Blood transfusions are a revolutionary technology that has saved countless lives both in the operating room and on the battlefield. But longterm storage of blood may diminish its life saving properties, a new study says.

A report in the journal Anesthesia and Analgesia from Johns Hopkins researchers indicated that storing blood for extended periods may reduce the flexibility that red blood cells have to fit into small capillaries. This would limit their ability to bring lifesaving oxygen to starved areas of the body such as vital organs and the brain when someone is in need of a transfusion.

The shelf life of blood, according to standard medical procedure is six weeks and is usually stored at a cold temperature.

"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," said 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."

A previous research article in the New England Journal of Medicine showed that blood stored for just 10 days and used for transfusion correlated with a twofold incidence of dying after cardiac surgery.

The current study looked at 16 patients who had spinal fusion surgery. Samples of the blood that they had been transfused with were taken and were found to contain red blood cells whose membranes were more rigid than found in fresh blood.

Researchers then took blood samples from the patients that had transfusions and saw that even when put back inside of a person under the right physiological conditions, the red blood cells remained less flexible and that the damage to the red blood cells had been done.

There are currently two larger studies underway to determine if older blood is indeed worse for patients than new blood and what time limits for storage should be implemented.

There is currently a shortage of blood in the United States and medical centers are in desperate of fresh blood. To find out more about blood donation, please visit the Red Cross Website and find a donation center near you. You could save a life.

The article published in the journal Anesthesia and Analgesia can be found here.