Blood pressure: it’s often cited as the most important indicator of human health. Its fluctuations can be induced by both internal and external influences, and these can do many things to the body. However, the only way to monitor blood pressure currently is by using a sphygmomanometer, a cuff-like device, which, while accurate and vital in modern medicine, is bulky, inconvenient, uncomfortable, and outdated (it was invented in 1881).
A close-up of the most common blood pressure monitoring device, the sphygmomanometer. While accurate, the discomfort experienced when using a sphygmomanometer makes the non-invasive nature of the Infineon BGT60TR13C radar chipset all the more significant. Image Credit: ML5, Wikimedia Commons.
That’s why, earlier this year, Infineon Technologies announced an agreement with Blumio for the co-development of a wearable blood pressure sensor based on Infineon’s Xensiv sensors. If the collaboration ultimately proves a success, the new sensor is expected to make waves in the $45 billion cardiovascular monitoring device market for wearables—thus enabling the simple, seamless, and accurate monitoring and measuring of blood pressure round the clock, and without the need to wear the bulky and inconvenient cuff-like device that is the sphygmomanometer (pictured above).
Infineon’s Radar Expertise Plus Blumio’s Software Technology
The co-development project will combine Infineon’s proven expertise in radar sensors with Blumio’s software technology. This, the companies say, will lead to a kit that combines the two, leading to a much faster time-to-market for simple integration when it comes to blood pressure monitoring devices.
Using radar technology offers several advantages over passive infrared (PIR) technology that’s found in motion detection applications. Such advantages include increased general accuracy as well as the more precise measurement of detected objects.
An example of a wearable designed to measure its wearer’s heart rate in BPM (beats per minute). Image Credit: Pixabay.
Said Catherine Liao, Blumio’s founder and CEO: “We wanted to know how to use the radar to measure things that are very, very close, and with tiny movements. I’m sure all of us have measured our heart rate by … putting our finger on our neck or … wrists and felt the pulsation of the artery with each heartbeat.
“The strength of the pulsation is caused by the amount of pressure that is traversing through your body, and propagates outwards from your vessel out to the surface of the skin.”
Further Benefits of the Radar Chipset for Blood Pressure Sensing
Unlike other sensors and signals, such as electrocardiograms (or ECG) and photoplethysmography, the chipset’s reliance on radar means it is unaffected by skin colour and variations in ambient light. By measuring electromagnetic waves reflected from a target area inside the body, radar can capture and record clean signals through the use of low-pressure chipsets with high sensitivity.
Each time a person’s heartbeats, the pulse travels along the artery. This creates microscopic movements on the skin’s surface, which can be registered by the radar and translated into a blood pressure waveform. This is then analysed by an algorithm to give a precise blood pressure reading and other cardiovascular metrics.
Although Infineon and Blumio’s monitoring device is not the first time that an alternative solution for blood pressure monitoring has been engineered (others include applanation tonometry and volume clamping), it is nevertheless the first that could be set to find widespread use outside of clinical and hospital settings.
Pictured above a matchstick for scale: the Infineon BGT60TR13C radar chipset (the front and back views of which are pictured left to right respectively). At the time of writing, it is not known if this is the chipset used in the blood pressure sensor device or if a new one has been developed. Image Credit: Infineon Technologies AG.
Overcoming Current Technological Limitations
Infineon and Blumio’s sensor is designed to overcome the limitations of existing technologies through constant, direct contact with the user’s body.
The main challenge, the companies say, is to find the right place on the body to capture and record artery pulsation, while also ensuring that the radar is sensitive enough to capture motion accurately. Another major challenge is in engineering the technology so that it can reject irrelevant motion artefacts.
Once these obstacles have been overcome, the partnered organisations claim that the Infineon BGT60TR13C radar chipset will be able to achieve regular, high-speed data acquisition without creating uncomfortable pressure points (consider, for instance, the discomfort that can be caused as a blood pressure cuff inflates and deflates).
“We are currently in the process of performing clinical data collections on humans,” says Adrian Mikolajczak, head of the Infineon Silicon Valley Innovation Center, Power and Sensor Systems.