title: Emergency department blood transfusion: the first two units are free.
abstract: BACKGROUND
  Studies on blood product transfusions after trauma recommend targeting specific ratios to reduce mortality. Although crystalloid volumes as little as 1.5 L predict increased mortality after trauma, little data is available regarding the threshold of red blood cell (RBC) transfusion volume that predicts increased mortality.
  
  
  METHODS
  Data from a level I trauma center between January 2000 and December 2008 were reviewed. Trauma patients who received at least 100 mL RBC in the emergency department (ED) were included. Each unit of RBC was defined as 300 mL. Demographics, RBC transfusion volume, and mortality were analyzed in the nonelderly (<70 y) and elderly (≥70 y). Multivariate logistic regression was performed at various volume cutoffs to determine whether there was a threshold transfusion volume that independently predicted mortality.
  
  
  RESULTS
  A total of 560 patients received ≥100 mL RBC in the ED. Overall mortality was 24.3%, with 22.5% (104 deaths) in the nonelderly and 32.7% (32 deaths) in the elderly. Multivariate logistic regression demonstrated that RBC transfusion of ≥900 mL was associated with increased mortality in both the nonelderly (adjusted odds ratio 2.06, P = 0.008) and elderly (adjusted odds ratio 5.08, P = 0.006).
  
  
  CONCLUSIONS
  Although transfusion of greater than 2 units in the ED was an independent predictor of mortality, transfusion of 2 units or less was not. Interestingly, unlike crystalloid volume, stepwise increases in blood volume were not associated with stepwise increases in mortality. The underlying etiology for mortality discrepancies, such as transfusion ratios, hypothermia, or immunosuppression, needs to be better delineated.
authors.affiliation: Department of Surgery, Division of Trauma and Critical Care, Cedars-Sinai Medical Center, Los Angeles, California 90048, USA. Eric.Ley@cshs.org
authors.forename: Eric J
authors.initials: EJ
authors.lastname: Ley
authors.forename: Douglas Z
authors.initials: DZ
authors.lastname: Liou
authors.forename: Matthew B
authors.initials: MB
authors.lastname: Singer
authors.forename: James
authors.initials: J
authors.lastname: Mirocha
authors.forename: Nicolas
authors.initials: N
authors.lastname: Melo
authors.forename: Rex
authors.initials: R
authors.lastname: Chung
authors.forename: Marko
authors.initials: M
authors.lastname: Bukur
authors.forename: Ali
authors.initials: A
authors.lastname: Salim
mesh_terms: D000328:Adult; D017677:Age Distribution; D000368:Aged; D000369:Aged, 80 and over; D001810:Blood Volume; D000077324:Crystalloid Solutions; D004632:Emergency Medical Services / Q000706:statistics & numerical data; D017707:Erythrocyte Transfusion / Q000401:mortality* / Q000706:statistics & numerical data; D005260:Female; D006801:Humans; D007552:Isotonic Solutions / Q000008:administration & dosage; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D016017:Odds Ratio; D012189:Retrospective Studies; D012307:Risk Factors; D014193:Trauma Centers / Q000706:statistics & numerical data*; D014947:Wounds and Injuries / Q000401:mortality* / Q000628:therapy*; D055815:Young Adult
chemical_list: D000077324:Crystalloid Solutions; D007552:Isotonic Solutions
keywords: Blood transfusion; Mortality; Trauma