Current status of cell-free hemoglobin solutions

Abstract

Current Status of Cell-Free Haemoglobin Solutions. Persisting concern about the risks of allogeneic blood and the impending shortfall of such products have reinforced the search for alternative erythrocyte substitutes in recent years. With the absence of toxic side effects of modern, ultrapurified and chemically modified haemoglobin-based oxygen carriers (HBOC), many studies in animals, volunteers and patients have shown their effectivity and tolerability. HBOC can be applied in patients without prior cross-matching and one product, which is available as room temperature-stable formulation with a shelf-life of > 2 years, has recently been approved for the treatment of peri-operative anaemia in South Africa. While clinical studies with human cross-linked haemoglobin (DCLHb) were discontinued because of an increased mortality of patients receiving DCLHb after stroke and multiple injury shock, phase III studies with polymerized bovine haemoglobin (HBOC-201) have been completed showing that peri-operative infusion of HBOC-201 was able to avoid or reduce allogeneic blood transfusion. Different human, recombinant and bovine hemoglobin solutions are currently under investigation in cardiac surgery, sepsis and tumour patients. Extensive laboratory investigations have shown that HBOC are highly effective oxygen donors with regard to tissue oxygenation rather than erythrocyte substitutes in case of bleeding, because they provide plasmatic oxygen delivery under physiological concentrations of inspired oxygen. HBOC have advantages over red blood cells because of their easier oxygen release per se and from adjacent erythrocytes, and their capability to reach poststenotic or poorly perfused tissues with the plasma stream.