A prospective study of peritoneal transport in CAPD patients

A prospective two year follow-up study of the functional characteristics of the peritoneal membrane was conducted in 61 CAPD patients. Peritoneal transport of solutes, calculated by mass transfer area coefficients for urea and creatinine, peritoneal clearances for proteins, percentage of absorption of glucose, as well as net ultrafiltration were measured every four months. After five months on CAPD a decrease was found for the transport of most solutes (P < 0.05, mean values, ml/min/1.73 m2): urea 18.1 to 16.2, creatinine 9.5 to 8.4, IgG 0.049 to 0.040 and alpha 2-macroglobulin 0.020 to 0.015, as well as for the absorption of glucose (57.9 to 53.2%, P < 0.05). Net ultrafiltration increased simultaneously from 44.6 to 100.5 ml/4 hr/1.73 m2, P < 0.05. From five months to two years on CAPD a significant increase in the transport of all solutes except alpha 2-macroglobulin was found, as well as a decrease in net ultrafiltration. Peritoneal transport at the end of the study was not significantly different from the starting values. Our findings indicate an initial effect of CAPD itself on peritoneal transport, probably due to the recent start of the treatment. Baseline values were reached after five months on CAPD. Thereafter a gradual increase in peritoneal solute transport occurred during two years of treatment. This can be explained by an increase in the effective peritoneal surface area.

Peritoneal kinetics in children undergoing continuous ambulatory/cycling peritoneal dialysis

We present a report on peritoneal kinetics in children undergoing continuous ambulatory/cycling peritoneal dialysis (CAPD/CCPD). The effect of long-term treatment with CAPD/CCPD, peritonitis episodes, and dialysate inflow volume on peritoneal kinetics in children was evaluated. Peritoneal kinetic studies (PKSs) were performed in 47 pediatric patients at different times following initiation of CAPD/CCPD. In 18 of these patients, PKSs were repeated up to four times with an unchanged dialysate inflow volume after up to 55 months of CAPD/CCPD treatment. The PKS consisted of a 120-minute dwell with a 1.5% dextrose dialysate solution. Peritoneal clearance, dialysance, and dialysate to plasma (D/P) concentration ratios were calculated after 30, 60, and 120 minutes. The results of the serial PKSs demonstrate stable peritoneal creatinine and urea-N clearance, dialysance or D/P concentration ratios. Furthermore, there was no adverse effect of 32 peritonitis episodes. Finally, inflow volumes correlated directly with clearances of creatinine (P less than .01), urea-N (P less than .001), and potassium (P less than .001), and there was an inverse relationship to the D/P concentration ratios of creatinine (P less than .01), urea-N (P less than .01), potassium (P less than .01), and uric acid (P less than .01). Thus, CAPD/CCPD is a useful and effective long-term treatment modality for pediatric patients. Maximal dialysate inflow volumes should be provided to enhance peritoneal kinetics.