Medical devices and human factors design

Guest blogger Rob Packard is a quality and regulatory expert with over 20 years of experience in managing product development for the medical device, biotechnology, pharmaceutical industries.

In last week’s Tangents installment, “A Way Forward for Medical Device Innovation”, Trig’s Ty Hagler mentioned that the US Food and Drug Administration (FDA) has acknowledged the need for greater emphasis on industrial design by adding a new requirement for medical devices regarding human factors. Industrial design covers a much broader spectrum of product design subjects, while human factors is an extension of industrial design that focuses on the human-machine interfaces to ensure proper function of the machine and human safety.

The FDA actually enacted the “new” requirement mentioned in Ty’s piece on July 18, 2000 ); but it was never clear what was required for approval and the FDA did not apply this guidance document consistently. This fall (2012) the FDA is expected to release a final version of an updated guidance related to human factors engineering. These requirements are most important for “active devices” or medical devices that have a power source and/or software. These devices are prone to “use error”. In the past, companies would blame patient injury upon “user error” when a doctor would use a device incorrectly. However, this term has lost favor. The FDA prefers the term “use error”, because it is not always clear if the fault lies with the user or the company that designed the device.

Complaints are the primary tool the FDA utilizes to determine if there is a human factors issue with a product.  Medical Device Reports (MDRs) detail injuries and deaths to the FDA, but the agency also requires the results of an investigation of root cause. The FDA monitors trends of MDRs, and the causes, by product code. For each 3-letter product code, there is a Total Product Lifecycle (TPLC) report available on the FDA website. If a product code exhibits a trend of complaints related to “use errors”, the FDA will begin to require companies to include Human Factors as part of the Design Validation for 510(k) approvals.

One example of a requirement for Human Factors Validation is in this guidance document for infusion pumps can be found here. This document is a “Special Controls” document. It defines all the required verification and validation testing required for devices with well-established risks and user needs. For devices with a significant percentage of use errors, the FDA will add a requirement for Human Factors Validation. For infusion pumps, the “user” is typically the patient. Therefore, there are many product malfunctions and injuries resulting from a graphical user interface (GUI) that is difficult for some people to understand. For example, when I tell my daughter Gracie to “double-click” a mouse, she can do this with no difficulty. When I tell my 98 year-old grandmother to double-click a mouse, she doesn’t have the manual dexterity to click twice in the same place (I also have to remind her of what a “mouse” is). The FDA is aware of the gap in perception of “easy to use”—designers need to be aware of this gap too. It all depends upon the perspective of the user—not the designer.

The Medical Device Division of the FDA (CDRH) has a Human Factors Team. This team is part of the Office of Device Evaluations (ODE) that processes 510(k) submissions for medical devices. This team is also available to answer the question of whether a company’s approach to human factors assessment is appropriate. However, the FDA expects companies to conduct their own research and analysis of current medical device development practices. For Human Factors, this should begin with a thorough review of the draft Guidance Document and other recognized Standards, such as: AAMI/ANSI HE75:2009 (Human Factors Engineering – Design of Medical Devices), ISO 14971:2007 (Application of risk management to medical devices), and ISO/IEC 62336:2007 (Application of usability engineering to medical devices. Table A-1 of the guidance document also includes a seven-part outline for a human factors (HFE)/usability engineering (UE) report. This is the FDA’s preferred format for the output of a Human Factors Validation.

As a regulatory affairs expert, I hope I have bombarded you with all of the boring references that you’d expect; however, I also enjoy providing some practical advice for navigating the world of human factors in device design.  Before you even think about verification and validation, start by reviewing complaints that other companies have received (i.e. – the TPLC report for your three-letter product code). This report has a wealth of information that is readily available—if you can double-click a mouse.

Rob Packard is a regulatory and quality expert with 20 years of experience developing products and managing projects in the medical device, biotechnology, and pharmaceutical industries. His array of experience includes research, product development, operations management, manufacturing engineering, equipment design, regulatory affairs, quality assurance, and fund-raising.

For a related article, check out, What is Human Factors Engineering?