Transfusion of red cells is associated with increased incidence of bacterial infection after colorectal surgery: a prospective study.

BACKGROUND

Several studies suggest that perioperative blood transfusion is a major independent risk factor for postoperative bacterial infections. Transfusion-induced immunosuppression is thought to mediate this effect.

STUDY DESIGN AND METHODS

In a randomized clinical trial comprising 697 patients with colorectal cancer, the relationship between two types of red cell components (buffy coat-depleted packed red cells and white cell-reduced [filtered] packed red cells) and postoperative bacterial infections was analyzed.

RESULTS

Both types of red cells appeared to be associated with a greater incidence of postoperative infection than was no transfusion (39 vs. 24%, p < 0.01). A dose-response relationship could be demonstrated: the corrected relative risk was 1.6 for 1 to 3 units of red cells and 3.6 for more than 3 units. Multivariate analyses identified the transfusion of red cells and tumor location as the only significant independent risk factors for postoperative bacterial infection.

CONCLUSION

Because allogeneic white cells, plasma, microaggregates, citrate, and platelets could be ruled out as risk factors for transfusion-associated postoperative infections, it is hypothesized that the transfusion of red cells is a potentially detrimental factor that transiently impairs the clearance of bacteria by phagocytic cells.