Natural logarithmic estimates of Kt/V in the pediatric hemodialysis population

The natural logarithm formula for Kt/V proposed by Daugirdas is recognized as a valid and simple alternative to formal urea kinetic modeling (UKM) in adults receiving hemodialysis, No data have been published to validate the use of this formula in infants, children, and adolescents. We compared Kt/V derived by formal UKM with the natural logarithmic formula for 103 treatme nts in 21 pediatric end-stage renal disease patients receiving chronic hemo dialysis. Values for Kt/V derived by formal UKM ranged from 0.65 to 2.06. P atients ranged In age from 1.8 to 22.5 years and in dry weight from 10.2 to 82.5 kg. The largest percent error between the two methods for any data po int was less than 6%, The total error (absolute value percent error + 2 SD) was less than 6% across the entire range of dry weights. Our data show exc ellent agreement between formal UKM and the natural logarithm formula for K t/V in pediatric hemodialysis patients, even those weighing less than 30 kg . These results support the use of the natural logarithm formula as a valid alternative to formal UKM in children. The simplicity of this formula shou ld allow for the use of KW as the best measure to study the relationship be tween delivered dialysis dose and outcomes in children. (C) 1999 by the Nat ional Kidney Foundation, Inc.