IMPPACT (Intravenous Monotherapy for Postoperative Perforated Appendicitis in Children Trial)

Background: Perforated appendicitis is the most common cause of intraabdominal abscess (IAA) in children. The optimal postoperative antibiotic regimen to reduce IAA has evolved in the last decade from triple-drug to 2-drug therapy (CM). Recent retrospective studies show decreased infectious complications with monotherapy PT. To date prospective comparative data are lacking. Therefore, a prospective randomized trial comparing PT versus CM was conducted. Methods: A multi-institutional prospective randomized trial was performed in children with perforated appendicitis comparing postoperative antibiotic regimens PT or CM. The primary outcome was 30-day postoperative IAA formation. Perforation was strictly defined as a hole in the appendix or fecalith in the abdomen, documented with intraoperative photographs. Results: One hundred sixty-two patients were enrolled during the study period. No differences in age, weight, or duration of presenting symptoms were identified. In addition, length of stay, duration of intravenous antibiotic treatment, discharge oral antibiotic treatment, and antibiotic-related complications did not differ between groups. Compared to the CM group, the PT group had significantly lower IAA rate [6.1% vs 23.8%, odd ratio (OR) 4.80, P = 0.002], lower postoperative computed tomography imaging rate (13.9% vs 29.3%, OR 2.57, P = 0.030), and fewer emergency room visits (8.8% vs 26.4%, OR 3.73, P = 0.022). Multivariate logistic regression analysis found the use of CM versus PT (OR 9.21, P = 0.021) to be the most significant predictor for developing IAA. Conclusions: In children with perforated appendicitis, postoperative monotherapy with PT is superior to standard 2-drug therapy with CM and does not increase antibiotic-related complications or antibiotic exposure duration.