R. Amin1, S. Walker1, K. Somers1, M. Arca1 1Medical College Of Wisconsin,Milwaukee, WI, USA
Background: Our practice for ruptured appendicitis has evolved from administering intravenous (IV) and oral antibiotics for a predetermined number of days postoperatively, to only giving inpatient IV antibiotics until the following criteria is met: afebrile for 24 hours, tolerating oral diet, and pain control without IV medications. We aimed to determine whether the timing of preoperative antibiotics relative to incision, and duration of immediate postoperative antibiotics impact the development of surgical site infection (SSI).
Methods: We performed an IRB-approved single institution retrospective review of all patients with ruptured appendicitis based on a prospectively collected registry from January 1, 2013 until October 31, 2016. Univariate and multivariate analyses were performed with CI >95%.
Results: There were 406 patients; 62% were male. Median age was 10.3 years (IQR, 7.3, 13.2). The majority of our patients had an American Society of Anesthesiologists (ASA) classification of 1 or 2 (78.5%), while 21% were ASA 3, and 0.5% classified as ASA 4. Laparoscopic surgery was performed in 89.9% of cases, 5.7% of these cases were converted to open, and 4.4% were performed in an open fashion. Sixty-three patients (15.5%) developed SSI: 5 (1.2%) superficial, 2 (0.5%) deep, and 54 (13.3%) organ space. There were two wound dehiscence’s. There was no statistically significant difference in sex, age at operation, or ASA in terms of SSI development.
Pre-operative antibiotics: All patients received IV antibiotics at time of diagnosis, leading to an average interval of 96+90 minutes between preoperative antibiotic administration and incision. When comparing patients who received preoperative antibiotics <60 minutes or >60 minutes before incision, we found no statistical significance in SSI development (p=0.64).
Post-operative antibiotics: We grouped patients using the number of antibiotic days they received immediately following surgery. There was no difference in SSI based upon timing of the immediate postoperative antibiotic dose (p=0.707). Predictably, patients with SSI had longer median antibiotic treatment (9 days [IQR 5,13]) than those without (5 days [IQR 3,6], p<0.001).
Antibiotics and complications: Patients that developed SSI were grouped by the total number of postoperative antibiotic days received. The distribution was as follows: 1 day (n=10, 3 SSI), 2 days (n=31, 1 SSI), 3 days (n=62, 6 SSI), 4 days (n=76, 3 SSI), 5 days (n=74, 3 SSI) and >5 days (n=153, 47 SSI).
For each additional hour of case length, the odds of complication roughly double (OR= 2.08 [95% CI 1.27, 3.39], p=0.0034
Conclusion: Timing of preoperative antibiotics relative to incision did not affect SSI rates. Duration of immediate postoperative antibiotics does not affect SSI development, provided clinical criteria are used to guide antibiotic management. Longer operative time is associated with higher complications.