UMEM Educational Pearls

Title: Ultrasound and Volume Assessment

Category: Critical Care

Posted: 5/12/2009 by Mike Winters, MBA, MD (Updated: 5/24/2009)
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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.