Risk factors for sternal wound infection in children undergoing cardiac surgery: a case-control study

Complex and prolonged cardiovascular operations are increasingly performed on young infants and children. The aims of this study were to define the incidence, causative bacterial pathogens and risk factors for sternal wound infections (SWIs) in infants and children undergoing cardiac surgery. The study group included all children who underwent cardiac surgery by median sternotomy at a tertiary paediatric centre from 1999 to 2003 and who were diagnosed with a postoperative SWI. Charts were reviewed for pre-, intra- and postoperative variables. The findings were compared with control patients operated on immediately before and after the cases and analysed by a stepwise logistic regression model. Of the 1821 children who underwent cardiac surgery, 49 (2.69%) had SWI; full data were available for 47. Twenty-nine (61.7%) had superficial wound infection and 18 (38.3%) deep wound infection. The main bacterial pathogens were Staphylococcus aureus in 14 patients (39%) and Pseudomonas aeruginosa in 12 (33%). Three variables emerged as significant independent risk factors for SWI: young age (odds ratio: 0.63; 95% confidence interval: 0.47-0.85; P<0.001 for each additional year), cyanotic heart disease (4.93; 1.98-12.3; P<0.001), and central venous catheter (CVC) dwell time (1.15; 1.06-1.24; P<0.001 for each additional day). Gram-negative infections were significantly associated with preoperative oxygen treatment (P=0.007) and prolonged urinary catheter dwell time (P=0.004). This study confirms younger age as risk factor for SWI and adds cyanotic heart disease and duration of CVC as new independent risk factors. Specific risks for Gram-negative infections are identified and should help to introduce new preventive strategies to decrease the incidence and severity of SWI.