COMPUTER SIMULATIONS OF CONTINUOUS FLOW PERITONEAL DIALYSIS USING THE 3-PORE MODEL-A FIRST EXPERIENCE

Background: Continuous flow peritoneal dialysis (CFPD) is performed using a continuous flux of dialysis fluid via double or dual-lumen PD catheters, allowing a higher dialysate flow rate (DFR) than conventional treatments. While small clinical studies have revealed greatly improved clearances using CFPD, the inability to predict ultrafiltration (UF) may confer a risk of potentially harmful overfill. Here we performed physiological studies of CFPD in silico using the extended 3-pore model. Method: A 9-h CFPD session was simulated for: slow (dialysate to plasma creatinine [D/P crea] <0.6), fast (D/P crea > 0.8) and average (0.6 <= D/P crea <= 0.8) transporters using 1.36%, 2.27%, or 3.86% glucose solutions. To avoid overfill, we applied a practical equation, based on the principle of mass-balance, to predict the UF rate during CFPD treatment. Results: Increasing DFR > 100 mL/min evoked substantial increments in small- and middle-molecule clearances, being 2 - 5 times higher compared with a 4-h continuous ambulatory PD (CAPD) exchange, with improvements typically being smaller for average and slow transporters. Improved UF rates, exceeding 10 mL/min, were achieved for all transport types. The beta(2)-microglobulin clearance was strongly dependent on the UF rate and increased between 60% and 130% as a function of DFR. Lastly, we tested novel intermittent-continuous regimes as an alternative strategyto prevent overfill, being effective for 1.36% and 2.27%, but not for 3.86% glucose. Conclusion: While we find substantial increments in solute and water clearance with CFPD, previous studies have shown similar improvements using high-volume tidal automated PD (APD). Lastly, the current in silica results need confirmation by studies in vivo.