A surgical site infection (SSI) is an infection that occurs after a surgical procedure. Despite a variety of infection prevention strategies, SSIs still occur often and impose a significant burden on patients and the healthcare system. Intraoperative irrigation (or washing of the surgical incision before closure) may reduce SSIs, but this is uncertain.

The Clinical Evaluation of Adults Undergoing Elective Surgery Utilizing Intraoperative Incisional Wound Irrigation (CLEAN Wound) trial aims to determine if incisional wound irrigation with an antiseptic or salt water solution can reduce SSIs within 30 days of surgery compared to no wound irrigation. 2,500 patients aged 18 years or older who are planned to undergo an abdominal or groin open or laparoscopic procedure will be randomly assigned to incisional wound irrigation with povidone-iodine solution; or incisional wound irrigation with saline; or no irrigation and followed for 30 days after surgery to assess the incidence of SSIs, with additional outcomes collected up to 90 days after surgery.

Even with significant advances in medicine over the past decades, there are still many fundamental issues in perioperative care that remain unclear due to lack of evidence. If this trial were to demonstrate that intraoperative wound irrigation reduces the incidence of SSI, these practice-changing findings could greatly benefit patients worldwide.

Background/Rationale: Recent international guidelines and reviews have highlighted that studies of intraoperative irrigation were conducted in small samples over 30 years ago and no longer reflect the standard of care, judging the evidence to be of very low to moderate quality, and have called for additional RCTs. For example, as per the WHO Guidelines, RCTs are needed to assess frequently utilized irrigation solutions and their effect on SSI risk and state that a suitable alternative to povidone-iodine is currently unknown. Furthermore, determining whether irrigation with antiseptics and antibiotics can reduce SSIs was listed as a key research recommendation by NICE, in addition to determining cost-effectiveness of the intervention. Additional evidence is therefore required to support or refute the effectiveness of intraoperative irrigation in reducing SSIs and to address practice heterogeneity, with a focus on establishing whether irrigation is needed, and if so, which solution should be used.

Objectives: The primary objective is to determine if intraoperative incisional wound irrigation with povidone-iodine or saline in participants undergoing surgery can reduce incisional SSIs within 30 days of surgery compared to no irrigation. The secondary outcomes include: quality of life (QoL), proportion of participants prescribed systemic antibiotics, wound care received via home care services (all within 30 days of surgery); length of stay (LOS) during index hospitalization; wound dehiscence requiring reoperation, postoperative complications, mortality and healthcare utilization (all within 90 days of surgery), including: number of re-interventions (i.e. radiologically guided drain insertion or revision); number of all-cause reoperations; number of all-cause emergency department visits; number of all-cause family physician or walk-in clinic visits; and number of all-cause readmissions and length of stay of each readmission.

Study Design: This is a multicentre, pragmatic, participant and adjudicator-blinded, three-arm RCT. Participants will be randomized using an adaptive design to incisional wound irrigation with povidone-iodine versus incisional wound irrigation with saline versus no irrigation and will be followed until 30 days after surgery to assess the incidence of SSIs, with additional outcomes collected up to 90 days after surgery. The trial is adaptive, in that one of the arms may be discontinued as the trial progresses if it reaches a threshold for inferiority, and will be a continuation of our pilot trial (i.e., a vanguard design).

All participants must meet all of the following inclusion criteria to participate in this study:

1. Aged 18 years or older;

2. Ontario Health Insurance Plan (OHIP) holder (for Ontario sites)

   And planned to undergo any one of the following surgical procedures:

3. a) Laparotomy, CDC Class II (clean-contaminated) or III (contaminated) incision b) Laparoscopy with a planned extraction site ≥3 cm, CDC Class II (clean-contaminated) or III (contaminated) incision c) Groin incision for open or hybrid arterial procedure

All participants meeting any of the following exclusion criteria at baseline will be excluded from participation in this study:

1. Contraindication to receiving povidone-iodine irrigation (i.e., known allergy)
2. Any active skin or soft tissue infection (at any site, including gangrene)
3. Known or anticipated CDC Class IV (Dirty) incision