A victim of severe trauma who gets as little as a single unit of blood that’s been stored for more than a month is twice as likely to die as an equally injured patient transfused with fresher blood, a study found.

Red blood cells stored longer than 28 days significantly increased trauma patients’ risk of developing fatal deep vein thrombosis or multiple-organ failure for six months after transfusion, a team of pediatric intensive-care specialists in Connecticut reported Wednesday in the journal Critical Care.

The new study is the latest to raise concerns about rules governing the use of about 29 million units of blood transfused every year in the U.S. The American Red Cross says donated blood has a “shelf life” of 42 days, after which it must be discarded if not used.

Two earlier studies -- one of a general hospital population requiring transfusion and a second of heart surgery patients -- found that transfusions of longer-stored blood resulted in poorer outcomes.


Hospital patients administered blood stored longer than four weeks were three times as likely to acquire an infection in the hospital than those who got fresher blood. Heart patients infused with blood stored longer than two weeks were 64% more likely to die than those whose red blood cells were more briefly in storage.

Hospitals typically use longest-stored blood first to avoid wasting the resource, but the new study’s authors suggest that physicians consider “preferential use” of younger blood on the most critically injured trauma patients.

The result would probably mean more blood reaches its expiration date unused. But lives could be saved.

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melissa.healy@latimes.com