Efficacy and safety of haemodialysis treatment with the Hemocontrol™ biofeedback system: a prospective medium‐term study

Background. Hypovolaemia has been implicated as a major causal factor of morbidity during haemodialysis (HD). A model biofeedback control system for intra‐HD blood volume (BV) changes modelling has been developed (Hemocontrol™, Hospal Italy) to prevent destabilizing hypovolaemia. It is based on an adaptive controller incorporated in a HD machine (Integra™, Hospal Italy). The Hemocontrol™ biofeedback system (HBS) monitors BV contraction during HD with an optical device. HBS modulates BV contraction rates by adjusting the ultrafiltration rate (UFR) and the refilling rate by adjusting dialysate conductivity (DC) in order to obtain the desired pre‐determined BV trajectories. Methods. Nineteen hypotension‐prone uraemic patients (seven males, 12 females; mean age 64.5±3.0 SEM years; on maintenance HD for 80.5±13.2 months) volunteered for the present prospective study that compared the efficacy and safety of bicarbonate HD treatment equipped with HBS, as a whole, with the gold‐standard bicarbonate treatment equipped with a constant UFR and DC (BD). The study included three phases: Medium‐term studies started with one period of 6 months of BD and always had a follow‐up period of HBS treatment ranging from 14 to 30 months (mean 24.0±1.6); short‐term studies started in September 1999, when all patients went back to BD treatment for a wash‐out period of 4 weeks and a short‐term study period of a further 3 weeks (phase A). Afterwards, they once again started HBS treatment for a wash‐out period of 4 weeks and a short‐term study period of a further 3 weeks (phase B). Every patient underwent acute studies during a single HD run, once during phase A and once in phase B. Resistance (R) and reactance (Xc) measurements were obtained utilizing a single‐frequency (50 kHz) tetrapolar bioimpedance analysis (BIA). Extracellular fluid volume (ECV) was calculated from R, Xc, and height and body weight measurements using the conventional BIA regression equations. Results. The overall occurrence of symptomatic hypotension and muscle cramps was significantly less in HBS treatment in both medium‐ and short‐term studies. Self‐evaluation of intra‐ and inter‐HD symptoms (worst score=0, best score=10) revealed a statistically significant difference, as far as post‐HD asthenia was concerned (6.2±0.2 in HBS treatment vs 4.3±0.1 in BD treatment, P