TRAUMA AND TRANSFUSION: Edited by Andrea U. SteinbickerOld, older, the oldest: red blood cell storage and the potential harm of using older red blood cell concentratesBaron, David M.a; Lei, Chongb; Berra, Lorenzoc Author Information aDepartment of Anaesthesia, Intensive Care Medicine and Pain Medicine, Medical University of Vienna, Vienna, Austria bDepartment of Anesthesiology and Perioperative Medicine, Xijing Hospital, Fourth Military Medical University, Xi’an, Shaanxi, China cDepartment of Anesthesia, Critical Care and Pain Medicine, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts, USA Correspondence to David M. Baron, Department of Anaesthesia, Intensive Care Medicine and Pain Medicine, Medical University of Vienna, Waehringer Guertel 18-20, 1090 Vienna, Austria. Tel: +43 1 40400 41000; fax: +43 1 40400 40280; e-mail: [email protected] Current Opinion in Anaesthesiology: April 2020 - Volume 33 - Issue 2 - p 234-239 doi: 10.1097/ACO.0000000000000824 Buy Metrics Abstract Purpose of review Over the last decades, clinical studies have suggested that transfusion of red blood cells (RBCs) might negatively impact patient outcomes. Even though large randomized clinical trials did not show differences in mortality when transfusing fresh versus standard-issue RBC units, data imply that RBCs at the very end of storage could elicit negative effects. Recent findings Certain alterations of RBCs during cold storage -- such as an increase of potassium and lactate in the storage solution -- have been discovered a century ago. In recent years, proteomic and metabolomic studies have shed more light into pathophysiological changes of RBCs during storage and have helped to specify the definition of old blood. These advancements are now utilized to increase the quality of stored RBCs and devise therapeutic strategies (e.g. nitric oxide, haptoglobin, or reduction of the iron load) when transfusing old blood. Summary Further research to improve the quality of RBC units and to study populations potentially at risk is warranted. Until the question whether transfusion of old blood is detrimental for specific patient populations has been answered, a deliberate use of RBC transfusion should be implemented. Copyright © 2020 Wolters Kluwer Health, Inc. All rights reserved.