Stored blood yields more infections

LOS ANGELES -- Hospitalized patients who received blood that had been stored for more than four weeks were nearly three times as likely to develop infections as those who received fresher blood, researchers said yesterday.

The blood itself was not infected, but the release of chemical agents called "cytokines" in stored blood may have affected the recipients' immune systems, rendering them more susceptible to infection, said Dr. Racquel Nahra of Sparks Regional Medical Center in Fort Smith, Ark.

The patients typically suffered an increase in urinary tract infections, pneumonia and infections associated with intravenous lines, but those who were infected were no more likely to die, she told a meeting of the American College of Chest Physicians in Philadelphia.

And while the apparent increase in risk was large, the overall number of infections remained small, she said.

Current rules permit blood to be stored for 42 days before it must be discarded. Blood banks typically use the oldest blood on hand first so it will not be wasted.

The new study follows a March 2008 report that heart surgery patients who received blood that had been stored for more than two weeks were 64 percent more likely to die in the hospital than those who received fresher blood.

LOS ANGELES TIMES