The effectiveness of preoperative skin preparation is thought to be determined by both the antiseptic agent used and the method of use
Nicola Ward DPharm MRPharmS
Senior Lecturer in Clinical Pharmacy and Pharmacy Practice,
Leicester School of Pharmacy, De Montfort University,
Surgical site infections (SSIs) can occur following invasive surgical procedures, and are currently one of the most common but usually preventable causes of hospital-acquired infection; accounting for 14% of all hospital acquired infections and affecting at least 5% of all surgical patients.(1) SSIs are associated with significant morbidity and mortality, increased length of hospital stay and a potential doubling of healthcare costs.(2) The most common source of SSIs is contamination of the surgical incision with commensal or transient micro-organisms from the patient’s skin, most commonly Staphylococcus aureus.(3) Using an effective antiseptic skin preparation before making the surgical incision to remove transient micro-organisms and to reduce the number of commensal micro-organisms is therefore recommended to minimise the incidence of SSIs.(4,5) The effectiveness of preoperative skin preparation is thought to be determined by both the antiseptic agent used and the method of use.
In order to maximise the reduction in microorganisms on a patient’s skin it is essential that the preparation used rapidly reduces the number of transient and commensal microorganisms before the surgical incision is made and suppresses rebound growth for six hours after application. There is no definitive level of bacterial skin load that should be removed before surgery; therefore regulatory authorities have set standards that must be met before a preoperative skin preparation can be marketed as such. The US Food and Drug administration specifies that products should reduce colony-forming units (CFU) by more than 2log10 at dry sites and by 3log10 at moist sites.(6)
The properties of the ideal preoperative skin preparation agent are listed in Table 1.
The most commonly used skin preparation solutions in Europe are based on aqueous or alcoholic solutions containing either chlorhexidine gluconate or iodophors (comprised of free iodine molecules bound to a polymer; usually named povidone–iodine). Alcohol has been used as an antiseptic for many centuries, but is highly flammable and is not effective against bacterial spores. Para-chlorometaxylenol is used predominantly in the US, with some initial studies indicating some benefits over chlorhexidine and povidone-iodine.(7) Octenidine dihydrochloride is also used in some countries before minor procedures, such as line insertion.
Iodophors have replaced aqueous iodine, with the exact mechanism by which the free molecular iodine destroys microorganisms being uncertain. Povidone–iodine solutions have been widely used for antisepsis of skin, mucous membranes and wounds as they have a broad spectrum of activity. Both aqueous and alcoholic solutions are available. However, there is a potential for local skin reactions(8) and also systemic absorption of the free iodine. The residual effect at the skin surface is only moderate and of limited duration.
Chlorhexidine gluconate is available as both a 4% aqueous solution and an alcohol-based solution. Chlorhexidine is widely used as it is demonstrated to have a rapid bactericidal effect and a persistent residual effect; with the alcoholic solutions demonstrated to have a more effective antimicrobial action.(9) The incidence of skin reactions is comparatively low, but use in the eye and ear is not recommended.
A dye or tint is sometimes added to chlorhexidine-based skin preparation solutions to facilitate application and to prevent pooling and reduce the fire risk from excess solution on the skin. It is important that any dye is safe and non-irritant, does not increase infection and does not obscure surgical skin markings.
Microorganisms have been found to contaminate chlorhexidine and povidone-iodine solutions, with some reports of clinical infections causing significant morbidity and mortality.(10) Subsequent to this, the FDA has endeavoured to increase awareness that not all topical antiseptic products are sterile, and recommends that antiseptics used for preoperative skin preparation be packaged in single-use containers.(11)
Mode of delivery
Most guidelines recommend a scrub-paint technique for applying the preoperative skin preparation solution, however, the evidence for any technique being superior to another is limited.(4) US guidelines from the Centres for Disease Control (CDC) provide more specific recommendations, including that the solution be applied in concentric circles and a single-use swab or sponge should be utilised to apply the solution.(5) Single-use applicators containing an alcoholic chlorhexidine gluconate solution are available to facilitate ease of use and have been demonstrated to be cost effective.(12)
The European Commission recognises antiseptic preoperative skin preparation products containing povidone–iodine or chlorhexidine as medicinal products. Chlorhexidine is classified by the FDA as a ‘New Drug’, whereas single-agent preparations containing either alcohol or povidone–iodine fall within the ‘generally safe and effective’ category; therefore do not require agency approval before marketing.
Choice of antiseptic product in clinical practice
The World Health Organization (WHO) includes minimising the risk of SSI as one of their ten essential objectives for safe surgery, but do not recommend a specific agent.(13) The National Institute for Health and Care Excellence Guidelines published by the Department of Health in the UK recommend using an antiseptic preparation – with either povidone–iodine or chlorhexidine being the most suitable, with no evidence of superiority of either agent.(4) The Cochrane Review Group also concluded that there was limited quality evidence regarding preoperative skin preparation in clean surgery but suggested that there was some evidence from one study that chlorhexidine 0.5% in methylated spirits was associated with lower rates of SSIs following clean surgery than alcohol-based povidone iodine paint.(14) However, in clean-contaminated surgery there is evidence to support chlorhexidine over povidone-iodine.(15–17)
While the Cochrane review suggests that other considerations such as costs and side effects may also significantly influence the final choice of product used, licensed products utilised according to the manufacturer’s recommendations should be used whenever possible to minimise additional risk management and clinical governance issues. Some centres continue to utilise products for off-label uses, particularly for skin preparation before neuraxial blocks.
Therefore, as a result of a lack of specific recommendations, the products available for use are usually determined locally based on the consensus of a multi-disciplinary group including infection prevention specialists and surgeons. Final choice will always consider individual patient factors and, to a lesser extent, the preference of the individual surgeon.
- Surgical site infections are associated with a potential doubling of healthcare costs.
- The effectiveness of preoperative skin preparation is determined by the antiseptic agent used and the method of use.
- Chlorhexidine and povidone–iodine are the most commonly used antiseptics for preoperative skin preparation.
- There is a potential risk of bacterial contamination of solutions for preoperative skin preparation.
- There is some evidence to support the use of chlorhexidine over povidone–iodine-based solutions.
- Smyth ET et al. Four country healthcare associated infection prevalence survey 2006: overview of the results. J Hosp Infect 2008;69:230–48.
- Plowman R et al. The rate and cost of hospital-acquired infections occurring in patients admitted to selected specialties of a district general hospital in England and the national burden imposed. J Hosp Infect 2001;47:198–209.
- Wiley AM, Ha’eri GB. Routes of infection. A study of using “tracer particles” in the orthopedic operating room. Clin Orthop Relat Res 1979;139:150–5.
- National Institute for Health and Clinical Excellence. CG 74: Prevention and treatment of surgical site infection. NICE;2008.
- Mangram A et al. Guideline for prevention of surgical site infection, 1999. Hospital Infection Control Practices Advisory Committee. Infection Cont Hosp Epidemiol 1999;20:250–78.
- US Food and Drug Administration. Tentative final monograph for healthcare antiseptic drug products: proposed rules. Fed Regist Part III 1994; 59:31401–52.
- Zinn J et al. Differences in intraoperative prep solutions: A retrospective chart review. AORN Journal 2013;97:552–8.
- Murthy MB, Krishnamurthy B. Severe irritant contact dermatitis induced by povidone iodine solution. Indian J Pharmacol 2009;41:199–200.
- Larson EL et al. Alcohol for surgical scrubbing? Infect Cont Hosp Epidemiol 1990;11:139–43.
- Chang CY, Furlong LA. Microbial stowaways in topical antiseptic products. N Engl J Med 2012;367:2170–73.
- Drug Safety Communications: FDA requests label changes and single-use packaging for some over-the-counter topical antiseptic products to decrease risk of infection. US Food and Drug Administration 2013. www.fda.gov/Drugs/DrugSafety/ucm374838.htm (accessed 13 March 2014).
- Lee I et al. Systematic review and cost analysis comparing use of chlorhexidine with use of iodine for preoperative skin asepsis to prevent surgical site infection. Infection Cont Hosp Epidemiol 2010;31:1219–29.
- World Health Organization. WHO Guidelines for Safe Surgery: Safe Surgery Saves Lives. World Health Organization 2009;Geneva.
- Dunville JC et al. Preoperative skin antiseptics for preventing surgical wound infections after clean surgery (Review). The Cochrane Collaboration 2013;John Wiley & Sons Ltd.
- Noorani A et al. Systematic review and meta-analysis of preoperative antisepsis with chlorhexidine versus povidone–iodine in clean-contaminated surgery. Br J Surg 2010;97:1614–20.
- Darouiche R et al. Chlorhexidine–alcohol versus povidone–iodine for surgical-site antisepsis. N Engl J Med 2010;362:18–26.
- Health Protection Scotland. What are the key infection prevention and control recommendations to inform a surgical site infection (SSI) prevention quality improvement tool? Health Protection Scotland 2012. www.documents.hps.scot.nhs.uk/hai/infection-control/evidence-for-care-bundles/literature-reviews/ssi-review.pdf (accessed 13 March 2014).