DEVICE DESIGN

Certain macrotrends in the healthcare and medical device industries have created an environment in which it is critical that products do a better job of supporting patients' needs. In general, the population is aging. People are living longer and therefore require more care. But hospitals and physicians struggle to balance profitability with care excellence. The average length of stay for a patient decreased consistently throughout the 1990s. The shift in care has moved from the hospital to the home and from clinicians to family caregivers and the patients themselves.¹

Advances in technology have been able to support this trend. With the miniaturization and ruggedization of key hardware components such as pumps, processors, and displays, devices have become far more portable, and small enough to be hand carried, worn on the body, or transported on a wheelchair.

Patients themselves have also changed in recent years. Because patients (and their family caregivers) are able to access information via the Internet, they are becoming more knowledgeable about the care options—including devices, therapies, and interventions—they may receive to address their condition. Patients are also participating in virtual and real-world communities, and so are more empowered, invested, and active in the decisions related to their care.²

The Challenges

Because of these macrotrends in healthcare, medical devices (both critical and noncritical) are used more often in the home and are used in different ways from in the hospital. It is useful to explore these thematic differences before discussing how medical products need to be designed specifically for home use.

Variable Use Environments. Home-use environments include both the physical spaces in which devices can be found and where devices may be placed in relation to the patient. For discharged patients, especially those who are mobile, the environments of use are extremely varied. A personal oxygen device may be jostled as it is transported in a car, or it may be temporarily left in the car (with the window rolled up on a hot summer day) while the patient runs an errand. Broad variations in lighting, noise level, humidity, temperature, vibration, and stability need to be factored into development.

Differing Goals, Concerns, and Expertise of the Communities of Use. Communities of use refers to the people who interact directly and regularly with a device or who influence how the device is used. Communities of use typically include patients, family caregivers, nurses, physicians, and device suppliers and manufacturers. Each community of use has different goals for medical products in general, including specific goals for devices that are to be used by patients in the home. Understanding the goals, concerns, and levels of expertise of these communities is key to developing successful products.

Range of Clinical Scenarios and Patient Life-styles. A home-use medical device may be expected to support a broad range of etiologies (the causes or origins of the disease state), symptoms, therapies, data requirements, and patient life-styles. For example, an enteral feeding pump may be set to deliver continuous nutrition to one patient during a 10-hour period. For another patient, however, a 30-minute bolus of formula may be clinically appropriate. A pulse oximeter would provide varied readouts based on factors such as whether a patient is wearing nail polish one day versus the next.

Emotional Needs of Patients. Traditionally there has been limited focus on designing medical products that address the emotional needs of patients. Clinical requirements and the capabilities of the product have been the deciding factors while selecting products for patients. Patients had been given prescriptions and had little decision-making power regarding which product they used. As patients become more informed, however, their needs have become a more important factor in determining which products they end up including in their care.

Creating Positive Experiences

Designing medical products for the home, given all the challenges, may seem like an insurmountable task. However, if we think about the ways in which people connect with products to have a positive experience, it is possible to target areas of development that benefit from specific research and design techniques.

People connect to a product in three ways: through its usefulness, through its usability, and through people's affinity for the product. Product developers have traditionally focused on usefulness and usability as the ways in which people can connect with products. Methods for achieving usefulness and usability are well established, but can be challenging to implement when designing medical products for the home.

Usefulness. Usefulness is defined as the reason someone seeks a product or service. These reasons are simply so they can live better, achieve their goals, or be more productive. Observational or ethnographic techniques and open-ended discussions help developers discover what people need, or what would be useful to them. Validation methods such as scenario board development and directional testing can help determine whether concepts in development are delivering the promise of usefulness.

Usability. Usability refers to whether someone is able to use the product to an effective end, as the product is intended. Task analysis (analyzing the information and controls a user needs to successfully complete tasks) and usability testing (evaluating how well people understand what a product does and how well they make it do what it is supposed to) are two tools for understanding a product's usability. These methods, along with others such as heuristic evaluations and secondary physical and cognitive human factors data, are well proven in providing guidance to ensure a product's usability.

Figure 1. (click to enlarge) Designing for affinities requires a formal, iterative process that integrates research and design. Affinity. Affinity in product design is the emotional connection some individuals may have for a product. Perhaps they are drawn to its aesthetics or identify with the product and the message it conveys. In contrast to usefulness and usability, affinity is about want or unexplained desire. Specific narrative, projective, and associative research methods enable investigations into what leads to positive brand affinities with products. Specific approaches can be used to design for affinities based on the core values people would like the products in their lives to embody. The device should project the appropriate character, tone, or personality (see Figure 1).

Medical products are, by necessity, becoming more like consumer products. They need to be useful and usable, but they also need to build affinity with patients. Pharmaceutical companies are already responding to these trends with direct-to-patient advertising. This strategy is based on connecting emotionally with patients and playing off their new sense of empowerment. By doing so, a patient may be more likely to request a certain brand of drug from their physician.

To develop successful products for the home environment, we must consider the products' usefulness, usability, and affinity throughout the development process. What makes this integrated, iterative, multidisciplinary approach successful is strong collaboration between research (methods), design (creativity), and engineering (execution).

Successful Development

Specific product development techniques can be used to address a patient's need for usefulness, usability, and affinity for home medical devices. The best way to understand these techniques is to examine the design process and its influence on how products fit into patients' lives and support clinician needs.

Understanding Behaviors and Needs. Generative research borrows ethnographic and contextual techniques (including shadowing, narrative tours, and observations of use) and includes focused interviews (with open-ended and directed questions). The results define the needs, tasks, activities, and patterns of product use in various communities. Generative research is the main method for understanding what would make a product most useful. The insight derived from generative research defines opportunity areas for new products or features and improvements to existing products. It provides input that guides the overall product strategy and development process, ensuring that divergent user needs are met.

Designing for Environment Fit and Mobility. The industrial design process aims to create a range of physical solutions as informed by the generative research for what would make a product useful. Through the development of multiple, varying concepts, the team is better able to identify optimal approaches that align proposed feature benefits with engineering, manufacturing, and marketing goals and constraints.

Appropriate industrial design provides products that perform effectively across different environments and can move seamlessly between them. This may result in configurable concepts that can change in size or weight depending on circumstances and still operate successfully. At other times, the industrial design must consider appropriate, informed trade-offs to arrive at a singular, unchanging design that functions successfully across varied scenarios. A home ventilator that is used at the bedside needs to have a handle placed to facilitate transport without taking up valuable space needed for other equipment such as humidifiers and oxygen reservoirs.

Designing for Ruggedness. Effective industrial design also accounts for likely misuses associated with mobility. This includes preventive design measures such as ensuring proper distribution of component weight and ergonomic carrying affordances to minimize the likelihood of drops. It also includes thoughtful implementation for all of the device's functional details. For example, a device shouldn't have tube connections that overtly protrude or include any part that might be prone to breaking. Also, using innovative materials can provide robust, wear-resistant surfaces that soften the impact of collisions.

Designing for Confidence. The design of the device must promote confidence and compliance, as well as minimize intrusion on the quality of life for patient and caregiver. Therefore, the design must present interaction points in an obvious and fail-safe manner that reduces the steps required to use the device. Hose and cable connections should be clearly differentiated as much as possible, utilizing size, shape, and color, to prevent incorrect use. Removable parts such as batteries or disposable cartridges should be designed to clearly indicate proper alignment and prevent improper loading.

Designing for Ease of Use and Learning. Ease of use directly affects the success of home healthcare devices. One aspect of ease of use is the appropriateness of information and controls to the user's tasks. If a wound-prevention mattress (used in the home to prevent pressure ulcers) enters an alarm state because there is insufficient airflow, ease of use dictates that controls for increasing airflow should be readily available with the alarm. Usability testing of various scenarios helps developers map device information and controls for user tasks.

Ease of use also relates to the readability and clarity of instructions, graphics, and icons. With therapy devices such as volumetric infusion pumps (for delivering very accurate flow rates of intravenous fluids), setup errors can result if the home caregiver inputs incorrect numeric settings, such as volume to be delivered. Often, these mistakes occur because simple elements such as decimal points may be too small to see.

Because most home caregivers do not have a clinical background, devices should be usable with little or no training. Ease of learning reduces user errors, improves patient safety, and increases user satisfaction. Borrowing from interaction models established by consumer products like televisions, cell phones, and personal computers is an effective method for increasing ease of learning. For example, a glucose meter may use soft keys, similar to those found on ATMs, for selecting options or initiating processes. Ease of learning benefits suppliers and manufacturers by reducing the costs of training and ongoing support.

Designing for Safety

A device's ease of use and ease of learning directly contribute to the overriding goal of safety. Designers need to integrate safeguards so that stopping the airflow to a ventilator-dependent patient, for example, is a two-step, intentional process. Device alarms, though stressful, can alert caregivers to problems and provide information to help resolve the alarm condition.

In addition to audio alarms, distinct visual shifts in screen color or layout can draw a caregiver's attention to scenarios in which the device is one of many medical devices in a busy room. Iterative interaction design helps developers strike the proper balance between ease of use and safety.

Evaluating Concepts

Evaluative research can narrow a wide range of potential designs into a single, viable direction for further development (a process known as directional testing). Evaluative research can also be used to refine the usability (including both physical and cognitive human factors) of a more advanced concept before it is finalized for implementation (typically called usability testing). Directional and usability tests should be conducted with both primary and secondary stakeholders in the actual environments of use. For best results, use the highest-resolution prototypes possible, although there is also a lot of value from getting input on more basic prototypes early in the development process.

Investigating Affinity

Affinity is a key aspect of how people connect with products. Designing for affinities is one of the most challenging parts of developing medical products for the home. Affinities are hard to investigate because emotions are often linked to memories and can change over time. Emotions are also delicate and tricky to communicate accurately, and people are uncomfortable revealing emotions to strangers (such as researchers). Affinities are also challenging to capture. Typical contextual research techniques of observation do not offer value because it is rare to witness meaningful emotions. Traditional interviewing techniques often fail because emotive words may mean different things to different people.

However, there are some things that people do well in relation to communicating their emotions. For example, people are comfortable telling stories about their experiences in their own terms and responding to stimuli. Specific techniques tap into these tendencies and can reveal individuals' emotional connections to products.

Encouraging participants to engage in storytelling may reveal emotional connections that do not surface with other investigational methods. Storytelling. Storytelling is a narrative technique in which participants tell a story about an image they have selected from a collage. Participants choose the images they are most passionate about. The choice indicates emotional triggers and connections. This technique encourages recall of memories, aids in describing emotions, and focuses the participant on a single feeling, making the discussion less abstract. Storytelling explores influences beneath behaviors that are typically observed and reveals how affinities change over time.

Scenario Building. Scenario building is a technique in which participants project their ideal experiences onto abstract, open-ended scenarios. For example, a participant is encouraged to build on a cardiac care device, to say ideally how the device would behave, act, and respond. The person may describe an entity that continuously monitors heart health and that can also do anything else asked of it. This method allows participants to think beyond constraints of current technology and exposes true desires.

Style Boards. With style boards, designers and researchers collaborate to build frameworks of images of existing products clustered into distinct aesthetic categories (see Figure 2). Clusters are meaningful to designers (they contain obvious form, color, material, or finish elements) and represent semantic opposites to participants. Participants respond to the image boards and indicate the cluster in which they would expect to see a product concept and explain why.

Sensory Stimuli. Associative techniques, such as having participants react to texture and material samples, color swatches, word cards, or sounds, draw out stories and emotions related to all senses. These stimuli serve as a catalyst to start dialogue and enable sharing of information throughout discussions. They represent all senses and allow for subtle unarticulated preferences.

Designing for Affinity

Designing for affinity requires a formal process. Once the core values that patients would like a product to embody are understood, designers can think about how a device can best address those values. The character of the product is manifested through its industrial design (the way the product looks and what it does) and its experience design (the way the product acts and how you interact with it). Design principles define character as the signature elements and specific features, functions, attributes, behaviors, and affordances that are concrete and actionable.

Visual Language. Visual language communicates the character of the product through aesthetics (form, color, material, and finish), graphics, and defining signature elements. If a visual language is to be successful, it must systematically relate to the core values of patients and the experience they desire. For example, if a glucose meter is targeted for teenagers, it may be designed so that it presents an image of a “cool” consumer device (e.g., an MP3 player). The method addresses teenagers' need for discretion while still communicating advanced technology.

Experience Design. Part of product satisfaction comes from supporting the type of experience people want to have. For instance, if research indicates that people want to be uninhibited by their personal oxygen system, designers must ask themselves what they can do to promote a feeling of freedom. One approach might be to introduce more automation into the device such as pressure sensing so that more oxygen is delivered when the patient is active.

Alternatively, the designer may introduce single-handed or hands-free operation elements. Designing for affinities in medical products often requires careful balance between divergent goals; elements of a product's character or personality may be in conflict. For example, the development team may need to balance a friendly and approachable tone with trustworthiness, seriousness, and reliability expected in a life-sustaining device.

Conclusion

By using a multifaceted suite of methods along with an expert, multidisciplinary team, it is possible to develop medical devices for the home environment that address patient and family caregiver needs for usefulness, usability, and affinity. Developing products that connect with patients in these three ways has many benefits including increased sales via patient pull-through, word-of-mouth publicity, and brand recognition and loyalty. Most importantly, good design leads to increased patient compliance and better clinical outcomes.

Matthew Jordan is director of research and interaction design at Insight Product Development (Chicago). He can be reached at [email protected].

References

1. Report to the Congress: Medicare Payment Policy Appendix D, Table D-3, “Change in Medicare Inpatient Length of Stay, 1991–2000” [online] (Washington, DC, Medicare Payment Advisory Commission, March 2003 [cited 7 January 2008]); available from Internet: www.medpac.gov/publications/congressional_reports/Mar03_AppD.pdf.

2. “E-Patients with a Disability or Chronic Disease” (Washington, DC, PEW Internet and American Life Project, October 2007 [cited 7 January 2008]); available from Internet: www.pewinternet.org/pdfs/EPatients_Chronic_Conditions_2007.pdf.

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