1. The aim of this study was to define the factors influencing plasma separation from the continuous flow celltrifuge and to evaluate plasma as an alternative to whole blood for perfusion of exchange resins as part of a system of artificial liver support.
2. Studies in vitro showed the importance of packed cell volume, centrifugal force and duration of centrifugation on the degree of plasma separation. From these data it was possible to calculate plasma flow rates likely to be obtained from the celltrifuge when used in vivo. These predicted values correlated closely with plasma flow rates obtained in twenty-six studies in dogs.
3. Comparison of whole blood perfusion with plasma perfusion of exchange resins in another series of dog experiments showed that with whole blood perfusion there was often a considerable rise in pressure across the resin column but that this did not occur with plasma perfusion.
4. Measurements of platelet losses in the same series of experiments showed a 50% reduction of arterial platelet counts over a 3 1/2 h period of perfusion when whole blood was perfused. Although the fall was lower with plasma perfusion, the difference was not statistically significant.
5. Use of the celltrifuge provides a means of resin perfusion free of the mechanical difficulties of whole blood perfusion, but platelet losses still remain a problem.