What ever happened to blood substitutes?

Objectives After reading this article, the reader will be able to:  Briefly discuss the significant milestones in the search for a substitute for human blood.  List several factors driving the search for a blood substitute.  List the characteristics of an ideal blood substitute.  Name and explain the four phases of clinical trials required before a drug can be approved by the Food and Drug Administration (FDA).  Name and characterize the two types of blood substitutes that have been studied most extensively to date.  Differentiate among the following terms, and explain which term is preferred and why: o blood substitute o RBC substitute o oxygen therapeutic o artificial oxygen carrier (AOC)  Name the countries where artificial oxygen carriers are approved for clinical use.  Summarize the current status of artificial oxygen carriers in the U.S.  Predict the future of artificial oxygen carriers based on current knowledge.