Age of transfused blood is not associated with increased postoperative adverse outcome after cardiac surgery.

BACKGROUND This study investigated the hypothesis that storage age of transfused red blood cells (RBCs) is associated with adverse outcome after cardiac surgery, and examined association between volume of RBC transfusions and outcome after cardiac surgery. METHODS Adult patients undergoing first time elective/urgent cardiac surgery who had received RBC transfusion perioperatively were included. Three prospective institutional databases were linked. Patients were grouped according to the oldest storage age of any RBCs transfused: those who received only RBCs stored for ≤14 days, only RBCs stored for >14 days, and a mixture of both ages of blood. The effect of RBC age on early mortality, postoperative ventilation ≥72 h, renal failure, pulmonary and infectious complications, length of intensive care stay, and postoperative ventilation time was examined using regression analyses with adjustment for confounding factors, including number of units transfused. RESULTS Data were analysed on 1153 patients who received a total of 5962 RBC units. There was no difference in adjusted odds of any outcome between the ≤14 days group and the group who received RBCs aged >14 days. Multivariate logistic regression analyses disclosed number of RBC units transfused as the most consistent factor associated with major postoperative complications, P<0.0001 in all cases. A trend of increasing complication rate was observed with more units transfused. CONCLUSIONS Storage age of RBC transfusion up to 35 days was not associated with increased postoperative adverse outcome after cardiac surgery. The number of RBC units transfused is consistently associated with adverse outcome.