Aqueous Povidone-Iodine Versus Normal Saline for Intraoperative Wound Irrigation on the Incidence of Surgical Site Infection in Clean-Contaminated Wounds after Gastroenterological Surgery: A Single-Institute, Prospective, Blinded-Endpoint, Randomized Controlled Trial

Objective: This trial evaluated the superiority of intraoperative wound irrigation (IOWI) with aqueous povidone-iodine (PVP-I) compared with that with saline for reducing the incidence of surgical site infection (SSI). Background: IOWI with aqueous PVP-I is recommended for the prevention of SSI by the World Health Organization and the Centers for Disease Control and Prevention, although the evidence level is low. Methods: This single institute in Japan, prospective, randomized, blinded-endpoint trial was conducted to assess the superiority of IOWI with aqueous PVP-I in comparison with IOWI with saline for reducing the incidence of SSI in clean-contaminated wounds after gastroenterological surgery. Patients 20 years or older were assessed for eligibility, and the eligible participants were randomized at a 1:1 ratio using a computer-generated block randomization. In the study group, IOWI was performed for 1 minute with 40 mL of aqueous 10% PVP-I before skin closure. In the control group, the procedure was performed with 100 mL of saline. Participants, assessors, and analysts were masked to the treatment allocation. The primary outcome was the incidence of incisional SSI in the intention-to-treat set. Results: Between June 2019 and March 2022, 941 patients were randomized to the study group (473 patients) or the control group (468 patients). The incidence of incisional SSI was 7.6% in the study group and 5.1% in the control group (risk difference 0.025, 95% CI -0.006 to 0.056; risk ratio 1.484, 95% CI 0.9 to 2.448; P=0.154). Conclusion: The current recommendation of IOWI with aqueous PVP-I should be reconsidered.