Current Status of Dialysate Regeneration for the Treatment of Chronic Uremia

The removal of uremic solutes from dialysate by chemical compounds with adsorptive capacity provides a methodology for achieving a major reduction in the volume of dialysate necessary for conducting effective dialysis. Sorbent regeneration of dialysate permits a system with a small volume of recirculating dialysate to maintain maximal blood to dialysate concentration gradients and to potentially achieve mass transfer efficiency equal to that of a large volume recirculating or single pass dialysate flow system. Activated carbon, by virtue of its ability to adsorb organic nitrogenous compounds has served as the basic component of virtually all sorbent systems applied to the treatment of uremia. Yatzidis(1) demonstrated that activated carbon could adsorb creatinine, uric acid, phenols, indolic compounds, guanidines and organic acids. The adsorption of endogenous uremic metabolites of middle molecular weight configuration has also been demonstrated and there is presumptive clinical evidence derived from patients treated with sorbent systems that activated carbon probably adsorbs all organic uremic metabolites, known or as yet unidentified, which are of toxic significance(2–4). Unfortunately, there is one exception to this remarkable affinity of carbon for nitrogenous uremic metabolites.