Transportable, portable, wearable and (partially) implantable hemodialysis systems: comparison of technologies and readiness levels

Background Dialysis modalities and their various treatment schedules result from complex compromises (‘trade-offs’) between medical, financial, technological, ergonomic and ecological factors. This study targets summarizing the mutual influence of these trade-offs on (trans)portable, wearable or even (partially) implantable hemodialysis (HD) systems, identify what systems are in development, and how they might improve Quality-of-Life (QoL) for kidney failure patients. Methods Hemodialysis as defined by international standard IEC 60601–2-16 was applied on a PUBMED database query regarding (trans)portable, wearable and (partly) implantable HD systems. 24 out of 159 search results were included and scanned for specific HD devices and/or HD systems in development. Additional information about weight, size and development status was collected via internet and/or contacting manufacturers. International airplane hand baggage criteria formed the boundary between transportable and portable. Technology Readiness Levels (TRLs) were assigned by combining TRL-scales from the European Union and NATO medical staff. Results The query revealed 13 devices/projects: 7 transportable (6xTRL9, 1xTRL5); 2 portable (1xTRL6-7, 1xTRL4); 2 wearable (1xTRL6, 1xfrozen); and 2 partly implantable (1xTRL4-5, 1xTRL2-3). Discussion 3 main categories of technical approaches were distinguished: Single-pass, Dialysate regenerating, and Implantable HD filter with extracorporeal dialysate regeneration (in climbing order of mobility). Conclusions Kidneys facilitate mobility by excreting strongly concentrated waste solutes with minimal water loss. Mimicking this kidney function can increase HD system mobility. Dialysate regenerating HD systems are enablers for portability/wearability and, combined with durable implantable HD filters (once available), they may enable HD without needles or intravascular catheters. But lack of funding severely hampers progress.