Blood loss and blood transfusion.

Homologous, or banked, blood is chronically in short supply. In addition, it is associated with a number of significant risks, including transfusion-related infection with hepatitis and acquired immune deficiency syndrome (AIDS), transfusion reactions, and alloimmunization. Therefore, the benefits of reducing the dependence on banked blood are clear. Several techniques are being used to transfuse the patient's own blood during surgery. With the predeposit technique, a patient anticipating surgery donates blood during the month preceding operation. During or immediately following surgery, the patient's blood can be collected and reintroduced (whole blood salvage and reinfusion) or it can be collected, washed, and reinfused in the form of packed cells. Expanded use of these techniques and efforts to reduce blood loss during surgery can reduce the incidence of transfusion-related complications. In the future, synthetic blood substitutes may further reduce the need for homologous transfusions in surgical patients.