Controlling Critical Indoor Air

By Laura Rygielski and Maureen Lally

Human comfort is just one factor the facility staff needs to consider when deciding how to control the air in an operating room — air quality in the surgical suite also influences patient outcomes, staff productivity and infection levels.

When it comes to operating room temperature, there is often a comfort clash between patients and surgeons. Patients on the surgical table are usually clad in paper-thin gowns, while surgeons are decked out in full-length scrubs, goggles and masks. The situation becomes more complicated depending on the patient and the procedure. For example, small children require higher temperatures than adults, and certain cardiac surgeries require a dip in temperature followed by a warm up, while others require above-normal temperatures throughout.

That is why surgical suites need highly responsive heating, ventilating and air conditioning (HVAC) systems, with controls that can quickly and precisely adjust both temperature and humidity. While conventional HVAC technologies are often slow to the task, the latest advanced systems can provide the unique air control required to satisfy everyone in the surgical suite, while helping to minimize infections, improve patient outcomes and regulate energy costs. Innovative systems feature advanced computer and software programs that can adjust and maintain the indoor environment faster than ever.

Enhancing Staff Comfort

Staff comfort is an increasing concern for hospitals as they work to retain employees. In 2007, nearly half of hospital leaders reported decreased staff satisfaction because of workforce shortages, according to the American Hospital Association’s “State of America’s Hospitals” report.

According to the report “Affects of Excessive Humidity on Infection Control and Comfort in the Operating Room,” by Mark Nunnelly, PE, and Susan Louis, RN, CIC, one of the greatest concerns of medical staff and facilities personnel is the excessive humidity levels often experienced within the operating rooms, especially when the temperatures are maintained well below the intent of the original HVAC design.

Fortunately, advanced HVAC technology is helping ease these concerns. In Florida, for example, summer heat and humidity are often extreme, and the ability to control the indoor environment is key to both surgeon and staff satisfaction. Before a recent update, the 14,600-square foot Tallahassee Single Day Surgery Center facility had 14-year-old rooftop air conditioners that provided unreliable temperature and humidity control. A new HVAC system has provided complete control over the facility’s surgical-suite temperature and humidity. Surgeons and staff can keep humidity at 40 to 42 percent or lower, while temperatures remain at their desired point.

Most hospital HVAC systems are designed to condition operating rooms to temperature and humidity levels indicated by the guidelines outlined by the American Society of Heating, Refrigerating and Air Conditioning Engineers (ASHRAE) and the American Institute of Architects (AIA). In general, the design temperature range for operating rooms is between 68 F and 73 F, and the design humidity range is between 30 percent and 60 percent relative humidity.

A relative humidity of 50 percent can help control airborne bacteria. Humidity levels lower than 35 percent may cause drying of mucous membranes and hypothermia in patients during lengthy procedures. Humidity much above 55 percent may cause undue sweating by surgeons and operating personnel. Unfortunately, when surgeons become uncomfortable, operating room personnel might choose to open windows or leave doors open, thus placing the patient at a higher risk of infection.

Improved Patient Outcomes

Typically, operating rooms are kept warm for patient arrival, but then cooled for the actual surgery. Comfort aside, this cooling process is critical to keep patients healthy — lowering humidity levels helps to control and reduce bacteria growth.

St. Vincent’s Hospital, serving a five-county area near Birmingham, Ala., consistently ranks among the top 15 percent nationally for in-patient satisfaction. Recently, the 338-bed hospital installed an HVAC system that uses 100 percent outside air, rather than recycling indoor air, to accommodate a new orthopedic medicine division. The new division has healthy air circulating throughout, while simultaneously meeting the precise demands of the hospital’s surgical suite and occupants.

The ability to quickly and easily control temperature has other important clinical implications. A cold, shivering patient will require more anesthesia than one who is relaxed with a normal body temperature. Moreover, properly controlled temperature and humidity levels can reduce patient bleeding and speed recovery. For example, lower humidity and cooler temperatures enable adhesives to bond easier, making for quicker orthopedic and arthroscopic procedures.

Surgical site infections are the third most commonly reported infections in hospitals, according to a study on nosocomial infections published in the Clinic Microbial Review. Excessive humidity is one of several factors contributing to these infections. In the operating room, excessive humidity can cause sterile wrappers on surgical packs to become damp, allowing germs to travel through them and thus compromising the sterility of the instruments inside. According to the Association for the Advancement of Medical Instrumentation and also the Association of Operating Room Nurses, sterile items that become wet are considered contaminated because moisture brings with it microorganisms from the air and surfaces.

Meeting Business Goals

Because of a reduction in the time surgeons and staff must wait for the room to reach their preferred temperature and humidity levels, installing responsive HVAC systems in the surgical suite can also boost a healthcare facility’s bottom line. Thus, productivity increases because more surgeries can be performed in less time.

Franklin Memorial Hospital, in Farmington, Maine, wanted a new HVAC system to help optimize its surgical suites and satisfy the needs of surgeons and anesthesiologists. “We always had problems being able to satisfy the surgeons, who wanted the temperature at 62 F to 65 F, while the anesthesiologists and other staff wanted higher temperatures. It’s hard to make everyone happy with air that has a lot of moisture in it,” said Don Garrison, the hospital’s chief of facility management.

Excessive humidity can also require resterilizing surgical kits, adding thousands of dollars of expense, so Franklin Memorial wanted the latest in HVAC technology to control temperature and humidity.

The new packaged HVAC system was built off-site, allowing for a complete changeover in a single weekend. The system delivers 50 F air at a 35 F to 40 F dew point and keeps surgical suites at 62 F to 65 F and 35 to 50 percent relative humidity. “It’s refreshing and rewarding to get the testimonials from the doctors,” Garrison said. “I’ve talked to perhaps 10 of the operating room doctors who have stopped me in the halls to say they love the new system because it keeps them so comfortable.”
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