Evaluation of a system for sorbent-assisted peritoneal dialysis in a uremic pig model

A system for sorbent-assisted peritoneal dialysis (SAPD) has been developed that continuously recirculates dialysate via a tidal mode using a single-lumen peritoneal catheter with the regeneration of spent dialysate by means of sorbents. SAPD treatment may improve plasma clearance by the maintenance of a high plasma-to-dialysate concentration gradient and by increasing the mass transfer area coefficient (MTAC) of solutes. The system is designed for daily 8-hr treatment (12kg, nighttime system). A wearable system (2.3kg, daytime system) may further enhance the clearance of phosphate and organic waste solutes during the day. Uremic pigs (n=3) were treated with the day- (n=3) and nighttime system (n=15) for 4-8hr per treatment. Plasma clearance (Cl), MTAC, and total mass transport (MT) of urea, creatinine, phosphate, and potassium were compared with a static dwell (n=28). Cl, MTAC, and MT of urea, creatinine, phosphate, and potassium were low in the pig as compared to humans due to the pig's low peritoneal transport status and could be enhanced only to a limited extent by SAPD treatment compared with a static dwell (nighttime system: Cl urea: ×1.5 (p=.029), Cl creatinine: ×1.7 (p=.054), Cl phosphate: ×1.5 (p=.158), Cl potassium: ×1.6 (p=.011); daytime system: Cl creatinine: ×2.7 (p=.040), Cl phosphate: ×2.2 (p=.039)). Sorbent-assisted peritoneal dialysis treatment in a uremic pig model is safe and enhances small solute clearance as compared to a static dwell. Future studies in humans or animal species with higher peritoneal transport should elucidate whether our SAPD system enhances clearance to a clinically relevant extent as compared to conventional PD.