Blood substitutes.

Red cell substitutes are a group of oxygen carriers designed to temporarily replace transfused blood. Each product is unique in its limitations and advantages. Research and development has been slow because of the far-reaching consequences of replacing an oxygen carrier outside of the red cell. Nevertheless, a number of products are in advanced clinical trials and nearing the market. When they are available for use it is likely that development will accelerate and even better products will substantially alleviate the world-wide shortage of blood for transfusion and enable the delivery of medical care to underserved populations. An important consequence of the development of these products has been a better understanding of how oxygen is delivered to tissues.