Background: The purpose of the present study was to determine the relationship of inferior vena cava diameter (IVCD) and its respirophasic variation (IVC collapsibility index: IVCCI) with central venous pressure (CVP), and thereby to provide reference cut-offs for such IVC parameters to estimate elevation in CVP in pediatric patients with cardiovascular disease.
Methods and results: The study involved consecutive pediatric patients (n = 118) with various heart diseases who either had a central venous catheter in the cardiac intensive care unit or underwent cardiac catheterization. The maximum (IVCD(max)) and minimum (IVCD(min)) diameters of IVC were measured on ultrasound simultaneously with measurements of mean CVP. IVCD(max), IVCD(min) and IVCCI correlated significantly with CVP (R² = 0.26, 0.47 and 0.41, respectively) in spontaneously breathing patients, but not in mechanically ventilated patients. Receiver operator characteristic curve analysis indicated that IVCCI under spontaneous breathing had the best area under the curve, with sensitivity of 1.0 and specificity of 0.98 for a cut-off of 0.22 to predict elevated CVP ≥ 10 mmHg.
Conclusions: IVCCI seems to be a useful and accurate non-invasive index for estimation of elevated CVP in pediatric patients with cardiovascular disease.