Risk factors for deep sternal wound infection after cardiac surgery: Influence of red blood cell transfusions and chronic infection

- Case-control study of DSWI over 3 year period in a contemporary cardiac surgery service, including a period of increased incidence.
- Corroborates the role of red blood transfusions as a risk factor for DSWI, with an interaction with preoperative anemia.
- Novel finding of chronic infections (defined as HIV, HBV, HCV, or bacterial infection ≥ 4 weeks, on antibiotics at surgery) as a risk factor for DSWI.
- Antibiotic prophylaxis chosen did not cover organisms found in 77% of DSWIs.

BackgroundDeep sternal wound infection (DSWI) following cardiac surgery is a serious complication, but risk factors associated with DSWI have not been fully elucidated.MethodsWe analyzed all DSWI cases at our institution from 2010-2013 in adult cardiac median sternotomy cases, based on Society of Thoracic Surgeons or National Healthcare Safety Network definitions, but with 1-year surveillance postsurgery. Controls were matched 3:1 per case for procedure, age, and year of surgery. Demographic and operative data were pulled from Society of Thoracic Surgeons database and chart review. Potential variables were evaluated using univariate and multivariate conditional logistic regression.ResultsOut of 1,894 surgeries performed, 39 DSWI cases (2%) and 117 controls were identified. In univariate analyses, patients with red blood cell (RBC) transfusion ≥ 4 units, any platelet transfusion, previous infections, and chronic infections were associated with higher DSWI. RBC transfusion ≥ 4 units (P = .037) and chronic infections (P = .029) remained significant risk factors for DSWI in multivariate analysis. Preoperative anemia alone was not associated with more DSWI, but its interaction with RBC transfusion ≥ 4 units was significant.ConclusionsHigh-volume RBC transfusions and chronic infections were strongly associated with DSWI in our population and represent potentially modifiable areas for improvement.