One year's experience using a rotating filter for therapeutic plasma exchange

The authors previously demonstrated the feasibility of using a rotating filter system for therapeutic plasma exchange. They now report on the technical details of a 1 year clinical experience. Seventeen patients underwent 188 treatments. Hemoaccess was provided by antecubital veins (147 Rx), femoral catheters (37 Rx), or an a-v fistula (3 Rx). Blood flows ranged from 75 to 100 ml/min. Net plasma removed per treatment was 3,231 +/- 53 ml (mean +/- SE, n = 188). Mean plasma removal rate per treatment was 40.2 +/- 0.6 ml/min; mean treatment time was 83 +/- 2 min. Platelet counts before and after treatment revealed a 15 +/- 4% decline (n = 46 Rx). Despite filtration fractions up to 86% there was no evidence of significant membrane plugging or hemolysis. For semiselective removal of cholesterol, the rotating filter was used in a cascade system with a secondary filter. Eighty percent of processed plasma was returned to the patient, but the treatment time was prolonged by 37% and the total cholesterol removed was 26% less when compared with the single pass system. The authors conclude that an inexpensive rotating filter can provide a highly efficient plasma exchange. The inherent efficiency of this system must be considered when evaluating its use with secondary filtration techniques.