Blood Processor for Hydroxy Ethyl Starch

The long-term objective of this research is the development of a closed, sterile, fully automated system for thawing and washing red blood cells that have been frozen with the polymeric cryoprotectant hydroxyethyl starch (HES). The only currently available method for freezing red cells utilizes glycerol at high concentration. Since glycerol penetrates red cells, removing it following thawing creates osmotic stresses that can hemolyse cells, several successive wash solutions of decreasing osmolality are necessary and more than 30 minutes of relatively skilled technician time are required. The HES system has the advantage that HES does not penetrate the red cells and can be rapidly removed using a single wash solution without producing osmotic stresses. The system proposed will achieve washing by means of a hollow fibre fluid exchange device that achieves the wash without the disadvantages of moving parts and high disposable costs. We further propose to explore the feasibility of automated thawing between heated plates with the washing proceeding concurrently with thawing. Post-wash storage will be optimized to provide maximum refrigerated shelf-life consistent with established guidelines for free hemoglobin and in vivo survival. The proposed research will evaluate the feasibility of this approach by fabricating and testing disposable sets and the automated apparatus necessary to implement the process. The quality and clinical acceptability of red cells processed with this apparatus will be evaluated. This system provides red cells that can be stored indefinitely in the frozen state and rapidly thawed and washed for transfusion. A frozen red cell system with a less inexpensive, more rapid, fully automated reconstitution system is attractive for isolated locations and for uses such as the storage of autologous blood and rare blood types.