CONVECTIVE TREATMENTS WITH ONLINE PRODUCTION OF REPLACEMENT FLUID - ACLINICAL-EXPERIENCE LASTING 6 YEARS

Background. The introduction of techniques with on-line (OL) productio n of replacement fluid by filtration of dialysis fluid raises concerns about exposure of dialysis patients to pyrogenic substances. This wor k was undertaken to evaluate safety and feasibility of OL preparation of replacement fluid for haemodiafiltration (HDF). Methods. OL HDF was carried out with commercially available monitors without any adjustme nt in the operational organization of our Centre. Bicarbonate dialysis fluid was filtered twice before being reinjected into the patients. T he effects of acute load of OL fluid were assessed by very sensitive i n vitro and in vivo tests; the chronic effects were assessed by monito ring the patients for the appearance of any untoward clinical manifest ations and by measuring their cytokine response. Results. In a pilot s tudy the membrane filter culture technique of replacement fluid yielde d no bacteria or mycetes growth, while LAL test was <0.01 EU/ml. The n ormal human monocyte production of TNF alpha, IL-1 beta and IL-1Ra was not significantly different when cells were incubated with OL or comm ercial replacement fluid. The patients' body temperature profile (cont inuous recording during treatments and the following 24 h) overlapped with that of the control procedure. Over 6 years we performed 4284 OL treatments (total amount reinjected fluid 102900 litres) on 13 patient s treated for 26 +/- 9 months. In none of these treatments did we obse rve pyrogenic reactions. In comparison with the previous period on sta ndard bicarbonate haemodialysis, OL HDF afforded significantly better cardiovascular tolerance to fluid removal and higher Kt/V values. The nutritional status did not deteriorate, while the acute-phase reactant s and serum beta(2)M levels did not increase. Moreover, no translucent cysts or destructive arthropathy were observed on bone X-rays. The pa tients' plasma cytokine levels and monocytes cytokines production, mea sured either before or after a single OL HDF, were comparable with the values obtained in controls treated with standard HDF. Conclusions. W e conclude that OL-prepared replacement fluid is as safe as that of th e commercial bags with regard to sterility and non-pyrogenicity. OL HD F can be readily implemented in any dialysis centre without bringing a ny further burden on the staff.