30 Prophylaxis of incisional surgical site infection with antibiotic lavage of the surgical wound. A prospective double-blind randomised multicentre study

Abstract Objective Surgical site infection (SSI) is the most common complication of surgery. Prevention of incisional SSI (I-SSI) by topical prophylaxis is controversial. Human studies on topical antibiotic wound lavage are old and inconclusive. Current meta-analyses and WHO recommendations do not recommend it. The aim of the study was to evaluate the efficacy of wound irrigation with an antibiotic solution on the rate of I-SSI. Methods Prospective, multicentric, randomised, double-blind clinical trial to compare irrigation of surgical incisions with amoxicillin-clavulanate solution (ATB-Group) with saline lavage (Saline-Group). The study was conducted in three types of surgery according to their risk of SSI: clean surgery (abdominal hernia repair), and clean-contaminated (caesarean sections and colorectal surgery). The primary endpoint was the incidence of I-SSI within 30 days of surgery according to CDC criteria. Secondary endpoints were: length of stay (LOS), 30-day reoperation rate, 30-day wound complication rate (other than SSI), 30-day mortality rate, microbiology of infections, 30-day adverse event or complication rate. Surgical complications were categorised according to the Clavien-Dindo classification. The severity of wound infection was assessed according to the ASEPSIS score. Results The trial included 685 patients (200 hernia repairs, 218 caesarean sections and 272 elective colorectal procedures), 351 in the ATB-Group and 334 in the Saline-Group. Both groups were comparable in age, sex, BMI, comorbidities, ASA score, and operative time. The overall rate of SSI for the entire cohort was 5.9%, being 2.5% in the Saline-group and 3.4% in the ATB-group, P = 0.51. No differences were detected when SSI was subdivided by surgical site level. There were also no differences in secondary outcomes such as: time to onset of SSI, postoperative complications, other infectious complications or microbiology of the infecting flora. LOS was 3.8 days in both groups. Mortality was 0.4% in the ATB-Group and 0.3% in the Saline-Group. Analysis of primary or secondary endpoints by subgroups of type of surgery also showed no differences between the two study groups. Conclusions Wound irrigation with antibiotic solution was not superior to saline lavage for I-SSI prophylaxis in clean and clean-contaminated surgery. Probably, the low rate of SSI obtained in the two arms of this study did not allow to find differences between the two study groups. The study was registered with ClinicalTrials.gov (NCT04476212), was authorised by the Spanish Medicine Agency (EUDRA CT:2017-002669-23), and received grant PI19/01294 for Health Research Projects from the Ministry of Science, Innovation and Universities of Spain.