Chlorhexidine-Alcohol Is Superior to Povidone-Iodine for Pre-op Prep

Abstract & Commentary

By Robert Muder, MD, Hospital Epidemiologist, Pittsburgh VA Medical Center, Section Editor Hospital Epidemiology, is Associate Editor for Infectious Disease Alert.

Dr. Muder does research for Aventis and Pharmacia.

Synopsis: In a randomized, multicenter trial involving patients undergoing clean-contaminated surgery, use of chlorhexidine for pre-operative skin preparation was associated with a 40% decrease in surgical-site infection, compared with use of povidone iodine.

Source: Darouiche RO, et al. Chlorhexidine-alcohol versus povidone-ioding for surgical-site antisepsis. N Engl J Med. 2010; 362:18-26.

The superiority of a particular surgical-site preparation regimen in preventing surgical-site infection (SSI) has not been determined. Darouiche et al conducted a randomized, multicenter trial of pre-operative chlorhexidine-alcohol vs. povidone-iodine in patients undergoing clean-contaminated surgery. The study was conducted at six university-affiliated hospitals in the United States; patients were stratified by institution. All patients received pre-operative antibiotics within one hour of the start of surgery. A total of 849 patients, 409 randomized to chlorhexidine-alcohol and 440 randomized to povidone-iodine, qualified for the intention-to-treat analysis. The patient groups were well matched by age, type of procedure, duration of surgery, and underlying illness.

The incidence of SSI in the 30 days following surgery was 9.5% in the chlorhexidine-alcohol group, compared with 16.1% in the povidone-iodine group (p = .004, relative risk 0.59). Superficial incisional infections were significantly less frequent in the chlorhexidine-alcohol group (4.2%) than in the povidone-iodine group (8.6%), as were deep incisional infections (1% vs. 3%). There was no difference in the number of organ-space infections. The organisms causing SSI were similar in both study arms. The rate of adverse events was similar in both groups, and the rate of adverse drug-related events, primarily mild-to-moderate skin irritation, was 0.7% in each group. The authors estimate that 17 patients would need to be treated with chlorhexidine-alcohol to prevent one SSI.


Povidone-iodine has been a standard pre-operative skin preparation for decades. To my knowledge, there are no controlled trials comparing any two agents for comparative efficacy in preventing SSIs. In this meticulously conducted randomized trial, Darouiche et al demonstrate conclusively that chlorhexidine-alcohol is superior to povidone-iodine for pre-operative skin preparation. In contrast to povidone-iodine, chlorhexidine-alcohol has both a rapid onset of bactericidal action and has prolonged antibacterial action on the skin's surface. Since the skin is a significant source of the organisms causing SSI, these properties may explain the superiority of chlorhexidine alcohol. It's notable that the incidence of organ-space infection was similar in both study arms. Since nearly 70% of procedures were abdominal operations in both groups, it's likely that most organ-space infections were due to contamination of the field by enteric flora, which would not be affected by skin antisepsis. Although use of alcohol in the operating room is a potential fire hazard, no fires occurred in the trial.

The CDC estimates that 300,000 SSIs occur in the United States each year. Adoption of chlorhexidine-alcohol as the standard of practice for surgical-site antisepsis is an easy way to implement action that has the potential for enormous benefit.