Tiny Wearable Sensor Measures Blood Pressure Without a Cuff

Blood pressure is one of the most important signs of heart and blood vessel health, but it is still usually measured with an inflatable cuff that captures a reading at just one moment in time. Researchers at the Technion-Israel Institute of Technology have developed a tiny wearable sensor that could one day measure blood pressure continuously, comfortably, and accurately, with no cuff and no action required from the user.

The device combines silicon photonics, a technology that uses light on tiny silicon chips, with optoacoustics, in which light is used to produce sound waves. Short pulses of light create ultrasound waves inside an artery, and a tiny sensor called SPADE measures both the artery’s absolute diameter and the minute changes in that diameter with each heartbeat. From these measurements, the system can reconstruct the full blood pressure waveform and estimate blood pressure in real time over long periods.

Measuring the artery’s absolute diameter is a key advance. This miniature sensing approach is the first to do so, overcoming a major limitation of earlier technologies. Paired with advanced artificial intelligence modeling of how arteries behave, this ability gives the system a more complete basis for accurate, continuous blood pressure estimates.

The system is also simple. Many other approaches require complex arrays of sensors and precise placement on the body. The new technology instead uses a single, tiny sensing component and is relatively tolerant of shifts in the sensor’s position and angle. In proof-of-concept tests with volunteers, the system produced promising results, capturing features of the blood pressure waveform at a rate of 100 measurements per second.

Looking ahead, the researchers believe the technology could eventually be built into smartwatches, medical patches, and other wearable devices. This would let people monitor their blood pressure continuously at home, at work, and throughout their daily activities. The resulting information could improve monitoring for people with cardiovascular disease.