Patient Survival Unaffected by Age of Transfused Blood

Authors: Lacroix J et al., N Engl J Med 2015 Mar 17;

The use of fresh red cells did not improve 90-day mortality for intensive-care patients.

Red blood cells are stored for as long as 42 days prior to transfusion. Because prolonged storage induces red cell deterioration, the freshest units are often selected for transfusion of critically ill patients. However, the value of this practice is unclear.

To determine whether the duration of blood storage affects patient survival, investigators conducted a multicenter, randomized, blinded trial of 2430 patients admitted to an intensive care unit. Half of the patients received fresh red cells that were stored for a mean of 6.1 days (range, 1.2–11.0 days), and half received older red cells that were stored for a mean of 22.0 days (range, 13.6–30.4 days). Patients received a mean of 4.3 red cell units.

Ninety-day all-cause mortality (the primary outcome) was similar in the fresh-blood and older-blood groups (37.0% and 35.3%, respectively). Mortality was also similar between the two groups based on age; number of units transfused; APACHE II score; illness category; duration of respiratory, hemodynamic, or renal support; or length of hospital stay.

Comment
A previous trial showed that new blood was superior to old blood (NEJM JW Oncol Hematol May 2008 and N Engl J Med 2008; 358:1229), but that study differed from the current one in that the patients were undergoing heart surgery, they might not have been as anemic as those in the current trial (mean hemoglobin, 7.7 g/dL), and some of the units transfused might not have been leuko-reduced. The new study clearly shows that for patients admitted to an intensive care unit, fresh blood does not offer advantages over older blood.