Blood Transfusions During Heart Surgery Increase Risk of Pneumonia

Patients who receive red blood cell transfusions during coronary artery bypass grafting (CABG) surgery are at an increased risk of developing pneumonia.

Pneumonia is a known risk following CABG surgery, and developing it has been shown to significantly increase a patient's risk of morbidity and mortality and previous studies have shown that one in every 20 CABG patients develop a major infection, with pneumonia being the most common type of infection.

Scientists at the University of Michigan Health System (Ann Arbor, MI, USA) examined data on 16,182 patients who underwent CABG surgery between 2011 and 2013 at any of the 33 hospitals participating in the Michigan Society of Thoracic and Cardiovascular Surgeons Quality Collaborative. Among participants in the study group, 6,451 (39.9%) received red blood cell transfusions and 576 (3.6%) developed pneumonia.

The scientists found a significant association between red blood cell transfusion and the occurrence of pneumonia. They also found that the risk of developing pneumonia increased with the volume of red blood cells transfused. Results showed that patients receiving one or two units of red blood cells had double the odds of developing pneumonia compared to patients not receiving transfusion, while those who received six units or more of red blood cells had 14-fold increased odds of developing pneumonia. The dose-dependent relationship was consistent across clinical subgroups and was not affected by other blood products, such as platelets.

James R. Edgerton, MD, from The Heart Hospital, Baylor (Plano, TX, USA) who was not affiliated with the study, said, “The ability to store and transfuse blood is one of medicine's greatest accomplishments, but we are continuing to see that receiving a blood transfusion may alter a patient's ability to fight infection. In the University of Michigan study, the investigators have identified an increased risk of pneumonia after transfusion, which is an important breakthrough because it allows physicians to remain vigilant for the onset of pneumonia and initiate therapy early in hopes of shortening its course and severity. It also enables physicians to initiate preventive therapies in patients who have been transfused, which will contribute to better care of our patients.” The study was presented at the 51st Annual Meeting of The Society of Thoracic Surgeons, held January 24–28, 2015, in San Diego, CA, USA).

Related Links:
University of Michigan Health System
The Heart Hospital, Baylor