Photos by TAKAAKI IWABU - tiwabu@newsobserver.com
Lisa Webb and husband Kyle of Garner donate blood at an American Red Cross in Raleigh Thursday. Donations are at a 12-year low, but this couple has been donating every two months for the past 17 years, she said.
DURHAM -- A Duke University Medical Center study has found a problem in red blood cells stored for long periods that may explain why older blood has been shown to cause heart attacks, respiratory failure and other problems in patients who get transfusions.
The finding could open the way to changes that could make blood safer and ease periodic shortages in the blood supply, like the one now gripping the nation.
Even slightly more shelf life might help, said Sherry Mitchell, director of blood services for the Triangle chapter of the American Red Cross.
"We'd still be faced with having to collect 1,600 units a day (for 103 hospitals in North Carolina, Georgia and Tennessee), but it might buy us a bit more time when we have these down cycles."
Under federal law, whole blood can be stored for up to 42 days. Some studies have found, though, that patients who receive blood stored even for a couple of weeks are more likely to suffer infections, cardiovascular problems and even organ failure, particularly those who use several units of older blood.
Anything that could increase the nation's blood supply even slightly has big implications for the Red Cross, which takes in about 14 million pints from donors and moves it to hospitals in a complicated logistical web. Currently, that web faces a shortage because collections in May and June hit a 12-year low.
Previous studies of older blood have mainly focused on outcomes for patients using it, rather than the specific mechanisms that lead to the problems.
The new Duke study, published Friday in the journal Critical Care Medicine, found that stored red blood cells begin to lose the ability to release a key molecule called adenosine-5'-triphosphate (ATP), which helps prevent the cell from sticking to the walls of blood vessels.
The researchers think the stuck cells cause a number of problems, from obstructing blood circulation in the lungs to hampering the bloodstream's ability to deliver oxygen around the body, said Dr. Timothy J. McMahon, an associate professor of medicine at Duke and senior author of the study.
"We show that the export of ATP is important to prevent red blood cells from sticking to the inner lining of blood vessel walls," McMahon said.
The sticky cells may increase the risk of heart attacks and other problems that have been tied to transfusions of older blood.
McMahon said he and other researchers are now studying methods of boosting ATP in older blood.
Eventually, he said, additional research on ATP and older blood could lead to blood that is safer and lasts longer.
Another outcome might be a determination that, in some situations, patients are better off receiving no blood at all rather than using older blood, McMahon said.
