The Hospital Built Environment: What Role Might Funders of Health Services Research Play?

Chapter 6. What is the Research Base for the Hospital Built Environment?

Hospitals are among the most expensive facilities to build, due to complex infrastructure, expensive diagnostic and treatment technology, prevailing government regulations, and safety codes.11 Deciding to invest in hospital design, and deciding what elements to incorporate into a newer facility, requires a clear understanding of the intended outcomes.

Of the 328 articles recovered from PubMed and other sources (Table 3), 168 pertained primarily to improving patient outcomes, 182 examined patient or staff safety issues, and 44 focused on areas of patient or staff satisfaction and efficiency, as described in the following sections. The majority of the studies were observational studies (n = 212), including 88 case studies, 66 cohort studies and 58 case series studies. Twenty-five RCTs were identified, most of which studied the relationship between hospital design and patient outcomes. Additionally, there were 20 other controlled trials, 2 systematic reviews, 1 practice guideline and 68 non-systematic review articles.

Table 3. Articles by study design and key topic

Studies Patients and Families Staff Totals*
Safety Outcomes Satisfaction Efficiency Safety Satisfaction Efficiency
Primary Studies
Experimental Studies
RCT   0  19   5 2  0 1 0  25
Other Controlled Trials   5  15   0 0  3 0 0  20
Observational Studies
Cohort Studies  23  31   9 0   5 1 4  66
Case Series  20  35   1 0  14 1 0  58
Case Studies  51  28   3 0  23 2 0  88
Secondary Studies
Systematic Reviews   1   1  0 0  1 0 0   2
Guidelines   1   0  0 0  1 0 0   1
Other Reviews  25  39 10 0  9 2 3  68
Total 126 168 28 2 56 7 7 328

* Citations pertaining to more than one key topic are counted for each such topic, but only once for the Totals column.

Figure 1 illustrates what percentage each study design represented out of the total number of articles recovered. Among these, 64 percent of articles were observational studies, 21 percent were review articles, 8 percent were RCTs, 6 percent were other controlled trials, 1 percent were systematic reviews and less than 1 percent were practice guidelines. While observational studies may be more feasible and less costly in many settings, they are less effective than RCTs and other controlled experiments in demonstrating a causal relationship between hospital design and patient outcomes, and patient and staff safety, satisfaction and efficiency.

Among the more comprehensive resources was a review of existing literature published in 2004 by Craig Zimring, of Georgia Tech, and Roger Ulrich, of Texas A&M University. This review was sponsored by CHD and funded by The Robert Wood Johnson Foundation.8 The review concluded that evidence-based design can improve hospital environments in three main ways:

  1. Enhance patient safety by reducing infection risk, injuries from falls and medical errors.
  2. Eliminate environmental stressors, such as noise, that negatively affect patient outcomes and staff performance.
  3. Reduce stress and promote healing by making hospitals more pleasant, comfortable and supportive for patients and staff alike.8

The body of literature assembled here is organized into the main categories of patient outcomes, patient satisfaction, patient efficiency, patient and staff safety, staff efficiency and staff satisfaction. These categories represent current areas of emphasis in research on the built environment, although there is considerable interaction across these main categories. For instance, environmental stressors, such as noise pollution, affect patient outcomes; noise pollution also is disturbing to hospital employees and, therefore, may affect staff efficiency.

Environmental factors, such as access to bright light, may improve patient outcomes and reduce length of stay. These effects may be achieved through the higher levels of patient and staff satisfaction that have been shown to improve with access to sunlight.15 Also, as communication contributes to staff efficiency, it also positively influences patient safety.16

Patient Outcomes

There were 168 relevant articles pertaining to patient outcomes. Articles pertaining to patient outcomes focused on noise pollution, improving sleep, reducing depression and on a smaller group of studies of various factors affecting patient length of stay. We identified 19 RCTs addressing patient outcomes. Most of these were concerned with the influence of noise on patient outcomes.

Noise Pollution. Seventy-five articles focused on the impact of noise pollution in the hospital setting. Many studies indicated that hospital noise levels frequently rise above the recommended guidelines set forth by the World Health Organization. Five studies demonstrated that hospital noise levels are often in the range of 45 dB to 68 dB, while the guidelines recommend that noise levels not exceed 35 dB.17-21 Factors contributing to noise in hospital settings include paging systems, alarms, telephones, staff voices and surfaces, such as walls and ceilings, that are not sufficiently sound absorbing.

Of the 75 articles recovered, 35 examined the impact of noise in the intensive care unit, with particular focus on neonatal and pediatric intensive care units. Several studies found that patients in the pediatric ICU sleep significantly less than is normal for children of the same ages, and their patterns of sleep are seriously disturbed.22,23 According to a study conducted at the National Maternity Center in Dublin, Ireland, physiological and psychological changes associated with sleep disturbance decrease the ability of critically ill children to adapt to hospitalization and, thus, hamper recovery. Research indicated that higher noise levels increase heart and respiratory rates in infants and children.24

Open bay areas in pediatric wards reportedly are common, despite their being known to generate high traffic volumes and coincident noise.25 According to research conducted at the Christiana Hospital's Special Care Nursery at the University of Delaware, installing sound-absorbing walls and ceilings and modifying or abolishing open bay areas may help to reduce noise pollution in these settings.26

Factors Affecting Length of Stay. A small body of research has been conducted on whether environmental factors influence the length of patients' hospital stays. According to an RCT conducted at the Department of Neuropsychiatric Sciences at the University of Milan, bipolar patients assigned to rooms with more sunlight had a mean 3.67-day shorter hospital stay than patients with the same diagnosis in rooms with little or no sunlight.27 As noted above, studies also have demonstrated the negative effects of windowless hospital rooms on patient outcomes and satisfaction.28 Much of the research suggests that access to sunlight has positive effects on patient outcomes and patient and staff satisfaction.

A separate study found that psychiatric and orthopedic patients treated in new or upgraded units rated their experience and treatment significantly higher than those on old wards.29 In addition, length of stay on new psychiatric units was lower than in old units, although it is not clear whether there were particular aspects of the new unit that were preferred to the old unit or whether patients simply perceived "new" as better than "old."

Several research articles found under the positive distractions section of this report demonstrated significant improvements in patient outcomes resulting from factors such as music, access to sunlight and views of nature. Better outcomes may decrease length of stay.

Patient Satisfaction

There were 28 articles focused on patient satisfaction. Articles pertaining to patient satisfaction focused on design aspects mediating family interactions and positive distractions.

Family Interactions. Family visits to hospitalized patients provide a form of social support that can help to alleviate the effects of stress that can arise with an illness or associated hospitalization. Several studies addressed whether family involvement or interactions affected patient outcomes during hospital stays. One study concluded that family presence during invasive procedures in the pediatric intensive care unit decreased procedure-related anxiety.30 Several studies also found that there are barriers to involving families and social support networks during a patient's hospital stay, such as restricted visiting hours or a lack of beds or rooms where parents can stay with hospitalized children.31,32 According to the literature, single rooms allow for increased privacy and confidentiality, as well as decreased stress of family, staff and patients.

Positive Distractions. Twenty-three articles focused on the effects of positive distractions on patient outcomes. Positive distractions have been defined as "environmental-social conditions marked by a capacity to improve mood and effectively promote restoration from stress."33 Positive distractions may include views of nature, bright light (natural or artificial) and the arts or entertainment. Several studies evaluated patient and staff satisfaction in hospitals that have incorporated design elements such as access to nature, artwork, music and single-patient rooms.

Among the Pebble Project Partners, for instance, the Barbara Ann Karmanos Cancer Institute in Detroit, MI, renovated two inpatient nursing units. Following renovation, patient satisfaction rose 18 percent. In a separate study, patients who stayed in hospitals with well-decorated and well-appointed, hotel-like rooms provided more positive evaluations of physicians and nurses and more favorable evaluations of support and ancillary services than patients who stayed in typical hospital rooms.15

A considerable research base highlights the benefits of bright light for improving health outcomes, particularly for mental disorders. Several studies found that bright light, especially morning light, is effective in reducing depression among hospitalized patients with bipolar disorder or seasonal affective disorders.27,34-37 An RCT conducted by Columbia University found that bright light acts as an antidepressant in patients with seasonal affective disorder.38 Other studies have demonstrated the negative effects of windowless hospital rooms on patient outcomes and satisfaction.28 Such studies have linked the lack of windows with high rates of anxiety, depression, and delirium.

A growing body of research focuses on nature33, music and artwork in the hospital environment. An RCT conducted by the University of Washington compared patient outcomes and satisfaction on the Planetree Model Hospital Unit (which incorporated holistic healing, nature, and artwork) with those experienced at other medical-surgical units in the hospital that lacked these elements.39 Planetree patients were significantly more satisfied with their hospital stay than patients in the medical-surgical units, and they reported more involvement in their care while hospitalized and higher satisfaction with the education they received.

Other studies have focused on the benefits of playing music in the hospital setting. Playing music during stressful times has been demonstrated to have a positive effect on patient comfort and to lower heart rate and anxiety.16,40-42 Another RCT investigated the effect of music during bronchoscopy on patient perception of the procedure.40 Patients who received music during the procedure reported significantly greater comfort and less coughing than the patients who did not receive music. Post-operative patients with views of nature also have less anxiety and require fewer strong pain medication doses.43 Several studies also found that patients in single-bed rooms reported higher levels of satisfaction than did patients in multi-bed rooms due to a variety of factors, including avoidance of transfers, and improved continuity of care.29,44-46

Patient Efficiency

There were two relevant articles for patient efficiency, both of which focused on wayfinding in hospital settings. Difficulty navigating hospitals is costly to patients, families and staff. According to a study conducted at Emory University, it was estimated that the annual cost of supplementing its formal wayfinding system exceeded $200,000. This cost was attributable largely to time spent giving directions by hospital staff whose job assignments did not include that responsibility. Time spent giving directions by these individuals exceeded 4,500 staff hours over the course of a year.

Two articles highlighted the difficulty that elderly and post-operative patients experience in navigating hospital corridors and hallways.47,48 Today, hospitals more often are designing systems that include clear and consistent verbal directions, easy-to-understand signs and numbers and an intuitive architectural design. For example, an improved unit design and layout at a new comprehensive cardiac care unit at the Methodist Hospital/Clarian Health Partners reportedly resulted in increased caregiver time with patients and increased nursing efficiency.

Patient and Staff Safety

There were 131 articles that focused on patient or staff safety. Articles pertaining to patient and staff safety included reports of research on hospital-acquired infections and handwashing practices, single-bed rooms, air filtration, reducing medication errors and reducing patient falls.

Hospital-acquired Infections. More than 100 articles were recovered that addressed the relationship between the hospital environment and hospital-acquired infections. Hospital design strongly affects hospital-acquired infection rates. Several studies focused on hospital employees' risk of contracting infectious diseases from patients due to airborne and surface contamination.8,49-53 Factors affecting infection rates include handwashing compliance (which can be influenced by the built environment), multi-bed rooms, air filtration and construction.

Rates of handwashing by health care staff are lower than accepted standards, and handwashing rates are observed to be even lower in units that are understaffed and have a high bed-occupancy rate.54,55 Several studies examined whether handwashing is improved by increasing the number of sinks or hand-cleanser dispensers in the wards; however, there was limited evidence for the benefit of increasing the number of sinks in the wards.56-58 There is also little evidence regarding the advantages of introducing educational programs to improve handwashing practices.59

Additional studies demonstrate the benefit of providing single-patient rooms with a conveniently located sink in the room.60-63 A before-after study of an anesthesiology department in Israel found a nearly 50 percent reduction (3.6 percent to 1.9 percent of patients) in nosocomial infections coinciding with a shift from multi-bed units to single-bed units in 1995.64 Reasons given for lower nosocomial infection rates include the relative ease of decontaminating single-bed rooms and decreased opportunities for person-to-person spread of infection.

Studies also were recovered that demonstrated the advantages of using HEPA air filtration in reducing hospital-acquired infection rates.65-68 Another study conducted in an Israeli hospital found that keeping acute leukemia patients in a special ward equipped with air filtration through a HEPA system eliminated the rate of pulmonary aspergillosis, as demonstrated by a decrease in the rate of pulmonary aspergillosis, from 50 percent in 1993 to 0 percent in 2001.68

Medication Errors. There is limited evidence regarding the influence of environmental factors on errors in prescribing or dispensing medications. Factors associated with medication errors include frequent interruptions or distractions, inadequate space for performing work and insufficient lighting.69,70 One study found that medication errors are closely associated with daylight and darkness hours.69 There is also a small body of evidence that links patient transfers to medication errors. Investigators call for further studies in these areas.71

Patient Falls. Patient falls are costly to patients, their families and to hospitals. It is estimated that, by 2020, falls will cost hospitals more than $30 billion annually.72 Patient falls also result in longer hospital stays and may prolong recovery times. Most falls that occur in the hospital are due to slippery floors, poor placement of handrails and inappropriate door openings or furniture heights.73

A growing body of research suggests that most falls occur when patients try to get in and out of bed without the assistance of hospital staff. According to an Australian study, transfers to and from bed were the cause of 42 percent of inpatient falls.73 After the hospital implemented fall-prevention strategies, such as a hospital design that enabled staff to view all patients simultaneously and more attention to ergonomic design elements, the number of falls decreased to less than 25 percent. According to Zimring and Ulrich's research, Methodist Hospital/Clarian Health Partners decreased the number of patient falls per day from six falls per thousand patients in 1997 to two falls per thousand in 2001 as a result of switching to single-bed rooms and incorporating decentralized nurse stations into the hospital's design.71

Staff Efficiency

A total of seven articles focused on patient efficiency. Articles on staff efficiency focused on ways in which the hospital environment affects staff communication and productivity.

Staff Communication. A small number of articles address how the hospital environment, including single versus double rooms and hospital layout, affects staff communication. Some of these articles also address how improved staff communication, in turn, affects patient experience. According to Zimring and Ulrich's research, in double rooms, staff may be reluctant to discuss patient issues or give information in the presence of a roommate, out of respect for the patient's privacy. Compared with those staying in double rooms, patients in single rooms report that staff communicate better with them, based on their willingness to discuss patient information more freely.8

More open communication between patients and staff appears to improve patient outcomes by alleviating anxiety and increasing the likelihood that patients and families will continue to deliver adequate care once they leave the hospital.16 Other research suggests that sound-reflecting surfaces and noise sources, such as paging systems and telephones, adversely affect the caregiver's ability to communicate with other staff and with patients.18

Productivity. Several studies indicate that the type of unit layout influences the amount of time nurses spend walking. For example, one study found that a radial nursing unit reduced the amount of nurse walking time. This translated into more time for patient-care activities and reduced exhaustion.74 A separate study found that redesigning placement of an outpatient pharmacy to be better aligned with staff work patterns led to improved work flow, reduced waiting times and increased patient satisfaction.75

Staff Satisfaction

A small number of articles addressed how aspects of the hospital environment affect staff satisfaction, ranging from safety hazards to positive distractions.

Staff Turnover. Low nurse retention rates and the growing nursing shortage have direct implications for the quality of care and overall patient satisfaction with the care provided in hospital settings. In the United States, the average annual nurse turnover rate is 20 percent and the average age of nurses is 43 years.76

Working conditions, including matters of workplace safety and stress, are among the key factors contributing to staff turnover. According to a 2002 Peter D. Hart Research Associates study reported by the Joint Commission on Accreditation of Healthcare Organizations, the top reason, after retirement, why nurses leave patient care is to seek a job that is less stressful and less physically demanding (56 percent).76 Several studies examined factors that create more stressful or dangerous work environments, including studies that evaluated health care employees' risks of contracting infectious diseases from patients.

A separate body of literature deals with staff risk of injury from medical equipment.49,50 There is also evidence that staff perceive higher sound levels as stressful and sufficiently high to interfere with their work.53 All of these factors may influence staff job satisfaction and turnover rates. Moreover, there is strong evidence that design changes that make the environment more comfortable and aesthetically pleasing will increase staff satisfaction. Design features that encourage positive staff interactions, such as gardens and lounges, could promote greater job satisfaction.16

Summary of the Research Base for the Built Environment

While the evidence linking hospital design to patient outcomes, patient and staff safety, and patient and staff satisfaction is growing, much of the literature comprises observational studies and review articles that are qualitative and anecdotal. As noted in Table 3, of the 328 studies identified, 45 are reports of controlled clinical trials, including 25 RCTs, 19 of which addressed patient outcomes. About 65 percent of the studies identified here are observational studies, most of which addressed patient outcomes and safety and staff safety. There appears to be little empirical evidence on how the built environment affects staff efficiency and satisfaction.

Although we identified 68 other review articles, there were only 3 reports of systematic reviews or guidelines. This suggests that much of the diffuse literature in this field has not been well consolidated. Certainly, as noted, there are many interactive effects among the impacts of the hospital built environment on patients and families and staff. Improved patient satisfaction likely contributes to patient outcomes, improved staff efficiency and safety likely contribute to staff satisfaction which, in turn, likely contributes to lower staff turnover. Better communication and improved satisfaction among staff and patients likely contribute to patient outcomes.

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Chapter 7. What are the Major Challenges in Building the Field of Evidence-based Hospital Design?

Hospital designers, administrators and researchers face challenges in building the field of evidence-based hospital design and incorporating what is learned toward improving patient safety, other outcomes and satisfaction. Based on our review of the literature and feedback from expert interviews, five major challenges are:

  1. Insufficient resources for conducting evaluations of the built environment.
  2. Difficultly gaining provider input and feedback on design.
  3. Reluctance to learn from design strategies that were ineffective.
  4. Obsolete or ineffective laws and regulations regarding hospital design.
  5. Capital costs of evidence-based design and renovation projects.

Insufficient Resources in Conducting Evaluations of the Built Environment

Currently, there are no major funders for research focused on the built environment. Many of our interviewees highlighted the need for more funding to support empirical studies that can be published in peer reviewed journals. Some studies have been funded by companies that provide services and products for office interiors, such as Herman Miller and Steelcase. However, our interviewees noted the need for research that is funded by unbiased and objective sources.

Provider Input

A second obstacle in building the field of hospital design and construction is the challenge of obtaining provider input and feedback. Hospital staff members spend much of their working lives—including interactions with patients—in the context of the hospital physical environment. They are likely aware of changes that could to be made to create safer, more effective and more efficient hospitals. Certainly, clinicians are among the professionals, along with architects, engineers and other professionals, who provide input to standards. However, the level of provider interaction with designers and architects during the hospital design and construction typically is limited and focused on capital planning issues rather than evidence-based design.

Information Sharing

There is an apparent reluctance to learn from design innovations that have been ineffective or harmful to patients and staff and insufficient incentives to share best practices in hospital design. According to several experts, architects and designers are hesitant to share "lessons learned" with colleagues, and there is little financial incentive for architects to measure and evaluate the success of their work after the completion of a project. As a result, limited opportunities exist for designers and architects to learn from hospital design innovations, whether successful or not.

Laws and Regulations Regarding Hospital Design

Our interviewees indicated that obsolete or ineffective laws and regulations also interfere with building the field of evidence-based hospital design. One expert estimated that 85 percent of the codes are promulgated for safety purposes, which are important for eliminating risks and hazards in the hospital. However, only 15 percent of the regulations pertain to other design factors, such as incorporating sound-absorbing walls and ceilings and adequate HEPA air filtration systems.

Many prevailing codes are ineffective or irrelevant today because of new hospital standards. For instance, most hospitals are required to have a shower that can be rolled into a patient's room for every 100 beds in the facility. However, all patient rooms are equipped with built-in bathrooms and showers, making this regulation irrelevant. Our interviewees suggested that eliminating antiquated regulations would unencumber certain hospital resources for investment in design innovations for use in hospital design toward improving patient care and the working environment for staff.

Some interviewees noted that most building codes are prescriptive rather than proactive. These tend to restrict the freedom and flexibility of designers and architects to incorporate new elements into the built environment. Hospital architects are subject to accepting the status quo dictated, at least in part, by the regulatory environment and are less inclined to advance the evidence base or implement current knowledge regarding ways in which hospital designs contribute to improved patient and staff outcomes.

Most of the architects we interviewed observed that building codes—including those that are no longer relevant and can be wasteful—are in place largely to protect patient and staff safety. However, without sacrificing safety in the current environment, building codes and other regulations could be modified to enable or facilitate more therapeutic hospital environments.

Capital Costs of Evidence-based Design

Renovating or building new hospitals is costly, particularly for hospitals that operate in competitive environments and generate low profit margins. Many hospitals have limited access to capital for construction projects and are under pressure to recoup their investment as rapidly as possible.

As noted by some of our interviewees, there is a perception among many providers that there is insufficient evidence to demonstrate that investing in this type of design produces an adequate return on investment, and that implementing what is known about evidence-based design is significantly more expensive than traditional design.

To help address the issue of whether there is a financial incentive for investing in evidence-based design, researchers at the Center for Health Design conducted quantitative modeling of a "fable hospital," based on design elements incorporated into various Pebble Project Partner hospitals. They calculated that an array of therapeutic design innovations, such as single-patient rooms and decentralized nursing stations, added almost $12 million in cost (about 6 percent) to the hospital reconstruction.

However, the researchers also determined that the hospital would recoup these costs in as little as one year through operational savings and increased revenue.8 This modeling exercise was shared with other hospital administrators with a desire to learn whether incorporating therapeutic design elements can achieve return on investment in a relatively short period with the potential for longer-term efficiencies.77

Despite their efforts, controversy remains regarding whether the high cost of hospital design and construction outweighs the operational savings and increased revenues that may be generated from design innovations. Among our interviewees and in the literature there is a lack of consensus regarding whether sufficient evidence exists to support the business case for better built environments, or whether the evidence is sufficient, but has not been presented or transferred effectively to health care executives, designers, and other decisionmakers. This apparent lack of consensus suggests that what is known must be shared and applied more effectively, and that more work is needed to validate the business case (or lack of it) in ways that will be persuasive to decisionmakers.

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Page last reviewed October 2005
Internet Citation: The Hospital Built Environment: What Role Might Funders of Health Services Research Play?. October 2005. Agency for Healthcare Research and Quality, Rockville, MD. http://www.ahrq.gov/professionals/systems/hospital/hospbuilt/hospenv2.html