Usability Engineering Standard Helps Device Design Process

NEWS TRENDS

There is no excuse for failing to incorporate usability engineering into the medical device design process. That's not just a random thought. It's the opinion of Peter Carstensen, CDRH's top human factors expert. And, according to Carstensen, that means device companies need to become familiar with IEC 62366, “Application of Usability Engineering to Medical Devices.”

Carstensen, CDRH's senior systems and human factors engineer, made the case for a strong usability engineering program at the March AAMI/FDA International Conference on Medical Device Standards and Regulation.

In particular, he said, there are strong usability elements in a proper corrective and preventive action (CAPA) program.

“A common pitfall is that manufacturers don't adequately investigate use error in the CAPA process,” he said. “The intent of CAPA is to identify and fix problems and to prevent repeating problems. Blaming the user does not remove responsibility for good design.”

That means attempting to fix a problem with labeling when it could be fixed by design changes is a poor and potentially costly strategy, he said (see Figure 1). He cited the example of Alaris Medical Systems' infusion pumps.

“Alaris had to have a recall because of a keypad problem. The keys would sometimes stick, pressing a number more than once, which could lead to an overinfusion. The company chose to deal with it by putting [the following] in its manual: ‘Before executing the action, verify what you keyed in on the display.' FDA did not see eye-to-eye with the company on this, and we told them to fix the problem. We ended up seizing their inventory. That was a very expensive mistake. [It cost the company] more than $10 million. If they had paid more attention to usability and safety, they could have avoided it.”

FDA requires a systematic and scientific process that includes contextual inquiry, usability objectives, and usability testing with iterative design, he said. Human factors activities should take place throughout all phases of the design control process, from concept through validation. Notably, he said, risk analysis should occur at most of these phases.

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