The Human Factors Methodology in Medical Device Design for Food and Drug Administration Approval

Written by Sean Hagen, Founder and Director of Research and Synthesis, BlackHägen Design

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Human Factors Engineering (HFE) must be considered by every medical device manufacturer at some point in the design and development journey to ensure that the final product can not only gain FDA approval, but also meet the needs of users and patients. The classification of regulatory risks, the level of potential harm associated with the use of the device, and the complexity of the product are general determinants of the scope of HFE’s involvement.

While some companies may view HFE activities as a required final check in the overall design and development process, human factors processes are a critical component to consider throughout the development continuum. If the HFE is left to fill in regulatory mandates during the last steps in the design cycle, the final validation results can give rise to unrecognized usability and safety issues that could require expensive redesigns and costly delays to bringing the device to market. Of course, this affects the final result in addition to delaying the launch of the product, which gives the competition a huge advantage.

So the question is, at what point in the design/development cycle does a company get involved in the HFE process? This article will review HFE practices and discuss how, if started early, they can be an important driver in identifying key product safety issues and usability challenges and how they impact development time efficiencies and successful regulatory compliance.

So what is the overall HFE process?

HFE is sometimes just a focus on regulatory approval, but in fact it is a core process that must be an integral part of the entire product development cycle, and therefore must be partnered with project management and system engineering from the start of the project.

quote from Food and Drug AdministrationHFE is “Understanding how people interact with technology and studying how user interface design affects people’s interactions with technology is a focus on how Human Factors Engineering (HFE) and Usability Engineering (UE).” The definition attempts to cover all factors involved in the design and use of a medical device, whether it is to be administered by a trained medical practitioner or by a patient in a home environment.

Generally, in the context of medical device development, HFE defines exactly how the user interacts with the device or system, including performing a task analysis, and then characterizes those interactions in such a way that usage challenges are identified and subsequent usage-related risks are codified. Ultimately, the results of the HFE process generate design inputs that drive user interface design features, which are intended to block usage errors that have been identified as essential for safe and efficient operation.

When should HFE practices be involved in the design process?

The short answer is “as soon as possible”. If HFE is involved early on, there are methodologies such as contextual inquiry and comparative studies where the development team can watch and participate in generating relevant design inputs at the systems engineering level. During earlier development stages such as feasibility, cross-functional teams must develop and design a usability engineering plan for the project in order to enable this process.

There should be a portion of the Design History file, called a Usability Engineering (UE) file (as per IEC 62366-1), where the HFE process documents usability engineering activities and design inputs, such as inputs into system level requirements. The product development team should be oriented in the process that developed the UE file as well as the internal insights.

One example supporting the early integration of HFE is the opportunity for usability specialists to conduct rigorous studies directly in the context of use, including observations of typical behavior for both clinicians and patients, a function that development engineers typically do not perform. In this approach, if the device has a user interface with which the patient interacts directly, patients will be recruited for usability studies. These studies are performed in a controlled laboratory or simulated environment. Design development teams can often monitor these studies in real time and contribute to questions.

Companies that don’t bring the HFE team into the process early on and simply carry the device to HFE validation testing greatly increase the chances of usability-related errors being discovered after a design has been frozen, and making design changes is significantly more expensive and impactful in marketing schedules.

Product teams that proactively assess HFE early in the product development cycle can increase their confidence in product performance during final testing.

What will the FDA look for in compliance?

The US Food and Drug Administration (FDA) is tasked with determining that medical devices are safe to use and effective. This requires examining all elements, from users, usage scenarios, and usage environments, and including them in a plan to conduct rigorous analysis of HFE testing and usability testing with intended uses and users. This process should include a summary of the risks associated with the use; A common tool for this is the Failure Mode and Effects Analysis (UFEMA), which provides the Food and Drug Administration with critical information about a usage error.

There are discussions within the HFE community questioning whether a distinction should be made between UFEMA and/or Use-Related Risk Analysis (URRA). The talks address the development of a standardized and comprehensive tool for assessing risks related to use that either complements or replaces existing UFEMA. Keep in mind that the FMEA Adapted Tool (UFMEA) was developed for characterization reliability In a system or part (objective), not usability (subjective).

URRA may share items with UFMEA but seldom have the same metrics for tracking design controls process mitigating risks and subsequent residual risks, for not duplicating tracking information in two different documents. URRA also does not include frequency because it is not specific to assessing the importance of the task. URRA may also have more details regarding usage scenarios, tasks, user types, and user error profiling in order to inform design mitigations.

URRA must address at least the following parameters:

  • Use the job description
  • Possible usage error
  • Description of potential clinical harm
  • damage severity
  • mission critical? Yes No
  • risk control procedures
  • Validation methods

The landscape of healthcare scenarios, device technologies, integrated drug and delivery systems, and software with AI applications in which clinicians and patients interact is constantly changing. The Food and Drug Administration is sensitive to these new developments, which means that its processes, methodologies, and policies will continue to evolve. However, the industry is an important part of this development. By providing input to FDA processes and technologies and engaging the agency early on, prior to submission, medical device developers can get an alignment of their human factors engineering approach before submitting a device for validation.

In summary, engaging in the HFE approach to medical device design early in the development stages, such as during a feasibility assessment, allows cross-functional teams to develop and design a usability engineering plan for the project. Recognizing human factors engineers as partners in the overall product development process greatly reduces both usage and commercial risks. This approach will enhance the chance of a successful product launch and help eliminate the emergence of last-minute risk factors that require costly redesign that may affect the success of the FDA required for product launch.

About the author:

Sean Hagen is the founding director and director of research and synthesis at BlackHägen Design. He led design research and usability design, in both institutional and home environments, in 20 countries. His role focuses on the user research and synthesis phases of product development, including usability engineering, user-centric innovation techniques, and the identification of user requirements. Hagen holds a BA in Industrial Design with a minor in Human Factors Engineering from Ohio State University. He is a member of IDSA (Industrial Design Society of America) and HFES (Human Factors and Ergonomics Association), having served two terms on the previous board.

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