
   2. Alt diag less likely --> high

• PROBABILITY --> W/O

1. Low
   1. No sx DVT --> d-dimer
   2. Neg --> R/O
   3. Pos --> CT
   4. sx DVT --> US
      1. neg --> go to I.1
      2. pos --> R/I
2. Mod/high
   1. no sx DVT --> spiral CT
   2. sx DVT --> US
      1. neg --> go to II.1
      2. pos --> R/I

Risk Factors

1. Age >50y
2. Obesity >35 (BMI)
3. Pregnancy
4. Malignancy
5. Bed Rest (3 days or more)
6. Surg (<4wk)

SEVERE (DEFINITION)

1. Syncope
2. BP <90 with HR >100
3. Requires O2
4. New onet R heart failue

TYPICAL (DEFINITION)

1. (>=2 of A plus >=1 of B)
   1. A
      1. dyspnea
      2. pleuritic CP
      3. hemoptysis
      4. rub
      5. PaO2 <92%
   2. B
      1. HR >90
      2. low grade fever (<101)
      3. leg sx
      4. CXR c/w PE

• Does not apply to pregnant women*

Source

Tintinalli UpToDate