The objective of the work was to evaluate the results of sonographic examination of the diameter of the vena cava inferior (VCI) as a parameter of hydratation of haemodialyzed patients. In a group of 84 haemodialyzed patients, mean age 66.32 years, the collapsibility index of the IVC was measure. The collapsibility index (CI) was calculated according to the formula: [formula: see text] where IVCexp = the maximum diameter of the IVC in maximum inspiration. Values of the index within the range from 40-75% corresponded to normal hydratation. The results were compared with ultrafiltration (total and expressed as % of body weight after haemodialyzation), "dry" body weight and with changes of BP during haemodialysis. The mean value of CI was 63.24 +/- 18.54. In 54 instances it was within the normal range (62.26 +/- 11.4), in 10 it was lower (27.7 +/- 6.02; possible sign of inadequate ultrafiltration during dialysis) and in 20 instances it was higher (84.9 +/- 7.53; risk of excessive ultrafiltration). Clinically assessed "dry" weight was adequate in 64% cases. In 24% UF was excessive. With this corresponded also the incidence of hypotension (40%) and in these patients the "dry" weight was subsequently elevated. The predictive importance of low values of CI for inadequate UF is however not unequivocal. Some of these patients were hypotensive even in case of low UF and did not tolerate its increase.

Keywords: Adult; Aged; Aged, 80 and over; Female; Hemodiafiltration; Humans; Male; Middle Aged; Renal Dialysis; Ultrasonography; Vena Cava, Inferior /diagnostic imaging/