A study found that death rates after heart surgery are five times higher for patients who are given blood stored for more than 31 days then those who are given blood stored for 19 days or less.
If the finding is confirmed by larger studies, it could suggest that high-risk patients should be given fresher blood, which may be better able to deliver oxygen.
Donated blood doesn't last forever as red blood cells run down metabolically over time. In the 1980s, however, new preservatives doubled the original shelf life of donated blood to an apparent 42 days--a point at which 75% of red blood cells survive in the body after 24 hours. Still, Elliott Bennett-Guerrero, who directs perioperative clinical research at the Duke University Research Institute in Durham, North Carolina, realized that no large randomized study had tested for possible adverse effects of such old blood.