Expected Service Life of Medical Devices

[Marcelo]

Hello people

The new version of IEC 60601 asks that the manufacturer define the expected service life of the medical device in question. This does not have to be based on engineering calculations, but can be based, for example, on financial factors (also, ISO 13845 asks for a lifetime definition - see more on that on this thread - Lifetime of the Medical Device - What is the most appropriate definition?)

Anyway, i´m trying to figure out how to do that using engineering analysis. I mean, in my opinion it would be a blend of reliability and mantainability analisys paired with financial and liability analysis and other factors; this surely would not be an easy thing to do.

Problem is, i´m having difficult finding literature on this in a system level. The only focused book on this topic, Medical device reliability and associated areas, touch all the areas i mentioned, but separated, not together. I do think that this kind od thing depends on the particular equipment and company. Anyone would have some examples to put some light on the subject?

 

[Duke Okes]

You're on the right track. R & M, lifecycle costs, etc. are what need to be taken into account. This should all be done as part of the design concept and design detail phases.

 

[jkonholm]

UMDNS based Guidance Paper from Biomedical Engineering Advisory Group (BEAG) : "Life span of Biomedical Devices" Attached...

 

[AimeeC]

You're right: there is no hard and fast rule; requirements vary by geographic region, device type, and subcomponent failure modes as well as other factors.

If you are selling a durable medical device in China, the average lifespan is about 25 years and the device needs to be labeled as such (with supporting data in your FMEA and DHF). In any case, you need to take into account the integrity of the most risk-prone individual component(s), as applicable, and make your justification for lifespan conservative, and be able to prove that your lifetime claim is balanced by safety measures to detect earlier fault or failure—and the risk of its mitigation—should early failure occur.

If you're selling an active implantable device, ask yourself: is it accessible externally for examination, calibration, maintenance, and/or repair, OR, if you are selling a passive implantable device: how much clinical or statistical failure data do you have to make a robust claim of the device's longevity?

Also consider your patient population, remembering that passive devices implanted in children, for example, may need replacement as the child grows and thus are somewhat self-limiting in their functional durability. Likewise, devices implanted in an elderly population may well have the ability to far outlast their host.

The list of considerations goes on and on...I hope this reply does not frustrate you, but instead prompts you to look at your device from many perspectives.
Business reasons should certainly be taken into account, but solid data and patient welfare should always be the more heavily weighted factors supporting your claim.