Effects of ultrafiltration on solute clearances in cuprophan and cellulose hollow fiber dialyzers: in vitro and clinical studies.

Hollow fiber dialyzers are currently available with either regenerated cellulose or thinner walled cuprophan fibers. In vitro and clinical studies were undertaken to compare a cellulose with a cuprophan dialyzer in regard to (1) UF's, (2) small and large solute clearances at high and low TMP's, (3) SC's, and (4) effects of ultrafiltration on diffusive and convective components of clearances. The results show that per square meter of surface area, the cuprophan dialyzer has higher rates of UF per TMP and greater clearances, particularly of larger solutes; also with cuprophan the SC for vitamin B12 is higher. Thus all findings suggest greater permeability of cuprophan fibers. In both dialyzers, total clearances increased with UF by amounts compatible with predicted increases in convective transport; diffusive transport remained stable as TMP was increased.