To assess a patient’s intravascular volume status with ultrasound, use a cardiac probe with depth set to at least 18 cm, depending on body habitus.
- Place the probe subxiphoid
- Identify the right atrium above the liver
- Trace the inferior vena cava from the right atrium
- Rotate the probe until you are able to get a longitudinal view of the inferior vena cava
Once a longitudinal view of the inferior vena cava is obtained, estimate the degree of collapse with each inspiratory effort.
The patient is likely volume depleted if the degree of collapse is:
- Over 50% for spontaneously breathing patients
- Over 15% for intubated, non-spontaneously breathing patients