Model for a one-step plasma treatment device: feasibility of cholesterol removal

A self-contained plasmapheresis device based on Starling flow has been proposed. A computer model was developed to describe the device performance, and a device using conventional cellulose tri-acetate (CTA) fibers was modeled. Predicted pressure drops and ultrafiltration flow agreed well with measurements using bovine blood in prototype devices made with CTA fibers. The model predicted the expected Starling flow and predicted the observed high hematocrit region near the fiber wall and a layer of packed red cells on the wall. Typically, 15% of the ultrafiltration flow occurred in the first 2-3% of the fiber length where no packed cell layer was present. The entrance header was predicted to cause lower blood pressures in the peripheral fibers, producing a net plasma migration from the central to the peripheral fibers. As an example application for this device, the computer model was used to assess the feasibility of reducing LDL-cholesterol in patients. The use of sequential 1 hour treatments by a modified device was predicted to reduce the cholesterol in a standard man from 200 mg% to 150 mg% in less than 3 hours.