Acquiring the Intrarenal Vein View with Ultrasound:
The intrarenal vein assessment is probably the most difficult assessment to do out of all of the vessels. This is because the intrarenal veins are fairly small and the patient’s breathing patterns may limit your views. But don’t be discouraged and keep trying your best to get these views. With practice, you will get better at acquiring them.
View the kidneys on either side at the posterior axillary line. Turn on the color Doppler and then look for the Interlobar vessels. Place the pulse wave Doppler gate where you see the best color Doppler signal and activate pulse wave Doppler. TIP: You may need to adjust the color and pulse wave Doppler scale and gain to get optimal settings. I have found having the Color Doppler scale around 10-25 cm/s is ideal.
The vessels are so small that you will be able to detect BOTH the arterial and venous flow of the intrarenal vessels in the same view. For the VExUS exam, you will mainly be focusing on the venous component (the bottom portion of the Doppler tracing).
Interpretation of Intrarenal Vein Doppler findings:
The Intrarenal vein Doppler pattern is usually a nice continuous monophasic flow. As venous congestion starts to increase there is a decrease in the systolic component of the wave with progression to biphasic (systolic/diastolic phases) and with renal congestion leading to complete absence of systolic flow showing only monophasic flow (only diastolic phase).