When it comes to medical device safety, having fully-integrated human factors engineering (HFE) processes in place throughout development is absolutely critical.
Integrating HFE from Day One of development may seem counter-intuitive. The iterative testing process HFE calls for can be frustratingly non-linear, and may appear expensive. But the alternative – taking a product all the way to pre-market testing before identifying potential user error – is much riskier. At that point, when testing reveals use-based safety concerns, you'll be forced to choose between a costly redesign or a hasty, less-than-effective retrofit. The further along in development your product goes before HFE integration, the riskier and more expensive neglecting it becomes.
Broadly speaking, HFE aims at reducing hazard risks arising from user error during normal use of your product. Successful HFE integration forces your whole development team to stay focused on users, use environments, and user interfaces throughout product lifecycle. HFE recognizes that a well-designed user interface (UI) not only encourages correct use of your product, but also discourages incorrect (and potentially hazardous) use errors.
(The FDA defines UI for medical devices as all elements of the device that a user interacts with – sees, hears, or touches).
It should come as no surprise that modifying product design is more effective at combating user-error hazards than training or labeling. Training is subject to “knowledge decay” – we forget training with time – and we don't necessarily have or take the time to locate and read instructions, especially in urgent medical situations. Users interact with devices primarily on intuition and expectation, biases and instincts which are reactions to product design and influenced by previous interactions with similar products. We've got to anticipate these and keep them constantly in mind in order to “design out” user error.
In general, the FDA believes that user-based medical device safety should be prioritized like this:
- Safety Through Design
- Protective and Preventative Measures
- Safety Information and Training
One of the biggest challenges we face in design is the expectation of simple interfacing. I once heard a microwave repairman claim that they should put only "+30 second" buttons on microwaves instead of all the other numbers because that's the one that malfunctions from overuse.