Surgical wound infection surveillance: the importance of infections that develop after hospital discharge

The aim of this study was to evaluate two methods of post-discharge surgical wound surveillance and to compare the incidence and outcomes of wound infections that develop prior to patients' discharge with those that develop after hospital discharge.

One thousand, three hundred and sixty inpatients who underwent major elective surgery in an 800-bed teaching hospital in western Sydney between February 1996 and July 1997 were followed prospectively. Pre-discharge wound surveillance was performed by clinical assessment by an independent researcher on the fifth (or later) postoperative day. Post-discharge wound surveillance was performed by a mail out of questionnaires completed independently by patients and surgeons.

Overall, 138 wound infections were diagnosed (incidence 10.1%), of which fewer than one-third (n = 44) were diagnosed before discharge (average 10.4 days postoperatively) and the remainder (n = 94) after discharge (average 20.6 days postoperatively). Seven hundred and eighty-two (57.5%) post-discharge survey forms were returned by patients and 680 (50.0%) by surgeons. When forms were returned by both surgeons and patients for the same wound (641 cases), there was substantial agreement in diagnosing infection or no infection (kappa = 0.73).

The majority of nosocomial surgical wound infections develop after the patients' discharge from hospital. A post-discharge surveillance programme including self-reporting of infections by patients and return of questionnaires by patients and surgeons is feasible in an Australian hospital setting. However, such a programme is labour and resource intensive and strategies to increase return of questionnaires are required.