Rapid platelet separation and collection for postoperative autologous transfusion

The authors describe a technique for rapid, on-line, precardiopulmonary bypass separation and collection of 10-20% of a patient's platelets for storage and postoperative reinfusion. In a three stage process, blood is diverted through a hollow fiber hemofilter and platelets are concentrated near the fiber walls; the core is flushed of whole blood and the concentrated platelets are collected. Process mechanics were investigated in vitro with bovine blood; efficacy was studied with in vivo ovine experiments; and platelet function and viability were examined with in vitro human blood tests. Using commercially available hemofilters with 13,000 polyacrylonitrile fibers, the authors collected 1 x 10(11) to 2 x 10(11) platelets in 250 ml in 3.5 min. With fresh human blood, collected platelets exhibited normal morphology and aggregation response to adenosine diphosphate, collagen, and thrombin for 4 hours after collection.