Potential of hemoglobin-based oxygen carriers in trauma patients

Injured patients have a unique requirement for early blood transfusion. A product that can be used in the pre-hospital setting that adequately carries and delivers oxygen to peripheral tissues would potentially be life saving for severely injured patients. Allogeneic blood is not the ideal agent in the pre-hospital setting. Present limitations in the allogeneic blood supply include the need for cross-matching, refrigeration, marginal supply, transfusion reactions, infectious disease transmission and immunomodulation increasing the risk of organ dysfunction after transfusion. Hemoglobin-based oxygen carriers have been under present development for the last 25 years. These compounds use either human or bovine hemoglobin that is then chemically altered to improve safety. These compounds exhibit many desirable characteristics that make them potential therapeutic agents in the treatment of the injured patient. These compounds do not need to be cross-matched, have favorable oxygen dissociation characteristics, long half lives, do not transmit disease, appear to be less immunoreactive than blood and theoretically can be used in the pre-hospital setting as a low volume oxygen carrying solution without need for refrigeration. There are at least three agents presently under development that use different techniques to alter the basic hemoglobin tetramer. While there is no FDA approved hemoglobin-based oxygen carrier approved for use in injured patients at this writing, phase III studies are currently either underway or being developed. There is high likelihood that one or more of these agents will be approved for clinical use in the near future.