Peritoneal Transport Characteristics of Water,Low-Molecular Weight Solutes and Proteins during Long Term Continuous Ambulatory Peritoneal Dialysis

Peritoneal transport of water, low-molecular-weight solutes and proteins was studied on 75 occasions in 38 CAPD patients. Maximal ultrafiltration capacity decreased with time on CAPD, while there was an increase in the number of hypertonic bags used and the peritoneal absorption of glucose. A relationship was found between maximal ultrafiltration capacity and glucose kinetics. The duration of CAPD was longer in the patients with poor ultrafiltration, while they had a faster transport of glucose and creatinine, but not of proteins. In the group as a whole, no obvious changes were found in the mass transfer area coefficients of urea, creatinine and glucose, nor in the clearances of albumin and IgG. In the five patients with severe ultrafiltration loss, we found evidence of either decreased or increased peritoneal solute transport. Contrasting findings in transport of small solutes and proteins may reflect increased effective peritoneal surface area combined with decreased peritoneal permeability.