This is the largest trial (over 1,200 patients per group) to compare extremely fresh (less than a week old on average) with standard (about three weeks old) blood transfusion in sick adult patients. ‘Old’ blood has lower oxygen carrying capacity than fresh blood, and accumulates potentially harmful metabolites. However, there are costs associated with trying to give everyone fresh blood. In the end this study showed a null result with the point estimate favouring old blood. The death rate was high (over one third) so the trial ‘excluded’ the rather large adverse effect of a 16% increased death rate found in observational studies.
— Richard Lilford, CLAHRC WM Director
- Lacroix J, Hébert PC, Fergusson DA, et al. Age of Transfused Blood in Critically Ill Adults. New Engl J Med. 2015;372:1410-8.