Taking the Pulse: Human Factors Engineering and Its Application to Medical Devices

The era of learning about human factors engineering (HFE) and how to apply it to medical devices, which began in earnest by the late 1990s, is ostensibly over. After all, it has been about 25 years since the Quality System Regulation (QSR) in the U.S. called for devices to be designed in accordance with users’ needs and then be validated as enabling people to use them safely and effectively.

Medical device companies have had a quarter century to integrate HFE into their development processes and quality systems. That’s quite a long time to “come up to speed,” considering some people born when the QSR evolved in 1996 are in fact working as HFE specialists in medical companies. Therefore, it is problematic when a medical device company attempts to excuse their inattention to HFE because the requirements are “new.”

Fortunately, most medical device companies seeking to sell products in the U.S. (as well as in the EU, U.K., Canada, China, Japan, and several other markets) are practicing HFE comprehensively and vigorously. Many companies have established sizable internal HFE teams, some boost their inhouse team with consulting support (i.e., taking a hybrid approach), and some mostly outsource the work to consultants. All three models for applying HFE during medical device development can work well, while the hybrid model appears to be the most common.

There are several beneficiaries when HFE is effectively applied to medical technology. An obvious one involves the patients receiving medical care; care delivered by clinicians using devices designed to meet their needs and particularly, to prevent harmful use errors (i.e., mistakes). This truly makes patient care safer. Clinicians benefit because user-friendly medical devices can help them do their best work and do it efficiently with less concern for becoming the victim of poor design that can trigger a mistake. Finally, medical device companies benefit in myriad ways, which might include moving faster from design idea to regulatory approval, enabling them to bring a device to market that promises to protect and satisfy users. Moreover, the smart application of HFE can produce products more likely to enjoy commercial success, delivering financial rewards to the manufacturer.

Therefore, you would expect companies to invest heavily in HFE these days, and this is indeed the case. In just the past five years, it seems spending on HFE has gone through the roof. At the same time, the spenders are expecting a strong return on their investments. Companies are building sometimes spectacular usability test laboratories to bring prototype products and intended users together to study interactions. These showcases are nice but companies can also conduct usability tests in free conference rooms in many cases.

Companies are also clamoring for HFE talent, which has created a tight labor market. The high demand for talent has lured more than a few HFE specialists working in aviation, consumer products, and software to the medical industry. Companies are fortunate when they find a reasonably experienced HFE specialist who understands how to develop products for sale in a regulated market.

The onset of the COVID-19 pandemic in early 2020 presented a speed bump. You can imagine the challenges posed by social distancing when a significant part of practicing HFE comes down to observing people at work, conducting interviews, running usability test sessions, and related activities that normally involve close contact. In the first few weeks of the pandemic and social isolation in the U.S., for example, HFE activities largely ground to a halt. However, folks quickly pivoted to using various means to conduct user research remotely, including having people interact with virtual devices shown on a computer.

There was also a sudden, high demand for HFE practitioners to apply their skills to high-demand equipment such as ventilators, personal protection equipment, infection tracing solutions, and test kits. Ultimately, the HFE community worked in impressive harmony to identify new methods and tools to optimize non-contact methods of research, as well as ways to conduct in-person usability tests with effective safeguards in place. Today, HFE is being applied in most regions with compromises (e.g., maintaining social distancing) related to COVID-19, when necessary for human subject protection purposes.

Presently, there are some particularly “hot” areas of HFE focus. The application of HFE to classic medical devices, such as anesthesia machines, intravenous infusion pumps, blood analyzers, and hospital beds continues at a good pace. In parallel, attention to combination products (devices that deliver drugs) seems to have grown exponentially, perhaps because few drug companies were paying attention to HFE as recently as 10 years ago. These companies came to realize the U.S. Food and Drug Administration (FDA) and other regulators were rejecting applications to bring “combo” products to market without evidence the people dispensing, administering, and taking the meds could do so correctly. You could say these companies (and more broadly speaking, the pharmaceutical industry) accelerated from 0 to 100 MPH when it comes to applying HFE to their drug product development processes. As a result, we all have better combo products, such as pen-injectors, inhalers, nebulizers, drug patches, and wearable drug pumps, plus improved instructions for use that come with them.

Another “hot” area of focus is connected devices. It seems like every newly developed combo product and medical device is used in conjunction with a smartphone app and/or a website. This assessment is a bit of hyperbole, but you are seeing insulin pens that communicate wirelessly with a smartphone app to track delivered doses. You are seeing infusion pumps placed at a patient’s bedside programmed by people working in a hospital’s central pharmacy who send the pump orders over the air. You are seeing hospital beds that use air mattress sensors and clever algorithms to tell when a patient awakens and wirelessly alerts the patient’s nurse. Although amazing, perhaps none of these impressive capabilities is surprising at a time of remote control over home thermostats, smartphones that enable you to deposit a check in the bank by photographing it, and wrist watches that can detect atrial fibrillation.

Clearly, new technologies are enabling products to do more for people. However, HFE specialists also play an enabling role. They “fight the good fight” against functional complexity that can overwhelm users as well as user interface design shortcomings that distract, frustrate, and induce use errors. Following are just a few of the things HFE specialists in user interface design roles are doing to make medical technology safer and more satisfying to use.

• Simplifying how a device’s functions are organized to match the mental models people bring to their work.
• Presenting the most essential and commonly used controls at the top level of a user interface (e.g., main menu, physical control panel) for user awareness and rapid access purposes.
• Applying population conventions and standards intended to create some consistency in how various types of devices work, rather than requiring users to master the special interaction language “spoken” by a given device.
• Building in protections against use error (i.e., risk mitigations) such as physical and software-based interlocks, requests to confirm critical actions, and automation that eliminates the need for human action that might be prone to error.
• Designing learning tools such as printed instructions, video animations, and simulators that help people move smoothy along the journey from novice to master regarding how to operate a given device.

In summary, the “patient” is doing well. In this case, the patient is the medical device industry (including pharmaceutical combination product and IVD developers) and the chronic condition is technologies that may become difficult to use and capable of inducing harmful use error. Many HFE specialists working in the medical device industry are having a positive impact, but there is still more that can be done.

The industry will get through the current period during which there is a shortage of HFE specialists because many universities are steering their HFE programs to include a focus on medical technology.

Meanwhile, the larger and persistent challenge is to apply HFE on a continuing basis, like committing to a routine exercise program for the sake of good health, rather than the metaphorical equivalent of taking a short course of antibiotics. The key is to integrate HFE into the entire product development process, rather than apply it only when a product is nearly finished. Applying too little HFE and applying it too late can be painful, as it is still expensive, frequently reveals the need for extensive and expensive rework, and delays regulatory approvals and market access. 

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Michael Wiklund serves as general manager of the human factors engineering practice at Emergo by UL, a consulting practice within UL Solutions. The consulting practice includes 60 HFEs working at dedicated sites in the U.S., the U.K., The Netherlands, and Japan. Previously, he was president of Wiklund Research & Design, a human factors consulting firm that UL acquired in 2012. A Certified Human Factors Professional, Wiklund has more than 40 years of experience in human factors engineering, much of which has focused on medical technology development. He is author, co-author, or editor of several books on human factors, including “User Interface Requirements for Medical Devices,” “Medical Device Use Error – Root Cause Analysis,” “Writing Human Factors Plans & Reports,” “Designing for Safe Use,” “Usability Testing of Medical Devices,” and “Handbook of Human Factors in Medical Device Design.” He is one of the primary authors of today’s most pertinent standards and guidelines on human factors engineering of medical devices: AAMI HE75 and IEC 62366. In additional to leading UL’s human factors engineering practice, he is a professor of the Practice at Tufts University where he teaches graduate courses on HFE, including applying HFE in medical technology development. In 2018, he received the Human Factors and Ergonomics Society’s (HFES) A. R. Lauer Safety Award.