Smart Devices Require Smarts

Medicine has relied on mechanical devices to help treat patients for decades. These devices have ranged in complexity from stents and shunts to dialysis machines and ventilators. As we settle into this age of data, the pressure to connect, control, instrument and analyze the operation of such devices and their impact on health has grown exponentially. After all, at a time when my watch can share heart rate and oxygen saturation, surely any physician-prescribed monitoring device should be able to provide relevant medical insight too?

For many companies producing these devices, the challenge is how to move from an analog mechanical device design to a connected model. After all, it is not an incremental step but rather one that requires  a substantial shift in in a company’s skills, expertise, outlook and business model. Moving to designing and manufacturing connected devices introduces two notable disciplines not previously required as part of the development process – electronics design and embedded software design. This increases design complexity that must be addressed by introducing a third discipline of systems engineering. Linking such devices to a cloud-based backup and analysis service adds further complexity as the process shifts from standalone device design to connected device design capable of coordinating data collection, data reporting, and data analysis services in the cloud.

Transitioning to connected devices also complicates the qualification and regulatory requirements for the design. These can include, for example, compliance to the EN62304 standard covering design controls for medical device software, and requirements of the IEC-60601-1 technical standards for the safety and performance of medical electrical equipment and systems used in home healthcare. There’s a lot of work to be done just to understand what the standards cover, which parts of the standards are relevant to a given design and what processes and records are required to achieve the necessary compliance certifications.  As just one example, IEC-60601 defines sub standards for many different types of device designs and aligning to those nuances will be vital to securing approval.

Shifting from producing a purely mechanical medical device to one that involves embedded electronics and software, connectivity, and cloud analytics also changes how a device is priced, moving from a simple purchase to a more complex cost model.  The design process becomes driven, in part, by the utility of the data that the device is collecting, who it is being collected for, and how much that data is valued.

Let’s look at a very basic example. If it is important to continuously monitor a patient’s temperature and the device is being  sold to consumers, the device will likely call for a small screen and a simple human/machine interface. If the device is slated for use purely for data collection and paid for by a health insurer, you may have to discard the user interface and add more memory to ensure that it can store all of the patient readings. In the second case, cost control becomes a much more critical factor in the overall design trade-offs.

One way of addressing the connected device design challenge is to start by focusing on the type of data to be gathered and how it will be leveraged.  Is it supposed to display a value on a user interface, sound an alarm when a value slips out of range or is it only for feeding data back to a healthcare provider?

Once the type of data is determined,  the next step is to decide how the data should be sensed. The choice of sensor will usually be decided through a trade-off between the desired accuracy of its readings, the direct cost of the sensor and its supporting circuitry, and related factors such as the resultant power consumption and possibly the sensor’s operating lifetime.

The power consumption issue is critical to the device’s utility and perfectly illustrates the additional complexity of connected device design. Using a large battery will extend the interval between charging cycles, protecting the integrity of the data-gathering process. On the other hand, patients may simply not want to wear, carry, or use a bulky device, completely undermining its utility.

The connected device design process becomes one of trade-offs, balancing the integration of electronics, implementing the necessary mechanical features, and deciding on the overall physical packaging. This involves exploring the right form factors for the design and choosing the right kinds of printed circuit board (PCB). For example, a flexible PCB might enable the development of a denser device. Is that a desired outcome? And, defining the right materials is critical as well. Further, this must be done while ensuring that the human-machine interface has been developed using best practices for human-factors engineering.

The first pass at making these multi-disciplinary trade-offs usually ends up with a proof of concept, which demonstrates that the device will work as designed and enables relevant feedback to be shared by potential users about the design. This information can then be fed back into repeated cycles of product optimization, miniaturization and cost reduction that eventually delivers a production-worthy design. All this work must be carried out under design-control practices that help ensure that the product will meet regulatory requirements.

A good design is worth very little if you can’t get the parts to make it. As such, specifying and sourcing components with the right specifications and certifications for use in medical devices becomes critical. That may be easier said than done when the component supply chain is constrained. And although many early phase medical devices are produced in short runs, designers still need to think about specifying parts that can be easily handled by automated manufacturing systems. Further,  there’s an emphasis on minimizing the bill of materials in order to ensure simpler and more cost effective design and manufacture of the device.

Finding the right manufacturers to make the devices can also be a challenge. Facilities may require special certifications to make medical devices, as well as specialty equipment for handling processes such as populating flexible PCBs or integrating very dense circuitry into small enclosures. The real-world constraints imposed by these manufacturing processes must be considered in the design and also vetted through manufacturing process  validation, which is also a highly specialized capability in healthcare.

Finally, second source supplies and manufacturing partners are also vital as demand and supply fluctuates with frequency and even the best forecasting may not support unexpected shifts in the market and the conditions and raw materials supporting it.

None of the issues involved in moving from a mechanical medical device design to a connected model are insurmountable. The challenge is to take on these new disciplines with both speed and sensitivity to the market opportunity window.  Molex offers end-to-end connected device development expertise, from ideation to global manufacturing at scale. Collaboration with an industry partner who both understands the nuances and also brings the vertically integrated capabilities and engineering expertise is key to driving the outcomes that deliver smart, connected devices – wherever in the world they are needed.

Director, Connected Health Device Technology for Phillips-Medisize