DVT ultrasound

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Background

  • Bedside ultrasound can be used to conduct compression testing on lower extremity vasculature to assess for DVT
  • Intended to be rapid, limited, but revealing most clinically significant DVTs
  • Amongst ED providers, there is a sensitivity of 95% and specificity of 96%[1]

Indications

  • Clinical suspicion of DVT: edema, tenderness over the calf, Homan's sign
  • Clinical suspicion of PE: chest pain, shortness of breath, tachycardia, tachypnea

Technique

Sites of Compression for 3-Point Evaluation

Compression of Lower Extremity Veins.png

  1. Common Femoral Vein
  2. Saphenofemoral Junction
  3. Popliteal Vein

Steps

  1. Select transducer
    • Linear array vascular probe 6–10 MHz
    • For morbidly obese patients, consider abdominal probe
  2. Common Femoral Vein and Saphenofemoral Junction
    • Patient positioning
      • Reverse Trendelenburg or semi-sitting with 30 degrees of hip flexion
      • Mild external rotation (30 degrees) hip
    • Probe at medial inguinal crease
    • Apply generous compression every centimeter
    • Continue distal to 1-2cm beyond bifurcation of the common femoral vein
  3. Popliteal vein
    • Patient positioning
      • Prone, decubitus position, or seated on edge of gurney
      • Knee flexed 10–30 degree
      • Reverse Trendelenburg
    • Apply generous compression over the popliteal vessals
    • Vein usually superficial to the artery (artery is anterior)

Findings

  • Each segment of vein identified must be assess as compressible and noncompressible
    • Touching of the anterior and posterior walls indicates a normal exam
    • No touching with pressures sufficient to deform the artery indicates DVT

Images

Normal

Compression at the Level of the Femoral Vein Compression at the Level of the Popliteal Vein

Abnormal

DVT of the Femoral Vein

Pearls and Pitfalls

  • Arteries are the thick walled and more circular vessels identified
  • Doppler flow can be used to identify different directions of flow in vessels and to identify no vascular structures
  • Noncompressible vein may be mistaken for an artery, leading to a false negative result
  • An artery may be mistaken for a non-compressible vein, leading to a false positive result
  • Lymph nodes may be confused with noncompressible vein and if found, can be identified by moving up or down 1 cm
  • Does not rule out calf DVTs
  • For a more thorough exam, scan from the saphenofemoral junction down through the adductor canal in addition to the areas described above
  • Use a curvilinear probe for obese or edematous patients
  • An appropriate amount of pressure gives complete collapse of the vein as well as some (but not full) compression of the adjacent artery.[2]

Documentation

Normal Exam

A bedside ultrasound was conducted to assess for DVT with clinical indications of edema and pain. The extremity was assessed at 3 locations – common femoral vein, saphenofemoral junction, and the popliteal vein. Sequential compressions at these sites showed fully compressible veins. No sonographic evidence of DVT at these sites.

Abnormal Exam

A bedside ultrasound was conducted to assess for DVT with clinical indications of edema and pain. The extremity was assessed at 3 locations – common femoral vein, saphenofemoral junction, and the popliteal vein. Sequential compressions at these sites showed a noncompressible popliteal vein. DVT is present at the level of the popliteal vein.

Clips

Normal Study - No DVT

No DVT fem.gif No DVT fem 2.gif No DVT pop.gif

External Links

See Also

References

  1. Burnside P, Brown M, and Kline J. Systematic review of emergency physician-performed ultrasonography for lower-extremity deep vein thrombosis. Acad Emerg Med. 2008; 15:493–498.
  2. Kline JA et al. Annals of Emerg Med, 2008. PMID: 18562044

Authors

Neil Young