Fouling process of hemodiafiltration membranes by hemodialysis and hemodiafiltration therapy.

During hemodialysis, proteins, such as albumin and globulin, are deposited on the dialysis membrane surface, causing fouling that affects solute removal and biocompatibility. This study aimed to measure the filtration coefficient as an index of dialysis membrane conditions in hemodialysis, pre-dilution online hemodiafiltration, and intermittent infusion hemodiafiltration modes using two different hemodiafiltration membranes ex vivo. The filtration coefficients of hemodiafiltration membranes in hemodialysis, pre-dilution online hemodiafiltration, and intermittent infusion hemodiafiltration modes were continuously measured for 123 min using 2 L bovine blood, which was adjusted with 32% hematocrit and 6.5 g/dL of total proteins. Polysulfone and cellulose triacetate were used as test membrane materials, and both membrane structures were asymmetric. The first fouling step was observed 20 s after filtration of both polysulfone and cellulose triacetate membranes in each mode. Thereafter, the filtration coefficient recovered in the pre-dilution online hemodiafiltration mode. However, it plateaued in the cellulose triacetate membrane and decreased in the polysulfone membrane. A flushing effect of the intermittent infusion hemodiafiltration mode was observed in both the cellulose triacetate and polysulfone membranes. The differences in fouling steps in each of the three modes-hemodialysis, pre-dilution online hemodiafiltration, and intermittent infusion hemodiafiltration-can be identified by continuously measuring filtration coefficient values.