Alcoholic versus aqueous chlorhexidine for skin antisepsis: the AVALANCHE trial.

BACKGROUND: Preoperative skin antisepsis is routine practice. We compared alcoholic chlorhexidine with aqueous chlorhexidine for skin antisepsis to prevent surgical site infection after minor skin excisions in general practice. METHODS: We conducted this prospective, multicentre, randomized controlled trial in 4 private general practices in North Queensland, Australia, from October 2015 to August 2016. Consecutive adult patients presenting for minor skin excisions were randomly assigned to undergo preoperative skin antisepsis with 0.5% chlorhexidine in 70% ethanol (intervention) or 0.5% chlorhexidine aqueous solution (control). Our primary outcome was surgical site infection within 30 days of excision. We also measured the incidence of adverse reactions. RESULTS: A total of 916 patients were included in the study: 454 underwent antisepsis with alcoholic chlorhexidine and 462 with aqueous chlorhexidine. Of these, 909 completed follow-up. In the intention-to-treat analysis of cases available at follow-up, there was no significant difference in the incidence of surgical site infection between the alcoholic chlorhexidine arm (5.8%, 95% confidence interval [CI] 3.6% to 7.9%) and the aqueous chlorhexidine arm (6.8%, 95% CI 4.5% to 9.1%). The attributable risk reduction was 0.010 (95% CI -0.021 to 0.042), the relative risk was 0.85 (95% CI 0.51 to 1.41), and the number needed to treat to benefit was 100. Per protocol and sensitivity analyses produced similar results. The incidence of adverse reactions was low, with no difference between groups (p = 0.6). INTERPRETATION: There was no significant difference in efficacy between alcoholic and aqueous chlorhexidine for the prevention of surgical site infection after minor skin excisions in general practice. Trial registration: https://www.anzctr.org.au, no. ACTRN12615001045505.

Protocol for a randomised controlled trial comparing aqueous with alcoholic chlorhexidine antisepsis for the prevention of superficial surgical site infection after minor surgery in general practice: the AVALANCHE trial.

INTRODUCTION: Surgical site infection (SSI) after minor skin excisions has a significant impact on patient morbidity and healthcare resources. Skin antisepsis prior to surgical incision is used to prevent SSI, and is performed routinely worldwide. However, in spite of the routine use of skin antisepsis, there is no consensus regarding which antiseptic agents are most effective. The AVALANCHE trial will compare Aqueous Versus Alcoholic Antisepsis with Chlorhexidine for Skin Excisions. METHODS AND ANALYSIS: The study design is a prospective, randomised controlled trial (RCT) with the aim of investigating the impact of two different antiseptic preparations on the incidence of superficial SSI in patients undergoing minor skin excisions. The intervention of 0.5% chlorhexidine gluconate (CHG) in 70% alcohol will be compared with that of 0.5% CHG in aqueous solution. The trial will be conducted in four Australian general practices over a 9-month period, with 920 participants to be recruited. Consecutive patients presenting for minor skin excisions will be eligible to participate. Randomisation will be on the level of the patient. The primary outcome is superficial SSI in the first 30 days following the excision. Secondary outcomes will be adverse effects, including anaphylaxis, skin irritation, contact dermatitis and rash and patterns of antibiotic resistance. ETHICS AND DISSEMINATION: The study has been approved by the James Cook University Human Research Ethics Committee (HREC). Findings will be disseminated in conference presentations and journals and through online electronic media. DISCUSSION: RCTs conducted in general practice differ from hospital-based projects in terms of feasibility, pragmatism and funding. The success of this trial will be cemented in the fact that the research question was established by a group of general practitioners who identified an interesting question which is relevant to their clinical practice and not answered by current evidence. TRIAL REGISTRATION NUMBER: ACTRN12615001045505; Pre-results.