Demystifying the Human Factors Plan for Medical Device Projects

 In Medical Product Design, User Insights & Design Research

Over the past few years the FDA has increased their emphasis on the importance of applying sound human factors procedures during medical device development. That means they’ve increased their scrutiny of submissions and their expectations for how medical device makers will ensure the safety of people who use their products.

The last thing you want to receive in response to submission is a letter from the FDA requesting additional information that questions how you mitigated the risk of use errors. Rather than being able to focus on the next steps forward toward market launch, you would find yourself on your heels defending the past.

Creating a human factors engineering plan at the beginning of a project will help you avoid this situation. In addition to meeting the FDA’s expectations, there are other benefits to consider.

3 Additional Benefits of a Human Factors Engineering Plan

  1. A solid human factors project plan requires both time and money, so the sooner you plan the better. This applies to all medical device companies, both big and small. For example, startups that rely on a steady burn rate of their limited capital usually can’t handle a large surprise expense. And changing the master project plan at a large established company midstream to incorporate human factors activities is like asking an aircraft carrier to turn on a dime.
  2. You want to ensure the safety of people who use your medical devices. A well-executed human factors plan will reduce the risks related to use errors and lower them to acceptable levels.
  3. A human factors plan is much more than a way to assure safety and effectiveness. If you think about it for a moment, safety and effectiveness are merely table stakes. Proper execution of the right plan will set the foundation for a great overall experience with your product and in extension with your brand itself.

No Two Human Factors Plans are the Same

A human factors plan is custom and different for each type of project. To put this in perspective, that’s because projects can vary from a new bedpan to a surgical robot! It’s tempting to re-purpose one from a past project or even one you used at a previous company, but we recommend against it. You should build a plan according to your project’s unique requirements. It might be simple, spanning only a few weeks, or more complex, lasting for years. In either case, your human factors plan should be comprehensive stretching from concept to final design.

The best place to start is determining the project type in consideration of risk and potential harm. There are generally four types of medical product projects:

1. An update to an existing product without significant changes. In this case you can leverage much of your past human factors work and actual usage from the field. Minor changes that don’t present additional risk to users might not even require any human factors engineering work.

2. A line extension with a similar user interface to your current product and only a few new features added. It’s always a great idea to test new features even if they don’t present additional risk. A minimal plan and amount of work might apply.

3. A next generation device that replaces the existing one. In the medical device world, product life cycles are usually very long, sometimes spanning as much as five, 10, or even 15+ years. It’s more than likely your next generation product will need a comprehensive plan.

4. A new product without a predicate. Often this means an established or known protocol for the procedure or treatment doesn’t exist. For example, development of the first surgical robot surely included an army of human factors engineers and a robust, comprehensive human factors plan. They paved a new path to establish new industry standards and protocols. It was easier for the next company developing a similar but competitive product.

Objectives of Your Human Factors Plan

Understanding the key objectives for your plan upfront will help you write an even better one. The first thing to consider is that the plan is your high-level playbook on how users will be included in your design process. It describes the iterative human factors engineering process that starts with user research, proceeds with rounds of formative user evaluations, and ends with validation.

Proper execution of the plan is paramount in ensuring the safety of those who interact with your product. It does this by identifying and eliminating use errors.

The success of that effort is contingent upon carefully identifying and addressing all points of user interaction. This includes the physical product, software interface, user manuals, quick guides, labeling, and even training.

There are many ways to identify and evaluate user interactions. The plan will also identify the usability engineering methods that will be used. Annex E of the standard IEC 62366-2 Guidance on the application of usability engineering to medical devices has a fairly comprehensive list of the methods you might consider.

All of the outputs from your human factors engineering work will become part of your usability records. They will either be stored in or referenced by your usability engineering file. Your plan will identify all the required records upfront. And another important objective of the plan, the schedule itself, will ensure you create each of them throughout development.

Finally and maybe most important, the plan helps you prepare FDA submission.

Your Human Factors Plan Can’t Live in a Silo

It’s important to integrate your human factors plan into the master project plan as early as possible. Your first version won’t be perfect, but don’t let this stop you from inserting it into the master project plan. There are several reasons why this is important.

The first revision will act as a placeholder, giving the human factors plan visibility.  Executives and the rest of the team will see it when reviewing the master project plan.

Placing it front and center sends a clear message that human factors is important to and supported by the organization.  It will remain top of mind throughout all stages of the medical device development project.

As a key part of the master project plan it will force high level questions like: Do we have the in-house expertise? Do we have the bandwidth or manpower to handle the work? Have we accounted for it in the budget? Early allocation of people, time and money will help ensure successful execution of your human factors plan.

It also brings efficiencies that save time and money and lead to better outcomes. Your development team will already be creating prototypes for design and technical assessment. Your human factors team can use some of them for their testing. Technical and human factors feedback received in parallel means your designers can swiftly move on to design revisions.

The Outputs of Your Human Factors Engineering Plan

Your human factors plan will result in 10 important documents required for FDA submission. It’s a good idea to start the first draft of each at the beginning of the project. Then add to and revise them as more information becomes available and testing proceeds.

Here is a list of the 10 required end products from your plan according to annex D of the standard, International Electrotechnical Commission (IEC) 62366-2.

  1. Use specification
  2. User interface characteristics related to safety and potential use errors
  3. Known or foreseeable hazards or hazardous situations
  4. Hazardous related use scenarios
  5. Hazardous related use scenarios for summative evaluation
  6. User interface specification
  7. User interface evaluation plan
  8. Formative evaluation usability test reports
  9. Summative evaluation test report
  10. Usability engineering report

These documents are the evidence proving that your medical device is safe and effective. They are the main documents contained in your usability engineering file that the FDA will review in your submission.

Creating a human factors plan as early as possible will build confidence that all human factors engineering items have been considered. That gaps in time, money, and resources are uncovered, preventing surprises. Following it diligently to the end will help ensure that your product is safe, effective and a pleasure to use.

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