Risk factors for surgical wound infections in clean surgery: a multicenter study. Italian PRINOS Study Group

To investigate potential risk factors for surgical wound infections in clean surgery.

Multicenter prospective study in eight general surgical wards and one thoracic surgical ward.

All patients undergoing clean operations in the nine wards were included in the study. The following data were collected for each study participant: demographic characteristics, underlying disease, predisposing factors, type of surgery, length of operation, preoperative shaving, type and duration of surgical drains, and length of hospital stay. After surgery, patients were visited daily by an intern surgeon in order to detect infections. Infections occurring after discharge were not actively surveyed. A multiple logistic regression was performed to obtain an adjusted estimate of the odds ratios and to identify which factors were independently associated with surgical infection.

2,262 patients were included in the study: eighty three patients (3.7%) developed a surgical infection. The highest infection rates were observed following vascular surgery, thoracic surgery and herniorraphy. Seven factors appeared to be significantly and independently associated with an increased risk of SWIs in a logistic regression model; age greater than 85 years, obesity, patients undergoing high risk operations or more than one operation during stay, length of operation greater than 120, preoperative shaving, open surgical drains lasting more than three days.

The high incidence of infection observed in our study population indicates potential problems in quality of care. In order to prevent SWIs in patients undergoing clean operations, more efforts should be placed on the prevention of the risk associated with two modifiable risk factors, that is preoperative shaving and use of open surgical drains.