Haemoglobin-based red cell substitutes: current status

Chemically modified haemoglobin solutions represent a potential alternative to the transfusion of donor blood. The theoretical advantages of these products include an oxygen delivery potential greater than that of conventional plasma expanders, prolonged shelf-life, universal compatibility and the absence of pathogenic viruses. Principal concerns have been safety issues including renal toxicity, coagulopathy and vasoactivity. The proposed indications for these solutions are primarily resuscitation of patients in haemorrhagic shock and perioperative haemodilution during elective surgery. Three products have now undergone phase I safety trials in human subjects and phase II safety and efficacy trials are planned in the near future.