Ultrasonography of inferior vena cava to determine central venous pressure: a meta-analysis and meta-regression.

Background Until now, no valid alternative exists for predicting central venous pressure (CVP) with lower invasiveness than central venous catheter. Purpose To explore inferior vena cava diameter (IVCD) measurement accuracy by ultrasonography as a surrogate variable for determination of central venous pressure (CVP). Material and Methods A systematic review and meta-analysis of all published studies in PubMed, Scopus, Web of Knowledge, and Google Scholar were conducted from inception to July 2013. We used the STROBE checklist for quality assessment and meta-regression. Results Thirty-seven papers with 2843 cases were identified. The correlation coefficients between each one of IVCD, inspiratory IVC (iIVC), IVC collapsibility index (IVCCI), and expiratory IVC (eIVC) with CVP, were 0.68, 0.60, 0.54, and 0.44, respectively. There was no evidence of publication bias ( P = 0.28). Based on meta-regression, male gender was an important source of heterogeneity (OR = 1.01; 95% confidence interval, 1-1.03), which resulted in a higher correlation between IVCD and CVP. The present study showed a higher strength of association with CVP pertaining to IVCD, iIVC, IVCCI, and eIVC, respectively, and they were higher in men. Conclusion This study does not support the measurement of IVCD by ultrasonography as an acceptable surrogate variable to determine CVP among critical patients.