Mutual Benefits of Industrial Design and IEC 62366

Recent industry guidelines such as IEC 62366 and HE75 show an increasing obligation for medical device manufacturers to adopt a user-centered design approach. This strategy not only will improve device safety but also create better functioning and safer devices, resulting in more satisfied users. This article provides an overview of recent guidelines and explains how they can strengthen efforts to integrate human factors engineering into all phases of medical device design.

Background

One could argue that the risk analysis and mitigation that is part of ISO 14971 already takes into account potentially dangerous outcomes from using a device and effectively controls them in such a way that the benefit-risk ratio is favorable. ISO 14971 is an International Organization of Standards (ISO) document that identifies the process for manufacturers to use in addressing the risk management of a medical device.

This is true; however, there is room for improvement. The shift in process thinking toward "user" errors and not "use" errors begins to address this need. User error has often implied that a device is designed correctly and the operator made a mistake. Use error takes into account the individual situation and events to determine why the operator interacted with the device in the manner he or she did. The design development process of investigation, research and development allows an increased opportunity to mitigate use error when a user-centered design approach is incorporated.

Two documents published by the Association for the Advancement of Medical Instrumentation (AAMI) are driving this shift.

HE75, a 445-page document, provides human factors engineering guidance for medical device development. The current edition, which can be purchased from AAMI, is ANSI/AAMI HE75, 2009.¹ It contains guidelines, examples and case studies for human factors engineering and user interface design. These guidelines touch on a wide range of human-machine interactions from visual (e.g., screen display) to tactile (grip size, orientation, strength, etc.). There are sections on user data (anthropometrics and ergonomics), risk management, cross-cultural issues, user testing and more. These general principles facilitate user-centered design and are focused on its implementation with medical devices.

IEC 62366 acts as a standard for incorporating usability engineering into medical device development. The goal is a development process that recognizes, addresses and mitigates error caused by the device's use. The current edition, which also can be purchased, is ANSI/AAMI/IEC 62366:2007.² It outlines a process to facilitate analysis, develop usability specifications and design requirements and test them through verification and validation.

Currently, the bulk of the IEC 62366 document is a collection of annexes dealing with user-centered design. IEC 62366 is intended to work in parallel and interact with ISO 14971.

Usability Process

The usability process in IEC 62366 can be broken down into stages.

Stage 1, the application specification, captures important usability features early in the development process.These involve the intended use, user profiles, patient population, use environment and similar items.

Stage 2 notes frequently used functions of the user interaction with the device. These will be used later to help define usability specifications and safety characteristics and manage risks.

Stage 3 captures the device's safety characteristics and its interaction with the user. The frequently used functions identified in stage 2 help identify some of these characteristics.

Stage 4 identifies the known or foreseeable hazards and situations for patients, users and other involved parties. This information aligns and works with the risk analysis process of ISO 14971. Some of the elements to consider include identified users, task-related requirements, context, use scenarios and errors.

Stage 5 lists the primary operating functions involved with the use of the device. These include the frequently used functions from stage 2, and functions related to the device's safety.

Stage 6 creates usability specifications that will be verified later. This is important to keep the design of the device on track with the usability needs established from stages 1 to 5 described above. Primary operator functions should be part of this specification. Other elements to include are hazards, use-scenario description, worst-case scenarios, foreseeable errors and user-interface requirements. Criteria for risk control with regard to usability should be stated. Evaluation and adequacy for risk management can be found in ISO 14971.

Stage 7 develops and maintains a validation plan for evaluating the usability of the device, including primary operating functions. Success criteria, test users and use scenarios should be defined and should involve intended users and expert reviewers when possible. These can be quantitative or qualitative studies.

Stage 8 begins interface design and implementation based on a strong knowledge of what is needed and how to meet and test those goals (verification and validation). This likely will be an iterative process where the designs are developed and then tested and verified against the usability specifications. Findings and results help guide the next iteration of the design (if needed).

Stage 9 conducts validation of the design using the plan developed earlier. Testing of the device's usability is performed to determine whether the acceptance criteria are achieved. Preferably, these tests are conducted under actual conditions, although simulated conditions may be used.

User-centered Approach

Incorporating an industrial design team with the engineering department helps facilitate a user-centered design approach and can provide a competitive advantage. Industrial designers typically are focused on users and their interactions with the device when solving design issues. This naturally sets up a user-centered design focus as a starting point. A user-centric approach is also about providing what the user needs and wants rather than focusing on the device and its function. A former professor of mine said, "People want toast, not toasters," and I think that adage sums it up quite well.

While it is easy to say most, if not all, products would benefit from a user-centered design approach, the reality is that this approach is used on varying levels due to diverse business strategies. Budget and time can have a heavy influence on the thoroughness of user research and design development. There have been, and will continue to be, products where the user-centered design effort was reduced or sacrificed to accommodate a tight budget or short development time to meet product launch dates.

In industries such as consumer electronics, user-centered design is often a strategic business decision. In the medical device industry, it is a regulatory decision. Errors can have very serious consequences. Devices must be designed for safety, both in their construction and their use.

With the wide array of medical devices used in the patient population, it is conceivable that a considerable number of errors have occurred without being well documented and reported because they arose from the human-device interaction and not from device failure.

Such failures can be addressed by involving an industrial design and/or human factors engineering team at the beginning of device development. Also, user-centered design skills and toolsets should be applied throughout the various development stages. As the industrial design and/or human factors engineering team works directly with electrical, mechanical, software and other engineering teams, research, investigation and use-scenario risk assessments will bring to light many user needs that lead to device specifications.

But involvement does not end there. To be diligent, these specifications should be verified and validated with expected users. Test plans need to be well thought out and documented in a usability engineering file or other appropriate quality control document. Testing should be done in the user's environment itself, or in a simulated environment to accurately recreate the factors users will experience. It is important to focus not only on frequently used functions and operations of the device, but also worst-case use scenarios.

Conclusion

The increased use of resources and effort to investigate and test user-centric design factors will add to the cost of development for medical devices. The strategic rationale for a user-centered design approach is that the resulting product will be thought out more thoroughly, address more needs, be safer, perform better and provide a better user experience, thus contributing to its success in the marketplace. The new regulations and guidelines will help industrial designers and human factors engineers champion their cause in this balance of budget, timeline and scope.

References

1. ANSI/AAMI HE75, 2009 Edition - Human factors engineering- Design of medical devices. Association for Advancement of Medical Instrumentation website. http://www.aami.org/publications/standards/he75.html. Published 2010. Accessed 25 November 2013.
2. ANSI/AAMI/IEC 62366:2007/(R)2013. AAMI website. http://my.aami.org/store/detail.aspx?id=62366. Accessed 25 November 2013.

About the Author

Ryan Lee is an industrial designer (BID) who also has a background in mechanical engineering technologies. He designed medical devices for Starfish Medical in Victoria, BC, Canada for more than five years and for more than a decade he has incorporated a user-centered design approach in a wide range of products from motorcycle equipment to medical devices. Lee can be reached at [email protected].

Cite as: Lee R. "Mutual Benefits of Industrial Design and IEC 62366." Regulatory Focus. January 2014. Regulatory Affairs Professionals Society.