Risk factors for surgical site infection after cardiac surgery in children

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

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.

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.

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.