Effect of an imaging protocol on clinical outcomes among pediatric patients with appendicitis.

Objective: In 1998, we implemented a clinical imaging protocol in which children with suspected appendicitis underwent ultrasonography (US) followed by computed tomography (CT). We sought to determine the impact of the US-CT protocol on changes in perforation and negative appendectomy rates.
Methods: Children with unequivocal presentations for appendicitis went to the operating room without entering the imaging protocol. Using a modified time series design, we analyzed a prospective and retrospective cohort of consecutive patients who were admitted from the emergency department for suspected appendicitis. The perforation and negative appendectomy rates were computed for the periods before and after implementation of the imaging protocol and adjustment for time trends was made.
Results: A total of 1338 children were identified. Eight hundred ten (60.5%) children had equivocal clinical findings. A total of 920 patients were admitted for suspected appendicitis before the protocol was implemented; 526 (57.2%) of the 920 children had appendicitis, and 186 (35.4%) of them had perforation. A total of 91 (14.7%) of 617 had negative appendectomies. After the protocol was implemented, 418 patients were admitted for suspected appendicitis; 328 (78.5%) had appendicitis with 51 (15.5%) perforated. There were 14 (4.1%) of 342 cases of negative appendectomies. After implementation of the imaging protocol, the perforation rate decreased from 35.4% to 15.5%, and the negative appendectomy rate decreased from 14.7% to 4.1%. After secular time trends were adjusted for, the imaging protocol continued to have a strong association with a reduction in perforation rate and negative appendectomy rate.
Conclusion: The implementation of an imaging protocol using US and CT resulted in a marked decrease in the perforation and negative appendectomy rates in children with suspected appendicitis.