Blood Stored Longer May Increase Death Risk
The widely held assumption that blood may be safely transfused for up to 42 days is being challenged by several studies that found that blood stored this long caused significantly higher patient mortality than was found in patients transfused with fresher blood.
Federal Food and Drug Administration standards permit blood to be stored for 42 days before having to be discarded. However, Cooper University Hospital researchers found patients transfused with blood stored more than 29 days were twice as likely to get an infection while hospitalized, Dr. David Gerber, of the Camden, New Jersey hospital, told Reuters.
The researchers followed 422 patients in intensive care who were transfused between July 2003 and September 2006. Their average age was 66. Patients transfused with the older blood developed infections at twice the rate of those getting blood stored for less than 29 days.
What rendered patients more susceptible to infection, researchers said, was the fact that after two weeks stored blood begins to release biochemical substances called cytokines, which are known to weaken the immune system. As a result, patients become more susceptible to bloodstream infections, sepsis, heart valve and other infections.
Another survey, involving 9000 heart surgery patients and conducted at the Cleveland Clinic in Ohio, concluded that blood should be classified as out of date far earlier than the current FDA recommendations. Patients receiving blood more than 14 days old are nearly two-thirds more likely to die than those transfused with fresher blood, according to lead researcher Colleen Koch. Her team studied records of patients undergoing major heart surgery between June 1998 and January 2006.
The in-hospital death rate for the 2,872 patients receiving blood stored for 14 days or less was 1.7 percent—significantly below the 2.8 percent rate experienced by the 3,130 patients receiving blood that had been stored longer.