Use this prepping quiz and its evidence-based answers to review the fundamentals of skin antisepsis and generate discussions between your infection preventionists and surgical team. The latest studies, guidelines and expert advice are useless if the lessons they provide don't reach the OR.

1. There's a lack of outcome-based literature determining the optimal ingredient in surgical preps.
a. true
b. false

True. However, a recently published study has been creating some buzz in infection prevention circles. Brian R. Swenson, MD, MS, from the department of surgery at the University of Virginia Health System in Charlottesville, Va., led a team of researchers that studied the effects of 3 pre-op skin preparations on post-op wound infection. During separate 6-month intervals, the researchers prepped patients' surgical sites with povidone-iodine, 2% chlorhexidine and 70% isopropyl alcohol and iodine povacrylex in isopropyl alcohol.[1]

They tracked infection rates for 30 days post-op in 3,209 general surgery cases over 18 months. In the October 2009 issue of the journal Infection Control and Hospital Epidemiology, the researchers noted a 3.9% infection rate 30 days post-op in patients prepped with iodine povacrylex in isopropyl alcohol, compared to 6.4% in patients treated with povidone-iodine and 7.1% in patients prepped with chlorhexidine. Those results led the researchers to conclude that "iodophor-based compounds may be superior to chlorhexidine for (skin preparation) in general surgery patients."

The study's results were a bit of a surprise, particularly because of a general lack of other outcome-based literature identifying which preps' active ingredients are best for combating SSIs. While Dr. Swenson's study did not find chlorhexidine to be far and away the top-performing prep (as they expected), it opens the door for further studies about the efficacy of various prep formulas. There are limits to this study, however. In particular, it involved a relatively small patient sample at a single center, which limits universal application of the findings. To definitively say that iodophor-based compounds are superior to chlorhexidine in surgical settings is premature.

2. AORN recommends 1 pre-op shower with CHG when appropriate.
a. true
b. false

False. In its 2008 Recommended Practices for Preoperative Patient Skin Antisepsis, AORN states, "Patients undergoing open Class I surgical procedures below the chin should have 2 pre-operative showers with [CHG] before surgery, when appropriate." The recommendation notes that CHG showers reduce microbial counts on patients' skin, but stops short of linking CHG showers with lower surgical site infection rates.[2]

AORN states patients must thoroughly rinse after each CHG shower and dry off with a clean towel, as soiled towels contain microorganisms that colonize in the presence of moisture. While there's no definitive proof that pre-op showers with CHG reduce SSIs, the practice is gaining momentum.

3. Which of the following are the 2 most common pathogens associated with SSIs?
a. Staphylococcus aureus and acinetobacter
b. coagulase-negative Staphylococcus and Staphylococcus aureus
c. Pseudomonas aeruginosa and E. coli
d. coagulase-negative Staphylococcus and Enterococcus

(b) coagulase-negative Staphylococcus and Staphylococcus aureus. In the November 2008 Infection Control and Epidemiology, researchers described the frequency of selected antimicrobial resistance patterns among procedure-associated infections reported by hospitals in the National Healthcare Safety Network between January 2006 and October 2007. Most procedure-associated infections occurred after cardiac (29%), abdominal (26%), orthopedic (18%) and neurological (12%) surgeries. Out of 7,025 total pathogenic isolates reported, the study identified coagulase-negative Staphylococci (965) and S. aureus (2,108) as the most common causes of SSIs.[3]

The type of incision (superficial, deep or organ space) didn't affect the number of pathogens isolated following surgery, but the procedure type did: While coagulase-negative Staphylococci and S. aureus accounted for most SSIs following cardiac, neuro, Ob/Gyn, ortho, transplant and vascular procedures, gram-negative rods and Enterococci were the more prevalent SSI-causing pathogens following abdominal surgery, according to the study.

4. S. aureus from the patient's own microbial skin flora is the second most common pathogen isolated from post-op wound infections in clean surgical procedures.
a. true
b. false

False. S. aureus from the patient's own skin microbial flora is actually the most common pathogen isolated from post-op wound infections in clean surgical procedures.

It's widely accepted that the consistent and correct administration of antimicrobial prophylaxis is the most effective method to reduce the risk of SSIs in clean (surgical wounds are uninfected and procedures don't involve the respiratory, alimentary, genital or urinary tracts) or clean-contaminated (the respiratory, alimentary, genital or urinary tract is entered under controlled conditions in the absence of unusual contamination) surgeries.

Research has shown 90% of surgical patients receive antibiotic therapy before surgery, but the regimen is delivered incorrectly in as many as half the cases.4 With most antibiotics, patients must receive a first dose between 30 and 60 minutes before incision time and the last dose should not extend beyond 24 hours post-op. Surgeries lasting more than 1 hour might require re-dosing to maintain antibiotic levels in tissue surrounding the surgical site.

The effectiveness of pre-op antibiotics in the prevention of SSIs has been challenged by the emergence of antibiotic-resistant bacteria, notably MRSA. The number of S. aureus infections is a rising concern, thanks to virulent, antibiotic-resistant strains in the community setting.4 Since we're faced with the reality of battling antibiotic-resistant bacteria, properly preparing the surgical site with an effective prepping solution is paramount. To that end, research has shown the bactericidal activity of a 0.5% chlorhexidine and 80% alcohol solution to be more effective and more rapid at reducing bacterial counts against MRSA compared with 0.5% CHG and 10% povidone-iodine.[4]

5. Which of the following statements about skin antiseptic agents is false? They should:
a. significantly reduce microorganisms on non-intact skin
b. contain non-irritating antimicrobial preparation
c. be broad spectrum
d. be fast-acting and have a persistent effect

(a) Significantly reduce microorganisms on non-intact skin. Surgical prep solutions should be fast-acting, non-irritating to patients' skin and demonstrate persistent and cumulative antimicrobial actions to reduce microorganisms on intact skin.

Understanding how active ingredients match the procedure you are prepping for is the primary factor when deciding between surgical preps. The optimal antiseptic agent reduces the initial microbial count, persistently inhibits microbial growth during the course of the surgical procedure and is effective in the presence of blood.4

Alcohol boasts a fast-acting and highly effective antimicrobial effect, but lacks persistent activity. Combining it with CHG's persistent, cumulative activity creates a highly effective prep. Alcohol-based solutions that contain 0.5% to 1% CHG have a persistent antimicrobial activity that is equal to, or greater than, that of CHG alone.4 Alcohol-based preps shouldn't come in contact with mucous membranes, the eye or the ear, making them ill-suited for ophthalmic or GYN procedures. They carry their own inherent dangers, most notably as an igniter during electrosurgery procedures. Follow manufacturers' directives in relation to how much prep to apply (to avoid pooling) and how much dry time to allow before applying sterile drapes.

References:
1. Swenson B et al. Effects of Preoperative Skin Preparation on Postoperative Wound Infection Rates: A Prospective Study of 3 Skin Preparation Protocols. Infect Control Hosp Epidemiol 2009;30:964—971.
2. AORN, Inc. Recommended Practices for Preoperative Patient Skin Antisepsis. Perioperative Standards and Recommended Practices. AORN, Inc., 2008; 537-556.
3. Hidron A et al. NHSN Annual Update: Antimicrobial Resistant Pathogens Associated With Healthcare-Associated Infections: Annual Summary of Data Reported to the National Healthcare Safety Network at the Centers for Disease Control and Prevention, 2006-2007. Infect Control Hosp Epidemiol 2008;29:996-1011.
4. Florman S, Nichols RL. Current Approaches for the Prevention of Surgical Site Infections. Am J Infect Dis 2007;3:51-61.