Providing sterile instruments and using good surgical asepsis are important to safe perioperative patient care. But the environment of care (EOC) also includes vertical and horizontal surfaces, environmental conditions and OR-ventilation quality - all of which are equally weighty parts of the surgical-infection-prevention equation. One of the dilemmas of attempting to define clean is that direct observation will reveal visible soil, but microorganisms are more difficult to detect, inactivate and remove. Here are six factors you should monitor to ensure a clean-as-possible OR.

Heating, ventilation and air conditioning system
The importance of a properly functioning HVAC system has been highlighted by several recent investigations of infection clusters among patients undergoing surgical procedures. One involved Acremonium kiliense, a fungus that caused a cluster of endophthalmitis after cataract surgeries. The investigation found that four infected patients were the first case on a Monday and identified the cause as a routine practice in many outpatient surgery facilities: The ventilation system was turned off on the weekend, letting the organism grow in the vents. When the ventilation system was brought up to normal operating parameters Monday morning, the vents released the fungal organism into the OR.1 Sometimes, energy efficiency may not be consistent with good environmental conditions. An outbreak of six infections caused by another fungus, Aspergillus spp., over 12 days was probably related to insulation in HVAC duct work that had become damp.2

The takeaway point here is that you should arrange for routine inspection, testing and, if indicated, cleaning of your facility's HVAC system's ducts.

Positive pressure
Another real scenario highlights the necessity for the OR to be under positive pressure. This case encompassed a cluster of fungal contamination of saline breast implants.3 Here, two causes were identified. First: The saline used to fill the implants was stored just below a water-damaged area of the OR ceiling. When water penetrates a building, it can result in moist drywall or suspended ceiling tiles, which are good media for growing fungal organisms - and many times contaminants are above the substerile area's ceiling. In addition, the OR where the implants were done was in negative pressure with respect to the corridor. When the fungus is dry, it creates spores that travel through the air, especially in negative-pressure conditions. So it's important to keep the OR under positive pressure with respect to the corridor.

Your facility's HVAC professional can help ensure the ORs are in positive pressure. A simple way to check for positive pressure is to stand outside the OR, close the doors, then release a plume of smoke or hold a single-ply tissue near the bottom of the frame. The smoke or tissue should travel toward you, away from the OR.

Air quality
The Association of periOperative Register-ed Nurses (AORN) supports guidelines from the American Institute of Architects4 for OR air quality, including

• a minimum of 15 air exchanges per hour (three of which should be outdoor air),
• a relative humidity between 30 and 60 percent, and
• temperature between 68 and 70 degrees.5

Air filtration and exchanges are important to high air quality. An engineer or other air-balancing professional calculates air changes per hour. Contact your facility's HVAC specialist or engineer to determine whether this has been assessed. Another report points out the importance of keeping OR temperature and humidity within recommended parameters.5 Humidity isn't problematic unless it condenses to moisture, which can carry microbes. Condensation happens if you bring something cold to the high-humidity environment; stagnant air can accumulate enough moisture that it will condense. Keeping humidity in the prescribed range, then, prevents moisture from building in ceiling tiles and dry wall, and prevents surgical staff from perspiring, creating microbe-carrying moisture. Keeping the OR temperature in the optimal range also prevents perspiration.

Traffic control
There are two facets to traffic control during a procedure: allowing only staff needed for surgery in the OR and minimizing the number of times the OR doors are opened.

The CDC and AORN recommend keeping OR doors closed except for the passage of equipment, personnel and the patient.6,7 In most instances, equipment can be planned before surgery. By designating the OR off-limits to those not working on the procedure, you minimize OR doors' opening.

As soon as people enter the EOC, they shed microbes and disrupt the OR air-flow patterns, creating the potential for a surgical site infection. The fewer microbes shed, the smaller the SSI risk.

Filtration
Before air goes to the OR, it should travel through two filter beds: a 30-percent efficient pre-filter and a 90-percent efficient main filter.5

Filtration is especially important if you're doing procedures involving joint prostheses or implants. The CDC recommends you consider using high-efficiency particulate (HEPA) filters that result in ultra-clean air. However, this recommendation is Category II, meaning definitive scientific evidence on its efficacy is lacking. As a general design, introducing ventilation supplied to the OR at the ceiling and exhausting it near the floor makes sense. Keep equipment away from exhaust grills because this could affect air exchanges. Whatever filters you are using, it's best to check and replace them regularly.

Cleaning
When it comes to cleaning the surgical setting, help yourself by designing the environment to promote cleanliness, installing easily-cleaned floors and surfaces in the OR. Review CDC and AORN recommended practices. While not all parameters will apply, adapt these to your facility or practice setting, write your procedures in a manual and monitor them for compliance.

AORN recommends providing a safe, clean environment.8 This is a team effort that begins before the surgical schedule and includes intraoperative attention to minimizing environmental contamination. After each procedure, re-establish a safe, clean area. This would include wet-mopping visibly soiled areas of the floor or the immediate area (a three- to four-foot radius around the surgical field) with a hospital-grade germicidal agent, and cleaning to remove microbial debris from other surfaces.

If you have a spill, contain the contamination in the immediate area of the surgical field so you can remove it quickly after the procedure. There are specific disinfectants registered by the EPA and certain label claims required by OSHA for disinfecting blood spills. We use a quarternary ammonium compound for its cleaning and disinfecting properties, but you can also absorb spills with disposable materials, then disinfect the surface with a 1-to-100 dilution of chlorine bleach. For large spills, you may need a 1-to-10 dilution. Be sure to follow label instructions regarding surfaces and protective equipment. Also, remember to follow specifications for the specified dilution and surface contact time. Surface disinfects often take five to 10 minutes to kill germs.

Often, the areas you clean between procedures are high-touch or horizontal, where microbes or visible contamination fall. After each surgical day, clean the entire floor with a wet vacuum or mop with a single-use mop and an EPA-registered hospital disinfectant.

Unless the walls are visibly soiled, cleaning/disinfection shouldn't be needed between cases, but periodic cleaning certainly is warranted. No scientific evidence demonstrates prevention of infection from cleaning the walls and the en-tire floor after each procedure.

If you're mostly performing surgeries that don't involve a lot of splashing - the case with many outpatient procedures - tailor your cleaning practices accordingly. However, clean the OR regularly to reduce dust and microbial debris.

In the eye of the beholder
There are some ways to test how well devices are cleaned and sterilized, but regarding the OR environment, cleanliness is in the eye of the beholder. Main-taining a proper EOC is a matter of implementing processes and following through in addition to thoroughly training personnel and devising a good general quality-improvement program.

References
1. Fridkin, SK, et al. Acremonium kiliense endophthalmitis that occurred after catar-act extraction in an ambulatory surgical center and was traced to an environmental reservoir. Clin Infect Dis 1996; 22:222-7.
2. Lutz BD, et al. Outbreak of Aspergillus infection in surgical patients, associated with a contaminated air-handling system. Clin Infect Dis 2003;37:786-93.
3. Kainer, MA. Abstract Presentation at the 40th Annual Infectious Diseases Society of America Meeting 2002. Chicago, IL.
4. American Institute of Architects (AIA). Guidelines for Design and Construction of Hospitals and Health Care facilities. American Institute of Architects. AIA Press: Washington DC, 2001.
5. Everett WD, Kipp H. Epidemiologic observations of operating room infections resulting from variations in ventilation and temperature. Am J Infect Control 1991;19:277-82.
6. Managram AJ, et al. Guideline for prevention of surgical site infection, 1999. Am J Infect Control 1999;27:97-134.
7. AORN. Recommended practices for traffic patterns in the perioperative practice setting. In: 2003 Standards, Recommended Practices, and Guidelines. AORN: Denver, CO, 2003.
8. AORN. Recommended practices for environmental cleaning in the surgical practice setting. In: 2003 Standards, Recommended Practices, and Guidelines. AORN: Denver, CO, 2003.