Medical Device Design Standards: Necessary But Not Sufficient

Abstract

Within the European Union, medical device manufacturers are required to demonstrate compliance with agreed criteria relating to the safety, quality and performance of their products. In doing so, they are encouraged to adopt voluntary harmonized consensus standards. A similar situation exists in the US, with the Food and Drug Administration recognizing the adoption of consensus standards as demonstrating safety and/or effectiveness. This applies across many aspects of medical device design, although conformance with standards does not always provide a sufficient basis for regulatory decisions (FDA, 2007). Although standard solutions offer numerous benefits in terms of reducing duplicate labor and enabling the sharing of knowledge, there are also challenges regarding the application of generic solutions in variable contexts. For example when it comes to the demonstration of safety, lessons learnt in other industries show that despite systems being certified as technically safe (e.g. they meet an agreed specification), accidents still occur (Cullen, 1990). A similar situation exists, for medical devices such as infusion pumps. Despite the adoption of standards, an alarming number of device related incidents continue to occur (AAMI/FDA, 2010; JHUAPL, 2012). There are also differences between the equipment healthcare professionals want and need and the devices they end up getting. For example, users are adopting workarounds (Rayo, Smith, Weinger, Slagle, & Dresselhaus, 2007) and there are mismatches between the way that equipment is designed, what people want, and the characteristics of the wider workplace (Martin & Barnett, 2012). In this context, the idea of there being one right user interface solution is an over simplification. This is partly because people don't agree on what they want and there are numerous competing and conflicting requirements. Although standards serve a recognized purpose, there is also room for flexible, argumentation-based approaches. The community involved in design and development need techniques that allow for freedom, and the means to justify "why are we doing it like this." Design reasoning needs to be made explicit across a diverse range of stakeholders; the aim being to support communication and let communities find their own solutions, rather than forcing a solution upon them (Vincent, Li, & Blandford, in press). There are several ways to provide for this, using lightweight, agile, flexible tools that help professionals think about how devices will be used and who will be using them. The aim is not to impose a single solution, but to provide the means to explore multiple solutions, whilst at the same time capturing the reasoning behind the chosen design. An example would be the application of personas and scenarios to infusion pump design (archetypal descriptions of user and usage). These get design and development teams talking about the needs of the user, and help avoid the trap of designing for oneself. Another way of getting people to state their reasoning is through the illustration of a design rationale. This is documentation that provides details about why systems or artifacts are designed in the way that they are. The Questions Options and Criteria (QOC) scheme originally proposed by MacLean, Young, and Moran (1989) is one way of doing this. It provides a quick and accessible way to combine the multiple perspectives involved in the design and development of equipment. The benefit of the technique is that it can be used to articulate and resolve multiple and sometimes conflicting influences. A QOC diagram contains statements relating to design "Questions", which are the key issues for structuring the design space. These are linked to "Options" which articulate possible alternative solutions. "Criteria" provide issues against which to assess the strengths & weaknesses of alternative options. It is possible to show whether options support or challenge criteria. Once an option has been chosen, subsequent questions are generated and resolved in a similar way. A variant of this technique (QOC-E), allows the linking of an evidence base to justify criteria and consequently the chosen design option (Vincent, Blandford & Li, 2012). This is helpful, because for medical device design there are numerous classes of evidence that shape design but limited ways of articulating, combining and resolving them (standards, design guidelines, simulation studies etc). In this way, we promote methods that can be used to capture the tradeoffs and compromises made during design. The novelty of the work is that although there is a large volume of literature expressing process inherent in the design of medical equipment, there is very little advice on how to reconcile multiple perspectives on a design problem. Techniques of this nature support communication between different stakeholders; facilitate tempo in the design process; and avoid the potential for deadlock, missed requirements or over adherence to template solutions that don't meet the needs of the user.

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Cullen, W. Douglas Lord. (1990). The public inquiry into the Piper Alpha disaster. London: HMSO.

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Rayo, M., Smith, P., Weinger, M. B., Slagle, J., & Dresselhaus, T. (2007). Assessing medication safety technology in the intensive care unit. Paper presented at the HFES 51th Annual Meeting. 692-696, Balitmore.

Vincent, C., Blandford, A., & Li, Y. (2012). QOC-E: A mediating representation to support the development of shared rationale and integration of Human Factors advice. Paper presented at the HFES 2012 Symposium on Human Factors and Ergonomics in Health Care, Baltimore.

Vincent, C., Li, Y., & Blandford, A. (2014). Integration of human factors and ergonomics during medical device design and development: It's all about communication. Applied ergonomics, 45 (3) 413-419.