Table 3. Estimation of right atrial pressure from the inferior vena cava [8]
Inferior vena cava diameterChange with respirationEstimated right atrial pressure mmHg
Small <1.5 cmCollapse0
Normal 1.5–2.5 cmDecrease by >50%5
NormalDecrease by <50%10
Dilated >2.5 cmDecrease by <50%15
Dilated with dilated hepatic veinsNo change20