Changes in osmolal gap and osmolality in children with chronic and end-stage renal failure.

within the reference range in patients with renal failure [6] . However, the role of OG and serum osmolality in this condition was not established very well. The aim of this study is to determine the serum OG and osmolality in children with various stages of CRF and the effect of dialysis modalities on these parameters. We also investigated the possible relationship among the changes of OG and serum osmolality before and after HD in patients with CRF. We studied 101 patients (52 boys and 49 girls), with known CRF. Thirty-six patients (age range 5–16 years) underwent HD (HD patients), 29 patients peritoneal dialysis (PD patients) whose age range was 2–14 years, and 25 of them were on continuous ambulatory PD while 4 were treated by continuous cycling PD; 36 nondialyzed (age range 2–16 years) CRF patients (ND patients) were also included. There was a statistically significant difference in age between the PD and HD groups (p = 0.013). All HD patients were treated by bicarbonate dialysis 3 times weekly with 0.4–0.7 m 2 substituted cellulosic membranes. PD was carried out 4–6 times daily in continuous ambulatory PD patients and for 8–10 h/night in continuous cycling PD patients with 1.36% peritoneal dialysis solutions (Dianeal 1.36%, Baxter-Eczacıbası Healthcare, Istanbul, Turkey). There was no medication by mannitol in any groups. Samples of blood were obtained before and