Fluids as oxygen carriers and the potential role in trauma resuscitation

Patients with major trauma present a challenge, often using large quantities of banked blood both at the time of injury and during their hospital stay. Blood transfusion is not without risk and is associated with high costs; it is immunosuppressive, rendering patients more susceptible to infection. In the western world, banked blood is fully screened and relatively safe; the same is not true in parts of the developing world, where high rates of HIV carriage make blood transfusion a risky undertaking. Additionally, blood transfusion as a vector for transmission of illnesses such as prion disease is a distinct possibility, for both the developed and developing world alike. The introduction of artificial blood substitutes would ameliorate some risk and also remove the cost of extensive blood testing. For trauma outside hospital, blood substitutes could compete directly with fluid resuscitation as donated blood is not usually available. Patients with prolonged transport times would appear to be the most obvious beneficiaries and volume expansion, along with improvement in oxygen-carrying capacity would be the ultimate goal. All clinicians confronted with the need for transfusion of homologous blood would welcome the development of a safe and reliable alternative to red blood cells in order to ensure oxygen transport to the tissues. However, even though research on red cell substitutes started more than 100 years ago, even now none of the heavily investigated compounds based on haemoglobin or perfluorocarbons has been released in Europe or the USA for routine clinical use.