Transfusing fresh red blood cells might be dangerous

Trivella and colleagues present some caveats around the subject of duration of red cell storage and clinical outcomes.1 Studies have been widely interpreted as showing that transfusion is not associated with adverse clinical outcomes. I think this is a serious misinterpretation of the data.

In addition to the concerns raised by the authors, another valid hypothesis, which has received little attention, is that very short storage red cells might be more dangerous than medium storage periods (say 7-21 days) and equally dangerous as longer storage red cells (say 28-42 days). An inverted U shaped curve. The evidence for this comes from a meta-analysis finding that “ultra short” storage of red cells was associated with a post-transfusion increase in nosocomial infection.2 Shorter storage red cells have a greater imbalance of oxidation-reduction potential than longer storage red cells in preliminary studies in vitro.3 Red cell storage duration is also a poor predictor of post-transfusion free haemoglobin and heme, putative mediators of toxicity from transfusions.45

We need better metrics for predicting red cell transfusion efficacy and toxicity. The simple expedient of fresher red cells is clearly not that metric and might be leading us to transfuse more toxic red cells (very fresh) in the most fragile patients, such as premature newborns. A new approach is clearly called for by the current data. At our centre we define fresh as <21 days of storage, and we generally never transfuse a red cell that has been stored for much less than 7-10 days, for the above reasons as well as logistics of supply.