Blood Transfusion in Heart Surgery Increases Infection Risk

The risk of postoperative infection appears to increase when patients receive red blood cell (RBC) transfusion during or after cardiac surgery.

Cardiac surgery is the largest consumer of blood products in medicine; although believed lifesaving, transfusion carries substantial adverse risks and greater attention to practices that limit red blood cell use could potentially reduce the occurrence of major postoperative infections.

In a study sponsored by the US National Institutes of Health (Bethesda, MD, USA) and the Canadian Institutes of Health Research (Ottawa, ON, Canada) 5,158 adult cardiac surgery patients were enrolled between February and September 2010 to examine the relationship between transfusion and risk of major infection following cardiac surgery. Patients had a mean age of 64 ± 13 years and preoperative hemoglobin of 13 ± 1.8 g/dL; 33% were women and 19% had undergone prior cardiac surgery.

Among the patients in the study, RBCs were transfused in 2,481 (48%), and platelets were transfused in 1,599 (31%). The highest volume of RBCs was given during transplant or left ventricular assist device implantation (84%) and thoracic aortic procedures (63%), while the lowest volumes were given for isolated coronary artery bypass grafting surgery (45%) and isolated valve surgery (40%).

Within 65 days following surgery, 235 patients (5%) were diagnosed with one or more major infections, the most common being pneumonia, Clostridium difficile colitis, a bacterial infection in the colon, and bloodstream infections. The authors found a dose-related association between the quantity of RBCs transfused and the unadjusted risk of infection, with a 29% increase in infection with each RBC unit transfused. Conversely, a lower risk of infection was observed when platelets were also transfused in conjunction with more than four units of RBCs.

Keith A. Horvath, MD, the senior author of the study, said, “A common problem for many surgeons, and thereby the patient, is how to balance the risk of surgery-induced anemia with the increased risk of infection when using red blood cell transfusion to correct the anemia. Through this study we hoped to shed light on the problem and to encourage hospitals and surgeons to examine cell-salvage techniques and other alternatives to RBC transfusion during and after cardiac surgery.” The study was published in the June 2013 edition of the Annals of Thoracic Surgery.

Related Links:

US National Institutes of Health

Canadian Institutes of Health Research