Surveillance of Surgical Site Infections Post Cholecystectomy in Norway: An Example of Surveillance Tool Use for Research and Information

Background: The Norwegian Institute of Public Health has run a surveillance system (NOIS) on surgical site infections (SSIs) since 2005. It is mandatory that hospitals in Norway participate, reporting at least one type of surgery for three months each year. Over 3500 cholecystectomies are performed each year in Norway. However, little is known about factors influencing the likelihood of SSIs in these patients. 

Objective: 1) To use the NOIS surveillance tool to examine SSI infections post cholecystectomy in Norwegian hospitals. 2) Develop and provide reports at the national, hospital and departmental level of immediate use to health practitioners.

Methods: Data were obtained and analysed from NOIS. Discussions were held with reference groups as to how to make best use of resulting data with relevance to the prevention of SSIs and encouraging increased participation in surveillance of SSIs.

Results: We have data from 17 different hospitals. All but three performed both laparoscopic (LC): 90% and open cholecystectomies (OC): 10%. We achieved full follow-up data (30 days post surgery) in 92% of cases. The incidence of SSI was 7% after LC and 11% after OC. Over 80% of SSI infections following LC were classed as superficial. We found that NNIS risk stratification (LC mean scores SSI:-0.6  vs no SSI:-0.7), age or gender did not predict the probability of SSI. Antibiotic prophylaxis was given in 23% of cases with large inter-hospital variation. Whilst the mean length of stay post LC was 3 days, the mean days to infection was 15.  Furthermore, the mean length of stay was not statistically different between those that developed a SSI and those that did not.
We have developed reports that can be useful at the three different levels mentioned above. They are based on the easy generation of reports appropriate to the user. Our work has revealed that the wished-for final product is different for the different types of health practioner. We present examples of various reports with a discussion of their uses.

Conclusions: 1) The incidences of SSI following cholecystectomy in Norway are in line with international results. Although those undergoing open surgery had a greater risk of SSI, the Risk score based on the NNIS risk criteria, age and gender were poor predictors of the likelihood of SSI. There is a need for further consensus as to antibiotic use in cholecystectomy in Norway. Lastly, most of the infections were superficial and found post hospital discharge emphasising the need for active follow-up. 2)We have found that surgeons are generally interested in their departments year on year performance and how this compares with the national average. However information must be specific to their work and not at the level of a hospital for it to be of use and encourage participation. Infection control teams require more general results to target specific groups and ensure adequate post-op monitoring.