WASHINGTON (AP) -- A pair of studies are raising concerns about stored blood.
The research shows much of the banked blood given to millions of people every year may lack a component vital for it to deliver oxygen to the tissues.
The component is nitric oxide, which helps keep blood vessels open. The reports say it begins breaking down as soon as blood goes into storage.
In recent years, doctors have become increasingly concerned about levels of heart attack and stroke in patients receiving transfusions. The new findings may help explain that.
One possible solution would be to add nitric oxide to stored blood, but clinical trials would have to be conducted first.
The studies are in this week's online edition of Proceedings of the National Academy of Sciences.
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