Use of oral contrast for CT scanning and time to diagnosis and treatment of acute appendicitis

Background: The aim of this study was to investigate whether there is a delay in treatment for patients having pre-operative CT imaging with both intravenous and oral contrast (CTIVO) compared to intravenous contrast alone (CTIV). Methods: A retrospective review of patients who underwent emergency appendicectomy at a single hospital during a two-year period (1/1/2019–31/12/2020) was performed. Demographic details, imaging timing/modality; biochemical markers; American Society of Anaesthesiologists (ASA) physical status classification, anaesthetic induction time; operative report findings; histopathology, peri-operative complications, admission/discharge times were recorded. The Sunshine Appendicitis Grading System (SAGS) score was used for severity of appendicitis. Results: Pre-operative CT was performed in 294 patients; CTIVO: 159 (54%), CTIV: 135 (46%). Both groups were comparable for age, sex, ASA status and inflammatory markers. The median time from CT request to scanning was longer with CTIVO (CTIVO: 170 min, CTIV: 65 min, P < 0.0001). The median time from CT request to induction of anaesthesia was also longer with CTIVO (CTIVO: 780 minutes, CTIV: 406 min, P < 0.0001). A delay to theatre was not significantly associated with severity of appendicitis (SAGS score). The diagnostic accuracy was not reduced in the CTIV group compared to the CTIVO group. Conclusion: CTIVO scans significantly delay CT diagnosis and surgical treatment of appendicitis compared to CTIV. Omitting oral contrast does not result in a reduction in diagnostic accuracy for appendicitis.