However, any potential changes in dialysate sodium concentration can be mathematically modelled, accurately predicted and clinically compensated within the dialysis prescription such that any clinical consequences are avoided.19 Clearly, the introduction of any new technique – in any medical field – will require extensive staff training and familiarization. While an unavoidable disadvantage for any new method, this should not be allowed to impede the progress of a new technology if that technology is proven to clinically sound and advantageous. If sorbent dialysis

continues to prove clinically applicable and is confirmed to maintain other significant advantages over single pass systems, the difficulties and costs Pirfenidone in vitro of training may be more than

compensated by the potential for patient-specific advantage in size, portability and simplicity. The advantages and disadvantages of single pass and sorbent systems are compared in Table 1. To compete with a single pass system, a sorbent system must be cost-efficient. Table 2 shows the major competing cost components of the two systems. If sorbent costs can be made competitive – especially as economies of scale minimize cost through mass production find more – sorbent dialysis has much to offer in simplicity, portability and safety. Importantly, cartridge costs must be judged against the accumulated expense of R/O water delivery and wet-exposed maintenance that accrue in single pass dialysis systems. It has never been more important to have a basic knowledge of sorbent dialysis systems as it is now, as current dialysis equipment research is significantly sorbent-focused. The impetus for this focus comes, at least in part, from a worldwide resurgence interest in home-based haemodialysis – the needs of which are rooted in ease of use and portability.20 Size reduction, user-interface simplification, portability and travel capability and, in addition, a marked reduction in servicing

frequency, complexity and cost – all largely depend upon the elimination of a continuous water source. Efforts to design a wearable artificial kidney, whether for haemodialysis Pregnenolone or peritoneal dialysis, are also highly dependent on system and driver miniaturization. To restrict the dialysate volume to a ‘wearable’ weight, sorbent-based dialysate regeneration and recirculation seem essential design components. Several sorbent systems are now in various stages of research and development. The Allient® system (Renal Solutions Inc, Warrendale, PA, USA), after Federal Drug Administration approval and successful phase III trials across several sites in the USA,14 has since been acquired by Fresenius Medical Care. Sorbent technology is now being incorporated by Fresenius into options for both home and facility. The Xcorporeal® Wearable Artificial Kidney (the WAK, Lake Forest, CA, USA) has already been the subject of a limited eight patient clinical trial in the UK21 with reported clinical success and good patient acceptance.