Effect of chemical germicides on the integrity of hemodialyzer membranes

Epidemiologic investigations of bacteremia in dialysis patients by the Centers for Disease Control (CDC) identified an association with the use of dialyzers disinfected with a specific chemical germicide. A collaborative study by the CDC and the Food and Drug Administration (FDA) was conducted to determine the effect of dialyzer disinfectants on five types of dialyzer membranes: three cellulosic (Cuprophan, cellulose acetate, cuprammonium rayon); and two synthetic (polysulfone, polyacrylonitrile). The disinfectants tested were: 4% formaldehyde; Renalin; Cidex Dialyzer; Sporicidin HO; Warexin; and RenNew-D. Water was the control. Dialyzers were reprocessed up to 15 times. Each reprocessing consisted of rinsing, air-leak testing, filling with fresh disinfectant, and storing for 2 to 4 days. After 15 reprocessings or air-leak failure, each dialyzer was microbiologically challenged for membrane integrity. Membranes exposed to Renalin, Cidex Dialyzer, and water passed all tests. Cellulosic membranes exposed to Warexin failed all tests after 2 to 9 reprocessings. Cellulose acetate membranes exposed to Sporicidin HD failed microbiologic testing. One polysulfone dialyzer exposed to RenNew-D and one exposed to 4% formaldehyde failed microbiologic testing. These results and those obtained from epidemiologic studies suggest that membrane integrity testing (e.g. an air-leak test) should be an integral part of dialyzer reprocessing.