E1940. Effect of the COVID-19 Pandemic on Emergency Department Utilization of CT Scans of Appendicitis and Diverticulitis
  1. Brandon Collins; Memorial University of Newfoundland
  2. Nicholas Fairbridge; Memorial University of Newfoundland
  3. Evan Lockyer; Memorial University of Newfoundland
  4. Andrew Robart; Memorial University of Newfoundland
  5. Tara Rector; Memorial University of Newfoundland
  6. Angus Hartery ; Memorial University of Newfoundland
To help mitigate the negative effects of COVID-19, many countries implemented curfews, lockdowns, and stay-at-home orders which subsequently decreased the daily total of positive cases. Multiple countries showed a reduced amount of emergency department (ED) visits during the pandemic. Retrospective observational studies demonstrated lower amounts of abdominal surgical emergency admissions with increased severity of their abdominal conditions. Therefore, these patients may have avoided the ED during lockdown, whereas prior to the pandemic they might have sought healthcare earlier in their disease's natural course. The purpose of our project was to investigate the effect of the COVID-19 lockdown (March–June 2020) on adult patient visits and ED ordering trends for abdominal CT scans for appendicitis and diverticulitis.

Materials and Methods:
A retrospective quantitative analysis gathered ED visits and Canadian Triage and Acuity Scale (CTAS) scores. Keyword search identified abdominal CT scans of patients ordered by the ED for all presentations of abdominal pain. Radiology reports were subsequently read and categorized into either 1) normal/other, 2) uncomplicated appendicitis or diverticulitis, or 3) complicated appendicitis or diverticulitis. An experienced staff radiologist determined whether pathology was complicated via the presence of abscess, (micro)perforation or obstruction. Data from 2018 - 2019 were used to generate expected patient volume for 2020 with regards to demographics, CTAS scores, ordered abdominal CT scans, positive CTs and complicated or uncomplicated status.

Chi-squared goodness of fit tested for deviations from predicted mean values for 2018 - 2019, as well the 95% CI boundaries to confirm all results remained valid despite uncertainty of estimates. Compared to the expected values based on 2018 - 2019, total daily ED visits from January - August 2020 showed a significant (p < 0.001) decrease in total patient volumes, from approximately 255/day in 2018 - 2019 to an average of 131/day in April 2020. This was independent of sex and age, showing equivalent range and variation as 2018 - 2019. During and following lockdown, approximately 20% more (p < 0.001) abdominal CT scans were ordered in the ED compared to 2018 - 2019, with no difference in CTAS scores of the patients who presented to the ED. Uncomplicated cases of appendicitis and diverticulitis increased (p < 0.03) throughout the pandemic, with no difference in complicated cases (p = 0.20).

During lockdown, significantly fewer patients presented to ED. The number of abdominal CT scans increased significantly, per person seen, without a change in CTAS scores. Considering that uncomplicated cases increased during the lockdown, ED physicians were warranted in increasing the amount of abdominal imaging as patients did not avoid the ED. Instead, patients who visited the ED attended in earlier stages of their pathology, whereas complicated cases were well managed and unchanged from prior years.