UMEM Educational Pearls

Title: Beyond the IVC: VExUS Exam Ultrasummary

Keywords: VExUS, IVC, POCUS, Venous Congestion (PubMed Search)

Posted: 12/10/2024 by Cody Couperus-Mashewske, MD
Click here to contact Cody Couperus-Mashewske, MD

The Venous Excess Ultrasound (VExUS) exam integrates IVC, portal, hepatic, and renal vein findings to assess venous congestion and guide management, such as diuresis, in critically ill patients.

Technique:

IVC: Measure the IVC diameter. If <2 cm, significant congestion is unlikely, and further assessment is not well validated.
Hepatic & Portal Veins: Use a curvilinear probe with color Doppler in the RUQ. The hepatic vein flows away from the probe (blue), and the portal vein, with thicker walls, flows toward the probe (red).
Hepatic Vein Doppler: Apply pulse wave Doppler to the hepatic vein or a tributary. If the waveform is not clear, try a different vein.
Portal Vein Doppler: After evaluating the hepatic vein, place PW Doppler on the portal vein.

Tips:

Start from the right upper quadrant, Doppler signals are often easier to obtain and interpret here.
Delay learning renal vein assessment until comfortable with the other views.
If the IVC is hard to see subcostally, try a transhepatic view and adjust probe orientation (rotation and fanning).

Interpretation:

Hepatic Vein: A normal hepatic vein waveform reflects atrial contraction (a wave), atrial filling during ventricular systole (S wave), and atrial filling during early diastole (D wave). As congestion worsens, the proportion of atrial filling during ventricular systole (S wave) decreases and eventually reverses.
Portal Vein: Normally shows continuous flow. With congestion, it becomes more pulsatile.

Sometimes when other clinical information is contradictory, having the extra data point of the VExUS exam can be extremely useful to determine the best plan for a patient. Practice looking for the portal/hepatic veins and getting the waveforms on patients with a CLEAR clinical picture of venous congestion, then practice on more difficult cases.

References

Assavapokee, T., Rola, P., Assavapokee, N. et al. Decoding VExUS: a practical guide for excelling in point-of-care ultrasound assessment of venous congestion. Ultrasound J 16, 48 (2024). https://doi.org/10.1186/s13089-024-00396-z