Monthly Archives: March 2016

What A Difference A Medical Device Can Make

This week, a guest post…

John Lennon famously said, “Life is what happens while you are busy making other plans”. And so it did. I had planned a week of developing ideas, gathering data for a project, business meetings and so. Then life struck. With a bladder that felt like the size of a football I was rushed to the local Medical Centre where a urinary catheter was inserted to my great relief! Everything was put on hold. However, as an engineer with an interest in equipment that help people manage or recover from an illness the situation was one I had explore further during my recuperation.

The purpose of a medical device is to “diagnose, prevent, or treat a disease or other conditions, and does not achieve its purposes through chemical action within or on the body.” They can range from disposable gloves through to Robotic Surgeons. The market for medical devices is projected to be a market worth $398 bn globally by 2017. The urinary catheter market is estimated to be worth $2.37 bn by 2020. Big business !

The urinary catheter has been around for 3500 years. The earliest ones consisted of bronze tubes, reeds, straws and curled-up palm leaves ( ouch ! ). The device has evolved throughout the centuries to the one that I am using with all of its parts made from soft plastic. There must be many design challenges and off the top of my head they would include: minmise infection, no leakage, minimal pain during installation and extraction, ease of use. The actual list I am sure will be significantly longer.

It is interesting how the world changes for the user of a medical device. In my case, public toilets were key points of reference when out shopping. I developed a mental map of where and when the toilets were open. Of course planning is critical to cover all eventualities when out and about especially when drinking too much !

Using the catheter requires some basic plumbing skills that most of us who connect garden hose pipes can easily master. The valves used on the bags are an example of keeping it simple with an intuitive way of switching it off and on. Also, for my own interest, I started to gather data on how much I was drinking and volumes when emptying my bag ( inputs and outputs in engineering terminology ), which produced a fascinating insight into how my body was working. Given the problem that the catheter is managing – emptying urine from my body – and the constraints of everyday use, the one I used worked well.

One final point. The District Nurses gave me great practical advice based on their experience of helping other people managing their catheters. For any medical device designer getting feedback from the people who are using it is an invaluable source of information for revisions to the design. In general, the users of medical devices can very often find better solutions to the problems of using it even if it involves Duct Tape !

Next time I am sitting in the waiting room of my medical centre, probably listening to some John Lennon classics, I will be reflecting on the many people, over the centuries, who developed the urinary catheter and how the current version saved me from torturous pain !

Big thanks to the Doctors, Nurse Practitioners, District Nurses, and the people in the Dispensary for their professionalism and kindness during my urinary problem.

You can read this and other posts on a range of topics on David’s blog;  http://dtinblack.github.io

FDA finalises Human Factors Guidance – Existing products – Part 4

In this series of posts, we’re taking a look at the recently published final version of CDRH’s guidance “Applying Human Factors and Usability Engineering to Medical Devices”.

The document, published on 3 February, is the result of nearly 5 years of consultation with industry since releasing a draft guidance back in 2011.

FDA HF guidance FINALWe have covered a lot of ground already. In the first 3 parts, we heard about four of this list of the key topics covered by the Center:

  • Human Factors Engineering process
  • Risk Management and Human Factors
  • Design Verification
  • Summative Human Factors testing
  • Changes to products already on the market
  • Human Factors Engineering Summary report

In part 4, we’ll look at the Human Factors Engineering Summary report and submission of your HFE data. You may then want to think about how this may impact what you’re either already doing, or plan to do.

Changes to products already on the market

You may be wondering how this relates to devices that are already on the market? The agency has provided some guidance to help you understand when modifications to a device mean that it should undergo validation testing. The need for additional human factors validation testing should be based on risk management planning and risk analysis for the modified User Interface or Tasks, to determine the scope and nature of testing required and should focus on those hazard-related use scenarios and critical tasks. The test may, however, be limited to assessment of those aspects of users’ interactions and tasks that have only been affected by the design modifications.

The agency also recommend that for any further human factors validation testing consideration should be given to user’s comparison of the design modification to the previous design.

Human Factors Engineering Summary report

It’s often seen as the culmination of your HFE programme.

Expectations for content of the report have expanded, to require far greater information about analysis and elimination/reduction of risks and hazards associated with use of the device, critical tasks and use scenarios. Far greater detail is needed about the validation study, discussing test environments, training correspondence to real-life, data collection methods, test results, feedback, analysis of use errors, difficulties, root causes of problems and implications for risk elimination/reduction.

The Center are proposing to require submission of HFE data with your PMA or 510-K, for those devices where users performing tasks incorrectly or failing to perform tasks could result in serious harm. There’s a separately issued, draft, guidance that outlines current thinking on which devices would need this as a matter of course, which may well change between now and the final version of that document.

However, the agency has not removed the expectation that a human factors programme is present as an integral part of a robust design control system.

So you still have to do it, you just may not always need to include an HFE Summary report in your submission dossier.

When is the guidance effective?

You will have some time to assimilate the requirements…
A whole month, as they go live on 3 April 2016.
How will these changes will affect your product development?

What impact they will have upon your Human Factors Engineering programme?
Get in touch today to discuss how you can best navigate the changes and emerge with a Human Factors programme that is “just right”.

FDA Finalises Human Factors Guidance – summative testing – Part 3

In this series of posts, we’re taking a look at the recently published final version of CDRH’s guidance “Applying Human Factors and Usability Engineering to Medical Devices”.
We have already taken a look at the first three in this list of the key topics covered by the Center:

  • Human Factors Engineering processFDA HF guidance FINAL
  • Risk Management and Human Factors
  • Design Verification
  • Summative Human Factors testing
  • Changes to products already on the market
  • Human Factors Engineering Summary report

In part 3, we’ll look at how the topic of Human Factors testing (both formative and summative) may impact what you’re either already doing, or plan to do.

Formative Human Factors testing

Look upon this stage of testing as providing a toolkit to identify potential use-related hazards and hazardous situations. The agency emphasises the value of testing with participants who are representative of your intended users, as this yields early data on how your eventual users cope (or don’t) when using your prototype device.

The agency recognise that formative evaluations provide information about;

  • Design of the user interface (those parts of the device that are manipulated by the user, provide them with information or indicate function)
  • The effectiveness of features or changes implemented to reduce or eliminate use errors (otherwise known as mitigations)
  • The the need for training of users and inform the design of training materials
  • The design and content of labelling such as the Instructions For Use, product labelling, packaging.
  • The content and design of your summative testing.

In the guidance, the Center talk about the value of effective formative testing in preventing very costly errors in the design of your validation test protocol that render it just another formative study.

In a departure from previous guidance, there is information on the expected content of formative test protocols, which creates a coherent and building picture that results in the information now expected for your HF validation test protocol. It’s very much a case of using formative studies as building blocks that provide a robust foundation for your validation test.

Summative Human Factors testing

Summative testing is still in place. However, testing that demonstrates the “user requirements” or User Needs have been met will henceforth be referred to as “Human Factors Validation Testing”. One could perhaps see this as coming into line with the philosophy applied to validation of processes, test methods, production lines, etc

No longer does guidance expect you to just include critical tasks within your test design. Rather, the testing needs to be comprehensive, so that the results can be related to actual use.

Test participants

If your device is intended to treat patients with a condition that can cause them to have functional limitations, these conditions must be represented during both the formative evaluations and your HFE validation study. If you choose not to design your device to accommodate needs of those likely to use your device, then labelling should clearly explain the capabilities that users must have to use the device safely and effectively. You should, therefore, ensure that you’ve understood your Users’ needs thoroughly and scoped out the Usability Specification appropriately to know what capabilities/limitations are to be included in study participant groups.

Participant Training

If you anticipate that most users of your device would receive minimal or no training, the Center now expect that participants in your validation study do not receive training.

A period of time between training and participation in your validation study should be built in to the study design. How long that is will vary, depending upon what would happen in real life and the impact of training decay on the use-related risks that you’ve identified for your device. The important thing is to consider this topic and document your rationale for the chosen approach.

Study protocol

Manufacturers are now formally encouraged to submit draft HF Validation Test protocols for agency review, to ensure that the methods you plan to use are acceptable (via the pre-submission programme). We’ve been fortunate to have supported several clients in developing and submitting draft protocols to CDRH, so have benefited from a “heads up” about many of the changes that are now embodied in this final guidance document. The review can be a great way to confirm that your approach to HF Validation will satisfy expectations.

If testing of labelling formed part of the validation study, the agency now require this to be conducted separately after simulated use testing.

The test protocol must provide a rationale for the extent of device use and the number of times that participants will use the device. This means frequency of device use must be considered; for devices that are used frequently and have a learning curve that requires repeated use to establish reasonable proficiency, testing should allow participants to use the device multiple times, if appropriate.

Data collection should include capture of observational and knowledge task data and should be supplemented with subjective data through the use of de-brief interviews with the participants after the use scenarios are completed. The purpose of the de-brief is to assist with understanding of possible root cause of use errors detected during testing.

Study location

It has long been understood that there is an expectation for the validation testing to be performed in the US. It is an expectation that hasn’t been removed, as the results of studies performed in other countries may be skewed by differences between healthcare practices, cultural and language differences. However, the agency are open to considering exceptions, on a case by case basis, where there is a sound rationale that addresses the differences. In any case, as you might expect, the device, labelling and training must be those that would be used in the US. So, in the vast majority of cases, it is likely that testing in the US would be more straightforward.

When is the guidance effective?

You will have some time to assimilate the requirements…
 
A whole 5 weeks, as they go live on 3 April 2016.
 
How will these changes will affect your product development?
What impact they will have upon your Human Factors Engineering programme?
 
Get in touch today to discuss how you can best navigate the changes and emerge with a Human Factors programme that is “just right”.