Abstract

CANO SCH., Francisco et al. Evaluation of chronic peritoneal dialysis using urea kinetic modeling. Rev. bol. ped. [online]. 2006, vol.45, n.3, pp.185-190. ISSN 1024-0675.

Currently, urea kinetic modeling is routinely accepted to evaluate peritoneal dialysis (PD) through the calculation of Kt/V (normalized whole body urea clearence) and nPNA (normalized protein equivalent of total nitrogen appearence). In paediatrics, the exact meaning and target values for these parameters are still under debate. Objective: to evaluate the mean values and correlation between ureaKt/V and nutritional parameters in chronic paedriatric peritoneal dialysis. Patients and Methods: 186 nitrogen balance studies in a 6-12 month period were prospectively performed in patients on PD. Daily protein intake (DPI) was assessed by nutritional evaluation. Protein, albumin, urea and creatinine were analysed in dialysate and urine, collected once a month. Dialysis adequacy was evaluated through monthly measurements of ureaKt/V and creatinine clearence (CCr) in urine and dialysate. All statistical comparisons were done with paired t-test, and 2 way ANOVA for repeated measures was used to calculate correlations, p < 0.05 was considered significant. Results: 20 patients, mean age 5,1 ± 4,7 years, range 3 months to 14,8 years, 15 males were included. DPI was 3,52 ± 1,1 g/kg/day. Weekly total and residual ureaKt/V were 3,1 ± 1,35 and 1,69 ± 1,46 respectively, CCr was 72,4 ± 70 and 45 ± 44L respectively. PCR was 0,84 ± 0,33 showing a net nitrogen balance (NB= IDP-PCR) of +1,37 ± 0,4g/kg/day and mean nPNA was 1,38 ± 0,40, with a positive correlation with DPI, PCR and total Kt/V p < 0.001). Total Kt/V showed a significant positive correlation with PCR and nPNA (p < 0.001) but not to NB and DPI. A negative correlation was found between all urea kinetic parameters vs plasma bicarbonate p < 0.001. Conclusions: ureaKt/V and nPNA were found to be higher than the recommended values in adults. The positive correlation between ureaKt/V and nPCR and nPNA could not be demonstrated with DPI or NB, suggesting that it could be the result of a mathematical association. The negative correlation between plasma bicarbonate and urea kinetic variables suggests a negative impact of acidosis on the nutritional status of these patients.

Keywords : urea kinetic modeling; Kt/V urea; protein catabolic rate; PCR; dietary protein intake; DPI.

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