Human Factors Align At The RAPS 2017 Regulatory Convergence

By Bob Marshall, Chief Editor, Med Device Online

I had the privilege of co-presenting a session at the RAPS 2017 Regulatory Convergence with former colleagues from Regulatory & Quality Solutions (R&Q) and members of the FDA. The session focused on human factors, and began with an overview of the changes to the usability engineering/human factors process for medical device development, given the revision to IEC-62366 and FDA’s revised guidance for human factors finalized in 2016.

After the overview, I led an exercise where the roomful of attendees collaborated to work through an example human factor analysis: a medical hot/cold pack. We followed the process outlined in IEC-62366-1 and focused on items that should be in a use specification for this type of device, interface characteristics that would be important to safety, potential use errors, and hazards (or perhaps, more correctly, “harms,” as one gentlemen pointed out to me after the session).

Use Specification

 The use specifications identified in the session included:

• Target tissue temperature
• Duration of the tissue temperature change
• Rate of change in the tissue temperature
• Size of the area being treated

All of these specifications would be important to the designers of the device, as well as important for the appropriate analysis of human factors.

Interface Characteristics Important To Safety

During the exercise, we identified the following interface characteristics important to the safe use of a medical hot/cold pack:

• Heat/cold transfer to skin
• Difficulty with application of the device to regions exhibiting abnormalities (e.g., the foot)
• Skin-drying effect of heat application
• Impairment of local vascular supply due to uneven distribution of pressure on the anatomical region the device contacts
• Increased risk of burns for sensory impaired or mentally challenged users

Potential Use Errors

For potential use errors, the group brainstormed about the interface characteristics important to the safe use of a medical hot pack, and we compared our ideas to some real-world data. Prior to the session, I had gathered data from MAUDE database — events that resulted in injury for medical hot packs (product code IMD) from Jan. 1, 2017 through June 30, 2017. That data included 128 reports for medical hot packs, and is summarized below, with the number of occurrences at the left:

• 17 – Pack worn during sleep
• 12 – Pack applied directly to skin
• 10 – Did not check skin under pack during use
• 6 – Improper application (e.g., using wrist pad on neck)
• 4 – Excess application force (e.g., pack used under belt)
• 3 – Pack worn longer than specified
• 2 – Did not read IFU before use
• 1 – Pack integrity not checked prior to use
• 73 – Not specified

Hazards (Or Harms)

So what are we really worried about in using a medical hot/cold pack? What hazards or harms may occur to the user? We again had real-world MAUDE data for the same time period for 128 hot pack reports:

• 82 – 2^nd degree burns
• 30 – Burns (severity unspecified)
• 11 – 3^rd degree burns
• 2 – 2^nd degree burns (with resulting infection)
• 2 – Skin damaged from adhesive when heat pack removed
• 1 – 1^st degree burn

Summative Evaluation

After we walked through the above steps, we talked about the use scenarios that we would want to include in a summative evaluation. I was thoroughly impressed with the collective knowledge in the room as we worked together. Perhaps unlike any other medical device related event, the RAPS convergence is truly a place for professionals to share knowledge and learn from one another. If you are involved in the development of medical devices, and especially if you are responsible for the regulatory and quality aspects of that development, you really should be a part of the RAPS regulatory convergence.  

FDA Panel Discussion

The absolute highlight of this session was the panel discussion at the end, which included Dr. Xin Feng, Human Factors Reviewer at FDA/CDRH; Dr. Kimberly Kontson, Biomedical Research Fellow at FDA; Christine Santagate, Director of Boston Operations at R&Q; and me. As one might imagine, the majority of the questions were directed toward our FDA panelists. Everyone seemed to want to know what they would be looking for in device submissions related to human factors.

Three themes emerged in the responses that Dr. Feng and Dr. Kontson provided to the audience. The first was to focus on safety. Their expectation would be that usability engineering is rooted in thorough risk management and considers real-world data of user errors from similar devices. Secondly, they cautioned not to focus strictly on the IEC-62366 standard alone. The FDA guidance document indicates the deliverables they expect to see included in a device submission. And finally, Dr Feng and Dr. Kontson encouraged dialogue with the FDA as early as practical. They are active in the pre-submission process and would much rather have a discussion about what we intend to do rather than ask for more information or reject a device submission later.

Alignment And Convergence

My overall takeaway from preparing for, and participating in, this session is that the product development process is becoming more aligned. The experts who perform human factors/usability engineering and the specialists who perform risk management are converging with the engineers and designers who perform traditional product development under design controls. When human factors became more of a focus with the third edition of IEC-60601, I recall looking at the previous version of IEC-62366 and saying to a client, “This is not really something new. If we get good information from marketing and clinical about who the user is, and where and how they will use the device, and we do good risk management, we are 90 percent of the way there.”

There remained some confusion as to whether different initiatives, like human factors, required separate deliverables, but changes in IEC-62366-1 are clearing the murky water. The previous application specification has become a use specification, and traditional specification documents for devices have often covered how the device will be used. The previous usability specification is now called a user interface specification, which is a standard document that project managers include for device development. Frequently used functions are no longer part of the primary operating functions documented for usability (now only safety functions), because the frequently used functions are already specified in the traditional product requirements document or engineering specification for the device.

 Better alignment eliminates duplication and gets needed devices into the hands of users more quickly.