Cost effectiveness of blood transfusions: risk and benefit.

Allogenic blood transfusion carries the remote but well-known risk of disease transmission. The advent of an all-volunteer donor pool and modern screening techniques have made the blood supply the safest it has ever been. Despite these advances, however, clerical errors are still a cause of transfusion morbidity. Less well defined are the effects of allogenic blood on immunosuppression with resultant increase in infections and tumor recurrence. Strategies to reduce the need for allogenic blood include autologous predonation, acute normovolemic hemodilution perioperatively, and the salvage of shed blood. Autologus predonation eliminates many disease risks while keeping costs at least comparable to allogenic blood. Acute normovolemic hemodilution offers the advantage of low cost and the use of autologus fresh blood at the end of the operation. In the future, artificial blood substitutes now undergoing clinical trials, may play an important role in reducing the need for allogenic transfusions. Two promising agents are hemoglobin-based oxygen carriers and perfluorocarbons. Both offer the advantage of long shelf life and eliminate the need for crossmatching, but they are limited by short half-life.