IntroductionTransfusions 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. ObjectiveTo assess whether the risk of mortality is dose-de>pendent on the number of
packed red blood cells transfused after coronary artery bypass graft. MethodsBetween 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. ResultsThe 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. ConclusionThe 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.