Removal of lipid A and Pseudomonas aeruginosa endotoxin from dialysis fluids by high-flux polysulfone ultrafilter (dialyzer).

Ultrafilters (dialysis membranes) are generally considered to be impermeable to bacterial endotoxins (lipopolysaccharides) contaminating dialysates used for hemodialysis therapy, due to the self-aggregating properties of its molecules in aqueous media. The aim of the present investigation was to monitor the efficiency of high-flux polysulfone ultrafilters in removing lipid A and lipopolysaccharide (LPS) from dialysis fluids. To evaluate the safety of high-flux polysulfone membranes, an in-vitro circulation system (measuring lipopolysaccharide and lipid A penetrate from the ultrafilter to the other side and vice-versa), was utilized. Peritoneal dialysis solution was spiked with various concentration of Pseudomonas aeruginosa lipopolysaccharide (LPS) as well as lipid A diphosphoryl (E. coli F-583). Endotoxin and lipid A concentrations were detected by a chromogenic limulus amoebocyte lysate (LAL) assay. This investigation indicates that polysulfone ultrafiltration represents an efficient system to obtain an endotoxin and lipid A free dialysate when contaminated peritoneal solution was circulated through the dialysis membrane.