At first glance, people are often confused by the term “usability engineering” and do not know how to classify it. But in fact, the concept of usability is a very important one when it comes to the safety and effectiveness of medical devices. Usability engineering has been used for more than half a century in the automotive, aerospace or other industries, and only recently in the medical device industry. However, the impact of usability on healthcare should not be underestimated.

What is usability engineering and why is it important?

In a white paper, the BSI Group (British Standards Institution) presents the term “usability” as “a multidimensional quality that refers to the ability of a human to interact easily and relatively error-free with a system or product.” Therefore, over time, terms such as “user-friendly” or “intuitive” have become associated with the concept of usability. This also indicates that a system should work the way users expect it to work.

When it comes to healthcare and medical devices, usability has a big impact. However, if a medical device lacks usability, there is a higher likelihood that errors will occur or the use of the device may be slower, i.e., not as intended. As a result, therapy may not be delivered at all or may be delivered poorly, and patient safety may be compromised. Therefore, legislative institutions have become increasingly aware that usability engineering should be included in regulations, becoming an essential part of medical device requirements.

Regulatory framework

As with other aspects of medical devices, there is a regulatory framework for usability. It is provided by several institutions and their regulations, including the FDA, the MDR, and the IEC 62366-1 standard.

In the MDR, there are specific requirements on the usability aspect, most of which are part of the Essential Safety and Performance Requirements, which mainly state that a manufacturer should eliminate or reduce risks associated with incorrect use. Measures should be implemented that take into account the intended use, users and environmental conditions. In addition, products for use by laypersons must be designed and manufactured to ensure safety when used properly and to reduce the risk of error from handling the product. In addition, the technical documentation should include the results of product verification and validation, especially the results of usability-related activities such as formative and summative evaluation. In addition, usability is also important in post-market clinical follow-ups and PMS. Feedback from users and information about problems or errors must also be collected and evaluated.

Unlike the MDR, the FDA is very specific about usability regulations and has been addressing this issue for decades. It has published a guidance document entitled “Applying Human Factors and Usability Engineering to Optimize Medical Device Design.” This guide is not a standard, of course, but it contains many lists of requirements and references the important regulations and IEC 62366 (now superseded by IEC 62366-1). Nevertheless, it is a key reference point. From the FDA’s perspective, it describes what methods to use to analyze risks, how to mitigate them, the characteristics of the user and the user environment, and how to plan, implement, and document usability testing.

IEC 62366-1 and the usability engineering process

Although there may be different regulatory requirements for usability and medical devices depending on the country, there is an overlap: IEC 62366 Medical Devices – Application of Usability to Medical Devices. This standard is recognized to some extent by both FDA and MDR (it will be part of the harmonized standards).

In recent years, IEC 62366 has been replaced by IEC 62366-1:2015 + COR1:2016 Medical devices – Part 1: Application of fitness for use to medical devices. In addition, the technical report IEC/TR 62366-2:2016 Medical devices – Part 2: Guidance on the application of usability engineering to medical devices was published to support the usability engineering process.

 

Therefore, the UE process according to the IEC 62366 family of standards is important to ensure the usability of all medical devices. The process described focuses on product development, which culminates in validation of the final user interface design.

The following section provides a brief summary of each step of the process:

Risk assessment and identification of hazard-related use scenarios.

Use Specification: the manufacturer should document the intended purpose of the medical device in the Usability Engineering File (UEF). Include the medical intended purpose with intended medical indication, patient and user groups, application including intended body parts or tissue type applied to the use environment and functionality including physical principle and engineering structure.

Identification of safety-related features: part of risk analysis, focus on usability.

User interface (user interface) characteristics In terms of safety and potential application errors.

Identification of sufficiently known or foreseeable hazards and hazardous situations: The severity of potential harm must be determined.

User Scenarios: should include user interaction, must also be documented in the UEF.

Identification of hazard-related Use Scenarios

Risk control and design of the user interface

User Interface Specifications for usability verification derived from the Use Specification, known or foreseeable use errors associated with the medical device, and hazard-related Use Scenarios.

User Requirements Specification: Should include user interface design requirements.

Evaluation Plans: description of how to investigate and evaluate the user interface design.

User Interface Design and Implementation: appropriate usability engineering methods should be used to design and implement the user interface.

Risk Assessment

Optional risk control analysis: define risk control measures suitable for risk mitigation and implement them in the next step.

Risk management, formative and summative evaluation

Formative Evluation: perform iterative design and formative evaluation until it can be assumed that all use-related risks are adequately controlled and no further refinement of the user interface is required.

Summative Evaluation: performed to complete user interface development with the goal of demonstrating that the user interface can be used safely.

Risk Assessment

Residual Risk Assessment: Assessment of risk against criteria defined in the Risk Management Plan.

Risk from Risk Control Measures: Verify the impact of risk control measures.

Risk control completeness: ensure that risks from all identified hazardous situations have been addressed.

What’s next.

Once usability is implemented and all requirements are met, there are certain procedures that can be used to verify the usability process. A very common procedure is general testing. The next stage would be verification, which checks if certain product features are met. This is followed by validation, which checks whether the intended use in a specific application context can be achieved by a specific user. It must be determined whether these procedures can be performed by an automated computer process or by a person.

As this article illustrates, usability engineering is a central part of the medical device development process, affects every part of the process, and is intertwined with many other aspects (such as risk management, quality management, or requirements engineering). Therefore, a thoroughly implemented usability process is essential for any medical device manufacturer. If you need support or guidance in the implementation, please feel free to contact us, seleon gmbh.

Please note that all details and listings do not claim to be complete, are without guarantee and are for information purposes only.