Can Nephrologists Use Ultrasound to Evaluate the Inferior Vena Cava? A Cross-Sectional Study of the Agreement between a Nephrologist and a Cardiologist

BACKGROUND/AIMS The costs and the need for a specialist impair the implementation of ultrasonography for evaluating the inferior vena cava (IVC) to assess the volemic status in hemodialysis patients. We investigated whether a nephrologist with limited ultrasound training can accurately assess the IVC in patients undergoing hemodialysis. METHODS A cardiologist and a nephrologist consecutively measured the indexed IVC expiratory diameter (VCDi) and the IVC collapsibility index (IVCCI) of 52 patients during hemodialysis sessions. In protocol I, the nephrologist used a regular ultrasound system (RUS) and the cardiologist used a cardiovascular ultrasound equipment; in protocol II, the machines were interchanged. Pearson and kappa coefficients and the interexaminer agreement by the Bland-Altman method were calculated. RESULTS The VCDi measurements showed a strong correlation in both protocols (r = 0.88 and 0.84 in protocols I and II, respectively). The volemic classifications were excellent in protocol I (kappa = 0.82 and 0.93 by VCDi and IVCCI, respectively) and substantial in protocol II (kappa = 0.77 and 0.75 by VCDi and IVCCI, respectively). The interexaminer agreement on the VCDi measurements was very good in both protocols. CONCLUSIONS Ultrasound evaluation of the IVC can be performed by nephrologists using an RUS to assess the volemic status in hemodialysis patients.