The Built Environment as a Risk Factor for Infection
The focus on patient safety and the magnitude of healthcare-acquired infections (HAIs) demand that design professionals become well versed in knowing where risks occur, how they occur, and what they can do to reduce or minimize them. For many years, the primary goal has been to reduce the institutional appearance of hospitals—to make them less threatening through the careful selection of interior finish materials; the use of furniture with wooden frames and woven upholstery fabrics (as opposed to vinyl); and the introduction of texture, water features, artwork, and vibrant color. Materials selected for this purpose have to meet fire codes and be durable and easy to clean.
Since such an array of products that meet these general requirements is available, designers have usually not had to go beyond the specifications and manufacturers' printed literature to feel confident in their selections. Occasionally a call to the technical department about whether one product versus another is the best choice for a given situation is required. For example, hospitals often have moisture problems associated with both on-grade concrete slabs and below-grade slabs. This results in problems with many types of resilient flooring, which can lead to substantial risk—and possible litigation—for contractors, architects, and designers.
The situation today is quite different. The goal for design professionals needs to be enhancing patient safety; however, designers cannot necessarily rely on manufacturers' claims and recommendations as in the past because new environmental threats exist. The study by Lankford, et al. (2007), summarized by Leib and Rohde (2007), points out that manufacturers are sometimes out of touch with the cleaning agents and methods actually used by hospitals and that manufacturers' recommended cleaning processes may not result in eradicating pathogens. Nor can designers rely on an antimicrobial label to feel confident that these products will prevent the growth of pathogens (disease-causing germs).
The antimicrobial controversy
There is considerable ongoing debate about the appropriateness and effectiveness of products enhanced with antimicrobial properties for use in hospitals. Types of products currently being marketed include paint, upholstery and cubicle drape fabrics, ceiling tile, patient gowns, door handles, solid-surface material (used for countertops), as well as coating that can be applied to a variety of surfaces. Carpet with antimicrobial preservative has been available for a number of years. The debate or discussion is occurring between infection control specialists, microbiologists, and hospital facility managers who want to know whether such products are effective, safe, and worth the additional cost. Certainly, the ideal would be a variety of products that extinguish pathogens on contact. This would do much to solve the current infection-control crisis in hospitals, at least in terms of pathogens transmitted from environmental surfaces by contact. So kudos to manufacturers for trying to make this work.
The issue, however, is that antimicrobial agents come under the jurisdiction of the Environmental Protection Agency (EPA) Federal Insecticide, Fungicide, and Rodenticide Act, as opposed to public health products such as antiseptics and germicides, sterilizers, disinfectants, and other sanitizers also regulated by the EPA and the Food and Drug Administration.
The EPA requires data to support claims of efficacy against specific microorganisms as well as labeling that details the safe and effective use and also hazards associated with the product. Manufacturers are prohibited from making a public health claim for any product unless it has been approved and registered by the EPA or is exempt from registration (Kaiser Permanente 2006).
One has to read the claims on labels carefully. The antimicrobial properties may apply to the stability of the product itself (shelf life), prevention of odors due to mold or mildew, prevention of staining, or prevention of infection. A large manufacturer of modular carpet tile (and a company that has been a leader in the green movement in terms of manufacturing practices as well as the lifecycle impact of its products) makes these claims for Intersept, an antimicrobial preservative used in its own carpet brand and sold to other companies for incorporation into air filters, paint, fabrics, wallcoverings, ceiling tiles, adhesives, and HVAC equipment (Interface 2002).
It inhibits the growth of a broad spectrum of fungi, molds, mildews, bacteria, and odor-causing microorganisms that can affect carpet.
It is registered with the EPA for use in carpeting and other products.
It is guaranteed to maintain antimicrobial preservative effectiveness for the life of a properly maintained floorcovering.
It is low in toxicity and contains no arsenic, heavy metals, phenols, or formaldehyde.
The emphasis in the Interface technology brief is on Intercept's antimicrobial “preservative protection,” however, photos of petri dish cultures are included in the brief and point to the zone of inhibition around the treated sample, showing no microbial growth. According to the brief, Intersept “works by destabilizing cell membranes of bacteria and fungi, and inhibiting their ability to reproduce … and it is a broad-spectrum biostatic preservative, not a toxic pesticide … and has been certified to meet the three most recognized environmental quality standards.”
This sounds convincing to a nonscientist, but the controversy continues. Kaiser Permanente, in an internal 2006 position paper on antimicrobials, revealed that the “antimicrobial action of surfaces can only effectively treat the first cell layer of pathogenic material.” Beyond that, only mechanical debridement (scrubbing) with detergent and water will disinfect the surface. The conclusions of the Kaiser study (2006) are:
There is no scientific evidence that environmental surface finishes or fabrics containing antimicrobials help prevent infections.
No studies linked gowns made from antimicrobial fabrics to effective prevention of HAIs in the patient setting.
The impregnated silver ion particles found in some of these products are heavy metals and environmental toxins. “Whether these materials leach enough silver ions into rinse water upon cleaning or into the soil upon disposal has not been assessed here, however, it would be prudent to prevent a known hazardous material from entering into a product's lifecycle during manufacture, use, maintenance, or final disposal.”
“It is our considered opinion that due to the unproven benefits of antimicrobial healthcare finishes and fabrics … coupled with their cost and potential environment concerns, these products do not recommend themselves for use in healthcare facilities for the purpose of greater infection prevention and control. This position is subject to change as additional scientific-based evidence becomes available.”
Another leading manufacturer of healthcare carpeting outlines, in a white paper, a number of the issues mentioned in the Kaiser brief and, in fact, disputes the claims made by the manufacturer of Intersept (Evans 2005). Is this a battle of Goliaths for a larger share of the market or a true and sincere philosophical difference?
The increased burden on design professionals
The burden of understanding where the environmental risks lie and evaluating a variety of products against evidence-based studies is what design professionals will now be expected to do. This involves reading studies in their entirety to pick up all the nuances. Simply reading an abstract or summary of the findings will not provide the level of expertise needed.
Manufacturers of finish materials, fabrics, and furniture are working hard to incorporate various technologies into their products so that they extinguish pathogens on contact. For example, according to the product literature, AgION antimicrobial silver ion technology has a trimodal method of killing microorganisms: it interrupts the reproductive cycle, structurally breaks the cell wall, and affects cell metabolism. A number of fabric manufacturers have incorporated this into upholstery and cubicle drapery fabrics, but the evidence thus far has not demonstrated effectiveness in the patient care environment.
Nanotechnology has been applied to the manufacture of solid-surface materials used for sink countertops and other surfaces to kill pathogens on contact, however, as we learned from the Kaiser study, only the first layer of cells is affected. In addition, an infection control officer at a large medical center shared her concerns that, perhaps two years after installation of the countertop, there might be a new strain of pathogen and the microorganism might not be sensitive to the agents embedded in the countertop (personal communication with author).
No doubt, there is frustration, on all sides of this equation: Manufacturers see a great opportunity for the development of enhanced products to deal with a very serious problem, while scientists and those responsible for patient safety hunger for evidence-based proof. According to a recent article (Fields 2007), researchers at North Carolina State and Emory University have developed a “thinner-than-microscopic protective layer, called nano-coating, that can be applied to most any surface; that purports to kill 99.9% of most microbes through a chemical reaction caused by exposure to visible light.”
Clearly there is a new mandate for the design of healthcare facilities. It starts with a thorough understanding of patient safety and infection control issues, which must be interlaced with new layouts of patient units based on the research findings of the IHI's Transforming Care at the Bedside (2004) and Ascension Health/Kaiser Permanente's “Time and Motion” study of nursing work patterns. The ambience of patient care areas is also important. Design features as appealing as those in the lobby and public areas must be carried into procedure and treatment spaces as well as into patient rooms, bathrooms, and core areas. HD
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