Preoperative skin cleansing with chlorhexidine-alcohol reduces surgical site infection after clean-contaminated surgery compared with povidone-iodine
- Correspondence to Olivier Mimoz
Réanimation Chirurgicale Polyvalente, CHU de Poitiers, 86021 Poitiers Cedex, France;
More than 30 million operative procedures are performed each year in the USA.1 Despite the implementation of a bundle of preventive measures such as preoperative use of hair clippers or no hair removal (as opposed to shaving), initial administration of perioperative antibiotics within 1 hour before surgery, and maintenance of normothermia, normoglycaemia and hyperoxia during surgery and for the first 2 hours after surgery, between 300 000 and 500 000 patients develop a surgical site infection (SSI). These infections increase length of hospital stay, hospital costs and mortality.2 A patient's skin is a major source of micro-organisms; reducing the pathogens at the operating site by improving skin antisepsis may help decrease the rate of SSI. Chlorhexidine-alcohol has been recommended by the Centers for Disease Control and Prevention as the antiseptic of choice for catheter care because chlorhexidine-based solutions have been found to reduce catheter-associated infections by approximately 50% compared with povidone-iodine.3 However, no recommendations are available concerning the antiseptic solution to use before surgery because data are lacking.
Darouiche and colleagues conducted a study comparing 2% alcoholic chlorhexidine scrub and 10% povidone-iodine scrub and paint for preoperative skin preparation before clean-contaminated surgery. A total of 849 adults from six American hospitals participated in the study. The primary end point was the occurrence of any SSI within 30 days after surgery. The overall rate of SSI was lower by half in the alcoholic chlorhexidine group than in the povidone-iodine group. Alcoholic chlorhexidine was significantly more protective than povidone-iodine against both superficial incision infections (4.2% vs 8.6%, p=0.008) and deep incision infections (1% vs 3%, p=0.05) but not against organ-space infections (4.4% vs 4.5%). Adverse events were uncommon and not serious, and their incidence was similar in the two study groups. The authors concluded that preoperative cleansing of the patient's skin with chlorhexidine-alcohol is safe and superior to cleansing with povidone-iodine for preventing SSI after clean-contaminated surgery.
This is the first well-done study in a large cohort of patients comparing chlorhexidine with povidone-iodine for the prevention of SSI. Although the study could not be blinded because the two antiseptic solutions are different colours, the strictly defined end points and the review of all outcomes by site investigators unaware of the group assignments should have minimised any possible biases. The application of chlorhexidine reduced the risk of SSI by 41% compared with the most common practice in the USA of using aqueous povidone-iodine. This degree of protection is similar to the 49% reduction in the risk of vascular catheter-related bloodstream infection in a meta-analysis that showed the superiority of skin disinfection with chlorhexidine-based solutions over 10% povidone-iodine.4 These results correlate well with previous microbiological studies showing that chlorhexidine-based antiseptic preparations are more effective than iodine-containing solutions in reducing the bacterial concentration in the operative field for vaginal hysterectomy and foot-and-ankle surgery.5 6 The superior clinical protection provided by alcoholic chlorhexidine is probably related to its more rapid action, persistent activity despite exposure to bodily fluids and residual effect. As previously reported with catheters, both antiseptic solutions were safe. Although the use of alcohol-based products in the operating room poses a small risk of fire or chemical skin burn, no such adverse events occurred in this study or the other studies.
Although the study was conducted for clean-contaminated surgery, the results are likely to be generalisable to clean and contaminated surgery because these surgeries are similar in terms of the pathophysiology of SSI. Aqueous povidone-iodine was chosen as the comparator because it remains the antiseptic solution most commonly used before surgery worldwide. However, alcoholic povidone-iodine is more efficient than aqueous povidone-iodine for catheter care.7 In one study of central venous catheters, the use of a chlorhexidine-based solution rather than alcoholic povidone-iodine resulted in decreased catheter colonisation, but the sample size was insufficient to demonstrate any effect on catheter infection.8 Whether such superiority obtains for surgical patients remains to be demonstrated.
To conclude, the study by Darouiche and colleagues supports the value of a relatively inexpensive measure that is remarkably effective: the number of patients who would need to be treated to prevent one SSI was found to be only 17. Chlorhexidine-alcohol should replace povidone-iodine as the standard for preoperative surgical scrubs.
Competing interests None.