Risk factors of deep sternal wound infections in coronary artery bypass graft surgery

Abstract

Background: Major infections of sternal wounds after coronary artery bypass graft surgery (CABG) occur infrequently, but when they do, they contribute substantial morbidity and mortality. We identified significant risk factors of deep sternal wound infection (DSWI) following CABG and hoped to plan prophylactic measures for high risk patients in order to reduce the incidence of infection.

Methods: From 1996 to 1997, a total of 620 patients received CABG at a medical center in Taiwan. The surgical wound was examined every day. Wound infections were defined and classified according to Centers for Diseases Control (CDC) definitions. DSWI were defined as those involving the mediastinum, bone or cartilage, and infections beneath the subcutaneous tissue. Several risk factors were analyzed.

Results: We identified 17 (2.7%) DSWI. Univariate analysis indicated that ASA scores, surgical risk index, surgeon, postoperative low cardiac output, re-operation for bleeding, re-wiring of sternum, length of postoperative stay in the intensive care unit, postoperative duration of mechanical ventilation, operation time, duration of cardiopulmonary bypass. Independent predictors by multivariate logistic regression analysis were re-operation for bleeding and operation time. A total of 16 organisms were isolated among 14 patients. Staphylococcus accounted for most isolates (93.8%) and the most of them were methicillin-resistant (80%).

Conclusions: Re-operation for bleeding and operation time were the independent predictors.