Risk ManagementUsability

How Usability Brings Value to Risk Control in Medical Device Design

Rewatch the Webinar

Do it by Design: How Usability Brings Value to Risk Controls

Are you still questioning if usability can truly impact medical device design? The answer is yes. Specifically, it plays a crucial role in controlling risks throughout the development process.

Guided by the IEC 62366-1 standard, usability engineering primarily focuses on the risks of use error, in order to design safer, user-centered products.

Asra Saleh is a risk management expert in CLEIO’s Quality Assurance team. A few months ago, she hosted a webinar for Greenlight Guru discussing the role and impact of usability in risk control.

If you missed it, we’d like to take you back over the key concepts that were discussed.

Enhancing Medical Device Safe Use Through Usability Engineering

Use errors are the primary cause of incidents related to medical devices. To avoid them, it is necessary to pay more attention to human factors and usability. To gain a clearer understanding of the role usability can play in medical device design, let’s take an example of a scenario that could occur in real life.

We’re in a hospital, and a nurse needs to set her patient’s infusion pump to deliver a 130.1 ml/h dose of medication. To do this, she successively presses the “1”, “3”, “0”, “point” and “1” buttons on the pump’s interface. However, she is unaware that this pump model does not properly process values over 99.9. Consequently, the pump ignores the decimal point and starts administering 1301 ml/h of the medication to the patient – ten times the intended dose.
It goes without saying that depending on the type of medication, such an overdose could be extremely hazardous, even fatal, for the patient.

How could this error have been avoided? By focusing on users and the potential use-related risks when designing the infusion pump. For instance, setting dose limits could have been considered. This is where usability engineering plays a crucial role.

Medical Device Use-Related Risks

As we are all aware, an error in using a medical device can have serious consequences. Not only can it compromise the effectiveness of a treatment, but it can also cause irreversible harm to patients. To put this into perspective, one study reported 44,000 to 98,000 deaths per year as a result of medical errors in American hospitals.
These medical errors may have been caused by technical failures of the device that hindered proper functioning (such as electrical, mechanical, software failures), or from user-related errors. The latter may have been resulted from an overly complex user interface, inadequate training, unclear instructions or poor device usability.

The goal of usability engineering is to identify the potential use-related risks in order to mitigate them and make them acceptable: if zero risk doesn’t exist, our aim is to make the use as safe as possible.

User-Centered Design Cycle

The user-centered design cycle is an approach that involves end-users throughout the design process to ensure the final product meets their needs and expectations.
To ensure the effectiveness of the UI design, it is important to evaluate it in a realistic setting. Users are involved in this evaluation process, where they interact with the design and provide feedback. This evaluation helps assess how well the design meets users’ needs, it user-friendliness, and if it effectively facilitates the desired tasks or functions.

How to Design for Risk Control?

Through the example of the infusion pump, we’ve seen how a poorly designed user interface can lead to use-related risks that can negatively impact patient safety. This underscores the need to integrate usability engineering early in the development process, starting from the concept phase of the medical device. Incorporating it too late in the process would significantly reduce its effectiveness in controlling risks.

Here are several recommendations from our experts on incorporating risk management into design activities through usability:

Creating a Checklist for Use-Related Risks

A checklist of use-related risks can help in creating better test protocols and more focused usability tests, resulting in clearer definitions of acceptable risk and enhanced risk control measures.
For example, it could encompass the following aspects:

IEC 62366-1 also suggests examining public databases like TPLC (Total Product Life Cycle) to collect information on any recalls that have occurred due to adverse events with similar products.

Applying a Risk Control Approach

Once identified, risks are evaluated. High or medium risks must be mitigated by a risk control approach.
There are several approaches for controlling risk and the one selected should be thoroughly justified and documented in the usability engineering file.
Here are three potential approaches:
Modifying the device design to address use-related hazards is the most effective option for risk reduction. This approach directly targets the root causes of potential errors. In contrast, revising labeling and providing training are considered less effective because labeling may not be accessible when needed, and training relies on memory, which may not be accurate or complete.

Integrating Usability and Risk Management Activities

ISO 14971 outlines a risk management framework, crucial for medical device development, providing manufacturers with a systematic approach to identify, analyze, evaluate, and control risks associated with the intended use of their products.

On the other hand, IEC 62366-1 focuses on human factors and usability aspects of design and development, ensuring medical devices are designed with the end-user needs, capabilities, limitations, and potential use errors in mind.

Therefore, ISO 14971 is a decision-making process, vital for medical device development problem identification, while IEC 62366-1 is a design and development process, making them complementary.

The blue lines in the flowchart illustrate the connection between the usability engineering in medical device design process and the risk management process.

There are two key points of interaction between the activities of these two standards:
Managing use-related risks is primarily a design activity that can avoid or control risks.

Applying UX Methods

UX methods are an impressive toolkit available to usability engineers. Each engineer can select the appropriate tool based on the nature of the device being designed.
These methods, recommended by IEC 62366-1, are crucial to the usability engineering process:
Specifically, they enable us to:

When is it Good Enough?

The level of effort and the specific methods and tools employed to mitigate risk vary based on several factors: the size and complexity of the device’s user interface, the severity of the potential harm, and the complexity of the user specifications.
Generally, for risks to be judged sufficiently mitigated, it is considered adequate if 80% of a given user group can successfully perform a specific task with a certain degree of success.
For usability engineering to truly bring value to risk control, we believe that the usability engineer must collaborate closely with the risk manager.

This is the approach we take at CLEIO: our expert Human Factors Engineering team and Quality Assurance team work in close coordination. For the medical devices we develop, this means ensuring that risks associated with the user interface are mitigated and that overall residual risks are acceptable. All of this is done with one goal in mind: to create a product that is safe for both the patient and healthcare professional.

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