Aidan Petrie, Chief Innovation Officer and Co-Founder, Ximedica

Miniaturization – Small is Beautiful, Beneficial

By Aidan Petrie
Aidan Petrie, Chief Innovation Officer and Co-Founder, Ximedica

While an apple a day may not always keep the doctor away, a wireless patient monitor just might.

As the first of the baby boomers come of age in the U.S., we see a paradigm shift away from hospital-based care towards prevention-oriented, in-home monitoring and therapy. This shift is being driven by a desire voiced among this population to live independent, non-institutionalized, normal lives and the notion that aging does not mean sick.  
For medical device designers and manufacturers, the human factors of this populace are accelerating a trend already realized in the world of consumer electronics toward creating smaller, more discreet and more mobile products. Specific to healthcare these wearable, or implantable devices are being designed to meet health-driven needs such as monitoring, diagnosing or treating all within the context of the day-to-day existence of the patient. The advantages to both patients and providers are significant. So too are the challenges for developers as devices become more compact, user-friendly and versatile while simultaneously the expectations for functionality become greater, components more advanced and manufacturing technologies more sophisticated.
Through our experience here at Ximedica, on one recent project in particular, we learned quite a lot about engineering an adequately powerful, durable device with significant size constraints. We learned the strength of collaboration as the electrical engineer charged with the schematic design of the printed circuit board (PCB) and layout of the product was directly affected by the mechanical engineer team’s in terms of his component choices and placement, which in turn influenced decisions made by the software engineers and industrial designers and so on. Having all of our teams from designers to engineers and manufacturing working in parallel proved a great benefit in effectively and efficiently producing a portable, fully-functional, and aesthetically-pleasing device. 
During this process we also learned how to design around four other common challenges that occur when creating smaller, more portable devices worth sharing:
Challenge #1:  Balancing size and weight with additional functionality
Early on in this particular product design process a compromise needed to be struck amongst the design and engineering teams as to just how many additional features could be added into the device whose overall spec size was no larger than a highlighter marker. It’s hard in this day and age not to get swept up by the technological advancements that smack of possibility particularly for portable device integration such as sensors that can measure blood oxygen levels or computing and analysis abilities.  
However with each additional feature comes the need for additional space and power which in turn adds to the overall mass of the product. It also contributes significantly to the amount of heat generated as cramming too many components into a small sleeve leaves no space for heat dissipation meaning wearability and portability become less. In the end, a hierarchy of needs was assessed and the specs drawn up to explicitly meet these needs.
Challenge #2:  Body interfaces
Many wearable devices come directly into contact with a patient’s skin and must therefore be biologically compatible. We recognized that materials used in the product we were designing needed to be non-toxic and non-abrasive. Additionally, materials needed to be light and flexible insuring a better fit to the highly contoured landscape of the human body, particularly when considering an aging patient whose skin is more fragile and more contoured, and on whom it would be more difficult to locate a flat surface to apply the device.
Challenge #3:  Wireless connectivity
Since wireless connectivity is critical in the portability of medical devices, it was a primary consideration in our design process. There are two areas where wireless capabilities were considered specific to this device: the first was in powering the device. The design specs called for a wireless power transfer system to charge the unit’s battery without contacts, to ease clean-ability and limit corrosion. This meant looking towards inductive charging methods and how the necessary pieces needed to charge as such could be configured within the space allowable.  
The second wireless challenge was in developing a proprietary wireless communication protocol that could be used to transfer controls such as speed information from a foot pedal to the device. Again this mandated a need for additional components and space in a form factor that could support neither. Designers and engineers used virtual and physical component sets to Tetris the parts into the most compact configuration.
Challenge #4:  Manufacturing and quality control 
Early on it became apparent that with all the small components being sourced for this product, manual assembly and visual inspection would be challenging if not impossible. The manufacturing team set into motion means of automating assembly of the product through the acquisition of high-tech equipment to do so. Realizing the additional cost of procuring the equipment for assembly and quality assurance,  the team resorted to its Six Sigma credentialed colleagues to ensure quality, and thereby, curb costs as much as possible.
While designing for discretion and mobility can have its significant challenges, the advantages by far outweigh the stumbling blocks in development.

About The Author

Aidan Petrie, Chief Innovation Officer and Co-Founder, Ximedica