281 Evaluating a Diagnostic Algorithm for Adult Appendicitis – A Quality Improvement Project

Diagnosing appendicitis remains challenging, despite being the most common surgical emergency. We conducted a single-centre mixed method quality improvement project to assess the validity of a diagnostic algorithm for appendicitis and the diagnostic impact of increasing cross-sectional imaging during the Covid-19 pandemic. Method Adult histology reports and preoperative imaging data were retrospectively retrieved for patients operated on between 1/7/19-31/12/19 (‘baseline data’) and an appendicitis diagnostic algorithm was developed. Imaging and risk stratification data were prospectively collected, as part of a national audit, between 20/03/30-23/6/20 for all adult appendicitis patients. This data was used to evaluate the efficacy of the proposed diagnostic algorithm. Use of imaging and histological diagnoses was compared between datasets. Results 194 patients were included across both time periods. The rate of cross-sectional imaging increased from 36.6% to 76% and the normal appendicectomy rate (NAR) decreased from 5.22% to 2.4%. Thirty-six percent of patients in the latter time period were not managed in accordance with the proposed algorithm. The proposed diagnostic algorithm may have prevented up to 87.5% of normal appendicectomies across both time periods. Conclusions Increasing cross-sectional imaging was associated with a decrease in the NAR. The use of the proposed diagnostic algorithm may have reduced the NAR further.