Medical Device & Diagnostic Industry Magazine
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Originally Published February 2001

A little more than one year ago, Americans were shocked to learn that medical errors in U.S. hospitals were responsible for more deaths annually than were highway accidents, breast cancer, or AIDS. The significant number of ongoing references in the popular press to the Institute of Medicine's now one-year-old report on medical errors is a clear indication of the impact of the study on the consciousness of the general public. The fact that the study's findings attributed a considerable percentage of errors to product-design problems has also caught the attention of the device industry.

More and more, companies are realizing the importance of creating and following a coherent human factors program with the same diligence they might devote to instituting a Web strategy or preparing for ISO certification. Although it can be difficult to identify clear trends in the design world, there is definite movement toward an earlier and more-intensive consideration of human factors issues in the product development process. As reflected in the discussion that follows, the imminent release of the AAMI human factors standard makes it even more urgent for firms to have a viable human factors program currently underway—if a company's not up to speed now, they're already late.

This feature represents the second part of MD&DI's special human factors roundtable. Part I, entitled "The Regulatory Imperative," appeared in the January 2001 issue.

MD&DI: In the area of standards development, could someone give us a short history lesson on the AAMI human factors committee standards development efforts, and tell us when we might expect to see these standards published by AAMI?

Weinger: For more than 20 years, there has been a very close relationship between standards-making activities—both national and international—and regulatory activities by FDA. The AAMI human factors guidelines were first approved in 1988, but there was a period of approximately five years of activity prior to that approval. The guidelines were revised over the five-year period after 1988 by a committee that included several members of the present panel. The main changes reflected in the current version—which is designated HE48 1993 and is an AAMI/ANSI standard—are the inclusion of human-computer interaction guidance with regard to designing microprocessor-controlled devices, and the inclusion of a brief description of the human factors engineering process. Beginning in 1996, the committee began deliberating on how to revise the 1993 document, which was still insufficiently specific to medical industry needs and had some gaps because of evolving technology.

However, a larger concern of the post-1996 committee was that the general guidance about how one should design a display, for example, was perhaps less important than a broader approach that would define an optimal human factors design process—especially since this process could vary from device to device. So the committee began work on a separate document that was intended to be a national standard for the human factors design process. That document is currently out for final balloting, and is expected to be approved by July 1, 2001. Over the last year and a half, the committee has concurrently begun a parallel effort to revise and expand the classical "how-to" human factors design guidelines that are in HE48. Our current plan is to do this as a Web site, and in fact we very much need manufacturer support and encouragement to be able to deliver on this opportunity to provide good user interface design guidance.

I should have mentioned earlier that the AAMI human factors committee includes, in almost equal numbers, representatives from industry, clinicians, and others with interest or expertise in human factors and medical device design, including FDA representatives and human factors consultants.

Wiklund: Could you clarify one of the comments you made, which was that the last version of the standard was still considered less than ideal in terms of how well it is suited to medical devices? Perhaps you could retrace the history of why, even after a second revision, it still might not speak to medical devices as effectively as we'd like it to.

Weinger: I think the big problem, frankly, is that especially back in 1993—and even now—we just didn't have a lot of medical device–specific design guidance available. Even though individual device companies have a lot of knowledge and experience (although how much of it was documented is hard to say), this information was not public. The material that was available to the committee prior to the 1993 document consisted primarily of published standards from other domains, especially the military. And so the committee lifted heavily from military design guidance standards, and, together with some material from the NRC and other published design documents, tried to modify them as best they could for the medical industry. However, it was recognized at the time—and certainly since—that some of those modifications were more successful than others. In particular, the human-computer interface sections were not modified sufficiently to address the needs of medical device manufacturers with respect to building actual devices, particularly for critical-care applications.

MD&DI: Why did the committee initially focus on design process issues rather than principles of good design? What are the core elements of AAMI's recommended process?

Wiklund: What I can perhaps do is personalize the question. As a consultant, I'm asked from time to time to take a look at a medical device and render a judgment regarding its usability and safety by virtue of the quality of its user interface. Now, that's a really hard job to do. Occasionally there might be some low-lying fruit that you can pick—that is, obvious cosmetic shortcomings in the design, the nature of the labeling, the size of characters in a display, things that you can readily identify by inspection and application of known principles of good design. However, it's generally very difficult to make more overarching judgments about the usability of a device just by looking at it. Moreover, as a designer, you may come up with a design that you think would pass any litmus test in terms of good design practices, but, until you validate it in the context of a usability test, you can't be sure that you have developed a good design.

The AAMI work and FDA's guidance do stress good design processes, because we would all probably agree that such an emphasis represents our best hope for producing a high-quality user interface. As a practical objective, it's difficult to create perfection right off the bat by virtue of outstanding design talent being brought to a task. A more workable objective is to create an iterative process of researching users' needs and preferences, turning those into design goals, developing a design concept that reflects those goals as well as good design practices, then going ahead and modeling a design and having people interact with it and seeing how things go—and then repeating the process. You might liken it to the way you wash your hair: you wet, lather, rinse, and repeat. One could say the same thing about cleansing a medical device design of any kind of human factors shortcoming. The objective is to get end-users involved in the process of expressing their needs and preferences up front, and then evaluating the product by having them put their hands and minds on it and seeing how things go when they try to perform tasks. That's probably the most reliable way of producing a design that will perform well.

Hasler: One of the reasons we really focus on design process issues is that—despite the fact that people often want to just pick up some sort of a generic "cookbook" document and look for the exact "recipe" they want—there's simply too much variation in the user interface of medical devices for an encyclopedic guidance to work. In other words, if we're focusing on a ventilator or an infusion device, we could come up with great guidelines, but when it's a matter of the whole industry, an approach emphasizing good processes is initially the best way to proceed.

MD&DI: What is the status of international efforts to promote human factors in medical device design?

Carstensen: The International Electrotechnical Commission (IEC) is in the process of updating its big document, IEC 60601-1, which covers general requirements for the safety of electromedical equipment. As part of that undertaking, about a year ago they initiated efforts to develop a new collateral standard that, once in place, will become part of IEC 60601-1. Its number is IEC 60601-6; there are five other collateral standards, covering areas such as EMC testing. The first committee draft (CD) is scheduled for distribution to national committees for hearing and comment in February 2001, although the target date for publishing the final document is not until the fall of 2004. That sounds like a long time, but the good news is that, historically, companies will get wind of what's going on and procure copies of the first and second CDs and respond to them. They'll react in anticipation of a standard coming down the track, and derive much of the good effects well before the publication date of 2004.

The international standard—basically an international human factors engineering guideline—is based on the AAMI documents. But the IEC document itself probably doesn't occupy more than about 10 pages, plus an informative annex that tells you how to go about doing the job. That informative annex will be the newly revised AAMI human factors design process standard. The intent is to achieve global harmonization at the outset, as opposed to what we usually do, which is to have an international version of a standard and various domestic standards, and then get together years later and sort of argue about the differences and try to settle on something that is reasonably harmonious. This time, we're making sure it's harmonious from the beginning.

In addition, ISO Technical Committee 210 on quality systems has expressed an interest in joining the IEC working group that's developing the international version of the AAMI standard, so as to put out a joint ISO/IEC version of the standard. What that would do is allow us to expand the scope beyond electromedical devices to include all medical equipment.

MD&DI: Rod, as a human factors specialist working at a large company, what is your view of the new regulations? What are the greatest challenges you face in responding to them? What about cost pressures? Finally, are there differences in the way the regulations affect how you develop products for domestic versus foreign markets?

Hasler: Regarding human factors concerns in the medical device industry, companies can be divided into two camps. The camp I come from recognizes the importance of human factors at least as long ago as the early 1990s. At that time, we implemented a customer-focused process to define an IV infusion system, and quickly discovered that the feature most desired by the customer was ease of use. This drove us to see the importance of hu-man factors practices, and how good human factors could benefit us. So my introduction to human factors was really on the marketing side—how to make better-selling products that are easy for customers to use.

And I think that's probably where you're seeing the companies that jumped into the discipline of human factors early on—they were really utilizing it for the ease of use, and to drive a better product to the customer. Those who didn't recognize that are a little bit behind as far as converting.

I think that most of the larger companies followed this same route, and typically have long-standing human factors programs. Many smaller companies are still in something of a catch-up mode; they're trying to understand exactly what is required and how they can implement it. But I believe that this regulation has a very strong upside for the entire medical device industry—it will really improve the industry as a whole, as far as reducing design errors.

MD&DI: Do you notice any differences in the emphasis on human factors in products destined for the U.S. market versus the overseas market?

Hasler: What you see much less of in Europe is human factors used as part of a marketing strategy or approach. Regarding domestic and foreign markets, however, one of the problems in the device industry is that we tend to develop products that are oriented toward and designed for a specific customer in a specific country, but are then released to other countries with no changes. Whereas even though the actual clinical application may remain the same, there are often differences on a country-by-country basis in how the users react to the design and employ the device. So the biggest concern I have on a global front concerns releasing a product that was designed for one market into multiple markets.

MD&DI: How do the new rules affect the marketing of devices that were developed before the human factors regulations were adopted? What happens with products that represent slight modifications to older products that may not have incorporated good human factors design principles?

Wiklund: I'd be happy to answer this question from a consultant's point of view. I think this is going to be a great source of anxiety in the future for those companies that are not getting clear signals as to their vulnerability in terms of selling any product that hasn't benefited from a good human factors design process. Because many companies will be introducing products that represent slight variations of previous versions, one could argue that they should conduct a thorough human factors evaluation of the modified design—which might infer getting customer feedback in the context of usability tests, and so forth. Of course, a company that has marketed a product for a long time—a product that was originally approved by FDA—might ask itself whether it really needs to go through all of that effort after making only minor changes to the product.

Compounding this whole issue is the fact that, once regulations are in place and people become more aware of them, a company that doesn't follow good human factors processes could be accused of not applying due diligence in pursuing state-of-the-art practice. In other words, you raise the possibility of legal liability exposure if a firm fails to follow the new standard. My guess is that companies that carry out minor modifications to existing products will at least want to conduct a usability test to confirm that the new changes are in fact good changes. They'll want to make sure that they haven't inadvertently introduced other kinds of problems, or somehow corrupted the preexisting design in a way that could lead to user error. So at a minimum, I think that companies taking a conservative and careful approach will likely begin doing more usability testing than they would have before these regulations were in place.

Hasler: What I'm seeing in the industry reflects very much what Mike has just described. It can be quite confusing deciding how to handle a product that you've been producing for, say, 20 years once you recognize that a minor feature needs to be changed. According to all previous methods of evaluation, you would have gone ahead and made the change for any additional units sold. Now, however, once you start dealing, for example, with the user interface, you may realize that other aspects of the device may not meet the present standard and may need to be changed. Although a company certainly wants to support its customers, you're now faced with a full-blown project—a whole rework—of something that really isn't the product line you want to move into the future. In short, it is very difficult to understand how the regulations should be applied to older products.