title: Fresh blood and aged stored blood are equally efficacious in immediately reversing anemia-induced brain oxygenation deficits in humans.
abstract: BACKGROUND
  Erythrocytes are transfused to treat or prevent imminent inadequate tissue oxygenation. 2,3-diphosphoglycerate concentration decreases and oxygen affinity of hemoglobin increases (P50 decreases) with blood storage, leading some to propose that erythrocytes stored for 14 or more days do not release sufficient oxygen to make their transfusion efficacious. The authors tested the hypothesis that erythrocytes stored for 3 weeks are as effective in supplying oxygen to human tissues as are erythrocytes stored for less than 5 h.
  
  
  METHODS
  Nine healthy volunteers donated 2 units of blood more than 3 weeks before they were tested with a standard, computerized neuropsychological test (digit-symbol substitution test [DSST]) on 2 days, 1 week apart, before and after acute isovolemic reduction of their hemoglobin concentration to 7.4 and 5.5 g/dl. Volunteers randomly received autologous erythrocytes stored for either less than 5 h ("fresh") or 3 weeks ("stored") to return their hemoglobin concentration to 7.5 g/dl (double blinded). Erythrocytes of the alternate storage duration were transfused on the second experimental day. The DSST was repeated after transfusion.
  
  
  RESULTS
  Acute anemia slowed DSST performance equivalently in both groups. Transfusion of stored erythrocytes with decreased P50 reversed the altered DSST (P < 0.001) to a time that did not differ from that at 7.4 g/dl hemoglobin during production of acute anemia (P = 0.88). The erythrocyte transfusion-induced DSST improvement did not differ between groups (P = 0.96).
  
  
  CONCLUSIONS
  Erythrocytes stored for 3 weeks are as efficacious as are erythrocytes stored for 3.5 h in reversing the neurocognitive deficit of acute anemia. Requiring fresh rather than stored erythrocytes for augmentation of oxygen delivery does not seem warranted.
authors.affiliation: Department of Anesthesia and Cardiovascular Research Institute, University of California, San Francisco, USA. rwes@novonordisk.com
authors.forename: Richard B
authors.initials: RB
authors.lastname: Weiskopf
authors.forename: John
authors.initials: J
authors.lastname: Feiner
authors.forename: Harriet
authors.initials: H
authors.lastname: Hopf
authors.forename: Jeremy
authors.initials: J
authors.lastname: Lieberman
authors.forename: Heather E
authors.initials: HE
authors.lastname: Finlay
authors.forename: Cheng
authors.initials: C
authors.lastname: Quah
authors.forename: Joel H
authors.initials: JH
authors.lastname: Kramer
authors.forename: Alan
authors.initials: A
authors.lastname: Bostrom
authors.forename: Pearl
authors.initials: P
authors.lastname: Toy
mesh_terms: D019794:2,3-Diphosphoglycerate / Q000097:blood; D000328:Adult; D000740:Anemia / Q000097:blood* / Q000523:psychology / Q000628:therapy*; D001793:Blood Preservation; D001810:Blood Volume; D001923:Brain Chemistry / Q000502:physiology*; D003071:Cognition / Q000502:physiology; D004912:Erythrocytes / Q000502:physiology; D005260:Female; D006339:Heart Rate / Q000502:physiology; D006438:Hemodilution; D006454:Hemoglobins / Q000378:metabolism; D006801:Humans; D008297:Male; D010100:Oxygen / Q000097:blood*; D010101:Oxygen Consumption / Q000502:physiology*; D011597:Psychomotor Performance / Q000502:physiology; D013997:Time Factors; D016896:Treatment Outcome
chemical_list: D006454:Hemoglobins; D019794:2,3-Diphosphoglycerate; D010100:Oxygen