Hemodialyzer performance: an assessment of currently available units

The performance characteristics of nine currently available disposable parallel-flow dialyzers were assessed, both before and immediately following dialysis, by measuring: (i) in vitro clearances of C14 labeled urea, creatinine, and sucrose and H3 labeled vitamin B12 at standard conditions, (ii) ultrafiltration rates in saline at 37C, and (iii) loss in the mass transfer coefficient-membrane area product (hoA), following a single dialysis. Parallel-plate dialyzers underwent considerable membrane stretching during dialysis and exhibited greater variability, particularly regarding vitamin B12 clearance and ultrafiltration ability, than did capillary dialyzers. The variability in plate units was greater for large-area dialyzers where there were 25 to 26 blood channels. However, despite considerable differences in performance characteristics, all dialyzers were judged to be clinically acceptable in terms of both solute clearance and ultrafiltration characteristics.