Appendicectomies performed >48 hours after admission to a dedicated acute general surgical unit.

INTRODUCTION: Acute general surgical units (AGSUs) are changing the way in which acute appendicitis is managed. In the AGSU at John Hunter Hospital, some patients wait more than 48 hours from admission to undergo an appendicectomy, usually because they are not unwell enough to precipitate an operation before that time. We analysed this subgroup of appendicectomy patients to determine how effectively they are being managed and how this might be improved.

METHODS: A retrospective review of prospectively collected data was conducted of all patients who received an appendicectomy while admitted under the AGSU at John Hunter Hospital in the five years between January 2009 and December 2013.

RESULTS: A total of 1,039 appendicectomies were performed in the study period, with 81 patients (7.8%) waiting >48 hours for their operation (delayed appendicectomy group). Overall, the negative appendicectomy (NA) rate was 21.6%; the NA rate in delayed appendicectomies was 50.62% and a non-therapeutic operation occurred in 47% of this group (n=38). No significant difference was found in the incidence of perforation/gangrenous appendicitis between patients having surgery in <48 hours and the delayed appendicectomy groups (11.2% vs 9.9%, p=0.85). A combination of negative diagnostic imaging result, a normal white cell count and normal C-reactive protein (ie a negative 'triple test') was the best predictor of a negative appendicectomy (p=0.0158, negative predictive value: 0.91, 95% confidence interval: 0.59-0.99), in the delayed appendicectomy group.

CONCLUSIONS: In the delayed appendicectomy group, the incidence of perforation/gangrenous appendicitis was not significantly different from that found in patients having appendicectomy performed sooner. However, the NA and non-therapeutic operation rates were unacceptably high. An appendix triple test can improve diagnostic accuracy significantly without an unacceptable rise in the rates of perforation/gangrenous appendicitis.