Peritoneal resting is beneficial in peritoneal hyperpermeability and ultrafiltration failure

Ultrafiltration failure (UFF) is one of the most frequent causes of continuous ambulatory peritoneal dialysis (CAPD) dropout and is a common consequence of peritoneal hyperpermeability secondary to inappropriate regeneration of mesothelial cells. In this paper we present the results of 25 peritoneal resting periods of 4 weeks in 16 patients who showed UFF. The mean duration of CAPD was 44 +/- 22 months. All patients had been free of peritonitis for at least 3 months when included in the peritoneal resting trial. UFF was always defined as a long-lasting decrease of UF capacity such that dry weight could no longer be achieved by CAPD. The former incidence of peritonitis was 3.9 +/- 2.3 episodes. Results compared to the preresting data: urea MTC (mass transfer coefficient) decreased from 24.9 +/- 6.8 to 21.0 +/- 6.1 (p < 0.05), creatinine MTC from 16.5 +/- 6.0 to 13.8 +/- 4.0 (p < 0.05), and UF increased from 493.8 +/- 278.0 to 881.3 +/- 388.1 (p < 0.001). The response in terms of UF in patients with low permeability ultrafiltration (creat MTC less than 13) was heterogeneous and lower than in patients with criteria of hyperpermeability (greater than 13): 720 +/- 396 to 1150 +/- 533 (NS) versus 491 +/- 310 to 808 +/- 205, respectively. Simultaneously, creatinine MTC did not change in the former group (10.2), while hyperpermeability patients showed a remarkable decrease (19 +/- 5 to 15 +/- 2, p < 0.05). In conclusion, peritoneal resting is a useful tool in the management of ultrafiltration failure in CAPD patients, primarily in those with peritoneal hyperpermeability.