Are nosocomial infection rates in intensive care units useful benchmark parameters?

Background: The objectives of this study were to determine to what extent t he German national nosocomial infection surveillance system (Krankenhaus In fektions Surveillance System, KISS) can take into account the circumstances prevailing in various intensive care units (ICUs) and to establish whether KISS-ICU infection rates can serve as useful benchmark parameters. Methods: The investigation focused on th ree major factors: microbiological monitoring, severity of illness and the duration of surveillance, For each of these factors separate infection rates were calculated for various ICU groups and the differences compared. Results: Significant differences were found for catheter-associated urinary tract infections (CAUTI) with routine monitoring, but not for ventilator-a ssociated pneumonia (VAP). Significant differences were assessed for centra l venous catheter-associated bloodstream infections (CVCBSI), considering t he average ventilator utilization rate in the ICU as a surrogate parameter for the average severity of illness in its patient group. Surveillance peri ods of about 1 year were necessary to confirm definite outlier and nonoutli er positions for the majority of the ICUs. Conclusion: Using KISS data for internal orientation, it is possible to not e important differences between ICUs when interpreting infection rates; som e initial examples of successful use of surveillance data for the reduction of infection rates are already available. However, the use of such data fo r external assessment is not possible, because external observers a re ofte n unable to fully consider important factors in the interpretation of infec tion rates.