ASHE works with ASHRAE on Legionella Standard

The American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE) has been working on its new Standard 188 for the prevention of legionellosis (more commonly called Legionnaire’s Disease) for several years. The American Society for Healthcare Engineering (ASHE) and its members have been part of this process from the beginning to ensure that the document recognizes the challenges, expertise, and procedures unique to the hospital environment. ASHE has an organizational member on the committee, and several ASHE members also serve on the committee, including facility managers, epidemiologists, and infection preventionists. In addition, other ASHE members are participating in various working groups both to lend their expertise and to help ensure that the needs and capacities of hospitals and their unique environments are taken into account.

Legionella is a bacterium that occurs in fresh water environments. People infected with it can develop either a kind of pneumonia or Pontiac Fever. The former can lead to death, while the latter – which is more common – causes flu-like symptoms. Most people infected with the bacteria recover after being treated with antibiotics. But, the disease is fatal for between 5 percent and 30 percent of those infected.

Despite efforts to minimize such infections through new building design and management practices, between 8,000 and 18,000 people in the U.S. are hospitalized with Legionnaire’s Disease each year, according to the Centers for Disease Control and Prevention. Some of the cases are travel-related, but the vast majority are acquired in the local community, in ways we can’t fully determine. Very few cases actually originate in health care facilities.

The road to infection requires a complex chain of events. For infection to occur, the pathogen must be present in a particular place. The bacteria need to grow in numbers (amplification) to an infectious dose. Then, the bacteria need to become aerosolized. Next, a person must be exposed to the aerosolized bacteria long enough to become infected. Finally, the exposed person must have an immune system incapable of resisting the development of the disease.

Clearly, hospitals have larger concentrations of persons with compromised immune systems. As a result, hospitals need to, and routinely do, take special precautions to protect their susceptible patients.

At the same time, Legionella is only one of many infectious threats in a hospital, as well as only one of many waterborne threats in a hospital. As noted above, very few cases of legionellosis actually originate in hospitals, and Legionella is a very small percentage of actual infection risk in a hospital. So, hospitals have traditionally embedded their Legionella prevention planning in their overall infection prevention strategies, as they strive to reduce the risk of all infections to all of their patients, staff and visitors.

ASHRAE and ASHE have worked together on the proposed standard, with the goal of including consideration of health care facilities’ unique capabilities in infection control.

Tom Watson, chair of the committee developing ASHRAE 188P, said, “The purpose of the standard is to address risk management in a systematic way.”

An earlier version of 188P contained hazard analysis and critical control point (HACCP) plans, which have long been used in the food industry. But, in May the ASHRAE committee made several changes to the draft standard, including removal of HACCP terminology, although some principles from that approach are reflected in the new draft.

The standard in its current state offers supplemental guidelines suitable for managers of various facility types, from hospitals to hotels, according to Jim Kendzel, MPH, CAE, executive director of the American Society of Plumbing Engineers (ASPE), which is also weighing in on 188P.

Watson said the committee is still working on the latest iteration of 188P.

“The technical details are being ironed out,” Watson said. The ASHRAE committee is aiming to produce a public review version of the document later this year.

Unique hospital considerations

Hospitals have unique conditions that make them a special target for infection prevention programs. Specifically, hospitals have larger than normal concentrations of persons with a reduced ability to resist infection, especially in transplant and NICU spaces. Among the most vulnerable are those with malignancies, diabetes, chronic lung diseases, renal failure, heart disease, and bone marrow issues. Precautions for spaces that house these vulnerable patients must be especially stringent.

However, at the same time, the balance of the hospital building offers few unique problems. And, as noted above, Legionella is only one – and typically a very rare – infection concern in a hospital. Finally, hospitals often enjoy one thing most other buildings don’t – certified infection prevention staff, whose full-time job is to design programs to prevent infections of all kinds and to constantly survey the people in their buildings to ensure the effectiveness of these programs. These infection preventionists, working in conjunction with facility managers, who are similarly versed in the range of infection prevention procedures, needed to mitigate ALL infection risks, form the basis of an effective overall strategy for preventing, and manage infection risks.

One of the important accomplishments stemming from ASHE’s collaboration with ASHRAE is a proposed alternate compliance path pertaining specifically to health care facilities, according to Andrew Streifel, hospital environmental specialist, Department of Environmental Health and Safety, at the University of Minnesota Medical Center.

This is important because earlier versions of the proposed standard had the potential to be too inflexible, too much of a one-size-fits-all for commercial buildings, according to Steven Cutter, director of engineering services at Dartmouth-Hitchcock Medical Center.

Beebe said that in order to support infection prevention in hospitals, the standard must address risks beyond Legionella. For example, while a requirement might call for a range of water temperatures in a plumbing system to inhibit growth of Legionella, officials must make sure that range does not allow other pathogens to thrive.

“Health care-associated infections with other bacteria that grow in water, such as Pseudomonas or Acinetobacter, are more commonly seen [in hospitals],” said Linda Dickey, director of epidemiology and infection prevention at University of California-Irvine Health.

Better management practices

Of course, infrastructure is only part of the challenge facing facility operators. Water disinfection systems are standard fare at most institutions. At Dartmouth-Hitchcock, the disinfectant of choice is copper silver ionization. Others use chlorination. Facility managers say regular testing of disinfection levels is often more important than testing specifically for Legionella, as maintaining a certain level of disinfectant has proved to be an effective preventive measure against waterborne pathogens, including Legionella.

Tom Jung, CEO of the Facility Guidelines Institute, said “The physical plant is important, but it must work in concert with good practices in terms of policy and procedure.”

Legionella risk comes from more than the physical plant.

Dickey said ASHE is leading the way in its partnership with ASHRAE. “[ASHE remains] vigilant in pursuing best practices in design, operations and maintenance of plumbing systems to promote patient and staff and visitor safety.”

Deanna Martin is communications manager for the American Society of Healthcare Engineering.

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