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┬áspontaneously breathing patients
  • Over 15% for intubated, non-spontaneously breathing patients