Ultrafiltration and dialysis adequacy with various daily schedules of dialysis fluids

Dialysis regimens for continuous ambulatory peritoneal dialysis (CAPD) patients vary with the need for fluid removal, but also because of concerns about the local and systemic consequences of high glucose exposure. The implications of various regimens for dialysis adequacy--that is, fluid and small-solute removal--are not always clear. We therefore analyzed ultrafiltration (UF) and adequacy indices for 4 different combinations of dialysis fluid. Collections of 24-hour dialysate and urine were carried out in 99 patients on CAPD. On 4 separate occasions, each patient performed 4 exchanges in 24 hours, including 3 daily exchanges with 1.36% glucose and 1 night exchange with either 1.36% glucose (G1 schedule), 2.27% glucose (G2 schedule), 3.86% glucose (G3 schedule), or icodextrin (Ico schedule). Weekly, total, and dialysis Kt/V and KT were calculated for both urea and creatinine. The mean values of urea Kt/V and KT were significantly lower for the G1 schedule than for the G3 and Ico schedules. The adequacy indices for overnight application of 3.86% glucose and icodextrin were similar. Using dialysis fluids with 1.36% and 2.27% glucose overnight reduces glucose exposure, but those schedules may provide inadequate UF and small-solute removal in some patients (UF < 1 L daily, Kt/V < 1.7).