Both HFE and UE are based on the international usability standards IEC 62366-1 and IEC 62366-2 with consideration of risk management (ISO 14971). By planning and integrating usability testing for human interaction with medical device technology throughout the device lifecycle and risk management processes, HFE/UE ensures that medical devices meet the complex needs of healthcare professionals and patients, and that user-related and use-related risks are eliminated or mitigated.

Consequently, usability and HFE processes play a pivotal role in ensuring medical devices are safe, effective, and user-friendly. Only by identifying and integrating relevant human factors early in the design process can medical device engineers make informed design decisions regarding ergonomics, materials, and labeling.

The importance of usability and HFE in medical device design

Usability and Human Factors Engineering (HFE) in healthcare is not a recent requirement, but its importance has grown alongside technological innovations and the increasing complexity of interactions and use scenarios of medical devices, which can be more error-prone without meticulous design. An early empirical example of the effectiveness of usability and HFE in healthcare was seen in the redesign of a patient-controlled analgesia (PCA) pump’s user interface (Lin et al., 1998). The study showed reduced programming time, decreased mental workload, and fewer errors, highlighting the practical benefits of HFE in medical equipment design.

Usability and HFE considerations encompass three primary components: device users (e.g., nurse, professional caregiver, etc.), device use environments (hospital, home, etc.), and device user interfaces (visual displays, alarms, etc.). The concept of user-centered design is a strategic approach to design development that aims to place the end-user at the center of the design process and simulate real-life use scenarios to effectively identify usability issues.

Ultimately, the overall usability goal is to prioritize designing systems around people’s tasks and work, thereby minimizing human errors. To achieve this, manufacturers must first perform one or more formative usability evaluations (exploratory studies) of the reasonably foreseeable hazard-related use scenarios to explore and understand user interface design strengths, weaknesses, needs, pain points, and unanticipated use errors. Engaging with potential users such as healthcare professionals and patients can provide valuable insights for design decisions. Formative usability evaluations should be conducted during the development phases (concept generation phase) and are understood as development-accompanying evaluations of the user-product interface. At the end of design development (design validation), summative usability testing must be conducted to demonstrate that the device is safe for use by its intended users. Such summative usability testing should involve the intended users under realistic conditions and may be combined with clinical testing. This proactive approach to formative and summative usability testing (human factors studies) diminishes the necessity for extensive redesigns, thereby enhancing the probability of successful design development. By doing so, it saves valuable time and resources while optimizing human performance, ensuring that medical devices operate safely and effectively in their intended use environments. It is crucial that usability evaluations are conducted by teams that include engineers, designers, HFE specialists, and clinical experts. This multidisciplinary approach ensures feedback from all involved parties and integrates these diverse perspectives into the design and risk management processes.

However, usability does not stop after design development; it applies throughout the entire product development process and may include post-market evaluations for identifying design flaws or confirming adequate usability for design changes.

Balancing common usability elements and regulatory requirements

While the fundamental usability goals of improving safety and effectiveness are widely harmonized, regulatory bodies in various regions may emphasize specific usability or HFE guidelines or have unique interpretations and priorities. For example, China’s NMPA guidelines now align with the US-FDA recommended minimum of 15 users per group. Additionally, the approach and methods align with those recommended by the FDA and in IEC 62366-1 in the US and EU. However, testing in China mandates the use of Chinese for instructions and labeling, whereas English suffices in the US, and national member state languages (>20) are required in most countries of the EU. Therefore, depending on the users (specifically for lay users) and use scenarios, planning for multilingual testing may become essential during summative evaluations, not only to develop safe-to-use devices but also to meet basic regulatory requirements.

Regulatory submissions in the US, EU, the UK, and China necessitate formative usability evaluations and summative usability testing with a specified number of users in the intended use environments. This testing must be conducted with the final product design as part of the design validation. If not planned and carried out methodically throughout the design phases, the process of planning, selecting appropriate users (participants), testing, and providing comprehensive analysis and feedback into design as well as risk management documents can be time-consuming and expensive. Quite often, during reviews from authorities or Notified Bodies, documentation for usability is found to be inadequate, resulting in a non-conformity being raised, which often consequently requires re-testing or halting marketing. Therefore, manufacturers should carefully pay attention to these fundamental usability requirements to ensure regulatory compliance and ease of market success. Manufacturers aiming to sell across multiple regions and potential region-specific differences are recommended to familiarize themselves with relevant HFE standards and guidelines and to integrate these requirements early in the design process before starting usability testing.

Conclusion

Medical devices should be designed and developed to be safe and effective. The implementation and use of an adequate usability or HFE process is not only a reasonable way to make design development and risk management more efficient, but it is also a regulatory requirement for medical device manufacturers in most regions, and is increasingly reviewed during submissions by regulatory bodies. Regulators worldwide have harmonized the requirements for usability and use or refer to the international standard IEC 62366-1. This standard provides excellent guidance on how to implement formative and summative usability testing in the design development process. To confirm regulatory compliance in these markets, additional HFE guidelines that are specific to certain regions must also be followed. This is significant because these standards and guidelines are frequently the only basis for interpretation and expectations from regulators and reviewers. It might be acceptable for manufacturers to employ alternative techniques if they do not adhere to them closely enough, but doing so could also lead to serious concerns during regulator reviews. A thorough understanding and proper application of usability and HFE, along with their integration with risk management, are crucial for the entire design team in medical device companies. These elements form the foundation for developing safe and effective medical devices efficiently.

Editor’s note:  Oliver Eikenberg brings over 14 years of extensive experience in the medical device industry, covering R&D, manufacturing, QC, and product management, alongside 15 years in regulatory and quality affairs consulting. His expertise spans EU, US, and Australian regulations. Oliver has specialized expertise in IVD genetic tests, Companion Diagnostics, in-house tests (LDTs) and clinical performance studies and interaction with Notified Bodies and Competent Authorities.

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