Objective: To evaluate peritoneal transport kinetics and its changes over time in children with and without peritonitis, and to record possible differences between children under and over 5.0 years of age.
Design: A prospective study. The patients underwent a 4-hour peritoneal equilibration test (PET) comprising 2.27% dextrose with a dialysate fill volume of 1000 mL/m2 of body surface area (BSA), at baseline and after a mean of 0.8 +/- 0.4 years of uninterrupted dialysis.
Patients: We investigated 28 patients on maintenance peritoneal dialysis at baseline; 10 were under 5.0 years of age. The final PET was performed in 21 patients.
Main outcome measures: Peritoneal equilibration rates for urea (U), creatinine (C), glucose (G), sodium, potassium, phosphate, and albumin (A) were measured. Initial and final peritoneal equilibration rates were compared. Mass transfer area coefficients (MTAC) were calculated for urea, creatinine, glucose, and albumin. Residual dialysate volume was determined.
Results: Median age at first PET was 7.6 years (range 0.3-16.6 yr). The mean (+/- 1 SD) 4-hour dialysate-to-plasma (D/P) ratios for U, C, and A were 0.92 +/- 0.05, 0.70 +/- 0.12, and 0.014 +/- 0.007, respectively. The mean 4-hour D/D0 ratio for G was 0.32 +/- 0.10. D/P and D/D0 results were similar in the two age groups, and peritoneal membrane function remained stable over the study period. Mean MTAC (+/- 1 SD) values were: U, 22.3 +/- 4.8; C, 10.9 +/- 4.1; G, 11.1 +/- 3.3; and A, 0.07 +/- 0.03. MTAC data were similar in the two age groups and no significant changes occurred during the study period.
Conclusions: When the volume tested in children is proportional to BSA, the solute D/P ratios seem to be age-independent. Our data provide evidence that in pediatric patients MTAC is also age-independent.