Skin is our first line of defense against infection, but surgical incisions leave us vulnerable to microorganisms. That's why pre-operative skin preparation is essential to infection prevention efforts. You've got a wealth of choices in terms of skin preps. How much do you know about the differences between types, application techniques and uses? Take the quiz on page 73, then read on to learn more.

Types of preps
The objective of antiseptic skin preps is to lower the microbial counts on a patient's body in order to reduce the risk that an incision will result in post-op surgical site infection. The range of products available for this task can be broken down into categories, each with its own qualities and cautions:[1,2]

• Alcohol offers a rapid microbial kill but has no residual activity. It is not for use on mucous membranes, can cause corneal and nerve damage and can dry the skin. In addition, it's a flammable substance.
• Chlorhexidine's microbial kill is intermediately fast and its residual activity is excellent. While it can be used on mucous membranes, caution is advised. Like alcohol, it can harm the cornea, and can also do damage to the inner ear.
• Iodine and iodophors have intermediately fast microbial kills, though their residual activity is limited and they can be inactivated by contact with blood or tissue proteins. While they can be used on mucous membranes as well as in eye surgery, they may irritate some patients' skin.
• Chloroxylenol. Also known as parachloro-metaxylenol (PCMX), this substance has an intermediately fast microbial kill and a good residual activity. It can be safely used on mucous membranes and the eye.

Since some prepping agents compound chlorhexidine gluconate or iodophors with isopropyl alcohol to combine their antiseptic benefits, the cautions against alcohol's use would likewise apply to the resulting products.

The desired effect
The CDC's guideline on SSI prevention doesn't recommend one formulation over another. "No studies have adequately assessed the comparative effects of these preoperative skin antiseptics on SSI risk in well-controlled, operation-specific studies," its authors note.[1] Similarly, AORN's recommended practices on skin preparation advise only that skin preps should be selected based on their approval by the FDA and the surgical facility's infection prevention staff, their antiseptic effect and persistence, and an assessment of the patient and surgery at issue.[2]

No surgical skin prep is universally acknowledged as the most effective. "For a long while, there has been an unresolved debate over the comparative effectiveness of antiseptic agents," says Charles Edmiston, PhD, CIC, a professor of surgery and hospital epidemiologist for the Medical College of Wisconsin in Milwaukee. In his view, however, the balance of that debate may be tipping.

Three recent clinical studies and 2 instructional overviews have suggested that the ability of chlorhexidine agents to eliminate bacteria make it an ideal option for pre-operative skin antisepsis.

For a study published in last month's Journal of Bone & Joint Surgery, orthopedic surgeons from Northwestern University in Chicago randomly prepared 150 consecutive shoulder surgery patients with either 2% chlorhexidine gluconate and 70% isopropyl alcohol; 0.7% iodophor and 74% isopropyl alcohol; or a 0.75% povidone-iodine scrub and a 1% iodine paint. They found the CHG-and-alcohol solution "more effective at eliminating overall bacteria from the shoulder region."[3]

After treating 500 surgical patients with either povidone-iodine or chlorhexidine prior to their procedures, Thai researchers report in a study published in July that the chlorhexidine group showed lower rates of bacterial colonization and post-op SSIs. "Chlorhexidine antiseptic should be the first consideration for preoperative skin preparation," they assert.[4]

Noting the higher infection rates resulting from foot and ankle procedures than from surgeries elsewhere on the body, as well as the difficulty in eliminating bacteria from the forefoot, orthopedic surgeons at the University of California San Diego randomly prepped 125 consecutive patients with 0.7% iodine and 74% isopropyl alcohol; 3% chloroxylenol; or 2% CHG and 70% isopropyl alcohol. "Of the three solutions tested in the present study," they wrote in 2005, "the combination of chlorhexidine and alcohol was most effective for eliminating bacteria from the forefoot prior to surgery."[5]

Additionally, a 2007 evidence review on infection prevention practices notes that "current literature strongly suggests that chlorhexidine gluconate is superior to povidone-iodine for pre-operative antisepsis for patients,"[6] and a similar review of skin preparation studies from 2006 concludes that "the surgical site should be prepared with chlorhexidine. A second choice would be a one-step iodine application."[7]

"Povidone-iodine does have its benefits, and a broad spectrum of activity," says Dr. Edmiston. "It's taken some time, but there is great confidence in many of the modern prep products as well."

Preps in practice
Continuing research on comparative effectiveness doesn't mean your facility needs to stock just 1 type of skin prep, though. "Generally speaking, the one-size-fits-all approach to preps, regardless of what effect they have on SSI prevention, is a big misunderstanding," says Ruth M. Carrico, PhD, RN, CIC, an assistant professor at the University of Louisville School of Public Health.

The right prep to use in any given situation depends on the surgical site location as well as the patient's tolerance for it, she says. As noted above, some classes of preps are harmful to certain parts of the body.[1] The ingredients in some products may also trigger allergies or skin irritation among some patients,[2] effects that Dr. Carrico says may place patients at risk for the infections the preps are intended to prevent. "You don't want patients touching the incision site," she says. "You want them to be able to leave it alone and get on with their regular activities."

No matter which product is selected for the task, "the skin prepping technique should always progress from the clean to the dirty area," says Dr. Edmiston. This advice is AORN's exception to its recommended practice of working from the incision outward, but the intent is the same: to prevent the reintroduction of microbes into less contaminated areas.[2] Similarly, used sponges or applicators should not make contact with areas they've already treated, but should be discarded in favor of new supplies if another treatment is necessary.[2]

In addition to covering the immediate surgical site, the prepped area should anticipate the possibility of shifting or enlarged drape fenestrations, extended or new incisions or the need for drain sites.[2] A sufficiently large prepped area also prevents resident and transient flora on surrounding areas of skin from migrating to the surgical site.

While it has long been recommended that prepping solution should be applied by beginning at the incision site and circling outward,[1] that rule is no longer absolute. A circular motion works well for sponges or gauze dipped into povidone-iodine solutions, but newer prep formulations require single strokes or the exfoliating friction of back-and-forth strokes for full effect, and are supplied in applicators that facilitate this technique.[8] As a result, AORN now recommends that surgical personnel consult manufacturers' directions to determine the most effective application method.[2]

"We recognize that skin is not smooth as glass," says Dr. Carrico. "If you want to be able to reach all the skin cells, you've got to apply some effort." Dr. Edmiston adds that on larger patients who have skin folds, straight strokes prep more thoroughly than circular motion does.

Safety and savings The outpatient surgery OR is a time- and cost-sensitive environment, but despite the rush, it's critical that surgical personnel let prepping agents dry completely before continuing with the procedure. Not only does the resulting contact time enable skin preps to achieve their maximum antiseptic effectiveness, but also the evaporation of alcohol or other flammable ingredients reduces the risk of a surgical fire sparked by electrosurgery or laser equipment.[2]

Fire safety is also behind the recommendation that surgical personnel avoid using more prep than is necessary and prevent the dripping or pooling of solution beneath patients and equipment close to their skin, such as pneumatic cuffs. Prolonged exposure to large amounts of prep may also cause chemical burns.[2]

Overall, says Dr. Edmiston, "the skin prepping agent should have the following properties: fast-acting, persistent, have a cumulative activity and be non-irritating." When those factors are satisfied, says Dr. Carrico, consider convenience and your workflow. "This is going to be a staple in your surgery center," she says. "What allows you to move patients through quickly?"

Answers: 1. False; 2. True; 3. False; 4. False; 5. True; 6. False; 7. False; 8. False