title: Significance of positive mediastinal cultures in pediatric cardiovascular surgical procedure patients undergoing delayed sternal closure.
abstract: BACKGROUND
  Many pediatric cardiac surgery centers obtain mediastinal cultures at the time of delayed sternal closure (DSC). There are no recommendations regarding how to treat patients with positive cultures. We explored the clinical significance of positive mediastinal cultures with regard to surgical site infections (SSI).
  
  
  METHODS
  A retrospective study was performed on all patients who underwent DSC at our institution between December 2006 and December 2011. National Healthcare Safety Network criteria were used to prospectively identify SSIs. Univariate and multivariate logistic regression analyses were performed to evaluate potential risk factors for SSI and predictors for positive mediastinal cultures obtained at DSC.
  
  
  RESULTS
  A total of 178 patients underwent DSC during the study period; 155 patients met the eligibility criteria for the study and were included in the analysis. Of the 155 included patients, 11 patients (7.1%) experienced SSI. Patients with a positive mediastinal culture obtained at DSC were more likely to experience SSI than were patients with a negative culture (p=0.003). In univariate analysis, a positive mediastinal culture was the only factor associated with SSI (odds ratio [OR], 7.4; 95% confidence interval [CI], 2.1 to 26.7). In multivariate analysis, age at operation≥2 weeks (adjusted OR [aOR], 4.9; 95% CI, 1.84 to 12.8), receipt of stress-dosed hydrocortisone while the chest was open (aOR, 2.9; 95% CI, 1.1 to 7.6), and gestational age≤37 weeks (aOR, 2.7; 95% CI, 1.01 to 7.27) were independent predictors for a positive mediastinal culture.
  
  
  CONCLUSIONS
  Patients with positive mediastinal cultures obtained at DSC had a significantly higher rate of subsequent SSI, and a positive mediastinal culture was the only statistically significant predictor of SSI.
authors.affiliation: Seattle Children's Research Institute, Seattle, Washington.
authors.forename: Amanda L
authors.initials: AL
authors.lastname: Adler
authors.affiliation: Department of Infection Prevention, Seattle Children's Hospital, Seattle, Washington.
authors.forename: Julie
authors.initials: J
authors.lastname: Smith
authors.affiliation: Department of Surgery, University of Washington, Seattle, Washington; Seattle Children's Research Institute, Seattle, Washington.
authors.forename: Lester C
authors.initials: LC
authors.lastname: Permut
authors.affiliation: Department of Surgery, University of Washington, Seattle, Washington; Seattle Children's Research Institute, Seattle, Washington.
authors.forename: D Michael
authors.initials: DM
authors.lastname: McMullan
authors.affiliation: Department of Pediatrics, University of Washington, Seattle, Washington; Seattle Children's Research Institute, Seattle, Washington. Electronic address: danielle.zerr@seattlechildrens.org.
authors.forename: Danielle M
authors.initials: DM
authors.lastname: Zerr
mesh_terms: D006348:Cardiac Surgical Procedures / Q000379:methods*; D015331:Cohort Studies; D005260:Female; D006801:Humans; D007231:Infant, Newborn; D008297:Male; D008482:Mediastinum / Q000382:microbiology*; D011237:Predictive Value of Tests; D012189:Retrospective Studies; D013249:Sternum / Q000601:surgery*; D013530:Surgical Wound Infection / Q000453:epidemiology*; D013997:Time Factors