Surveillance of wound infections and a new theatre: unexpected lack of improvement.

In a new hospital, an operating theatre was designed, according to the best principles of infection control. An infection control nurse compared postoperative wound infection (PWI) rates before and after moving to the new site. PWI rates in clean general surgery were 28/1909 (1.5%) and 35/ 1891 (1.9%) before and after moving; in clean orthopaedic surgery they were 10/861 (1.2%) and 13/826 (1.6%). In patients undergoing joint replacement, followed up for one year, deep infections occurred in one out of 223 (0.4%) protheses in the old hospital and in one out of 252 (0.4%) in the new. These differences were not significant. We discuss whether the effects of the improvements were either too small (sterilization, clean-airflow) or insufficiently substantiated to be detectable in the period available. Such measures were directed against exogenous infections, which are rare compared with endogenous infections and have little influence on PWI-rates. Careful analysis of the results of existing surveillance data before designing new operating theatres are recommended.