Association of postoperative organ space infection after intraoperative irrigation in appendicitis

BACKGROUND The benefit of intraoperative irrigation on postoperative abscess rates compared to suction alone is unclear. The American Association for the Surgery of Trauma grading system provides distinct disease severity stratification to determine if prior analyses were biased by anatomic severity. We hypothesized that for increasing appendicitis severity, patients receiving (high, ≥2 L) intraoperative irrigation would have increased postoperative organ space infection (OSI) rate compared to (low, <2 L) irrigation. METHODS Single-institution review of adults (>18 years) undergoing appendectomy for appendicitis during 2010-2016. Demographics, operative details, irrigation volumes, duration of stay, and complications (Clavien-Dindo classification) were collected. American Association for the Surgery of Trauma grades were assigned by two independent reviewers based on operative findings. Summary, univariate, and area under the receiver operating curve analyses were performed. RESULTS Patients (n = 1187) were identified with a mean (SD) age of 41.6 (18.4) years (45% female). Operative approach included laparoscopy (n = 1122 [94.5%]), McBurney incision (n = 10 [0.8%]), midline laparotomy (n = 16 [1.3 %]), and laparoscopy converted to laparotomy (n = 39 [3.4%)]. The mean (SD) volume of intraoperative irrigation was 410 (1200) mL. Complication rate was 26.1%. Median volume of intraoperative irrigation in patients who developed postoperative OSI was 3 [0-4] compared to 0 [0-0] in those without infection (p < 0.0001). Area under the receiver operating curve analysis determined that 2 or more liters of irrigation was associated with postoperative OSI (c statistic: 0.83, 95% confidence interval, 0.76-0.89; p < 0.001). CONCLUSION Irrigation is used for increasingly severe appendicitis with wide variation. Irrigation volumes of 2 L or greater are associated with postoperative OSI. Improving standardization of irrigation volume (<2 L) may prevent morbidity associated with this high-volume disease. LEVEL OF EVIDENCE Therapeutic, level IV.