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Designing medical devices needs careful planning and, above all, patience

By 2045, according to the Office for National Statistics, the UK’s population will have risen to some 76million and almost 25% will be 65 or older. The health and social care implications will be significant – and that will create an opportunity for innovative healthcare devices.

It might be that your company has an idea for such a device, but if you have no experience of developing products for the medical sector, what process should you follow and, importantly, how long will it take?

Helen Simons, a quality specialist with technology and product design company Cambridge Design Partnership (CDP), said the first thing to determine is which market you’re going to address. “For medical devices, the two main markets are Europe and the US. Other health authorities tend to follow these requirements, although some – such as Australia and Canada – are beginning to develop their own regulations.

“If you’re targeting Europe, your product will have to comply with the Medical Devices Regulation or the In Vitro Diagnostic Medical Devices Regulation, both of which have been updated recently and replace previous Directives. These Regulations are mandated by law.” The fact the UK is leaving the EU in March 2019 is already muddying the waters, Simons noted. “It’s causing confusion, but it’s likely the Medical Devices Regulation will come into UK law, but it’s not clear how.”

The good news is that the EU and US regulations are published on the web and can be downloaded free of charge. The bad news, if that’s the appropriate term, is the sheer volume of information.

James Baker, a CDP partner, explained: “Take safety as an example. The top level standard for safety is 424 pages long, with 455 clauses. And there are another 92 standards. You can understand why people feel daunted.”

Simons said one of the main standards for medical device development is ISO13485. “This is a quality management standard and is the medical equivalent of ISO9001. A lot of companies choose to follow this because it provides a framework that helps them to meet most regulations, including how to control the design process. “There’s also ISO14971, which is about risk management. While neither standard is mandated, if you are seen to follow them, it’s likely things will be OK.”

Three other important standards need to be consulted along with way. “IEC60601 includes a whole suite of standards,” Simons pointed out, “and which part you use depends on the kind of product being developed. IEC61010 covers test equipment, while medical device software is covered by IEC62304. All three feature risk based approaches and levels of control While these are the key standards, others will need to be consulted.”

"If it isn't written down, it hasn't happened."
Helen Simons

Baker said CDP has a long history in designing products within regulatory frameworks. “We’re also doing more awareness training. That’s becoming more and more relevant, particularly when it comes to 60601-1 – electronics in medical. Traditional mechanical products are now integrating electronics and sensors, so companies coming at medical from the mechanical side need to plan more when integrating electronics.”

Patience is a virtue when designing for the medical sector. “Mind set is important,” Baker asserted. “When a market opportunity appears, some companies will see the regulations as burdensome and try to move ahead quickly. My advice is to take your time because, if you move too quickly, you could design yourself into a corner and, potentially, need to do a complete redesign. The best approach is defensive design; really analyse your product and make a decision about how the design will comply.”

So where do you start? Simons said: “It’s really important to think your design through at the earliest stage because authorities need documentation; evidence that you know how you’re going to produce it. Take the approach that if it isn’t written down, it hasn’t happened. “Write an intended use statement – Who will use it? What for? Where will it be made? That helps to generate the design inputs and which parts of the regulations you have to comply with.”

Baker focused on the software development process. “Taking this approach forces you to show that you have considered the process from end to end. You will be expected to show that you have analysed the project, how you will deliver the functionality and how you will test the software against requirements. Generally, this will be accomplished using the V model.”

Simons added: “Software needs to be thought about early in the project because you can’t always prove that software will do what it should.”

Risk management is another important element. “Getting this wrong could lead to a hardware redesign,” Simons cautioned. “Thinking about this at an early stage can save a lot of time and money.”

Baker explained that CDP’s approach to medical design is to consider how every element of compliance will be dealt with. “It depends on how you architect the product. For example, you may decide to eliminate software from the safety critical aspects and handle that element using hardware. It’s all about understanding the design and producing the documentation you need to prove compliance.”

Don’t be concerned about generating too much documentation. Simons said: “The amount of paperwork you will need to provide is an order of magnitude or two greater than for a consumer product. One design I was associated with required 20 lever arch folders for the paperwork – even before manufacturing.”

Safety is another element of risk management. “60601 has two elements – basic safety and essential performance,” Baker noted.

“With basic safety, it’s never acceptable to electrocute someone, for example. Essential performance is something the device needs to do, even if it’s gone wrong, because it could put people at risk.

"Essential performance is something the device needs to do, even if it's gone wrong."
James Baker

“When you’re analysing the design, ask what happens if a component is open circuit or short circuits or is the wrong value? That’s the level at which you need to demonstrate safety. Ask what happens in the event of a single point of failure, because your device must continue to be safe.”

Simons added: “While consumer electronics just fail, a medical device just stopping could be risky, so there is a need for graceful shutdown. Also think about design safety; if you are designing an implantable device, what are you going to do if it goes wrong?”

The regulations and the associated assessment periods are a challenge and this can see extended time to market – something which can, potentially, stifle innovation as companies fall back on proven designs. “However enthusiastic you might be,” Simons observed, “it’s going to take at least two years to get a medical product on the market.” Baker added: “It could be four years for more complex devices.”

Both emphasised that standards are there to help, so you should take time to read them and go through the detail. “Remember,” Simons concluded, “if you haven’t taken Directives and Standards into account, you don’t have a product – you only have a concept.”

Author
Graham Pitcher

Related Downloads
169277/P24-25.pdf

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