Inferior vena cava pressure as an estimate of central venous pressure.

OBJECTIVE: To determine whether pressure in the inferior vena cava (IVC) is similar to central venous pressure.

METHODOLOGY: Prospective measurement of both central venous pressure (CVP) and inferior vena cava pressure (IVCP) in the same child; each child had to have both catheters in situ. Two measurements of each pressure in reverse order (IVCP then CVP, and CVP then IVCP) were done and the mean of each was recorded. Comparison of the pressures was performed using the method of Bland and Altman.

RESULTS: Thirty-nine children had pressures recorded. The CVP ranged from 3 to 17 mmHg. In 22 of 39 measurements IVCP was equal to CVP; in 33 of 39 measurements IVCP was different from CVP by 1 mm or less and in 37 of 39 measurements IVCP was different from CVP by 2 mm or less. The mean difference between IVCP and CVP was +0.33 mmHg, the 95% confidence interval was 2.26 to +2.93 mmHg.

CONCLUSION: Measurement of IVCP is a good approximation to CVP and can be routinely used in clinical care of children who do not have raised intra-abdominal pressure.