OTTOWA, Ontario, March 17 (UPI) -- According to researchers at the Ottawa Hospital Research Institute, three-weeks-old blood is just as good as fresh blood, confirming the safety of transfusing older blood into the circulatory systems of critically ill patients.
Like most items in the refrigerator, blood has a shelf life. It doesn't stay fresh forever. Current guidelines suggest blood is good and safe (as long as it's properly stored) for as long as 42 days. But doctors performing transfusions routinely request the freshest blood possible, believing it's better for their patients. The motivation is understandable, but the pressure such a flood of requests puts on regularly thinning blood banks is unsustainable.
"Current blood bank practice is to provide patients with the oldest blood available. Some doctors, however, feel that fresh blood is better," Dr. Paul Hébert, an intensive care physician at the University of Montreal Hospital, explained in a press release.
To better understand this problem -- and how to combat it -- researchers at Ottawa Hospital set out to see if the use of fresh blood actually resulted in improved health outcomes. They compared mortality rates among critically ill patients who received transfusions of blood with varying ages. Researchers found no advantage to fresher blood.
"There was no difference in mortality or organ dysfunction between the two groups, which means that fresh blood is not better than older blood," said Dr. Dean Fergusson, a senior scientist at the Ottawa Hospital Research Institute.
Of the 2,430 adults who participated in the study, 423 patients died within 90 days of a transfusion of fresh blood; only 398 patients died after receiving an influx of older blood.
"Previous observational and laboratory studies have suggested that fresh blood may be better because of the breakdown of red blood cells and accumulation of toxins during storage," said Dr. Alan Tinmouth, a physician at the University of Ottawa. "But this definitive clinical trial clearly shows that these changes do not affect the quality of blood."
Scientists hope the new study -- published this week in the New England Journal of Medicine -- will give blood bank managers the justification to refuse requests for fresher blood, as well as calm worries among physicians that old blood will prove detrimental to their patients.
