Balancing infection control, care, and cost in isolation rooms

Best practices in mitigating the spread of nosocomial infection and airborne diseases in hospitals and emergency departments

By Terence Houk, AIA, NCARB, from HDR, Inc.

Headlines worldwide warn of severe acute respiratory syndrome (SARS), avian flu, influenza, antibiotic-resistant tuberculosis, and a host of other common-and not-so-common-contagions.

As a result, fear and fact have been placing hospitals’ airborne-infection isolation rooms at capacity. State and municipal health departments face increasing pressure to solve this problem. The states of Wisconsin and Minnesota, for example, are providing incentives to health-care facilities to build Airborne Infection Isolation (AII) rooms (see Figure 1). At the same time, the Centers for Disease Control and Prevention (CDC) has listed “reducing the risk of health-care-associated [nosocomial] infections” among its top 10 goals. These are the two main reasons regulators are acutely interested in facilities that can inhibit infections.

Figure 1: This picture shows an isolation room at the Wisconsin Heart Hospital in Wauwatosa, Wisconsin. Image courtesy of HDR, Inc. Photography by Mark Ballogg. ©Steinkamp/Ballogg, Chicago.
Click here to enlarge image

Many health-care facilities’ redesigns specify increased numbers of isolation spaces and areas that are flexible enough to convert into isolation spaces if necessary. The Health Resources Services Administration (HRSA) is defining these additional rooms as “surge capacity.” Health-care workers seek to both separate patients with unfamiliar or antibiotic-resistant infections and meet survivability requirements for potential biotech incidents. A recent survey of regional Minnesota hospitals revealed their capacity to initially evaluate and treat a minimum of 10 adult and pediatric patients (Health Resources Services Administration Grant for Critical Benchmark).

Good practices

During a pandemic, most hospitals’ plans call for emergency medical personnel to stage the masses in a quarantined area such as an emergency department (ED) parking lot or ambulance garage. Triage-the method in which conditions and patients are evaluated and prioritized-would happen at the ED entrance vestibule; contaminated or infected patients would be disseminated to treatment areas. In some cases, inflatable decontamination tents and showers would be deployed.

Within the ED, incorporating new and convertible isolation spaces for such patients is extremely expensive, so it’s important to assess the real need for them (for instance, whether evidence exists to support the need, or whether it’s just a capricious choice based on media sensationalism). For instance, during a bioterrorist mass-casualty incident, most facilities would like to switch all their rooms to negative pressure or HEPA-filtered air at a rate of 12 air changes per hour (ACH). Facility owners, however, must weigh the risks against the costs.

Thus, new designs typically incorporate more isolation rooms to cover this surge capacity. In general, more than one AII room should be built per ED and other patient-care areas. Up to six of these rooms can be included in a design. The most authoritative resource on AII is Guidelines for Design and Construction of Hospital and Health Care Facilities, Chapter 7.2, from the American Institute of Architects (AIA). These guidelines have been adopted as code in 40 states.

According to those recommendations, AII rooms must include the following items:

  • Negative pressure (airflows from outside to inside by at least 125 cubic feet per minute, or 12 ACH, and exhausts to the outside). Re-circulated air is allowed if HEPA-filtered and direct exhaust is impractical.
  • An ante area that precedes the AII room and contains a hand-washing lavatory and protective gear.
  • A dedicated bathroom.
  • Sealed surfaces to allow for easier cleaning and to reduce potential for airflow violation.
  • A monitoring device (electronic or calibrated ping-pong).
  • Self-closing doors.


It would be impractical to provide six AII rooms in every patient unit because of the extensive cost of changing the air 12 times per hour for each AII when in fact the room would only occasionally be used for a contaminated patient. By contrast, a negative-pressure room is similar to an isolation room but less expensive to build and operate.

Rather than specify spaces that continually operate at negative pressure, facility owners should consider including spaces that can convert from neutral to negative pressure. Technically, only one AII needs to be built to handle day-to-day infection control. All other additional rooms, under normal circumstances, can be utilized as generic exam rooms with neutral pressure and only six ACH.

However, in the event of a major incident, the mechanical systems of the rooms can then quickly ramp up to provide more frequent air changes that would be HEPA-filtered or exhausted to the outside.

Emergency departments

By code, ED waiting areas require 12 ACH under negative pressure, which is comparable to isolation rooms. Although this newer code helps prevent the spread of airborne diseases, it’s not a panacea. The best ED design methodology, therefore, is to mitigate the spread of infection among visitors, patients, and staff by creating two separate waiting areas-triage and post-screening-because any ED visitor could be harboring a contagion. One design, for example, might create a triage area with a small waiting zone immediately off the entrance. This zone would also be separate from both the triage area and the larger waiting room. Visitors suspected of having an infectious disease could be immediately directed to the AII.

Reducing human negativity

The ultimate dichotomy in modern health-care design is caused by the marriage of a highly technical environment and a comfortable healing environment. The increasing need to use rooms requiring a high volume of air changes-and the noise and air movement that go with it-places more stress on patients and their families. Applying certain design techniques can help reduce this negative impact, adding an element of “humanity” to the facility.

For instance, introducing noise-canceling apparatus will reduce unpleasant noise and sounds caused by hard, echoing surfaces and air movement through small orifices. White-noise devices can be tuned to the same frequencies as mechanical systems, thereby eliminating that noise. Other amenities, such as stereos, TVs, and DVD players, help ease anxiety and are becoming commonplace in patient rooms.

Yet, other common amenities-including carpets, drapes, and vinyl wall coverings-cannot be used in AII rooms. The reason for this is because the rooms need to be cleaned and sterilized regularly. So, in order to mitigate much of the isolation environment’s stark appearance, designers add warm colors and eggshell texture. New products, such as linoleum and fabrics, offer antimicrobial properties and have a much more pleasant look than sheet vinyl and epoxy paint.

Visitor, staff, and patient access is another major factor in stress reduction. Anterooms often are too small-barely big enough to accommodate one person, let alone a family who needs to wash and gown up before visiting a family member. Instead, a larger anteroom in a separate foyer or passageway is a more effective alternative (see Figure 2).

Figure 2: This drawing illustrates the floor plan of an isolation room and anteroom at the Wisconsin Heart Hospital in Wauwatosa, Wisconsin. Image courtesy of HDR, Inc.
Click here to enlarge image

Additionally, the following list of design elements can dramatically increase the appearance and function of the anteroom:

  • Enclosed gown cabinets
  • Stylish lavatory or sink basin
  • Larger area with private curtains for full gowning
  • Soft lighting that is separate from room lighting
  • Linoleum floor products

Changes for the best

According to the CDC, nosocomial infections account for an estimated two million infections, 90,000 deaths, and $4.5 billion in excess health-care costs annually in US hospitals alone (see for more information). And, according to the CDC, adherence to the recommended infection-control strategies is indeed most effective in protecting patients.

Health-care designers and providers need to do all they can to reduce the spread of airborne diseases such as SARS, avian flu, and influenza by designing rooms that adhere to those codes. Although much has been done in recent years to decrease infection rates, there’s still a long way to go. Balancing the healing environment with the high cost of isolation technology, providing comfortable surroundings, and adding a human touch are the best actions a designer can take to help contribute to that trend.

Terence Houk has worked in the health-care industry for more than 20 years. His project experience ranges from renovations in established community hospitals to large hospital replacement in urban academic medical centers. He believes in a holistic approach to health-care design, utilizing his understanding of technology and innovations in health-care delivery models. He can be reached at [email protected]


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