Noninvasive and continuous blood pressure measurement via superficial temporal artery tonometry.

The measurement of blood pressure is an important cardiovascular health assessment, yet the current set of methodologies is limited in resolution, repeatability, accuracy, simplicity, and safety. This paper presents the design and prototype implementation of a novel and easy-to-use medical device for noninvasive and continuous blood pressure monitoring through tonometry at the superficial temporal artery (STA). The device features a stable form factor inspired by over-ear headphones that adjusts easily from person to person using a combination prismatic and rotational joint. A stepper motor and pressure sensor, built into the device, apply a controlled force to flatten the artery and measure the wearer's blood pressure. The design is fully wireless, using Bluetooth communication to connect to a custom control and monitoring interface on the user's laptop that allows for easy calibration and real-time measurement. Preliminary testing of the device showed a percentage error from a blood pressure cuff mean arterial pressure measurement of 7.7% (7.0 mmHg). This was also compared to a Nexfin vascular unloading device, which showed a percentage error from the blood pressure cuff of 7.3% (6.6 mmHg).