Risk Factors for Surgical Site Infection After Cardiac Surgery in Children

Background: We sought to identify risk factors for surgical site infections (SSI) in children undergoing cardiac surgery.

Methods: A matched case-control study was conducted in the Children's Hospital Boston Cardiovascular Program. Surgical site infections were identified for 3 years (2004 to 2006). We identified two randomly selected control patients who underwent cardiac surgery within 7 days of each index case. Univariate and multivariate conditional logistic regression analyses were used to identify risk factors for SSI. In a secondary analysis, risk factors for organ space SSI (mediastinitis) were sought. Secondary analyses were also conducted using only those variables known preoperatively.

Results: Seventy-two SSI and 144 controls were included. Independent risk factors for any type of SSI were age younger than 1 year (adjusted odds ratio, 2.28; 95% confidence interval, 1.18 to 4.39) and duration of cardiopulmonary bypass greater than 105 minutes (adjusted odds ratio, 1.92; 95% confidence interval, 1.02 to 3.62). Independent risk factors for organ space SSI were aortic cross-clamp time greater than 85 minutes (adjusted odds ratio, 5.61; 95% confidence interval, 1.06 to 29.67) and postoperative exposure to at least three separate red blood cell transfusions (adjusted odds ratio, 7.87; 95% confidence interval, 1.63 to 37.92). When only those potential risk factors known preoperatively were considered, age younger than 1 year independently predicted the subsequent development of any type of SSI, and preoperative hospitalization independently predicted the subsequent development of organ space SSI.

Conclusions: Younger patients undergoing longer surgical procedures and those requiring more postoperative blood transfusions are at greatest risk for SSI. Additional preventive strategies, including restrictive blood transfusion policies, warrant further investigation.