Surgical site infection reporting: more than meets the agar.

BACKGROUND/PURPOSE: Surgical site infection (SSI) rate in pediatric appendicitis is a commonly used hospital quality metric. We hypothesized that surveillance of organ-space SSI (OSI) using cultures alone would fail to capture many clinically-important events. METHODS: A prospective, multidisciplinary surveillance program recorded 30-day SSI and hospital length of stay (LOS) for patients <18years undergoing appendectomy for perforated appendicitis from 2012 to 2015. Standardized treatment pathways were utilized, and OSI was identified by imaging and/or bacterial cultures. RESULTS: Four hundred ten appendectomies for perforated appendicitis were performed, and a total of 84 OSIs (20.5%) were diagnosed with imaging. Positive cultures were obtained for 39 (46%) OSIs, whereas 45 (54%) had imaging only. Compared to the mean LOS for patients without OSI (5.2±2.9days), LOS for patients with OSI and positive cultures (13.7±5.4days) or with OSI without cultures (10.4±3.7days) was significantly longer (both p<0.001). The OSI rate identified by positive cultures alone was 9.5%, whereas the clinically-relevant OSI rate was 20.5%. CONCLUSIONS: Using positive cultures alone to capture OSI would have identified less than half of clinically-important infections. Utilizing clinically-relevant SSI is an appropriate metric for comparing hospital quality but requires agreed upon standards for diagnosis and reporting. LEVEL OF EVIDENCE: II. TYPE OF STUDY: Diagnostic study.