Grundlagen der Nieren- und Leberdialyse

Recently we have devised and tested a biofeedback system for controlling blood volume (BV) changes during hemodialysis (HD) along an ideal trajectory (blood volume tracking, BVT), continuously modifying the weight loss rate and dialysate conductivity. This multicenter, prospective, randomized, crossover study aimed to clarify whether BVT (treatment B) can improve hypotension-prone patients' treatment tolerance, compared with conventional hemodialysis (treatment A). Thirty-six hypotension-prone patients enrolled from 10 hemodialysis (HD) centers were randomly assigned to either of the study sequences ABAB or BABA, each lasting four months. A 30% reduction in intradialytic hypotension (IDH) events was observed in treatment B as compared with A (23.5% vs. 33.5%, P = 0.004). The reduction was related to the number of IDH in treatment A (y = 0.54x + 5; r = 0.4; P < 0.001): the more IDH episodes in treatment A, the better the response in treatment B. The best responders to treatment B showed pre-dialysis systolic blood pressure values higher than the poor responders (P = 0.04). A 10% overall reduction in inter-dialysis symptoms was obtained also in treatment B compared to A (P < 0.001). Body weight gain, pre-dialysis blood pressure, intradialytic weight loss as well as Kt/V did not differ between the two treatments. An overall improvement in the treatment tolerance was observed with BVT, particularly intradialytic cardiovascular stability. Patients with the highest incidence of IDH during conventional HD and free from chronic pre-dialysis hypotension seem to respond better. Inter-dialysis symptoms also seem to improve with control of BV.

The removal of protein-bound substances of pathogenetic relevance from blood is of therapeutic interest for drug intoxications, renal and liver failure, and metabolic disorders. Current methods using adsorbents are effective but often not specific enough. This work presents an alternative method that enables the dialyzability of albumin-bound toxins from plasma by the use of a high-flux dialyzer (F 60 Fresenius) and an albumin solution circulating on the dialysate side to increase selectively the affinity for albumin-bound toxins. This method resulted in effective removal of unconjugated bilirubin, drugs with a high protein-binding ratio (sulfobromophthalein, theophylline), and a protein-bound toxin (phenol). The additional removal of PBS could extend the applicability of dialysis, for example, to drug intoxications and liver failure or could improve the elimination of protein-bound uremic toxins in chronic renal failure.