The debate over old versus fresh blood is older than, well, the longest stored blood. At the session on RBC Storage Lesion: The End of the Beginning, James Zimring, MD, PhD; Jason Acker, MBA, PhD; and Harvey Klein, MD, dove headfirst into the controversy.
Zimring reviewed the history of blood transfusion, particularly recognition of the storage lesion when the field of metabolomics showed an inflection point between blood stored for 14 versus 21 days. Care of chronically transfused patients with sickle cell disease led to a better understanding of the relationship between storage age and iron increases as a function of storage time and iron toxicity in . This decades-long history leaves us with the knowledge that the storage lesion comprises thousands of changes and varies based on donor and storage system. However, research also shows that the freshest blood does not necessarily lead to better outcomes compared with longer-stored blood, and may, in fact, lead to worse outcomes in certain patient populations.
Acker discussed what we know so far about the quality of stored RBCs, including the fact that when it comes to stored blood, there is no universally agreed upon definition of “quality.” Putting that aside, there is agreement that the duration of storage affects the quality of RBC products. Other factors that affect outcome that haven’t been adequately addressed by research include manufacturing method, donor age and sex, and recipient characteristics. New technologies, such as photoacoustic microscopy, may help us better assess RBC product quality at the individual cell level.
Klein summarized findings from studies of RBC storage age and the clinical implications of transfusing fresher versus older stored RBCs in different patient populations, including cardiac patients, premature infants and critically ill adults. He discussed complete and ongoing studies addressing questions of whether RBCs stored longer are effective at increasing tissue oxygenation and if old blood is associated with more adverse events than fresher units.
The Age of Red Blood Cells in Premature Infants (ARIPI) study showed no differences in composite primary outcome, intraventricular hemorrhage, positive cultures and clinically suspected infections in 377 very low birthweight premature infants. Similarly, the Age of Transfused Blood in Critically Ill Adults (ABLE) study found no difference in outcomes between blood stored longer and fresher blood, nor did the Effects of Red-Cell Storage Duration on Patients Undergoing Cardiac Surgery (RECERSS) study, the Effects of Short-Term vs. Long-Term Blood Storage on Mortality after Transfusion (INFORM) study or numerous other studies. The overall conclusion from this research is that fresher blood is not superior to standard-issue blood in the clinical settings studied. However, many questions remain. Do stored RBCs optimally increase tissue oxygenation? Does the oldest stored blood — 35-42 days — cause adverse effects? What are the clinical effects of older blood in other clinical populations? For example, data from an experimental canine model suggests older RBCs may cause injury when they hemolyze and release iron, resulting in bacterial growth.
Klein believes that the age of stored blood may be a U-curve, with the oldest and newest blood being associated with worse outcomes. While the issue of storage age remains contentious, most everyone agrees that more research is needed.
— Jerilyn Schweitzer