Application of the urea kinetic model to evaluate the adequacy of hemodialysis

The evaluation of dialysis adequacy still remains an unsolved problem. The mathematical model proposed by Gotch and Sargent is now currently used to quantify the dialysis need in urysiemic patients. In this study we evaluated the reliability of this kinetic model in 9 patients admitted to high efficiency hemodialysis. Only 5 out of the 9 patients showed a Protein Catabolic Rate normalized (PCRn) within 0.8-1.6 gr/kg/die a range considered optimal for hemodialysis patients. The other patients showed a PCRn higher than 1.6 gr/kg/die and were therefore excluded from this study. The volume of urea distribution (V) measurements deduced from urea kinetic model showed a great variability with a very high mean value (more than 78.3 +/- 6.3%). We therefore suggest that for the evaluation of dialysis adequacy in patients submitted to high efficiency hemodialysis an arbitrary value of urea distribution equal to 60% of the body weight should be used. However further clinical and biochemical evaluations are needed to confirm whether this model might be considered as a reliable parameter of dialysis adequacy.