"This [study] is an important reminder that while transfusions are lifesaving in some settings, there are also settings where we know patients do better with a restrictive transfusion strategy," McMahon said.
According to Katz, the results must now be replicated in controlled clinical trials. "If it is true, it raises the question of, are there things we can do in the bag [of donated blood] that would make this not a problem? Can you put nitric oxide in the bag?"
Stamler's group addressed that challenge in a study conducted with dogs. They found that human red cells' vasodilatory activity could be restored at any point up to 40 days following collection by treatment with NO, thereby improving blood flow to the heart in blood recipients.
"The hope would be that this will also work in humans," Stamler said. "We already know that the blood we give people is not normal and that it cannot open vessels properly. Our hope is if we put the nitric oxide back in, we could cure this problem."
In the meantime, those patients in need of a blood transfusion would do well to stay informed, Katz said. "The bottom line on transfusion is to ask what is the functional benefit of transfusion in this patient at this time," he said. "We (docs) are often guessing, but good docs make good guesses."
Both Stamler and McMahon noted conflicts of interest in their reports, including grant support and consulting fees from, and equity holdings in, Nitrox/N30 Pharma, "a company that is developing strategies for treating disorders of oxygen delivery," according to Stamler's manuscript.
For more on blood transfusions, visit the U.S. National Library of Medicine.
SOURCES: Jonathan S. Stamler, M.D., department
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