Duke Researchers Make Blood Transfusions Safer
Posted October 8, 2007
Durham, N.C. — Blood transfusions are known to make some patients' conditions worse, but Duke researchers say they have discovered why.
Doctors give blood transfusions for a variety of reasons, such as severe bleeding or low blood counts, because body tissues need the oxygen carried by the blood.
However, doctors have long been puzzled by the observation that heart patients are twice as likely to die during the first 30 days of hospitalization if they receive a blood transfusion for anemia, or blood loss.
Research by Duke doctors might hold the key to making blood transfusions safer for heart patients.
Dr. Jonathan Stamler, a professor of medicine at Duke, says human blood in banks around the world is missing a key ingredient: nitric oxide.
"We've learned that the stored blood loses its nitric oxide very rapidly and, therefore, can't open the blood vessels and can't get the oxygen to the tissues," Stamler said.
Nitric oxide is a gas in blood that opens vessels, so oxygen in red blood cells can reach body tissues, including the heart.
"As the blood moves into those tissues, it then just clogs up the blood vessels, rather than opening the blood vessels and getting the oxygen to the tissues," Stamler said.
The solution is to put nitric oxide back into the blood at the time of transfusion, Stamler said.
"We now have the means to put it back, and we have the means to improve blood flow to hearts that are in need of oxygen," said Dr. Stamler. However, he said perfecting that method will likely take more time and study, including clinical trials.
In the meantime, Stamler stressed that some patients can still benefit from a blood transfusion.
"Certainly, there are going to be some patients who will benefit from a blood transfusion. Benefits will outweigh risks in certain patients who have very bad bleeds," he said.
Stamler added the caution, "It doesn't mean that blood is good, even in those patients. It doesn't mean that the blood could not be made better."