title: Length of storage of transfused red cells and postoperative morbidity in patients undergoing coronary artery bypass graft surgery.
abstract: BACKGROUND
  The transfusion of old red cells (RBCs) may be associated with reduced delivery of oxygen to tissues and an increased risk of transfusion complications. The association of postoperative morbidity with the length of storage of perioperatively transfused RBCs was studied in 268 consecutive patients receiving a blood transfusion for coronary artery bypass graft surgery.
  
  
  METHODS
  The postoperative length of hospitalization, the postoperative length of stay in the intensive care unit, and the length of endotracheal intubation after the day of the operation were used as surrogate measures of global postoperative morbidity. The length of storage of the oldest transfused RBC unit, the mean length of storage of the oldest and second oldest RBC units, and the mean length of storage of all RBC units transfused to each patient were tested for association with the three outcome variables. Multiple linear regression analysis and Cox proportional-hazard analysis were used to adjust for the effects of confounding factors that pertained to each patient's severity of illness and the difficulty of each operation.
  
  
  RESULTS
  There were no significant associations after adjustment for the effects of confounding factors.
  
  
  CONCLUSIONS
  This study did not corroborate the previously reported association between transfusion of old RBCs and increased morbidity. However, there is surprisingly little research on the clinical outcomes of the transfusions of old RBCs, and this hypothesis should be investigated further.
authors.affiliation: Blood Transfusion Service, Massachusetts General Hospital, and the Department of Pathology, Harvard Medical School, Boston, Massachusetts, USA. Stephen.Vamvakas@med.nyu.edu
authors.forename: E C
authors.initials: EC
authors.lastname: Vamvakas
authors.forename: J H
authors.initials: JH
authors.lastname: Carven
mesh_terms: D001793:Blood Preservation; D001026:Coronary Artery Bypass; D017707:Erythrocyte Transfusion; D004912:Erythrocytes; D006801:Humans; D007362:Intensive Care Units; D007442:Intubation, Intratracheal; D007902:Length of Stay; D011182:Postoperative Care; D013997:Time Factors