WEARABLE ARTIFICIAL KIDNEY – EVOLUTION OF ITS CONCEPTS AND CURRENT STATE-OF-THE-ART

Shortly after intermittent haemodialysis became established treatment of chronic renal failure, the first wearable artificial kidney (WAK) device projected or even constructed to solve the problem of intermittent treatment unphysiology. Successful development of hollow fibres enabled construction of a sufficiently small dialyzer to be worn and recirculation of dialysate through a sorbent cartridge lead to tremendous drop in dialysate volumes needed. Tested were WAK devices based both on haemodialysis (HD) or on haemofiltration (HF) (after highly permeable membranes became available) as well as on peritoneal dialysis (PD). Later, some other techniques and processes appeared in armamentarium of WAK designers, such as charged membranes, electrodialysis, nanotechnological processes enabling to create membranes with solute-specific pores. Also a few hybride constructions appeared during the last decade using membranes coated with tubular epithelial cells to mimic tubular resorption of biological kidney. With current trends towards more frequent HD with higher material costs, WAK effort got another impetus, this time purely economical. The first commercially available WAK (although still waiting for a CE mark in Europe and FDA clearing in USA) was developed by a Singaporean company AWAK Technologies in 2011. A European WAK is being developed as a joint project in frame of FP7 and is expected to be ready by 2014. However, acceptance of WAK instead of conventional intermittent therapy both by physicians and by the patients themselves still remains unresolved