Dialysis Efficiency of AN69, a Semisynthetic Membrane Not Well Suited for Diffusion.

AN69 membrane is not suited for diffusion, with an suggested limit at 25 mL/min dialysate flow rate. When prescribing continuous hemodialysis this threshold must be surpassed to achieve. We designed a study aimed to check if a higher dose of dialysis could be delivered efficiently with this membrane. Ten ICU patients under continuous hemodiafiltration with 1.4 m2 AN69 membrane were included and once a day we set the monitor to exclusively 50 mL/min dialysate flow rate and 250 mL/min blood flow rate and after 15 minutes measured dialysate saturation for urea, creatinine, and -microglobulin. We detected that urea saturation of dialysate was nearly complete () for at least 40 hours, while creatinine saturation showed a large dispersion () and did not detect any relation for these variables with time, blood flow, or anticoagulation regime. Saturation of -microglobulin was low () and decreased discretely with time (, ) and significantly with TMP increases (, ). In our experience AN69 membrane shows a better diffusive capability than previously acknowledged, covering efficiently the range of standard dosage for continuous therapies. Creatinine is not a good marker of the membrane diffusive capability.