Presidential address. 1971-1972: the year of transition.
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Biomedical subjects
G Beaudoin
Publications and source records attributed to G Beaudoin.
Effect of membrane characteristics on the performance of Couette rotating plasma separation devices.
The concept of a cylindrical membrane rotating at high speed inside a concentric cylinder (Couette flow device) has proved to be very efficient for plasma separation from whole blood. The authors show that its high filtration velocity (about 0.5-0.6 cm/min) is due to the presence of Taylor vortices in the blood-filled annular gap, which greatly increase the shear rates, but not radial migration of formed elements under centrifugal forces. The variation of filtrate velocity with transmembrane pressure (ptm) markedly depends upon the type of membrane. With a 0.8 micron polycarbonate membrane and bovine blood at 40% hematocrit, the filtration velocity reaches a peak equal to 0.6 cm/min at 3,000 rpm, then decreases to 80 mmHg, reaching a plateau of 0.35 cm/min independent of ptm. With a nylon membrane of 0.5 micron pores under the same conditions, the filtration velocity does not present a peak, but rises continuously to reach a 90 mmHg plateau equal to 0.5 cm/min. Similar behavior, but with lower plateaus, is also obtained with polycarbonate membranes at pore sizes below 0.4 microns. At 3,000 rpm, hemolysis occurs if ptm exceeds 750 mmHg, far above the operating range.
Blood Flow Velocity↗
High efficiency plasmapheresis using rotating membrane device.
We report here an experimental investigation of the effects of inlet blood pressure and rotation speed on the performance of a rotating membrane device for plasmapheresis commercialized by Hemascience. The good performance of this device can be explained by a combination of high shear rate, centrifugation of red cells and platelets away from the membrane and large secondary flows.
Blood Flow Velocity↗