The importance of pre-operative skin preparation to a surgical facility's infection control and prevention protocol is perhaps most evident in the issue of surgical site infections. Although many post-surgical wound infections are minor in nature, the risk always exists that they'll result in prolonged illness, hospital admission or re-admission and even death. Clearly, they're a hazard that any infection control program must take seriously. In addition to exquisite surgical technique and appropriate pre-op antibiotic prophylaxis, effective and persistent skin antisepsis is fundamental to reducing the risk that patients will develop post-op surgical site infections. Here's a review of the basics.

Skin prep methodology
The epidermis serves as a patient's principal defense against infection. Surgery's incisions compromise this barrier, allowing a potential entry point for microorganisms from the skin's endogenous, or resident, flora — which are often implicated in post-op wound infections — as well as from the patient's body cavities and from transient flora in surface contaminants that have accumulated on the skin or exist in the immediate environment.

Ultimately, pre-op skin preparation aims to reduce the risk of post-op surgical site infections through the removal of surface contaminants and the reduction of the colony counts of microorganisms living on the skin, therefore enabling a more sterile incision to be made.

The process of preparing the skin over a surgical site has changed very little since it was introduced as a standard of care. But the selection of available prep solutions and delivery methods has changed. Active ingredients now include alcohol, chlorhexidine, iodine and iodophors, parachlorometaxylenol (also known as chloroxylenol or PCMX) and triclosan, whether by themselves or in combination, and are available in single-use applicators as well as multi-use bottles.

Types of agents
Currently, the two most commonly used types of skin prep solutions are povidone-iodine and chlorhexidine gluconate (CHG). Both are comparable in their spectrum of antimicrobial activity, although the CHG does exhibit prolonged activity on the surface of the skin.

Here's a summary of the major types of agents, their abilities and their drawbacks, as classified by the Centers for Disease Control and Prevention's Guideline for the Prevention of Surgical Site Infections:

• Alcohol. Offers the most rapid-acting microbial kill of all the prep solutions. It is rated excellent in its effectiveness against gram-positive and gram-negative bacteria and good against tuberculosis, fungi and viruses. But it has no residual activity, may dry the skin and is a volatile substance.
• Chlorhexidine. Has an intermediately fast microbial kill and excellent residual activity. Rated excellent against gram-positive bacteria, it's only good against gram-negative bacteria and viruses and fares poorly against tuberculosis and fungi. Its risks include ototoxicity (substance-related inner ear damage) and keratitis (corneal inflammation).
• Iodine and iodophors. Are intermediately fast in their microbial kills, but with limited residual activity. Against gram-positive bacteria, they're rated excellent; against gram-negative bacteria, tuberculosis, viruses and fungi, they're rated good. Their absorption may cause skin irritation or toxicity.
• PCMX. PCMX's microbial kill is intermediately fast and its residual activity is good. Its effectiveness is good against gram-positive bacteria and fair against gram-negative bacteria, tuberculosis, viruses and fungi. The guideline notes that insufficient data exists in terms of its toxicity.
• Triclosan. Also offers an intermediately fast kill and good residual activity. Against gram-positive and gram-negative bacteria and tuberculosis, its effectiveness is good, but against fungi it's poor. The guideline notes that insufficient data exists in terms of its effectiveness against viruses and its toxicity.

PCMX and triclosan were included in the CDC's guideline discussion even though they're primarily used as pre-op scrubs for hand antisepsis rather than as pre-op surgical skin preps.

Both the iodophors and CHG are frequently used in combination with isopropyl alcohol, since the combination of two antiseptics with different mechanisms for killing microorganisms has demonstrated better antimicrobial activity than any of the agents separately.

Prepping pointers
When using a pre-op skin prep solution, always follow the manufacturer's directions and keep the following factors, on which an appropriate and adequate prep depends, in mind:

• the volume of solution to be applied, which should be sufficient to enact optimal results and proportionate to the size of the treatment area;
• the solution's chemical composition and concentration, for optimal effectiveness;
• the manner in which the solution is applied (that is, by painting or by scrubbing); and
• the amount of time the solution is in contact with the skin, since the solution must be allowed enough time to dry in order to achieve maximum antiseptic effectiveness — a point at risk of being overlooked in fast-paced ORs.

Equally important to consider is the area of the body that is being prepped. Areas such as the groin and armpit, for instance, are extremely difficult to reach during the prepping process. In addition, both areas are loaded with sebaceous glands and sweat glands, and consequently harbor a high concentration of hard-to-reach microorganisms.

Beyond the OR table
Along with issues of effectiveness and safety, cost always plays a weighty role in terms of selecting surgical supplies. Given their frequent and voluminous use, skin prep solutions are no exception in this regard.

A product's packaging — and, in particular, its method of delivery — is an issue here. Many solutions are available pre-mixed, in single-use, ready-to-use applicators. Although these products can be more costly on an individual basis, many clinicians find that they're cost-effective in the long run, since appropriate application and product use are keys to the effectiveness of the prepping process.

These single-use units can prove faster for your nurses to apply and quicker to dry on the skin, increasing the drape's adhesion and reducing the risk of cross-contamination. Additionally, because only the appropriate amount is used, there is less chance of prep solution pooling beneath patients or surgical accessories — thereby reducing the potential for patient skin irritation and risk of surgical fire or chemical burns.

Prepping may also encompass a patient education component as well. There is evidence to suggest that a systems approach to pre-op skin preparation may have a positive impact on reducing infection rates. In this view, the cleansing of the skin with solution is only part of the prepping process.

A systems approach suggests that skin preparation should begin with a pre-op antiseptic shower or bath for the patient. The addition of the pre-op shower not only reduces the skin flora that surround the operative site and contribute to the development of surgical site infections, but some experts also believe that this approach may have a psychological effect on patients, empowering them to feel responsible for their own outcomes.

The surgical skin prep is a critical step in reducing post-surgical wound infections. Product selection, intended use and appropriate application are all important variables that contribute to the effectiveness of the prep and ultimately to improved patient outcomes.