Timing and incidence of postoperative infections associated with blood transfusion: analysis of 1,489 orthopedic and cardiac surgery patients.

Background: Transfusion rates remain high in cardiac and orthopedic surgery and differ widely across physician practices in spite of growing knowledge that allogeneic blood transfusion (ABT) is associated with a risk of postoperative infection.

Methods: This prospective observational study compared the timing and incidence of ABT-associated postoperative infections (PIs) in 1,489 orthopedic or cardiac surgery patients at nine hospitals.

Results: Of 455 cardiovascular and 1,034 orthopedic surgery patients, 415 (55.6% of the cardiovascular patients and 15.7% of the orthopedic patients) were given ABT. The overall rate of PI during hospitalization was 5.8%. The relative risk of PI was 3.6-fold greater after ABT (50 patients; 12.1%) than in patients not having ABT (36 patients; 3.4%; 95% confidence interval 2.4, 5.4; p = 0.001). Postoperative infections appeared both during hospitalization (n = 86) and within four weeks after discharge (n = 81).

Conclusions: Patients should be followed for as long as four weeks after discharge to determine the true incidence and risk of ABT-associated PI.