IVC Collapsibility (Fluid Status)

1. 1

   Position patient supine. Use phased array or curvilinear probe subxiphoid.

2. 2

   Place probe at subxiphoid region, marker to patient's right, angled toward the right shoulder.

3. 3

   Identify the IVC entering the right atrium in long axis — it runs to the right of the aorta.

4. 4

   Slide probe slightly right and fan to obtain a clear longitudinal IVC view.

5. 5

   Place M-mode cursor 2cm from the IVC–RA junction. Record diameter at max inspiration and expiration.

6. 6

   For spontaneous breathers: collapsibility >50% = likely volume responsive. <50% = euvolemic or hypervolemic.

7. 7

   For ventilated patients: distensibility index >18% with tidal volume challenge = volume responsive.

• Subxiphoid IVC (longitudinal)
• M-mode through IVC at 2cm from junction

• IVC diameter (max)
• Collapsibility with respiration
• Respiratory variation

• IVC vs. aorta confusion
• Spontaneous breathing vs. ventilated patients — opposite interpretation

Measure IVC 2cm from IVC-RA junction. Collapsibility >50% = likely volume responsive (spontaneous breathing).