Just like milk and many other foods, blood used for transfusions is perishable. But contrary to popular belief, new research shows that blood stored for three weeks is just as good as fresh blood.
The large clinical trial provides reassuring evidence about the safety of blood routinely transfused to critically ill patients. Supported by the Canadian Critical Care Trials Group and countless nurses, blood bank technologists, transfusion medicine and critical care physicians, Drs. Jacques Lacroix (Sainte-Justine University Hospital Research Center), Dean Ferguson and Alan Tinmouth (both of The Ottawa Hospital) led a team of dozens of researchers from 64 Canadian and European centers.
The researchers undertook the Age of Blood Evaluation (ABLE) study, a randomized double-blind trial to compare mortality after 90 days in intensive care patients transfused with either fresh blood (stored for an average of six days) or older blood (stored for an average of 22 days). A total of 2,430 adults participated in the study, including 1,211 patients in the fresh blood group and 1,219 in the older blood group.
"Current blood bank practice is to provide patients with the oldest blood available. Some doctors, however, feel that fresh blood is better", said Dr. Paul, an intensive care physician-scientist and professor at the University of Montreal.
The findings are unequivocal: "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 and the University of Ottawa.
Specifically, 423 patients died within 90 days post-transfusion in the group of patients who received fresh blood, compared to 398 patients who died in the group that received 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. But this definitive clinical trial clearly shows that these changes do not affect the quality of blood", said Dr. Alan Tinmouth, a physician and scientist at the Ottawa Hospital Research Institute and the University of Ottawa.
According to current standards, blood is stored up to 42 days. But many doctors have begun to ask for fresh blood in recent decades, thinking that it's the right thing to do. This is made difficult because of a limited supply and because blood collection agencies and hospital blood banks distribute blood on a "first-in, first-out" basis to avoid wastage.
"Canadian Blood Services is very pleased to see the publication of the ABLE study. The study supports our current inventory management practices for patients receiving transfusions in the intensive care setting", said Dr. Dana Devine, chief medical and scientific officer at Canadian Blood Services.
Blood transfusions save lives, affirm the authors. There is no need to worry about the safety of the age of blood routinely used in hospitals. The same research team is conducting a clinical trial in pediatric patients. "This study should verify whether children react to fresh blood and older blood transfusions in the same way as adults", said Dr. Jacques Lacroix of Sainte-Justine University Hospital Research Center and professor at the University of Montreal.