EFFECT OF CALCULATION OF DIALYSIS ADEQUACY AND UREA REBOUND

Calculation of dialysis adequacy using different formula is simple and useful is clinical practice. The estimation of KtlV by utilization of the pre and postdialysis urea concentration provides a simple and quick technique. However the accuracy of these techniques has been questioned. One possible reason for this inaccuracy may be the frequently observed postdialysis rebound in serum urea. We assessed the urea rebound at 30 min postdialysis in 47 hemodialysed patients and compared the calculation of KtlV using this urea concentration with that using the immediate postdialysis concentration. These results were then compared to the KtlV calculated by urea kinetic modelling (UKM), also utilizing the delayed serum urea concentration. 25.5 % urea rebound was observed. This degree of urea rebound was large. The formulae for calculation of KtlV all significantly correlated with KtlV by UKM. For assesment of KtlV by these formüle or by UKM, the urea rebound is too large to ignore in the setting of conventinal hemodialysis adequacy.