The effect of dialysate volume on ultrafiltration in young patients treated with CAPD

The effect of dialysate volume on ultrafiltration in young patients on continuous ambulatory peritoneal dialysis (CAPD) was studied. Twelve patients were evaluated. Each patient was studied with five different dialysate volumes (30, 40, 50 cc/kg and 2, 3 liters/1.73 m2) and two different dialysate glucose concentrations (1.5% and 4.25%). Dialysate osmolalities were measured at 30 minutes, one hour, two hours, and four hours. Dialysate volume was measured after four hours. Increased dialysate volume was associated with an increase in ultrafiltration rate and a slower fall in dialysate osmolality. It is concluded that since infants have a greater peritoneal surface area per kg than adults, they absorb dialysate glucose at a greater rate when related to body weight. This will lower dialysate osmolality at a faster rate and reduce ultrafiltration. Dialysate volume prescribed for children should not be extrapolated from the adult experience on the basis of 2 liters/70 kg, but rather by surface area (2 liters/1.73 m2).