UMEM Educational Pearls

Ultrasound of the IVC for Volume Assessment

  • In a recent pearl, I discussed that a 15% variation in IVC collapsibility could be used as a marker of hypovolemia
  • As a follow up and since % variation is sometimes difficult to calculate at the bedside, consider the following numbers:
    • The normal diameter of the IVC is 1.6 - 1.75 cm
    • Patients with hypovolemia typically have an IVC diameter < 0.8 - 1.0 cm
    • In general, the IVC diameter should increase 1 mm for every 100 ml of isotonic fluid


Wu T, Pregerson B. Assessing intravascular volume on an obese patient. Emergency Physicians Monthly. May 2009.