Alexander P (2016), Blood (Link to abstract)
This meta-analysis looked at 12 trials that enrolled 5229 participants, 6 compared fresher RBCs with older RBCs and 6 compared fresher RBCs with the local standard practice. All of the studies were deemed to be of good quality with low risk of bias. There appeared to be low or no effect of the age of RBCs on mortality. Interestingly, fresher RBC seemed to be associated with higher rate of nosocomial infections. Although the definitions of “new” or “old” blood were varied, the statistical heterogeneity between the studies was low.
* There is no rationale to favor fresher RBCs over older ones in terms of mortality. The increased risk of nosocomial infections with fresher RBCs is surprising and should be further analyzed. This well designed and executed trial may finally end the debate around using fresh RBCs.