title: Mortality risk is dose-dependent on the number of packed red blood cell transfused after coronary artery bypass graft.
abstract: BACKGROUND
  Transfusions of one or more packed red blood cells is a widely strategy used in cardiac surgery, even after several evidences of increased morbidity and mortality. The world's blood shortage is also already evident.
  
  
  OBJECTIVE
  To assess whether the risk of mortality is dose-dependent on the number of packed red blood cells transfused after coronary artery bypass graft.
  
  
  METHODS
  Between June 2009 and July 2010, were analyzed 3010 patients: transfused and non-transfused. Transfused patients were divided into six groups according to the number of packed red blood cells received: one, two, three, four, five, six or more units, then we assess the mortality risk in each group after a year of coronary artery bypass graft. To calculate the odds ratio was used the multivariate logistic regression model.
  
  
  RESULTS
  The increasing number of allogeneic packed red blood cells transfused results in an increasing risk of mortality, highlighting a dose-dependent relation. The odds ratio values increase with the increased number of packed red blood cells transfused. The death's gross odds ratio was 1.42 (P=0.165), 1.94 (P=0.005), 4.17; 4.22, 8.70, 33.33 (P<0.001) and the adjusted death's odds ratio was 1.22 (P=0.43), 1.52 (P=0.08); 2.85; 2.86; 4.91 and 17.61 (P<0.001), as they received one, two, three, four, five, six or more packed red blood cells, respectively.
  
  
  CONCLUSIONS
  The mortality risk is directly proportional to the number of packed red blood cells transfused in coronary artery bypass graft. The greater the amount of allogeneic blood transfused the greater the risk of mortality. The current transfusion practice needs to be reevaluated.
authors.forename: Antônio Alceu dos
authors.initials: AA
authors.lastname: Santos
authors.forename: Alexandre Gonçalves
authors.initials: AG
authors.lastname: Sousa
authors.forename: Raquel Ferrari
authors.initials: RF
authors.lastname: Piotto
authors.forename: Juan Carlos Montano
authors.initials: JC
authors.lastname: Pedroso
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001026:Coronary Artery Bypass / Q000401:mortality*; D017707:Erythrocyte Transfusion / Q000706:statistics & numerical data*; D005260:Female; D006801:Humans; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D016017:Odds Ratio; D011183:Postoperative Complications; D011379:Prognosis; D011446:Prospective Studies; D012016:Reference Values; D018570:Risk Assessment; D012307:Risk Factors; D013997:Time Factors; D016896:Treatment Outcome