Prescribing showers or baths with chlorhexidine gluconate to surgical patients in advance of their procedures is a common clinical practice. The antiseptic product is intended to aid the efficacy of the pre-operative skin prep and to reduce the risk of surgical site infections. But what results have the evidentiary studies to date borne out? Test your knowledge by answering the true-or-false statements below, then read on to learn more.

1. Studies have definitively shown that pre-op showering or bathing with CHG decreases microbial colony counts on a patient's skin.
2. Studies have definitively shown that pre-op showering or bathing with CHG results in a statistically significant reduction in surgical site infections.
3. The Centers for Disease Control and Prevention recommend that patients be required to take an antiseptic shower or bath before surgery.
4. Taking multiple showers with CHG is more effective in reducing microbial colony counts on the skin than taking one CHG shower.
5. Taking multiple showers with CHG has a greater effect on preventing SSIs than showering once with CHG.
6. Povidone-iodine- and triclocarban-medicated soaps are just as effective as CHG in reducing skin microbial colony counts through pre-op showers.
7. A pre-op antiseptic shower can decrease microbial colony counts on a patient's skin for up to three days after surgery.
8. Reducing skin microbial counts has been definitively linked to a lower incidence of SSIs.

Evidence and efficacy
There's no lack of evidence that pre-op antiseptic showers reduce microbial colony counts on patients' skin.^1-5 While some studies suggest that such reductions might help prevent post-op surgical site infections,^{1, 4, 11, 12} antiseptic showering has not been conclusively proven to lower infection rates.^{1, 3, 5-7}

While one review of the available evidence argues that "[e]fforts to reduce the incidence of nosocomial surgical site infection should focus on interventions where effect has been demonstrated,"⁷ infection prevention authorities stand by the practice of pre-op showers. The Centers for Disease Control and Prevention's Guideline for Prevention of Surgical Site Infection advises patients "to shower or bathe with an antiseptic agent on at least the night before the operative day," even as it acknowledges that the scientific evidence the recommendation is based on is not quite as strong as that which informs its highest-rated recommendations.5

The Association of periOperative Registered Nurses expanded its standards in 2008 to suggest showering twice, since multiple applications of CHG can strengthen its effects. "Patients undergoing open Class I surgical procedures below the chin should have two pre-operative showers with [CHG] before surgery, when appropriate," states AORN.¹³

Plus, the practice makes logical sense. "The operative site needs to be clean," says Linda R. Greene, RN, MPS, CIC, manager of infection prevention at Highland Hospital in Rochester, N.Y. "Bathing with an antiseptic agent is probably helpful. Observa-tional evidence isn't the highest quality evidence, but what's the downside of it? There probably is not a major downside to it."

The benefits of CHG
Antiseptic showers are particularly effective if CHG is used. Studies show it has a greater effect on reducing skin microbial colony counts than povidone-iodine- and triclocarban-medicated soaps,^{2, 5, 10} and while its effect is not as immediate as alcohol's, it has a longer residual effect.⁵ (Incidentally, non-medicated soap has been found in some cases to increase the amount of bacteria on the skin.^{1, 2})

"The use of CHG in a pre-op shower depopulates the patient, and it's the gift that keeps on giving," says Allan Morrison, MD, MSc, a hospital epidemiologist for Alexandria, Va.-based Inova Health System.

It's a unique ability, he says. The epidermis is made up of 7 different cell layers, with about 80 percent of resident and transient flora residing in the top five. To maintain a lasting antimicrobial effect, he says, "you have to have a product that penetrates deeply into the layers — CHG appears to do that — and one that can't be deactivated. Iodine, in comparison, can be inactivated by exposure to protein-laden material, such as blood or tissue interstitial fluids."

But for a CHG product to achieve its greatest effect, it has to be used properly. "That's where the variability lies," says Ms. Greene. "How does the patient apply it? Does she even use it?" If pre-op antiseptic showers are taken in the uncontrolled environment of a patient's home, she says, it is difficult to enforce the antiseptic's proper use. And if the product is simply squirted on, then quickly washed off, its effect may be scarce.

Antiseptic intervention
That's why patient education is critical. Identify the patient's point of entry into the surgical process, whether that's a visit to a physician's office or a pre-op screening, and give the patient clear, concise directions for CHG showering there, says Ms. Greene. "Sometimes we assume they're going to know exactly what to do," she says. Reinforce the directions with the patient's family, if necessary.

Alternatively, she says, you might schedule a patient's morning-of-surgery antiseptic shower at the facility with some degree of supervision. She also suggests that the directions might be simplified by prescribing the use of 2% CHG cloths — with which the antiseptic is wiped on after a shower, then allowed to dry completely — rather than traditional 4% CHG liquid soap. A study has shown that the cloths deliver as effective a concentration of antiseptic as the liquid soap does.¹²

Dr. Morrison even asks whether infection prevention efforts would benefit if all surgical participants took pre-op CHG showers. "A hand scrub is a time-honored practice. I would merely view this as an extension of that practice," he says. "All you're asking them to do is use a different soap in the shower."

Remember, though, that multiple interventions might not let you know for certain which are most effective, says Ms. Greene. "It can be difficult to show that one intervention has an impact or makes a difference," she says. "There's a difference between quality improvement and research."