Using the Caudal Vena Cava to Guide Fluids:
Interpretation of the caudal vena cava via the diaphragmatic hepatic view is a useful tool for assessing the volume status of a patient.

This is particularly helpful for those hypotensive patients that you are uncertain if they need more volume or need vasopressor agents or other management options. With regards to “more volume” this could be crystalloids, colloids or blood products, this depends on the patient.

How to find it:
– Place the probe under the xiphoid process – Increase the depth, adjust the focal point then reduce the frequency to be able to visualise the diaphragm completely – Find the gallbladder, fan laterally to the right slightly – The caudal vena cava is seen deep to the gallbladder as two parallel lines “equal sign” going through the diaphragm wall. – Assessment of volume status or more so fluid responsiveness is based on interpretation of the degree of collapse during inspiration.

Interpretation:
– If it does not collapse during inspiration “fat” then this can mean that they are adequate if not volume overloaded, this patient would most likely benefit with vasopressor agents or other management eg. Pericardiocentesis rather than further volume. – If it collapses more than 60% “flat” then the patient requires more volume – If it collapses between 20% to 60% “bounce” then further volume loading can be trialed.

 

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