TRIED AND TRUE There's still a role for povidone-iodine formulations in skin prepping. In fact, for eye surgeries they're the only choice.

Every surgical nurse should understand the importance of pre-operative skin antisepsis and adhering to the clinical guidelines governing its practice. Properly prepping the skin around the surgical site should be a top priority for OR staff, especially since it's a relatively inexpensive and easy-to-implement infection prevention effort. But, out of all of the products a facility may have on hand, which skin prep agent works the best? Consumed by that question, my nursing colleagues and I hit the books. Here's what we found out.

Questions of quality
We were certain that we weren't the only ones questioning the effectiveness of different skin prep solutions. It's well known that the leading infection prevention authorities, including the Centers for Disease Control and Prevention, the Association of periOperative Registered Nurses and the Association for Professionals in Infection Control and Epidemiology, haven't seen a sufficient range of clinical studies (or antiseptic products) to tip their scales toward a definitive recommendation.

Still, it's an important question to ask. As healthcare providers, we're driven to optimize patient outcomes by keeping hospital-acquired infections, and particularly surgical site infections, as low as possible. As businesses, we're always thinking about the bottom line and the benefits to be gained by cost-effective standardization. As nurses, it's in our nature to do the research required to ensure our practices are evidence-based.

With a go-ahead from administration, our team began searching the medical literature for evidence that would point the way. We reviewed more than a dozen published studies that focused on the specific characteristics and effects of pre-operative skin preparation agents, several of which were in common use at our center. But the results of our research weren't entirely open and shut. Here's why.

Drawing conclusions
In a comparison of skin prep products, the designation "most effective" can be quantified by clinical research in one of two ways. First, which prep has the highest antimicrobial efficacy rate (in the studies that examined microbial kills)? Or second, which prep is more able to reduce the incidence of surgical site infections (in studies that tracked post-op outcomes)?

It's also important to acknowledge that the CDC knows best. In the evidence-based SSI prevention guidelines its Healthcare Infection Control Practices Advisory Committee issued in 1999 (tinyurl.com/ocxokoo), it notes that "no studies have adequately assessed the comparative effects of these pre-operative skin antiseptics on SSI risk in well-controlled, operation-specific studies." Indeed, taken in the overview, the studies we reviewed didn't provide an apples-to-apples comparison across the board, either in the type of prep used or the anatomy and procedure for which they were used.

Even though they weren't unified in their focus, the range of studies we reviewed seemed to point in a similar direction, suggesting the antimicrobial and SSI-preventing effectiveness of chlorhexidine gluconate before several types of surgeries.

Research results
We compiled the studies' findings into a poster which we presented at AORN's annual conference in March. You can read the citations for the studies referenced below at outpatientsurgery.net/forms.

Regarding antimicrobial efficacy:

• On the abdomen and groin areas, a 2% CHG, 70% isopropyl alcohol prep and another CHG-and-alcohol combination provided the best microbial kill when compared to 2% or 4% CHG alone, 70% isopropyl alcohol alone, 10% povidone-iodine and an iodine-containing solution.^{2, 3, 4}
• In foot and ankle surgeries, a 4% CHG scrub followed by a 70% isopropyl alcohol paint delivered better antimicrobial effects than 7% and 10% povidone-iodine solutions5, while a 2% CHG, 70% isopropyl alcohol prep was more effective than a 0.7% iodine and 74% isopropyl alcohol or a 3% chloroxylenol formulation.6 Povidone-iodine (in gel form and in 7.5% and 10% formulations) were "not sufficient in eliminating pathogens in foot and ankle surgery."⁷
• For shoulder surgeries, a 2% CHG, 70% isopropyl alcohol prep was more effective in overall bacteria elimination when compared to an 0.7% iodine, 74% alcohol combination and 7.5% or 10% povidone-iodine.⁸
• In open hernia repairs, a chlorhexidine-ethanol preparation and povidone-iodine produced comparable reductions in skin flora bacteria at the site.⁹

Regarding surgical site infection rates:

• In addition to their similarly significant antibacterial effects, the chlorhexidine-ethanol preparation and povidone-iodine also delivered comparable reductions in SSIs following open hernia repairs.⁹
• CHG alone (in 0.5% or 4% formulations) and CHG (2%, 4% and 0.5%) with 70% isopropyl alcohol bested povidone-iodine in reducing SSI rates following clean-contaminated surgeries.^10-15
• he 2% CHG, 70% alcohol prep was found to be superior to povidone-iodine in preventing SSIs in clean-contaminated surgeries.¹⁶

SPOTLIGHT ON ANTISEPSIS Evidence, anatomy and proper application all affect the effectiveness of a skin prep agent.

Implications and iodine
The immediate practice implications for our nursing staff were clear. The collected research recommended chlorhexidine gluconate with isopropyl alcohol for pre-surgical skin prepping because of the high antibacterial efficacy and surgical site reduction rates the combination demonstrated in abdominal, groin, foot, ankle, shoulder and clean-contaminated surgeries.

That's not to say we've dumped the rest of our skin prep supplies down the drain. CHG plus alcohol may deliver a one-two punch to infectious bacteria, and we rely heavily on it, but there's still a role for povidone-iodine in most, if not all, surgical facilities.

Note that none of the studies referenced above examined the effectiveness of skin preps before eye, ear, head or neck surgery, or surgical sites that incorporate mucous membranes. For the most part, povidone-iodine is the only prep in town for those cases (see "Skin Prep Characteristics and Cautions"). It's also a useful alternative if a patient is allergic or sensitive to CHG.

As suggested by the open hernia repair study, povidone-iodine may do just as well as CHG in prepping for general and abdominal surgeries. One reason for this: The belly tends to be primarily colonized by gram-negative bowel flora, against which iodine has a strong antimicrobial effect, rather than the gram-positive skin flora that's the chief bacterial risk on the limbs and joints.

When povidone-iodine is combined with isopropyl alcohol — a formulation that wasn't included in several of the studies — its antimicrobial power is boosted. Povidone-iodine works fast against a wide range of bacteria, but contact with blood, bodily fluids, tissue proteins or other organic matter can leave it inactive. Those substances don't stop alcohol's effects, though (see "Don't Overlook Alcohol's Assistance").

Focus on the future
New studies comparing the effectiveness of skin prep agents are often emerging. There's a lot of room for research. One study we reviewed suggested the usefulness of further research to determine which preparation of CHG, out of all the concentration and combination options, is the most effective CHG for antimicrobial kill and SSI reduction.¹³

In the meantime, you can ensure effective and safe preps by training your staff on the proper application of each prep along with their safety precautions and contraindications. If you see new evidence-based studies, take note of the preps' active ingredients and the procedures they'd optimally serve. And if you discover a better option, you should recommend it. Skin prep shouldn't be just the surgeon's preference.