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Textile pressure sensor applications in healthcare scenarios

Wearable technology has primarily focused on the upper body via smart glasses, wristbands and chest straps. There is also a tremendous amount of potential in wearable technology to collect data from the foot. The foot is a very complex part of our anatomy and it is constantly under pressure and is under-served by technology and innovation. The foot contains 25% of all the bones in our bodies which equates to 26 bones, but also 33 joints, 107 ligaments and 19 muscles per foot.

Leonardo Da Vinci used to say, “The foot is a masterpiece of engineering and a work of art.” It only makes sense to concentrate efforts to this critical part of our body and keep it healthy.

Think of foot-related complications of diabetes as an example. The problem is of epidemic proportions and the numbers are absolutely staggering. There are 347 million diabetics in the world today with a projected growth to a half billion by 2030 according to the Center for Disease Control. Approximately 70% of these individuals suffer from measurable peripheral neuropathy, a disorder in the sensation in the bottom of their feet. Unfortunately, on average 5% of diabetic patients get foot ulcers and 1% of those require amputation. Diabetic foot ulcers (DFU) are the most common cause of amputations and are responsible for more hospitalizations than any other complication of diabetes. The good news is that DFU can be prevented by following simple guidelines like do not walk barefoot, use clean and soft socks, and inspect your feet daily. Unfortunately, many diabetic patients are also overweight and have real challenges in inspecting their own feet. Once a patient suffers from a DFU there are proven treatments for DFUs; the cornerstone of treatment is surgical debridement followed by “mechanical offloading” of the area, which attempts to reduce pressure on the plantar area of the foot. After surgery, it is important that the patient does not bear weight on that part of their foot to improve blood circulation and increase chances of healing. For this reason the patient may be asked to wear a cam boot or use a scooter. However, it has been found that patients with diabetic foot ulcerations only wear their offloading devices for 28% of daily steps taken. Treatment failure is the norm and it is our belief that inadequate use of offloading devices explains the reason why. Offloading can be verified in the clinic; however, the issue is much more relevant outside of those constrained parameters.

The solution? Textile pressure sensors

We believe the solution is a continuous foot monitoring system utilizing wearable e-textile pressure-sensor-enabled wireless devices for the diabetic foot. This product concept is designed to help three distinct groups of people: the primary care physician (PCP) or a podiatrist, the patient and the enterprise provider. Let’s take a closer look at each of these groups.

For the PCP, the product is designed to monitor the patient and guide in the adherence of offloading. For the patient, they would be provided with a tool because they are not able to sense the bottom of their feet. With this continuous monitoring system the PCP is able to measure and verify in real time that the patient is within a safe parameter of pressure under the foot. Lastly, for the enterprise provider, there are potential huge cost savings by reducing readmissions and recurrent procedures and surgeries to treat DFUs.

We are developing a continuous monitoring system product that is wearable with a microelectronic module that connects to proprietary sensors that could be placed on the patient’s dressing after surgery. It will include a mobile patient application component to detect pressure levels in real time and alert the patient when those levels become excessive. If the patient is unable to improve or reduce the pressure on their foot on their own, there is an alert mechanism to inform the patient’s care team, allowing the provider to reach out to the patient and help them achieve offloading.

There are potentially three scenarios in which this can be clinically useful: acute care scenario, secondary prevention and primary prevention. In the acute care scenario, a patient is diagnosed with a DFU and admitted to the hospital or they come to an orthopedic for surgery and at which point offloading is absolutely necessary. The patient cannot bear weight on that foot following the procedure or they will continue to worsen the wound.

Now, imagine a secondary prevention scenario which is predicated on the fact that once a patient has a DFU, their likelihood for re-ulceration is extremely high. Once the ulcer heals having gone through excessive treatments, they would now have the power to monitor their foot whereas before they would insensate. They can continue to wear the secondary prevention sock to monitor in real time pressures and maintain a threshold within a safe range.

The largest market opportunity most likely exists within the primary prevention scenario. The goal is to prevent DFU entirely by having the patient placed on a continuous foot monitoring system as soon as the physician diagnoses a diabetic patient with early-stage peripheral neuropathy.

In addition to the system, we envision a clinician dashboard used to calibrate the device for the patient and establish a monitoring system for the provider. The dashboard could use a traffic light scenario where the patients who are at the highest risk are coded in red and elevated to the top of the list so that a medical assistant can reach out to those patients when they arrive at the clinic in the morning. The patients that may be outside of acceptable parameters for a short period of time are marked yellow and the ones in the safe range are marked green.

The primary and secondary prevention requires a regular sock that the diabetic patient can wear. The DFU prevention sock is as soft and as comfortable as a normal sock. The thin textiles are woven into the sock itself so there will be no bulges causing additional pressure. The first iteration of the sock will only focus on monitoring pressure under the foot for neuropathic patients who wouldn’t otherwise know if there was something inside the shoe that was causing ulceration or excessive pressures, but with the use of the prevention smart sock the patient will be alerted and can act accordingly. In future iterations, we envision the ability to monitor activity, balance and gait to prevent and alert in case of falls with the accelerometer in the anklet and the reading of no pressure under the foot.

So, in totality, the wearable device, the smartphone app and the cloud-based dashboard create a robust, all-inclusive solution for the patient.

A similar approach may be applied to garments focused on prevention of decubitus ulcers. Decubitus ulcers are pressure ulcers that form on patients who are often immobilized in a wheelchair or in bed, and the parts of the body that are most protruding receive the most pressure and thereby form ulcers that require a great deal of treatment and produce a great deal of morbidity. Sadly, most of these usually occur under the watch of the hospital or a clinic. In terms of market size, there are 1.8 million nursing home beds in the U.S.; 870,000 acute care beds and 70,000 ICU beds — all of which would be an appropriate fit for real-time monitoring of pressure levels to prevent ulceration. In addition, there are approximately 1 million pressure ulcers occurring annually which equates to $6 billion per year in direct cost for their treatment.

Today hospitals utilize the “turning schedule clock” method to assure that bed-bound patients are turned every two hours. A new one is initiated every twelve hours. Currently, this system requires a nurse to come in and reposition the patient who is at risk for ulceration due to their immobility which is a highly inefficient way of triaging human resources. In the future, a continuous bed monitor will hopefully be able to measure pressure on the bed sheet and determine if the patient is at a critical level that puts them at risk for pressure ulceration. This would allow nurses to be able to recognize when a patient hits a critical threshold and determine the amount of time that threshold has been met to officially triage nurses to be turning patients and allow them to conserve resources for other purposes when ulceration is not a risk. The potential for that market is enormous based on the number of beds and the morbidity and the cost savings that the hospital could incur by preventing ulceration.

These are just two of the health care scenarios where we see enormous potential through the use of smart garments and textile pressure sensors due to the vast amount of people impacted as well as the potential for substantial cost savings.

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