At first glance, artificial blood seems like a good thing. It has a longer shelf life than human blood. Since the manufacturing process can include sterilization, it doesn't carry the risk for disease transmission. Doctors can administer it to patients of any blood type. In addition, many people who cannot accept blood transfusions for religious reasons can accept artificial blood, particularly PFCs, which are not derived from blood.
However, artificial blood has been at the center of several controversies. Doctors abandoned the use of HemAssist, the first HBOC tested on humans in the United States, after patients who received the HBOC died more often than those who received donated blood. Sometimes, pharmaceutical companies have had trouble proving that their oxygen carriers are effective. Part of this is because artificial blood is different from real blood, so it can be difficult to develop accurate methods for comparison. In other cases, such as when artificial blood is used to deliver oxygen through swollen brain tissue, the results can be hard to quantify.
Another source of controversy has involved artificial blood studies. From 2004 to 2006, Northfield Laboratories began testing an HBOC called PolyHeme on trauma patients. The study took place at more than 20 hospitals around the United States. Since many trauma patients are unconscious and can't give consent for medical procedures, the Food and Drug Administration (FDA) approved the test as a no-consent study. In other words, doctors could give patients PolyHeme instead of real blood without asking first.
Northfield Laboratories held meetings to educate people in the communities where the study took place. The company also gave people the opportunity to wear a bracelet informing emergency personnel that they preferred not to participate. However, critics claimed that Northfield Laboratories had not done enough to educate the public and accused the company of violating medical ethics.
Blood substitutes may be used as performance-enhancing drugs, much like human blood can when used in blood doping. An October 2002 article in "Wired" reported that some bicyclists were using Oxyglobin, a veterinary HBOC, to increase the amount of oxygen in their blood.
In spite of the controversy, artificial blood may be in widespread use within the next several years. The next generations of blood substitutes will also probably become more sophisticated. In the future, HBOCs and PFCs may look a lot more like red blood cells, and they may carry some of the enzymes and antioxidants that real blood carries.
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