Purpose or Case Report: A multi-disciplinary team of physicians developed a clinical practice guideline (CPG) in June
2010 to standardize the diagnosis and management of suspected appendicitis in pediatric patients (< 18 years) who
presented to a single institution’s emergency room. This study evaluated the utilization and efficacy of the CPG,
comprised of Pediatric Appendicitis Score (PAS) and staged ultrasound (US) and computed tomography (CT)
imaging, from 1/1/13-12/31/16. Using baseline data from the first year after implementation, we hypothesized that
increased US and PAS utilization would result in improved US performance and a concomitant decrease in CT
utilization without loss of diagnostic accuracy.
Methods & Materials: With IRB approval, a retrospective review of patients who had US for appendicitis was
performed using Epic and AGFA Impax 6.6.1.3525. Analysis of the utilization and efficacy of US, CT, and the staged
US/CT approach was conducted by determining the sensitivity, specificity, and positive and negative predictive values.
Results: 1,466 patient encounters, representing 1,390 different patients, met inclusion criteria. 1,466 US and 261 CT
scans were performed; 6 CTs with indications for other acute abdomen etiologies were excluded. 219 US were
interpreted as positive, 1,085 as negative, and 162 as equivocal for appendicitis (Table 1). Abdominal US had a
sensitivity, specificity, positive predictive value, and negative predictive value of 80.9%, 98.5%, 92.7%, and 95.5%
respectively. Abdominal CT had a sensitivity, specificity, positive predictive value, and negative predictive value of
98.4%, 98.9%, 96.9%, and 99.4% respectively. The staged US/CT algorithm had a sensitivity of 97.9%, specificity of
97.7%, positive predictive value of 91.3%, and negative predictive value of 99.5% (Table 2).
Conclusions: Experience and refinement of the appendicitis CPG led to improved US performance as sensitivity
increased from 63.9% to 80.9% and specificity from 92.6% to 98.5%. CT utilization decreased overall, with CT use in
only 17.4% of patient encounters; however, there was a trend of increasing CT use over time. Of the 316 with an
appendectomy, 24.1% had CT (previously 45.5%). An algorithm strength was continuous patient reevaluation by
clinicians. Thus, only 60.5% of equivocal scans did not have CT, avoiding 98 CT scans. However, despite a negative US, 174 patients
(16%) had a CT, only 32 of which proved to have appendicitis. 17 CTs were performed after a positive US, 15 of
which characterized suspected ruptured appendicitis.