12 Technique and Performing POCUS in Deep Vein Thrombosis

Technique of POCUS for DVT

POCUS for DVT involves either a 2-point or 3-point compression ultrasound technique, which assesses the compressibility of the venous segments to diagnose DVT. These non-invasive, bedside procedures are pivotal for quick and accurate diagnosis.

• 2-Point Compression Ultrasound: This method involves the assessment of the common femoral vein (CFV) at the groin and the popliteal vein (PV) behind the knee. A high-frequency linear transducer is placed perpendicular to the vein, and gentle pressure is applied to assess vein compressibility. A non-compressible vein segment suggests the presence of a thrombus.

• 3-Point Compression Ultrasound: This technique extends the 2-point examination to include the proximal deep veins of the thigh. The third point often consists of the superficial femoral vein (SFV) and the CFV and PV.

Interactive Video with Quiz regarding 2 zone technique on DVT scan. Adapted from “Video 18 Tutorial on ultrasound for DVT” by International Emergency Medicine Education Project is licensed under CC BY 4.0

Performing POCUS for DVT

Preparation:

The clinician should ensure the patient is comfortable, usually lying down with the leg slightly externally rotated for femoral vein access and the knee slightly bent for popliteal vein access.

Procedure:

Femoral Vein Assessment:

1. 1. 1. 1. Place the transducer in the inguinal region.
         2. Identify the CFV just below the inguinal ligament adjacent to the artery.
         3. Apply gentle, graded compression to assess for complete compressibility.

Popliteal Vein Assessment:

1. 1. 1. 1. Move the transducer to the popliteal fossa behind the knee.
         2. Identify the PV, often superficial to the popliteal artery.
         3. Apply compression to determine vein compressibility.

(For 3-point ultrasound) Thigh Vein Assessment:

1. 1. Assess the SFV in the upper thigh with similar compression techniques.

Interpretation:

1. 1. The inability to completely compress the vein suggests the presence of DVT. The echogenicity of the thrombus and the company of Doppler flow signals can provide additional information.

Post-Procedural:

1. 1. Document and interpret the findings with clinical symptoms for a comprehensive assessment. Immediate anticoagulation therapy can be considered based on POCUS findings and clinical judgment.

For the clinician performing POCUS, it is critical to have undergone adequate training, which includes a structured course and supervised practice scans to ensure proficiency. This training should focus on proper transducer handling, anatomical landmark identification, and interpretation of sonographic findings.

Education and Training

Effective use of POCUS requires appropriate training and experience. The American College of Emergency Physicians recommends a two-day course followed by 25–50 quality assurance reviewed studies before utilizing POCUS for clinical decision-making. While brief training sessions may seem attractive, inadequate training can lead to significant diagnostic errors, emphasizing the need for comprehensive and standardized training protocols. Studies suggest clinicians can achieve diagnostic accuracy in radiology or vascular laboratory studies​​with proper training.