Methods of reducing allogeneic blood demand in orthopedic surgery

Despite advances in this field, allogeneic blood transfusion still carries a lot of risk; the availability of heterologous blood is also constantly decreasing. We describe the most popular methods for reducing the allogeneic blood requirement. Basic information is presented about the physiological mechanisms of compensation for intraoperative blood loss, which can be compromised by respiratory and cardiovascular disease or infections. Preoperative anemia (manifested by low hemoglobin levels) is statistically the most significant factor that increases the need for allogeneic blood transfusion. This paper evaluates the importance of oral and intravenous iron supplementation in the perioperative period, and the use of erythropoietin to boost Hb levels. Minimizing intraoperative blood loss also decreases the need for transfusion, and may be accomplished via meticulous hemostasis, an appropriate surgical approach, atraumatic surgical technique, reduced surgery time, and rational tourniquet use. Controlled intraoperative hypotension is a method of proven efficacy. Synthetic antifibrinolytic agents are also used to reduce perioperative blood loss; however, few clinical trials have focused on the use of such drugs in orthopedics. The use of postoperative drainage is still debatable. The allogeneic blood requirement can also be reduced by autologous blood transfusion. Autologous transfusion can be accomplished by preoperative autotransfusion, preoperative hemodilution, and intra- or postoperative blood salvage. It is currently the safest method of compensating for perioperative blood loss, avoiding all the described risks of heterologous blood transfusion.