Artificial oxygen carriers. Alternatives to homologous blood transfusion?

The expected explosion of costs in transfusion medicine due to the shortfal l of healthy donors and the moro frequent treatment of transfusion-associat ed complications (chronic hepatitis, cirrhosis, wound infection, tumor recu rrence) increases the socio-economic importance of the development of safe and effective synthetic oxygen carriers as an alternative to the transfusio n of homologous red blood cells. Currently two types of artificial oxygen c arriers are experimentally and clinically investigated for their capacity t o ensure adequate tissue oxygenation in the case of severe anemia. In addit ion to their oxygen transport capacity solutions; based on free human or bo vine hemoglobin provide vasoconstrictor properties. Their hyperoncotic prop el-ties make them particularly attractive for the treatment of severe hemor rhagic shock. perfluorocarbon (PFC) emulsions allow an increase of the phys ically dissolved portion of arterial oxygen content. Due to their particula te nature (emulsion droplets) PFC may only be infused in low doses. Otherwi se there is risk of overload and malfunction of phagocytic cells of the ret iculo-endothelial system. In the case of an intraoperative blood-loss in pr eoperatively hemodiluted patients, bolus infusion of PFC represents an effe ctive means to avoid immediate retransfusion of autologous blood and allows for Further, extreme hemodilution without risking tissue hypoxia.