Unfamiliar sights, sounds, and smells can have a direct impact on human health and behavior, as explained in Cornell University professor Gary Evans’ seminal book “Environmental Stress.” A growing body of research examining the effects of sensory stress reveals that when sensory levels exceed a person’s threshold, cortisol levels and nervous system activity become elevated, which can cause the body to enter “fight or flight” mode. If stress levels continue to be elevated, research presented in the environmental health text “Environmental Health: From Global to Local” suggests that a person can experience anxiety, depression, and even PTSD as a result.

Intensive care units (ICUs) often have high levels of associated stress for patients and staff. Traditionally, ICUs have been designed in a radial layout with a central nurses’ station and surrounding patient rooms. While this design strategy creates good patient visibility for medical staff, it often sacrifices privacy and sensory balance. Humans use their five senses to experience an environment, and typical hospital sounds such as beeping equipment, noisy supply carts, and loud conversations, combined with visually cluttered patient rooms, strange scents, and bright fluorescent lights can cause sensory overload and trigger physiological reactions for everyone who experiences the space. A research study on sleep in the ICU, published in the Journal of Intensive Care Medicine in 2016, suggests that prolonged sensory stress can impact the body’s ability to heal and may prolong hospital stays.

Beyond its impact on patients, the ICU environment can also adversely affect nurses and staff, who can become overwhelmed by the constant combination of surrounding sights, sounds, and smells. Without a space within the facility to adequately decompress, medical staff can experience burnout and compassion fatigue.

In 2012, when Gresham Smith (Jacksonville, Fla.) began designing Tallahassee Memorial Hospital’s (TMH) M.T. Mustian Center in Tallahassee, Fla., a new critical care tower to replace the hospital’s decades-old ICU, the project team focused on increasing capacity and integrating new technology, but most important was challenging the status quo in critical care design using evidence-based design. At one of the first meetings, the TMH team made it clear they wanted to integrate an onstage/off-stage approach to separate public and private spaces. The goal was to create an ICU environment that supports improved outcomes by decreasing sensory stress, not only by concealing staff work areas using but also by minimizing noise levels, maximizing visibility, and increasing natural light throughout the space.

The resulting five-story, 346,270-square-foot ICU and surgery tower, which opened in May 2019, modernizes the hospital’s surgery suite and adult intensive care units, creating a sense of place and a calming environment for people experiencing what’s often an extremely stressful time in their lives.

Prioritizing patients and providers

Prior to the new tower opening, data gathered from patients, families, and staff on the former ICU identified three types of environmental stressors within the space: sound, overall distractions, and room layout. Sounds and overall distractions included alarms, equipment sounds, and interruptions from visitors and medical staff, while stressors related to room layout included room size, lack of computer access, and no visible connection to the outside.

This feedback guided the design and planning of the new unit, which is housed on three floors, with one floor accommodating cardiovascular patients, one floor for neurology patients, and another floor for medical/surgical patients. Using the onstage/offstage design, each 24-bed floor has a racetrack configuration, with beds organized into pods of eight near three centralized nurses’ team stations. The longer, more linear layout was a deviation from the former ICU’s radial layout, which offered excellent visibility but was noisy and lacked privacy. To address these concerns, as well as the stressors identified based on input from TMH medical staff, the design team included an internal corridor in the new layout to keep staff and support activity away from patient rooms so that patients can rest quietly, free of distractions. Additionally, glass-walled nurses’ stations were chosen to minimize noise created by staff interactions while maintaining good visibility, which is important as evidence supports the relationship between visibility and patient outcomes in the ICU. Decentralized work niches throughout the unit also increase visual access by allowing medical staff to quietly monitor patients through a window without entering the room, as well as provide space for performing charting or other administrative tasks, further eliminating in-room distractions.

To address some of the environmental stressors related to layout, the ICU patient rooms are designed with three dedicated zones: a staff zone, a patient zone, and a family zone. The staff zone serves as a work area and is designated by differentiated flooring, while the family zone is equipped with outlets for charging devices, a reading light, window shade controls, and a sofa that can be converted into a bed, while large windows offer ample access to daylight.

Studying design decisions

After the M.T. Mustian Center opened in 2019, Gresham Smith’s Healthcare Research and Innovation team partnered with TMH to conduct a research-focused post-occupancy evaluation to compare the campus’ former ICU with the new environment to better understand how the ICU design impacted sensory stress on patients and medical staff. To collect data from the new ICU after it was occupied, the team used Hospital Consumer Assessment of Healthcare Providers and Systems (HCAHPS) scores and discharge surveys to measure patient perception of the ICU space; focus groups and turnover rates to measure staff perception of the ICU space; and acoustical levels within patient rooms and nurse stations to measure noise reduction. The data collected from both the old and new spaces then was analyzed by an external statistician using multiple regression analysis, a type of statistical modeling that looks at the relationship between data points, and revealed that the total sensory stress in the new ICU tower was significantly lower than in the old space. Specifically, the findings supported that the ICU’s architectural elements, including acoustically rated glass around nurses’ stations, internal corridors for noisy back-of-house support activities, and decentralized work niches for patient monitoring and administrative tasks, successfully mitigate sounds and overall distractions.

Acoustic analysis showed that while the quantity and types of sounds did not vary from the old to the new ICU, the overall acoustic levels were lower around nurses’ stations and inside patient rooms in the new tower. For example, the new patient rooms measured 3 to 5 decibels lower than the old rooms, likely thanks to the onstage/offstage layout and the acoustic glass around the central nurses’ stations.

Additionally, the staff reported that the decentralized nurses’ stations enabled them to block out unwanted sounds and focus more closely on their patients while monitoring them less intrusively. By the nature of the ICU, patients are monitored around-the-clock by staff, but staff felt that these alcoves provided an opportunity to monitor with less in-room distractions.

The team also used a space syntax analysis to analyze and quantify how staff experience the longer layout compared to the former radial floorplan. After applying a grid to the floorplan, the software calculated correlations between physical and visual accessibility, connectivity, integration, and intelligibility and displayed the results using a heat map to show high visibility (red color) to low visibility (blue color). The analysis revealed that while the new ICU floors are nearly three times longer than the old space, and therefore the patient rooms are spread further apart, staff still had good visibility and walkability, lowering their sensory stress levels and enabling them to more easily care for their critically ill patients.

Application in a post-pandemic environment

As COVID-19 cases fill intensive care units across the United States, it may be more vital than ever to implement design strategies in ICUs that help decrease stress and support positive patient outcomes. For example, as patients spend time alone in the ICU, staff have increasingly taken on the role of emotional caregiver in place of missing family members. The increased stress caused by the pandemic, combined with the sensory stress traditionally associated with staying or working in the ICU, is impacting patients and providers alike. Design elements that optimize acoustics and increase patient visibility for nurses, such as floor layout, room configuration, and glass placement, can have a positive impact on stress levels for patients, family members and staff, ultimately benefiting the quality of care.

More generally speaking, it’s important to note that while offstage staff circulation and enclosed nurses’ stations were initially designed to decrease noise levels within the TMH ICU, these features can also support efforts to decrease virus exposure and prove beneficial for social-distancing norms for hospital staff who continue to work under new pandemic guidelines. Additionally, decentralized nurses’ stations disperse staff throughout a floor and encourage physical distancing, while dedicated zones within patient rooms create separation between staff and family members as visitation resumes in general care settings.

Finding a balance between supporting efficient, safe processes and providing a comfortable, accommodating environment will be essential to creating a cohesive ICU that supports patients and staff wellness. The activities within the ICU are and will likely always remain stressful due to the nature of critical care, but evidence-based, human-centered design principles can create truly healing environments.


Lesa N. Lorusso, Ph.D., NCIDQ, Allied AIA, is the director of research and innovation in the healthcare studio at Gresham Smith (Jacksonville, Fla.). She can be reached at lesa.lorusso@greshamsmith.com.