Objectives: To determine the degree of urea rebound in children on hemodialysis and compare the different calculation models for Kt/V.
Material and Method: The present study was performed in 50 hemodialysis sessions of 5 pediatric patients, 2 males and 3 females, aged 5-18 years, who had received hemodialysis for 7-48 months. Blood urea samples were obtained at the beginning, 70 minutes intradialysis, the end and every 10 minutes for 1 hour post- dialysis. The compared 6 different models of Kt/V were single pool, Daugirdas, equilibrated, rate equation, Maduell and Smye method.
Results: Urea rebound was found to be completed at least 60 minutes post- dialysis and mean percentage value was 30.68 ± 9.663.Mean value of equilibrated Kt/V was 1.442 ± 0.259 while that of single-pool Kt/V calculated by lnC1/C2 was 1.705 ± 0.252 leading to overestimation of Kt/V by 0.265 ± 0.075. Mean value calculated by Daugirdas method was 2.083 ± 0.336. Mean values obtained by rate equation, Maduell and Smye methods were 1.485 ± 0.209, 1.442 ± 0.209 and 1.379 ± 0.343 which differed from equilibrated Kt/V by 0.086 ± 0.058 (p = 0.002), 0.069 ± 0.063 (p = 0.967) and 0.132 ± 0.132 (p = 0.015), respectively.
Conclusion: Urea rebound in pediatric patients is completed at least 60 minutes after cessasion of hemodialysis. Kt/V calculated from single-pool is not suitable for children. The Maduell model gives the best correlation to equilibrated Kt/V when compared to rate equation and Smye models.

Keywords: Hemodialysis, Pediatric, Kt/V, Urea rebound, Urea kinetic models, Adequacy