Optimizing the value of measuring inferior vena cava diameter in shocked patients

Figure 2 Three dimensional diagram showing the longitudinal ultrasound measurement of the antero-posterior diameter. Measurements depend on the site and angle at which it crosses the IVC. Section A is the proper one as it crosses the IVC vertically at the midpoint. Section B crosses the IVC vertically but peripherally and gives a false low measurement of the IVC diameter. Section C crosses the IVC obliquely and gives a false high measurement of the IVC diameter. IVC: Inferior vena cava.