A Comparison of Peritoneal Water and Solute Movement in Young and Older Children on CAPD

Abstract

Continuous Ambulatory Pertioneal Dialysis (CAPD) has encouraged nephrologists around the world to reassess peritoneal dialysis as an acceptable replacement of renal function. Since CAPD is so applicable to children, especially infants, there is an added incentive for pediatric nephrologists to assess the dialytic characteristics of the child’s peritoneal membrane. Anecdotally, pediatric nephrologists have found peritoneal dialysis difficult to perform on very young infants. The most apparent and troublesome difficulty is a perceived reduction in ultrafiltration characteristics. One of the reasons for this impression is that infants, after cardiac surgery, may develop acute renal failure, and acute peritoneal dialysis is often the type of dialysis used. The reasons for the difficulty in removing fluid by ultrafiltration are multiple. Often, SVCH children have very reduced left ventricular function and therefore, a sluggish mesenteric circulation. Therefore, this impression concerning peritoneal dialysis in infants and young children may be incorrect and in fact may be the results of a number of other causes which do not necessarily involve the peritoneal membrane. We have previously reported that the glucose and protein concentration in “spent” or “used” dialysate from CAPD patients is different with respect to age [1]. Using 6 years of age as the dividing age, younger patients have a lower glucose and higher protein concentration in the dialysate compared to older children. Therefore, it would appear that with the loss of the glucose osmotic concentration gradient in the dialysate, there would be a decreased ultrafiltration capacity in younger children. There have been no reports comparing the effect of a child’s age on peritoneal membrane morphology. Esperanca et al. [2] reported that the infant’s peritoneal membrane is relatively larger than the adult’s: 383 cm² as compared with 177 cm²/kg body weight.