Evaluation of materials for use in extracorporeal circulation. In vitro serum-material interaction

Polymeric membranes used in extracorporeal circulation procedures of varying hydroxyl (-OH) percent were evaluated with normal human serum to detect differences between chemical composition and serum-material interactions. The materials were evaluated as hollow fibers built into modules, including polypropylene (PP; 0%), polyvinyl alcohol (PVA; 23.7%), ethylene vinyl alcohol (EVAL; 29.7%), Cuprophan (CP; 31.5%), and Hemophan (HP; 30.9%). Data from serum perfusions expressed as percent changes to sham (circuit minus module) showed that solute % decreases were from 0% to 10% in all materials except for PVA (10-22%). Complement activation product % increases were higher with PVA (606-4309%) and CP (48-567%), and mononuclear cell transformation functions (MNCTFs) were more suppressed with PVA (100 to 98%) and CP (10-18%). Despite EVAL and HP having an -OH %, complement activation products were relatively low with EVAL (less than 212%), HP (less than 13%), and PP (less than 131%). MNCTFs were stimulatory with the co-polymer of vinyl alcohol and ethylene (EVAL), and very suppressed by serums from PVA contact. Ethylene vinyl alcohol and modified cellulose (HP) had reduced complement activation despite higher or comparable bulk -OH. Bulk -OH content alone cannot explain the differences observed.