title: Erythrocyte storage duration is not associated with increased mortality in noncardiac surgical patients: a retrospective analysis of 6,994 patients.
abstract: BACKGROUND
  More than 5 million patients receive erythrocyte transfusions in the United States every year. Previous studies linked the storage duration of allogeneic erythrocytes to the risk of severe postoperative complications, especially after cardiac or trauma surgery. Limited data are available for noncardiac surgical patients. We therefore evaluated the association between storage duration of transfused erythrocytes and postoperative all-cause mortality among general surgery patients.
  
  
  METHODS
  Perioperative data corresponding to 63,319 adult, general surgery patients were obtained from our registry and merged with blood product data. Patients receiving solely leukocyte-reduced, allogeneic erythrocyte transfusions were included. Multivariable Cox proportional hazards regression was used to characterize the relationship between median erythrocyte storage duration and postoperative mortality rate, adjusting for characteristics plausibly influencing the storage duration of erythrocytes.
  
  
  RESULTS
  Of the 6,994 patients included in the final analysis, 23, 44, 11, 9, and 13% received 1, 2, 3, 4, and ≥5 erythrocyte units, respectively. The authors found no evidence that increasing median storage duration was associated with a difference in the risk of postoperative mortality (hazard ratio, 0.99 [0.94-1.04]; P = 0.64). Analyzing the mean storage duration of erythrocyte units as a function of year of transfusion, the authors demonstrate a relevant decrease in utilization of the oldest blood units, whereas young blood storage duration remains nearly unchanged.
  
  
  CONCLUSIONS
  The authors' study supports the recent literature in surgical and medical patients and underlines the importance of sufficiently powered randomized trials to finally resolve the erythrocyte storage duration debate.
authors.affiliation: Department of Outcomes Research, Pathology and Laboratory Medicine Institute, Cleveland Clinic, Cleveland, OH 44195, USA. saagerl@ccf.org
authors.forename: Leif
authors.initials: L
authors.lastname: Saager
authors.forename: Alparslan
authors.initials: A
authors.lastname: Turan
authors.forename: Jarrod E
authors.initials: JE
authors.lastname: Dalton
authors.forename: Priscilla I
authors.initials: PI
authors.lastname: Figueroa
authors.forename: Daniel I
authors.initials: DI
authors.lastname: Sessler
authors.forename: Andrea
authors.initials: A
authors.lastname: Kurz
mesh_terms: D000368:Aged; D001793:Blood Preservation / Q000379:methods* / Q000401:mortality; D001804:Blood Transfusion, Autologous / Q000401:mortality*; D002423:Cause of Death; D017707:Erythrocyte Transfusion / Q000379:methods / Q000401:mortality*; D004912:Erythrocytes; D005260:Female; D017052:Hospital Mortality; D006801:Humans; D053208:Kaplan-Meier Estimate; D008297:Male; D008875:Middle Aged; D011183:Postoperative Complications; D016016:Proportional Hazards Models; D012189:Retrospective Studies; D012307:Risk Factors; D013514:Surgical Procedures, Operative; D013997:Time Factors