Clinical and Microbiological Evaluation of a Postdilutional Hemofiltration System with In-Line Production of Substitution Fluid

Abstract

Safety and efficacy of a recently developed hemofiltration (HF) system with in-line production of substitution fluid (GHS-10; Gambro, Lund, Sweden) based on a sterilizing filtration of acetate buffered dialysate has been evaluated in 4 patients over a 6-month period. Two patients were prematurely excluded from the study: 1 because of acetate intolerance and the other because of kidney transplantation. Two patients completed the study (240 HF sessions). Treatment adequacy was maintained in the 2 medium term treated patients according to the usual clinical and biochemical criteria and a mean exchange volume of 100-105 liters/week (30-35 liters/session three times weekly). Urea kinetic modeling analysis performed over all HF cycles gave the following results: dialysis index (urea clearance · time-on HF/urea volume space) (KT/V) ≈ 1-1.1, urea time averaged concentration (UREA TAC) ≈ 15-20 mmol/l, and protein catabolic rate (PCR) ≈ 1.1-1.2 g/kg/day. Rare clinical adverse symptoms observed during the course of sessions were attributed to acetate intolerance. Microbiological safety was confirmed in vivo by the absence of pyrogenic reactions after 240 HF sessions (≈7m³ substitution fluid infused intravenously) and in vitro by the constant absence of bacteria and/or endotoxin content limulus amaebocyte lysate (LAL) sensibility threshold 10 pg/l within the infusate produced during the sham HF sessions. The fluid mass balance obtained with the GHS-10 monitor was excellent. The electrolyte composition as judged by Na variation remained in a range of 2-3%.GHS-10 used in this study for postdilutional HF confirms that a large quantity of intravenous quality fluid may be safely produced by ultrafiltration from dialysate. It also introduced a new dimension in biocompatibility of dialysis by demonstrating that sterile dialysate may be routinely produced and used for routine dialysis.

Microbiologic Purity of Dialysate:Rationale and Te chnical Aspects

“…To maintain optimal filtration capacity, by preventing membrane fouling and microbial-derived product accumulation, the ultrafilter must be disposed in a crossflow filtration configuration as presented in figure 5. To reduce the risk of device failure, two filters disposed in series on the dialysate pathway, as shown in figure 4b are recommended [56]. Large differences in the retention capacity of ultrafilters may exist for the same type of ultrafilter.…”

Ultrafiltration and Backfiltration during Hemodialysis

“…On-line filtration of dialysate with a 40,000 dalton cut-off polyamide hernofilter resulted in a reduction of the incidence of febrile episodes of unknown origin from 3.6 to 1.9% in patients dialyzed with low-flux plate dialyzers (80). Recently it was shown that on-line filtration of substitution fluid resulted in the absence of pyrogenic reactions in 240 hemofiltration sessions with a total infusion volume of over 7,000 L (76). These studies indicate that on-line filtration of dialysate and substitution fluid reduces the incidence of PR in hemodialysis and hemofiltraiion, respectively.…”

“…Several recent studies have shown that on-line ultrafiltration is effective at reducing bacterial counts and endotoxin levels in dialysate (73)(74)(75)(76)(77). Results of these studies are summarized in Table 2.…”

Online Hemodiafiltration

“…This technically advantageous and cost-competitive production of substitution fl uid has been employed to develop various forms of high-effi ciency HDF modalities (postdilution, predilution, mixed-dilution, middilution). The generic term commonly used to characterize these modalities is ol-HDF [15][16][17].…”