Agile medical device system design

The Agile revolution has definitely transformed the way software is built, to such an extent that it has become mainstream because it just works better. There are several factors to such a success: empowerment that helps get the best out of the people; automation that reduces costs, cycle time and errors. But to me, the most powerful practice of the agile toolbox is the incremental product design that reduces risks at all levels:

  • Integration risk: you integrate sooner (all the time, in fact), so the long-dreaded integration phase of the eighties (that could last for years and often end in project failure) is an everyday, routine task.
  • User needs risk: by implementing the most important features first and putting them into the hands of end users ASAP, you gain field feedback on what the users really need and want. You decrease the risk of creating totally useless or partially usable feature (80% of features in software are said to be never or seldom used).
  • Projects risks: by finishing the product often and measuring the team velocity, you know your real project pace and can adjust to it. Your team’s average velocity of the last three iterations is a good predictor of the team’s pace until the end of the project. I’m a big fan of this down-to-earth wisdom of measuring what’s too complex to be predicted and changing course accordingly.

When working on medical device projects with my colleagues from the hardware, electronics, reagent or system teams, I’ve often wondered why they wouldn’t use iterative development to their advantage. The counter arguments they gave me usually were the following:

  • Our iterations are too long. When designing hardware, the time needed to finish plans, order parts all over the world and receive them, test them and send them back for defects once in a while, assemble them, is ridiculously long – up to six months. The same with electronics if suppliers are expected to design and produce boards. Reagent teams may perform stability tests that last for years.
  • Our iterations cost too much. Big hardware prototypes can cost the price of several brand-new cars. Moulds are awfully expensive. Reagent production lines are a luxury item. Physical stuff cannot just be made and destroyed without a sizeable monetary footprint.

These hardships entice specialists to optimize their business with a typical waterfall process: long requirements elicitation, one-shot production of what they think should be made, oops we forgot something, some supplier is late, schedule is doomed. Local optimization is the enemy of the global optimization endeavor that is a systems project. I believe systems design must be iterative and thought as such from the very start.


System iterations
Hardware V1 and electronics V2 are combined with embedded software V5 to build embedded system V3. After some integration testing, embedded system V3 is combined with non-embedded software V6 and reagents V1 to perform the first round of tests of the complete system. This will lead to new insights and subsequent changes in the next iterations of all sub-components – a long time before the end of the project.


Software item iterations are likely to be always shorter. But that doesn’t mean that other specialties can’t plan iterations too. Some techniques that could be used to make it possible:

  • First hardware and electronics iterations can be made with prototyping material (for example: B&R automation products) that has unrealistic production cost or size but that allows fast creation of first versions. If first tests prove that the design is good, next iterations can focus on production cost, maintainability, assembly lines, multi-sourcing of providers, while the overall systems keeps on its journey.
  • Hardware stubs. First iterations can also use the technique we software developers know as stubs. For example, the first version of an automated and temperature-regulated drawer for reagent storage could be made without temperature regulation at all, and without automation (only fixed-position reagents, hard-coded in the code or loaded in the database via a script).
  • Design and usability are a big concern for marketing departments and regulators as well. I would suggest to meet your end-users ASAP by quickly manufacturing prototypes of all external interfaces. For example, you can use 3D printers or cardboard models or foam models. Have end-user representatives execute typical usage scenarios with it. What do they think? I remember using this technique for a device with a bar-code reader: we printed a 3D version of the casing in a matter of days only to realize that the bar-code reader was positioned in such a way that the end user would have to almost break its wrist to use it. So we moved it to the opposite very easily (no need to redesign all the internal parts of the device, no constraints!).
  • Reagents design is complex and slow. Help these guys by giving them ASAP a system prototype to test their stuff. They don’t care about chassis production cost, cybersecurity or electronic components triple-sourcing. They just need good biological performance.
  • Assembling subsystems is difficult. Something that has never been tested never works. So be sure to plan an integration and system debugging session every time you produce a system iteration, before downstream activities (such as biological performance tuning) can start.
  • As explained by the eXtreme Manufacturing movement, to plan for iterative, incremental system design, the priority would be to think carefully about the internal interfaces of the system and divide it into subsystems. Subsystems can evolve independently as long as they respect the interfaces – thus achieving fast-paced design.


ScrumInc eXtreme Manufacturing car
The modules that make up an extreme manufacturing build party at ScrumInc

This is no easy task. But a necessary one to tackle the top risks of a medical device project: biological risk and registration risk.

  • You should produce as fast as you can a functional system to tackle the biological risk – living matter is so unpredictable that you are better off observing how it behaves (just as project dynamics, by the way).
  • And once you have a complete system able to perform its biological task (stripped out of the bells and whistles), i.e. once you have tackled the biological risk, consider handling the registration risk by registering this minimalistic system. This will take lots of time (typically 2 years in China). The registration teams should be able to define the contour of a system that could be registered officially all over the world, but that you probably won’t sell (it’s ugly, it can’t be maintained, it has no advanced software features, but yes it performs its core biological mission pretty well). Meanwhile, you will prepare a second version with all the nice-to-have features that will be registered as a simple product evolution, with lower risk and delay, and that might well end up being available on the market little time after the first version is ready.

Lean Startup thinking promotes trying your concept with a Minimal Viable Product that you put into the hands of your end-users. Product registration authorities are a kind of VIP end-user. Maybe you should plan you entire project plan to build them a dedicated MVP to address the registration risk right after the biological risk is under control.

Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s