Allogenic blood transfusion does not predispose to infection after cardiac surgery

Background Many retrospective studies report increased postoperative infection after allogenic blood transfusion. To investigate this phenomenon, we prospectively studied 232 patients undergoing cardiac surgery. Methods Patients were screened daily for evidence of culture positive infections. Wounds were examined daily and defined on the ASEPSIS score. Chest radiographs and white cell counts and differentials were recorded on days 1, 2, and 4. The use of blood products was monitored blindly and independently. Patients were grouped according to transfusion status and compared using χ² or Fisher's test. Logistic regression analyses were performed to identify predictors of transfusion and infection. Results Of 232 patients, 116 (50%) received blood product transfusion. Patients receiving blood had lower preoperative hemoglobin, were older, with a greater proportion of urgent/emergency or revision surgery, and were higher risk. Despite this, there were no differences in the frequency of chest infection (20% versus 15%, p = 0.38), urinary infection (3.5% versus 5.3%, p = 0 0.75), wound infection (3.5% versus 8.0%, p = 0.16), or overall infection (28% versus 30%, p = 0.89) comparing the transfused versus untransfused groups. There was no evidence to suggest that administration of blood products was associated with infection (odds ratio 0.92, p = 0.77). Conclusions The administration of blood per se did not lead to increased postoperative infection. Clinicians should reconsider withholding blood transfusion in patients solely owing to concerns of predisposition to infection.