HERD: Health Environments Research & Design Journal

To describe the conceptual framework and methodology used to conduct a comprehensive literature review of current evidence evaluating the role of the built environment in the transmission of healthcare-associated infections.

A multidisciplinary approach to evaluating a vast and diverse dataset requires a conceptual framework to create a common understanding for interpretation. This common understanding is accomplished through the application of a “chain of transmission” model depicting temporal and physical paths of pathogens that cause healthcare-associated infections. The chain of transmission interventions model argues that infection can potentially be reduced by interrupting any of several links in the chain.

The key pathogens impacted by the built environment are identified. The chain of transmission and the conceptual framework are described. Opportunities for intervention through the built environment are presented, which in turn guide the subsequent methodology used to conduct the systematic literature review.

The chain of transmission interventions model is a multidisciplinary conceptualization of the interaction between pathogens and the built environment, and this model facilitated a systematic literature review of a very large amount of data.

To assess expert knowledge, perceptions, and experience on the role of the built environment in the acquisition and transmission of healthcare-associated infections (HAIs), facility design decision-making considerations, and strategies for intervention through facility design and technologies.

Healthcare-associated infections pose a serious and costly threat to public health in the United States. A growing evidence base suggests that the built environment can play a role in interrupting the chain of infection.

Semi-structured individual interviews and triads were conducted with 26 experts in hospital administration, architecture, interior design, infection control, and air and water quality. A grounded theory approach was used for interview coding and interpretation.

Participants characterized the shift in thinking about the relationship between the built environment and HAI transmission as a “progression,” as accountability for infection prevention has expanded beyond clinicians. Organizational leaders aim to make informed design decisions, but this can be challenging due to the paucity of efficacy and return on investment data. Emerging interventions include copper impregnated materials, seamless flooring, and chilled beams.

No single intervention is entirely effective in mitigating HAI risk; multiple interventions are needed. In addition to the built environment, human behavior must be considered, as noncompliance can render even the best designs ineffective. Increased multidisciplinary collaboration is needed to improve the application of evidence and experience in healthcare facility design. In the absence of conclusive evidence regarding interventions aimed at reducing HAI transmission, a combination of research data and practical experience should be used to inform design decisions.

This article describes the role of the hospital environment in the spread of pathogens by direct and indirect contact. In addition, the prevention of transmission through interventions involving the built environment is discussed.

The hospital environment can become contaminated with pathogenic microorganisms, some of which can persist for long periods of time. Although contamination is common, the contribution of the hospital environment to the development of healthcare-associated infections remains unclear. In part spurred by the development of newer technologies to enhance environmental cleaning or to prevent contamination, research into the role of the environment in causing healthcare-associated infections has accelerated.

A review of the recent literature finds an increasing body of evidence implicating contaminated surfaces in patient care areas in the transmission of pathogens and the development of infections. Single-patient rooms and optimally placed alcohol hand rub dispensers and other design features can mitigate infection risk. Enhanced environmental cleaning including touchless technologies and self-cleaning surfaces can reduce environmental contamination and may prevent infections.

The hospital environment contributes to transmission of pathogens in hospitals and to the development of healthcare-associated infections. Newer technologies to prevent environmental contamination or to enhance cleaning are promising although additional studies with the endpoints of reduction of infections are needed before the role of these technologies is known.

To assess and synthesize available evidence in the infection control and healthcare design literature on strategies using the built environment to reduce the transmission of pathogens in the air that cause healthcare-associated infections (HAIs).

Air can serve as a route for transmission of important HAI pathogens, including Mycobacterium tuberculosis and influenza, and may play a role for others typically transmitted by contact, including Staphylococcus aureus and Clostridium difficile.

Four primary interventions can be used interrupt the transmission of pathogens in air: ventilation, filtration, decontamination, and isolation. Many studies demonstrate that unidirectional airflows, when combined with very clean air and frequent air changes, reduce bacterial counts in the air, though mostly focused on the operating room. A high-efficiency particulate air filter removes almost all particles from the air and is used in protective environments such as the operating room, but little evidence supports its broader application. Ultraviolet germicidal radiation can augment the performance of heating, ventilation, and air conditioning systems. Isolation with negative pressure ventilation prevents spread of airborne pathogens such as tuberculosis.

Current evidence is limited by the complexity of the interactions between pathogens and potential hosts, and in the methods used to assess impact of these strategies. Because the factors that affect transmission of the pathogens are complex and transcend disciplines, a collaborative approach among the key stakeholders in healthcare facility design should be actively pursued from planning to completion of construction and in rigorous research to best determine how design can reduce HAIs.

To assess and synthesize available evidence in the infection control and healthcare design literature on strategies using the built environment to reduce the transmission of pathogens in water that cause healthcare-associated infections (HAIs).

Water can serve as a reservoir or source for pathogens, which can lead to the transmission of healthcare-associated infections (HAIs). Water systems harboring pathogens, such as Legionella and Pseudomonas spp., can also foster the growth of persistent biofilms, presenting a great health risk.

Strategies for interrupting the chain of transmission through the built environment can be proactive or reactive, and include three primary approaches: safe plumbing practices (maintaining optimal water temperature and pressure; eliminating dead ends), decontamination of water sources (inactivating or killing pathogens to prevent contamination), and selecting appropriate design elements (fixtures and materials that minimize the potential for contamination).

Current evidence clearly identifying the environment's role in the chain of infection is limited by the variance in surveillance strategies and in the methods used to assess impact of these strategies. In order to optimize the built environment to serve as a tool for mitigating infection risk from waterborne pathogens—from selecting appropriate water features to maintaining the water system—multidisciplinary collaboration and planning is essential.

To summarize the findings and provide recommendations based on the multidisciplinary literature review and industry scan, focusing on the links between the built environment and healthcare-associated infections. To propose a research agenda in order to increase informed design decisions and advance the evidence base.

The HAI-Design project explores the research linking a range of design interventions to healthcare-associated infection. The multidisciplinary team evaluated over 3,800 articles and conducted interviews with a range of stakeholders including CEOs, architects, designers, physicians and other healthcare experts, the results of which are featured in this special Supplement as topical papers.

The four topical papers describing the role of the built environment in the acquisition of healthcare-associated infections are summarized. The evidence evaluating the strategies for intervention through the built environment is analyzed, and a research agenda is proposed.

While the evidence base supporting the efficacy of strategies and technologies continues to grow, there are currently few data that demonstrate a reduction in infection rates. The need for multidisciplinary collaboration and increased efforts to standardize the evaluation of environmental studies are essential to overcome the many challenges and improve the reliability of data