Will Cochrane break through to the blood thirsty colleagues? The image is CC by Gaviota Paseandera.

I’ve previously written a two posts on blood transfusions from a surgeons perspective (End of the blood reign and A bloody mess) and I was therefore thrilled when I stumbled upon this [Cochrane review](https://www.ncbi.nlm.nih.gov/pubmed/27731885) that concludes:

The findings provide good evidence that transfusions with allogeneic RBCs can be avoided in most patients with haemoglobin thresholds above 7 g/dL to 8 g/dL.

They included 31 trials with a total of more than 12,000 patients and found that 30-day mortality wasn’t affected. They also didn’t find any difference regarding the incidence of complications. I was a little bummed that they didn’t find a reduced prevalence of infectious diseases with the more restrictive approach since blood is well-known to be a powerful [immune suppressor](https://www.ncbi.nlm.nih.gov/pubmed/12777903). I guess the fact that the restrictive approach reduced the transfusions by 2/5 should be enough for my colleagues to reconsider their previous beliefs.

[J. L. Carson et al., “Transfusion thresholds and other strategies for guiding allogeneic red blood cell transfusion,” Cochrane Database Syst Rev, vol. 10, p. CD002042, Oct. 2016.](http://onlinelibrary.wiley.com/doi/10.1002/14651858.CD002042.pub4/abstract;jsessionid=B28B2E04CE80F2F16BF40DDAAB811E3D.f03t01)