Researchers from the Cleveland Clinic, publishing in the New England Journal of Medicine, report that patients undergoing heart surgery seem to have fewer post-surgical complications when blood transfusions are done with "new" blood versus "old" blood.

The research team studied more than 6,000 patients and patient case reports from those who were given a blood transfusion during heart bypass surgery, heart valve surgery, or both. They found that patients transfused with "new" blood (average age = 11 days) seemed to do much better than those transfused with "old" blood (average age = 20 days).

Patients transfused with "new" blood were less likely to develop kidney failure, blood infections, or other organ failure. Overall, they were less likely to die in the hospital than those transfused with "old" blood.

If true, this new research could change the way that blood and blood products are handled by hospitals and other organizations. It is not known if the findings in this study - which are specific to patients having heart surgery - generalize to other patient groups. Developing profile data like this for other surgical situations could change the way that blood is allocated, with newer blood going to those types of patients most likely to benefit.