My wife walked in the door with a big sigh years ago after taking our young son to Toys ‘R Us. She realized he was going to take after his engineer father when, after picking an interesting toy off the shelf, he turned it over to see how it worked instead of just playing with it. Apparently, she thought one engineer in the family was enough. She worried about two of us constantly wondering how things worked, what would happen when those things were taken apart or how they might break. Fortunately, there’s a safe mental outlet for folks like us when we grow up and work as engineers – a tool to measure risk called the Failure Mode, Effects and Criticality Analysis, or FMECA.
The nuts-and-bolts of performing a FMECA can be tedious, but identifying all the ways a device can fail (“failure mode”) and the results of those failures (“effects and criticality”) is important in analyzing the risks involved with using a medical device. Perversely, I’ve noticed that figuring out how to break a device is often where an engineer’s creativity truly shines. Analyzing potential failures and risk is more than just therapy for frustrated engineers, though. While most in the med-tech industry recognize the need for a risk analysis from a Design Control and regulatory submission perspective, it also helps to set expectations for others in a company including the executive, legal, customer service and field service staff.
The FMECA process, when performed correctly, often resembles a brain-storming session. The environment in these FMECA meetings is usually the opposite of the “group think” that might be found in decision-making meetings; the emphasis is on diverse thinking rather than consensus (imagine if President Kennedy and his cabinet had used this process and asked “what could possibly go wrong?” before deciding on the Bay of Pigs invasion in 1961). And while engineers are particularly skilled at finding fault with a device, it is amazing how many times critical failure modes are identified by the Medical Advisory Board (“if I cut this lumbar device in half in the OR, can I implant it in the cervical spine?”) or by the Arizona sales staff (“will this balloon catheter still work if it sits in the trunk of my black car all summer?”). It may work best to start with the engineering group, but the FMECA process has to include the entire cross-functional project team to be truly effective.
Once the risks from using a device are identified and measured with the FMECA, the analysis helps in determining ways to reduce or mitigate those risks. This measurement & mitigation is intended as an iterative process in order to get the “residual” risk as low as possible, knowing that risk can never be completely eliminated. It is this final level of residual risk for each hazard that is factored into the risk-benefit discussion, with the obvious hope that the benefits to the patient will outweigh the residual risks.
Can all the risks involved with a medical device be accurately quantified and their acceptability determined by a simple chart or formula? No. There are always judgement calls to be made, and there are too many ways a device can be mishandled or misused to account for every eventuality. But if you want to deliver the best possible product and avoid your own “Bay of Pigs” fiasco, don’t just go through the motions – spend the time to perform an effective FMECA and risk analysis.