The medical community has long been aware of the benefits a blood substitute might bring when accidents occur in remote settings and during times of war but finding the right product has been difficult.  The current version of blood substitutes under development seemed promising for a while but a recent analysis of sixteen clinical trials reveals safety concerns.

The perfect blood substitute would be able to withstand long shelf life with no refrigeration and would not cause infection or other medical complications.  To date, blood substitutes have been designed around hemoglobin, the protein in red blood cells that carries oxygen throughout the body.  These hemoglobin-based blood substitutes (HBBSs) are not yet approved for use within the United States although they are in use outside this country.  The data from clinical trials in these countries is the basis for the current safety concerns.

At the National Institutes of Health (NIH) in Bethesda, Maryland, Charles Natanson, MD, and his colleagues assessed the connection between HBBSs and the incidence of death and heart attack when HBBSs were used on patients undergoing surgery, trauma, and stroke.  Sixteen trials involving five different HBBSs and 3,711 patients age 19 and older who received the blood substitutes for therapeutic reasons were selected for analysis.

Of all the patients in the study group, 164 patients receiving HBBS products died while the control groups counted 123 deaths.  The treated group saw 59 heart attacks while the control groups had 16.  These numbers represent a 30% higher risk of death when the blood substitute was administered and 2.7 times higher risk of heart attack.

The analyzed data was consistent for all products and settings without isolating any particular risk factors other than the administration of the HBBSs themselves, leaving the NIH research team to suggest the current and future clinical trials be done on animal models instead of humans until more is known about how these products work.

The team also calls on the scientific community to report findings promptly to the US Food and Drug Administration (FDA) after all studies are complete.  They say it is likely the FDA would have called a moratorium on further human clinical trials by 2000 if the results of the trials had been reported in a more timely manner.

Source: American Medical Association