Sorbent augmented hemodialysis systems: are we there yet?

Recent publications have reintroduced the concept of using sorbent systems to augment the efficiency of the dialysis process, either by making stationary or compact wearable devices to regenerate dialysis fluid or to target larger molecules for removal by direct blood or plasma contact with sorbent particles. Many of the inherent problems associated with older sorbents have been overcome by designing sorbents with improved biocompatibility and potential for removing molecules beyond the limits of conventional dialysis membranes. One system is approved for use in acute renal failure in the United States, but other devices are not approved for use in humans and continue to be tested in animals and humans. A prototype wearable sorbent device under investigation is not yet able to meet acceptable small molecular weight solute removal, and the other sorbent devices that possess the ability to remove unconventional uremic toxins have not been studied sufficiently in dialysis patients to define their role as augmentation devices. That there is a renewal of interest in sorbents in augmentation of dialysis points to the dissatisfaction with current dialysis technology.