Form equals function for wearable medical devices

Designing medical devices requires meeting rigorous regulations and ethnographic research for each project. Sara Urasini, of Design Partners, details a recent medical device design project.

Medical services design can learn from the consumer sector. Counting steps might not help in an emergency, but smartwatches have empowered people to take care of their own health to a certain degree. More to the point, it has made caring for your own health fashionable. People are able to manage the symptoms, for the most part, discreetly.

With life expectancy increasing, the number of people living with chronic or debilitating conditions will grow, adding pressure on healthcare systems.

Health self-management is not an entirely new concept; diabetics have been successfully using epi-pens and asthma sufferers have used inhalers for years. These devices are focused on doing what is required to get the data needed or deliver the medication required. If future ‘at-home’ medical devices cannot meet people’s new expectations they will simply fail, it will cause more complications for healthcare providers.

Design in a heartbeat

Design has the power to elevate human potential to address this challenge head-on, in this case, combining healthcare, consumer and wearable technology design to create an ECG monitoring device with the user experience at its heart.

Abnormal heartbeats are common, but can be a symptom of a serious condition, such as a stroke. Effective heart-rate monitoring is therefore a common and important procedure. The problem is that abnormal heart rates are notoriously difficult to spot. Most healthcare professionals advise suspected suffers to wear a Holter monitor for 48-72 hours. This is a small, battery-powered medical device that measures the heart rate and rhythm. Patients can take the device home, but it is cumbersome and uncomfortable, which is not only unpleasant for the user, but can affect data accuracy.

The brief was to create an ECG monitoring solution that would be as simple as putting on a T-shirt and enable the wearer to continue to do day-to-day activities. It would be required to capture accurate and reliable data without discomfort
to the wearer.

The resulting Viscero ECG vest uses electronic ink to pick up the signal of the heart rhythm and provide accurate, medical-grade data to a healthcare provider.

Electrode choices

One of the biggest challenges was ensuring accurate data capture through the T-shirt. The traditional Holter monitor uses wet electrodes that make contact with the skin through hydrogel. These electrodes are prone to slip off over the monitoring period and healthcare professionals are often required to reapply them.

The vest allows users to record heart rate signals from skin contact using dry electrodes, that is, ones that do not need hydrogel. These electrodes are situated beneath the fabric at designated compression points around the arm and waist. The points are integrated into the T-shirt using lamination and double-layer compression, and are positioned away from the chest to more peripheral locations to ensure consistent compression is maintained.

The ‘brain’ for the heart

Once captured, the data had to be filtered and sent to clinicians. A small pod device, the ‘brain’ was created with the ECG circuit. It includes a tiny accelerometer and gyroscope so that clinicians can get a fuller picture of recorded heart signals to highlight when there are changes caused by exercise, for example. The ‘brain’ can sit comfortably in the T-shirt pocket and can be removed for charging and when washing the T-shirt.

Ideally, data gathered would be sent directly to the healthcare professional’s computer dashboard and AI would filter the data to identify irregular patterns, saving hours. A mobile phone app, created for the patient and used by the patient and the healthcare consultant, would deliver updates on results and/or next treatment steps.

Cardiologists have described the signal quality of concept Viscero’s ECG waveforms as “diagnostic quality data”. There are indications that the connected world is changing the course of healthcare for the better, and before long will help the industry pivot to a system where people are able to manage their health as part of daily routines, assuage patients’ fears and fit seamlessly into lifestyles.