The operating room environment is not the primary source of surgical site infections (SSIs), thanks to traffic controls, efficient air flow and filtration systems, equipment draping, and good cleaning practices. Still, many members of the healthcare team take for granted that their environmental controls are working, and they may not truly understand the "hows" and "whys" of these controls. When members of your team are less aware than they should be, the chance of an SSI outbreak increases. To help you keep your staffers alert and educated, this article reviews some of the basic principles of environmental maintenance in the OR.

Control OR Traffic
Managing OR traffic is the single most important way to minimize airborne bacteria. To control OR traffic:

• Minimize the number of people in the OR. The microbial level in the OR is directly proportional to the number of people moving about in the room. As we breathe and speak, we shed bacteria, skin squamae, and hair. Surgical masks do not filter out 100 percent of the bacteria we exhale; rather, they provide 90 to 95 percent bacterial filtration efficiency. Skin squamae and hair also act as conduits for bacterial growth.
• Reduce movement into and out of the OR. When flowing properly, air moves from the clean areas like surgery suites (positive pressure areas) to the dirty areas like decontamination rooms (negative pressure areas). However, when we open and close the OR doors too often, air flow can equalize and draw contaminants into the OR.
• Ensure proper traffic flow. Most outpatient facilities have a "racetrack" or "clean core" design that moves traffic from entrance to exit areas and/or from clean to dirty areas. These designs have three basic traffic zones intended to prevent communication between clean and dirty areas. In unrestricted areas (entrances/exits, patient holding areas, postanesthesia recovery units, offices, locker rooms), street clothes are acceptable and traffic is not limited. Semi-restricted areas include access corridors to the ORs and substerile areas, clean and sterile supply storage areas, and work areas for storing and processing instruments and equipment. Surgical attire is required. The restricted area includes the ORs and adjacent substerile areas (scrub sink, sterilizer area). Surgical attire, including face masks, is required. Although healthcare workers are used to this concept, they may not fully understand where these zones begin and end in your facility. The facility manager should post signs to clearly identify each zone.

Move Supplies/Equipment Carefully
Supplies and equipment also need to follow designated traffic patterns. OR workers should remove supplies from shipping containers in the unrestricted area before transferring them to other areas of the surgical suite, as these containers pick up dust, insects, and lots of debris during shipping. Personnel should also cover clean or sterile supplies and uncover them before entering the semirestricted area. When the procedure is over, cover and contain dirty instruments and supplies before leaving the OR to prevent contamination of clean areas. I also strongly recommend processing instruments outside of the OR "proper" or the clean core area, because decontaminating instruments in this area can increase the risk of airborne bacterial transmission.

Maintain an Effective Air System
Outpatient facilities should place top priority on maintaining the ventilation system according to the American Institute of Architects" Guidelines for Design and Construction of Hospital and Healthcare Facilities. I recommend having an environmental engineer evaluate the ventilation system every six months for air flow and cleanliness. Among other things, the engineer should check to ensure that the ORs are still under positive pressure, particularly if you have added on to or redesigned your facility. There should also be at least 15 complete filtered air changes per hour, with a minimum of three (20 percent) being fresh air exchanges. Ventilation (continual fresh air supply and exhaust) is critical, as it dilutes microbes and reduces their overall concentrations. In addition, although most HEPA filters replace automatically as they fill with particles, it is important to monitor proper function and ensure a good supply of replacement filters. The engineer should also inspect and clean ductwork regularly, as the ventilation system is often a major source of microbial contamination. Coils, condensate pans, wet filters, and interior fiberglass lining in ductwork can all be microbial breeding grounds, and experience suggest that HVAC maintenance can reduce viable microorganism concentrations by 80 to 90 percent. The National Air Duct Cleaners Association (NADCA) offers standards for cleaning ventilation systems.

Keep Temperature/Humidity at Recommended Levels
The American Institute of Architects also recommends maintaining OR room temperatures between 68° and 73° F and relative humidity between 30 to 60 percent. Most pathogenic bacteria grow best at temperatures close to normal body temperature (98.6° F) and in environments with humidity greater than 60 percent. Conversely, do not let the air get too dry because bacteria can adhere to dust and become airborne. For this reason, I recommend a humidity level of 60 percent.

Clean Continuously
In the OR and out, cleaning should be a continuous process. In peripheral areas like the waiting room, for example, the maintenance staff should clean according to need rather than a predetermined schedule. That is, if peripheral areas get dirty between cleanings, adjust your cleaning schedule to allow for more frequent cleanings. A dirty periphery can increase the spread of contaminants into the OR.

Inside the OR, the cleaning staff should damp dust all horizontal surfaces with a facility approved disinfectant each morning before the first case. Damp dusting reduces viable microbial contamination from the air by up to 99 percent. After each case, the staff should spot-clean the OR by wiping down horizontal surfaces (e.g., the Mayo stand and back tables) and cleaning any visible soil on the walls, lights, and equipment. If blood dries on a light fixture, for example, it can flake off, become airborne, and may even fall into a subsequent patient"s surgical site. The staff should also remove garbage and pick up any papers on the floor.

At the end of the day, terminal cleaning of the entire surgical suite with a facility approved disinfectant is mandatory. The cleaning staff should wipe all walls, starting at the top and moving down, being sure to remove all tape. Then the staff should thoroughly wipe all light fixtures, equipment, and doors with an appropriate hospital-grade detergent. Next, the staff should clean buckets and the floor, being sure to remove all furniture from the OR first and use a phenolic cleaner, which eliminates spores. The floor should stay wet but not soaked with the phenolic solution for a full ten minutes to ensure sterility, and the person should "mop" him or herself out of the room. Wet vacuuming is the most effective way to clean floors but if your cleaning staff uses mops, be sure to change the mop head and disinfectant solution after each use. The cleaning staff should also clean ceilings, vent grills, sterilizers, and solution dispensers according to a regular schedule, usually weekly or monthly.

Appoint a Monitor
To ensure a clean environment, I recommend appointing a "cleanliness monitor." This person should evaluate the environment weekly or monthly for overall cleanliness as well as general condition. For example, is there dust on the ledge in the OR? Are there blood stains on the glass partition? Is there tape on the wall? Are there cracks, nicks, or grooves on the floor? If so, repair them immediately to prevent bacteria from festering in the spaces. The monitor should also evaluate storage areas because dust and moisture can increase the risk that supplies like sterile tape and gauze will become contaminated. Researchers have linked SSI outbreaks to contaminated supplies.

When creating this monitoring program, be sure to make it achievable. Regulatory and accrediting agencies will expect you to adhere to any program that you incorporate into your policies and procedures.

Maintenance is Key
Environmental controls play an essential role in preventing cross contamination in the OR. By following these common-sense principles, you can go a long way to ensuring a safe environment for your patients.