Manufacturers need to integrate the new usability standards into the product development process.
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Introduced in 2010, the new set of human factors standards (ANSI/AAMI HE75 and IEC 62366) aims to address the high number of medical device incidents that involve usability issues. By requiring companies to track user feedback and justify proposed use-error mitigation approaches, regulators are emphasizing the important role usability plays in product safety. These new regulations are also a response to the transition of device use away from clinical environments. Many medical devices are increasingly being used by patients who have less experience and training.
In addition to promoting safety and user compliance, integrating usability into a product development program is good design practice. Manufacturers should take a holistic view of usability, incorporate it as a key component of every product development program, and make sure that the specific market demands for each new product are understood from the onset.
Why Spend Time on Usability?
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If the patient is involved in using a product, human factors should be at the core of the development process. Integrating usability into this process is good design practice and ensures that a product is usable. If a product is user-friendly and designed appropriately, it is more likely to be used regularly and as intended, which ultimately leads to increased compliance and improved clinical outcomes. When usability is not properly considered, there is greater potential for incorrect usage, and clinical outcomes could be affected.
For example, a diabetic who needs to take medication while at a restaurant might want an insulin device that can be used discreetly, quickly, and with one hand. When designing products for diabetics who are visually impaired and have limited dexterity, the possible capability limitations are even more important to consider. An appropriately designed insulin device reduces the potential for use error and risk while maintaining patients’ comfort and confidence and inspiring their trust. By optimizing the user experience, the device will be desirable and facilitate customer loyalty.
The typical goal of a product development program is to ensure that a product works effectively, meets end-use objectives, and achieves target commercial return. Usability is often sidelined, delayed, or considered an add-on to technical development, but this notion is a mistake. Integrating human factors engineering can support all three elements of this goal. It provides essential insight that can balance, challenge, inform, and direct technical decisions throughout the development life cycle.
In extreme cases, poor usability can lead to product recalls. Aside from being costly to rectify, it can also have a damaging effect on a company’s reputation. It is important to note, however, that the converse is also true. A company can gain a positive reputation for product usability, leading to increased customer loyalty and sales across its entire product portfolio. Well-designed devices come with straightforward user manuals, simplifying customer support operations and reducing patient training time and sales support requirements.
Companies can take a flexible R&D approach when integrating human factors into a product development program. Strategies can range from the relatively simple, such as having a specific usability expert challenge product development at appropriate points, to more in-depth, such as using specific human factors tools throughout the development process.
What’s Your Approach to Human Factors?
Once the importance of usability is understood, the manufacturer should make a plea of action. The methods selected should provide insight into factors such as how the product is perceived, how it can be used or misused, potential use errors, and possible workarounds. The following is an overview of three groups of usability tools that are fundamental to any medical product development program.
Context Exploration. This tool helps to define target users and their use environment. It involves the exploration of task analysis, use scenarios, and potential use errors and hazards. Capability exploration should also be a key part of human factors. It involves exploring the physical, cognitive, and sensory boundaries of each user profile and should be used as a framework throughout user testing.
There are seven capability scales that can be used in isolation to explore and improve the usability of a device or concept. The seven scales are divided into within three categories: physical (locomotion, reach and stretch, and dexterity), sensory (vision and hearing), and cognitive (intellectual functioning and communication).
User Perspective Exploration. User study tools take many different forms, but all should explore potential use errors and hazards, user preferences and instincts, physical and cognitive demands, and user performance and capability boundaries. The study tools should be used to evaluate all influencing users, including a cross section of each user type as appropriate (i.e., patients, caregivers, and health professionals).
It is important to note that within patient groups there may be people with different capability types, product experiences, health requirements, support mechanisms, environments, and geographies. An expert opinion can also be used to supplement or, if necessary, serve as a substitute for input from real users. Experts can approach usability from a human factors perspective or, as with a caregiver, a medical care perspective.
Justification and Documentation Requirements for FDA Approvals. With the implementation of new human factors standards, additional documentation and justification are required. There are many tools that can be used to address this requirement. These tools include user failure modes and effects analysis or task analysis, which consists of an analytical process that follows the usage sequence to identify opportunities for usage error. In addition, reports from user studies verify usage against usability specification. One company developed a useful method that involves tagging and tracing all potential usability issues. This approach creates a single live document that captures all required information (including usability goals, potential use errors, observed usability issues, risk scoring, and proof of verified mitigation) structured around the task analysis for simplified management.
All FDA documentation must include an explanation of the company’s plan for managing and mitigating possible risks. The new standards (both HE75 and IEC 62366) specifically require companies to justify their device decisions from the user’s perspective. FDA may previously have accepted a design goal for, say, a simple task such as removing the cap of a diabetic pen, in which 80% of users could open the device on the first try.
However, the agency now wants to know more about the 20% that couldn’t use the device—including what those patients did and why, and what is the resulting safety risk. Then, a plan to mitigate or control expected or actual use error must be made. This plan may call for a product modification, changes to the user training manual, or printed warnings on packaging or the device. The crucial point here is that all outcomes must now be justified, tested, and documented.
Integrating Usability into Product Development
Human factors is a key but flexible part of a company’s product development process. The main principle for integrating usability into a product development program is that the specific nature and objectives of each device are understood and addressed. When deciding on the type, shape, and size of the usability tools, it is important to consider a number of factors.
When beginning the process, the following questions can be helpful:
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Is the product a completely new device being developed for a new market, or is it an existing device, redesigned for a highly populated market?
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How complex is the user interaction with the device?
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What is the potential for and severity of harm that can be caused by interacting with the device?
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How much time and how many resources are available to complete product development?
These factors have a significant effect on what and how many usability tools a company chooses, and when and how they’re integrated.
The new standards will have varying effects that depend on a company’s current approach to usability and human factors. If human factors are not significantly integrated into a company’s approach, the new standards should guide the tools it chooses and how they’re integrated into the process. Alternatively, if human factors are currently integrated, these standards may simply direct how a company documents, traces, and justifies the risk of potential use error.
Usability Issues in Medical Devices
The process of integrating human factors research into medical device design can vary considerably, depending on what device is being developed. A company should understand both the device category and the product’s specific objectives.
Drug Delivery. Drug delivery devices for personal use are well established. Products that deliver insulin, heparin, and etanercept (Enbrel) are notable examples. However, recently users have begun demanding more performance and functionality. Pharmaceutical companies are increasingly leveraging device usability as the primary differentiator in the market.
The diabetic market is a prime example of this shift. Insulin pens have significantly evolved since they became available in the early 1980s. First seen as a new and exciting drug delivery approach with limitations, the technology has since undergone reliability, performance, and usage improvements. Understanding the patient profile and scenarios of use are extremely important in this area. Diabetes affects a broad range of the population—including the young, old, active, and fragile. A person can have diabetes for a significant period of time, which will affect his or her attitude toward the disease and toward administering insulin. Their experiences using different devices, approaches, or routines to manage their condition also affect them. Manufacturers have been exploring how diabetes affects a person’s capability, preferences, and attitudes because understanding these changing factors is essential to designing a successful and usable device.
In comparison, the use of autoinjection devices for rheumatoid arthritis is a relatively new development. Enbrel launched the Sure-Click device in 2006. Having an autoinjector in this disease area is now seen as a necessity rather than an option. However, from a usability point of view, these devices are less mature than insulin pens. There is an opportunity to create differentiation and improve usability by taking into account disease condition and its effect on users’ capability, by gaining a deeper understanding of the potential scenarios of use.
Critical Care. The usability of devices and equipment in the critical-care sector has always been of paramount importance. Incorrect data interpretation or a wrong action can result in severe patient harm. Now, with the increasingly popular trend of treating many chronic conditions at home, manufacturers of critical-care equipment are facing more challenges. They must consider how to design for a future in which the user may not be a highly trained specialist, nurse, or technician, and the environment may not be quiet, clean, and closely supervised.
FDA is pushing for these factors to be a consideration now, even if the current generation of the device is designed specifically for the hospital. The aim here is to save the time and cost of subsequent product iterations for the home market. It could also mitigate the inevitable safety risks that result from using a device that has not been designed for an untrained user group or the home environment.
Companies that introduce new products for home use must be fully conversant with the usability issues that a change in environment and user profile brings, especially if they are designing a device that had previously been targeted for use by highly trained healthcare professionals. Human factors research can access and quantify the interaction design subtleties that provide confidence, trust, and product familiarity, providing valuable insights to the development team.
The following usability issues must be considered:
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The mental models of a specialist nurse versus a lay care worker or a patient are very different. In the case of a nurse, the designer will make usability assumptions based on operational skills that the nurse acquired by using similar equipment in a similar clinical environment. These assumptions are no longer valid if the equipment is meant to be used by a lay care worker or patient.
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A clear confidence and psychological disparity exists between patients and clinicians. A patient and their caregiver have a less intimate knowledge of the equipment than a trained specialist, who will know exactly why a particular alert light is flashing and what action needs to be taken. Where the caregiver and patient are concerned, significant emotional and psychological factors must be considered.
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The differences between the home environment and the hospital setting bring particular usability challenges, some of which are subtle and can be overlooked by designers. For example, in some scenarios, caregivers may not always be in the same room as patients, so they may not hear alarms. Supplies of consumables may run out, leading to the attempted reuse of disposable items. Utility supplies may be less secure. Untrained users may be unaware of the significance of extended power cuts.
Diagnostics. A prevailing trend in clinical diagnostic testing is to move from the central laboratory to the point of care in the clinical market. Some clinical diagnostic tests, such as those used to monitor blood glucose, are routinely used in the home environment. Although these diagnostics are ultimately ordered and managed by healthcare professionals, the devices are increasingly being operated by patients.
This theme is mirrored in the consumer healthcare market. The driver is the growing desire among consumers to manage health and wellness (i.e., fertility monitoring, cholesterol tests, pregnancy tests, and the monitoring of blood pressure levels). Although many of these diagnostic tests would not be considered life-critical, the market for home testing and monitoring is fast growing.
Infectious disease testing is an example of a fast-growing application of point-of-care diagnostics. Infectious diseases need to be detected and treated rapidly. In the future, the detection element of these tests could be performed in the home environment, increasing the speed and cost of detection. However, as designers begin making important like that for relatively unskilled users, it is crucial to consider the following:
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How the user interacts with the device. These devices are likely to be unfamiliar to general consumers. Devising a design that ensures correct usage will be challenging.
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Managing how the user understands, reacts, and responds to the result. Ensuring that the user interprets the results and responds appropriately can be as challenging as ensuring proper usage.
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Ensuring the reliability of the device and the result, given the variability of use conditions.
There are also additional points to consider, such as the ethical question of which types of diagnostic testing should be patient-driven. Where is the line between helping people take control of their health and enabling hypochondria?
Certain invasive diagnostic procedures, such as biopsies, cancer screening, and disease-specific diagnoses, will remain in the hands of healthcare professionals. However, when there is a clinical benefit to giving patients control over diagnostic tests and devices, it is crucial to fully integrate human factors into the product development process.
Surgery. Surgical devices are used by highly trained medical specialists. For this reason, there is a tendency to underestimate the benefit of usability analysis. However, in the often hectic environment of the operating room, a poorly designed device can distract medical specialists.
Examples of such situations are numerous and take many forms—optical aids that are difficult to adjust; buttons on devices that require surgeons to change their grip during surgery; and minimally invasive devices that require the surgeon to adopt an uncomfortable position. Packaging for disposable devices can be an overlooked component of surgical device design. Disposable devices are frequently unpacked by the operating room staff and handed to the surgeon prior to or during surgery. Packaging should be designed to make this transaction as easy and seamless as possible.
One emerging usability trend in the surgical sector is the growing popularity of robotic surgery. In some cases, surgeons have moved from a tactile experience at the operating table to a console where they perform surgery using remote controls. Having complete control during surgery is vital, and surgeons need to be confident in their ability to control the procedure. To develop a robotic system that enhances the surgeon’s experience, it’s important to understand the key aspects and nuances of nonrobotic surgery. This understanding will ensure that the user makes a comfortable transition to the remote approach.
Another trend in the operating room is the increased use of navigational technology during complicated procedures such as brain or orthopaedic surgery. Both the physical interaction with the navigation system as well as the provision of visual cues via monitors require a deep understanding of the user, the environment, and the clinical procedures. Context exploration can be used to gather this information in a structured format.
Finally, it is important to note that the design and usability of surgical devices is also important when viewed from a liability perspective. Once the product is approved, it will enter the market and, in some situations, could cause harm to patients or operators, resulting in product liability or other litigation. Although adhering to the new standards will not provide guaranteed protection against this threat, acting on and addressing the usage issues that arise from the process can help.
Human factors engineering can ensure that a surgical device is performing as intended. Potential errors, especially those that can lead to serious harm and fatalities, will be fully understood and addressed by the time a product is released. Human factors engineering can also reduce the risk of a successful claim. Failure to address potentially harmful usage errors identified in the development process is likely to complicate the defense of any future litigation. The company that sells the product will be exposed to accusations of recklessness and negligence.
Conclusion
In the past, some have dismissed human factors research as a step that could be sidelined if budgets and deadlines were too constraining. However, the implementation of standards are putting an end to this view. They support the growing awareness that integrating usability principles in the development process is good design practice and leads to safe and usable products. Device companies that understand this notion can gain a competitive advantage by offering the market differentiated and more desirable products.
To ensure that an effective and efficient approach is taken to usability, it is important to understand the use criteria and identify the best tools for a human factors specialist. The human factor needs may vary across the industry. Regardless of the different emphases or focal points, human factors research is growing in importance for all medical device makers.
Kay Sinclair is managing consultant at Sagentia Ltd. (Cambridge, UK). Natalie Scott is a consultant at the firm.