In a new study published in the medical journal Anesthesia & Analgesia, Johns Hopkins researchers report startling findings that surgery patients need to be aware of before having surgery that could make the difference between life and death for them: “How old is the blood that will be used in my transfusion during surgery?”
In the study, researchers have discovered that the current guideline of keeping stored blood on the shelf for up to 6 weeks may not be as safe as previously believed and could make the difference between whether a patient survives or dies from an operation.
According to a news release about the finding, the study’s lead author states that if he were the one having surgery that the age of the blood used in transfusion would be important to him:
"There's more and more information telling us that the shelf life of blood may not be six weeks, which is what the blood banks consider standard," says study leader Steven M. Frank, M.D., an associate professor of anesthesiology and critical care medicine at the Johns Hopkins University School of Medicine. "If I were having surgery tomorrow, I'd want the freshest blood they could find."
Dr. Frank’s research is predated by an earlier study that found that patients undergoing cardiac surgery who were transfused with blood stored for more than 3 weeks were approximately twice as likely to die in comparison to cardiac surgery patients who were given blood that had been stored for only 10 days.
In his study, Dr. Frank and colleagues report that they may have found an answer to the survival disparity between patients who are given relative old stored blood over those who receive fresher blood. Analyzing samples of blood transfused (from 53 separate bags) into 16 patients who had spinal fusion therapy, they found that older stored blood contains red blood cells that have less flexible cell membranes than that of the red blood cells found in fresher stored blood. They explain that this decreased flexibility may make it more difficult for the older red blood cells to effectively deliver oxygen to the body.
Furthermore, drawing samples of the transfused blood from the patients 3 days following surgery showed them that the older red blood cells do not recover after the transfusion and that they may actually be dysfunctional.
Another finding was that the amount of older blood transfused may make a difference in patient health as those who were given lesser amounts of transfused blood had overall healthier red blood cells in their blood following surgery.
The researchers report that typical practice in hospitals is to reserve the freshest blood for pediatric patients over adult patients, and that blood banks typically treat stored blood like milk at a grocery that is pushed for sale based on its expiration date.
The authors conclude that the current 6-week shelf life of stored blood may prove to actually be too long to be safe and that pending studies addressing this question may have a definitive answer by next year that could change the limit to how long blood can be stored.
Image Source: Courtesy of MorgueFile
Reference: “Decreased Erythrocyte Deformability After Transfusion and the Effects of Erythrocyte Storage Duration” Anesthesia & Analgesia (Published online before print February 28, 2013); Steven Frank, M.D. et al.