1. ICU Interpretation Tips

IVC small + collapses easily

→ Patient likely volume depleted

IVC large + does NOT collapse

→ Patient likely volume overloaded
→ Elevated right atrial pressure
→ Possible heart failure, tamponade, PE, RV failure

IVC normal but clinical shock

→ Could still be:

• Vasodilatory shock

• Sepsis

• Distributive physiology

IVC is one piece of the puzzle.

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2. Limitations (IMPORTANT in ICU)

Do NOT trust IVC measurements in:

• Obesity

• High PEEP (>10–12)

• COPD / hyperinflation

• Intra-abdominal hypertension

• Pregnancy

• Post-cardiac surgery

• Significant TR (tricuspid regurgitation)

IVC is less reliable in mechanically ventilated patients.

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3. ICU PEARLS

• Use IVC + RUSH exam (heart contractility, lungs, IVC, FAST)

• In shock, IVC alone is NOT enough—integrate with echo findings

• In ARDS on high PEEP, IVC often appears plethoric even when patient is dry

• Look for respiratory variation, not just size

• Compare with clinical context, MAP, lactate, UOP