Surgical site infections (SSIs) can occur when microorganisms naturally found on the skin of a patient enter the body when the skin's protective barrier is compromised during the surgical procedure. The skin is a dynamic home to a large number of bacteria, with up to 3 million microorganisms on each square centimeter of skin. Most commonly, an SSI occurs from organisms that are consistently present on a patient's skin, compared with transient organisms that are more easily removed. Although it's impossible to remove all microorganisms from the skin, a proper skin prep aids in preventing SSIs by removing debris from the skin, bringing the transient and resident flora to an irreducible minimum, and hindering the growth of microbes during the surgical procedure. Although it might sound easy, there are a few important steps in ensuring that the patient receives the optimum skin prep.

1 Select the appropriate skin preparation agent
Base the selection on a patient assessment for any allergy or sensitivity to skin preparation agents. The prep should:

• significantly reduce microorganisms on intact skin;
• contain a non-irritating antimicrobial preparation;
• be broad spectrum and fast-acting; and
• have a persistent effect.

Skin antiseptics are generally split into 3 major types: iodine/iodophor, chlorhexidine and alcohol-based preparations:

Iodine-based surgical antiseptics are effective against a wide range of gram-positive and -negative organisms (including methicillin-resistant Staphylococcus aureus [MRSA]), as well as tubercle bacillus, fungi, and viruses. Systemic absorption of iodine can occur, and in rare cases has led to iodine toxicity and death. Take care when using this preparation, especially in such high-risk populations as severe burn victims and newborns.

Chlorhexidine is commercially available in aqueous or alcohol formulations, and has broad activity against gram-positive and -negative bacteria, anaerobes, yeasts and some viruses. Unlike iodophor-based preparations, chlorhexidine is not inactivated by blood or serum proteins, and has been demonstrated to have a greater residual activity than traditional iodophors after a single application. It shouldn't be used near the eyes or ears due to the potential risk of damage to the cornea or inner ear. Caution is also advised in the vicinity of mucous membranes. Also, because there's insufficient evidence, CHG isn't recommended for newborns at this time.

Alcohol acts by denaturing proteins. Although rapidly bactericidal, alcohol, once evaporated, has no persistent antimicrobial effect and is not recommended as a single-agent surgical prep. For this reason, alcohol is often combined with either iodine or chlorhexidine in surgical preps that take advantage of alcohol's potential for rapid bacterial killing in aqueous preparations. Alcohol may also prolong the effects of other disinfectants.

2 Apply the prep correctly
The efficacy of an antimicrobial product is based on its proper application. Any surgical prep solution must be allowed to dry for maximum antimicrobial activity. Failure to follow manufacturers' directions for use could significantly impact the product's ability to kill microorganisms. Different prep products have different directions for application. Although alcohol-based preparations have excellent antimicrobial activity, avoid the risk of fire associated with inadequate drying or pooling of these products. Let any surgical preparation containing alcohol fully dry (> 3 min) to eliminate the risk of fire with the use of electrocautery.

3 Use a systems approach
Prepping is only 1 step in a comprehensive program to reduce SSIs. Train staff on skin preps and standardize preps to increase the effectiveness of the infection control process. The more things we can standardize in health care, particularly with similar surgical procedures, the more often we can identify when something doesn't go right because we know how it's supposed to go.