This product is a breakthrough in blood pressure monitoring technology (patent pending). It is an ingenious, wearable device that can continuously and accurately monitor blood pressure using photoplethysmography and chart beat-by-beat changes in blood pressure. I have designed and developed a low-cost and ubiquitous solution to allow for continuous blood pressure monitoring, both cufflessly and non-invasively. The ability to continuously monitor blood pressure, particularly during sleep, proves to be invaluable in anticipating strokes, heart attacks, and other cardiovascular events.

This device has the ability to monitor fluctuations in a patient’s blood pressure around-the-clock, something the healthcare sector has never seen before. Conventionally, a patient uses a blood pressure cuff (sphygmomanometer) to sit down and measure his/her blood pressure; however this is inconvenient and requires active patient involvement in the process.

A user must leave whatever they’re doing, sit still, and record their blood pressure, something which is cumbersome in today’s fast-paced lifestyle. Further, this may lead to anticipatory anxiety, and cause falsely elevated readings. My device overcomes all of these obstacles and is a complete solution to the problems presented by conventional methods of blood pressure monitoring. Healthcare professionals, including doctors at Sutter Health and researchers at Stanford, have had a unanimously positive response to the product and believe that this device is a game changer and will disrupt the medical sector when released for sale in the near future.

 

What inspired you (or your team)?

Hypertension, that is, high blood pressure, affects over 75 million Americans today, and fewer than 50% of those patients have their condition under control. My research began after seeing my dad, who has hypertension, measure his blood pressure manually using a loud and cumbersome cuff to take readings. After doing extensive research, I discovered that there is nothing on the market that can continuously monitor blood pressure, let alone take discrete measurements without a cuff. For a condition that affects over a third of the planet’s population, there hadn’t been any innovation in the field in the last two centuries. I was sure there is a better way, and I was determined to find it.

The purpose of this project was to design and develop a low-cost and effective solution to allow for continuous blood pressure monitoring. Current blood pressure monitoring methods only allow patients to “spot check” their blood pressure at certain times of the day, but nothing on the market can accurately monitor blood pressure at all times of the day. In fact, there’s been no major developments in the field of blood pressure monitoring since the advent of the sphygmomanometer (standard blood pressure cuff) since 1881—at least, until my device.

Blood pressure always has lability—it fluctuates mainly in response to stress, caffeine, and anti-inflammatory drugs, such as NSAIDs, among other contributing factors. Caffeine and NSAIDs are both vasoconstrictors, which means that they cause blood vessels to contract, resulting in an increase in blood pressure. True continuous monitoring should be able to monitor blood pressure changes in response to external factors such as these, and in turn, identify key causes which can drastically reduce the amount of blood pressure control medication that is given to patients by their doctors. Further, high blood pressure while asleep and shortly after waking, known as the nocturnal dip, is highly correlated with a person’s likelihood of having a stroke, heart attack, or other cardiovascular events. For this reason, it’s vital for patients to be able to monitor their blood pressure at all times of the day—not just when they’re aware that they’re doing so. This product is the first to be able to monitor actual trends in blood pressure, continuously, without the need for active user interaction.

This product is the first of its kind, and it uses an unconventional approach to monitor blood pressure. Instead of using conventional signal processing techniques, all of which have been tried before, this product uses the power of image recognition and feature detection and applies it to a numerical signal. In simple terms, here’s how the device works:

1. First, the device uses photoplethysmography, a technique that relies on the fact that blood absorbs green light. The device shines a green light into the user’s skin and measures the light reflected back by the blood. When the heart beats, more of the light is absorbed. At a sampling rate of 150 Hz, this outputs a PPG signal.

2. Next, the device converts the signal into a series of images using a continuous wavelet transform, which conveys important information (derivatives, scale, and rate of change) about a signal in the form of an image for further processing later.

3. Finally, using machine learning, the device processes the images in a convolutional neural network to recognize characteristics of the waveform and produce a blood pressure reading.

Not only does the product feature state-of-the art technology under-the-hood; it’s also been designed with the user experience and a sleek form factor in mind. The device can be comfortably worn throughout the day for “set-and-forget” blood pressure measurement. Another factor which was a major consideration during development was cost. Because of this, the manufacturing cost is projected to be under $5 to enable large profit margins and competitively price the product in the market. If priced at only $49, which is less than half the price of a traditional blood pressure cuff, the product will yield a 90% profit margin, which is unparalleled in the medical device sector.