Automated wearable artificial kidney (AWAK): A peritoneal dialysis approach

Abstract

Current work on wearable artificial kidneys is mostly based on hemodialysis or hemofiltration, either of which requires blood flow through an extracoporeal circulation (EC). This calls for anticoagulation and stringent monitoring and is encumbered with possible immunologic and non-immunologic complications secondary to blood-artificial membrane interactions. A peritoneal-based automated wearable artificial kidney (AWAK) requires no EC of blood and is therefore "bloodless." By the continuous regeneration and reuse of the spent peritoneal dialysate in perpetuity, and the elimination of the need for manufacturing and purchasing fresh dialysate, AWAK is also "waterless. " A new sorbentbased assembly is designed to regenerate both the aqueous (AqC) and the protein (PrC) components of the spent dialysate, producing a novel, autologous protein-containing dialysate. The regenerated and reconstituted AqC has the same composition as the commercially available peritoneal dialysate, but is bicarbonate-containing and has a more physiological pH. The regenerated PrC is recycled back into the peritoneal cavity, thereby ameliorating or eliminating protein-loss. Depending on the steady-state protein concentrations attained, the PrC may also have the potential of both augmenting ultrafiltration (through its colloidal oncotic pressure) and mediating the removal of protein-bound uremic toxins. Additional sorbents can be incorporated into AWAK for the removal of middle molecular weight uremic toxins. The first prototype under construction is designed to regenerate 4 L of spent dialysate per hour or 96 L per day, i.e., about 8-12 times of the currently practiced dialysate flow rates. Round-the-clock dialysis and ultrafiltration is anticipated to provide steady-state metabolic-biochemical and fluid balance regulation, thereby eliminating the "shocks" of abrupt changes in these parameters that characterize the current dialytic modalities. Importantly, dialysis-on-the-go allows patients to return to more normal living activities. © 2009 Springer-Verlag.