Lausanne, Switzerland-based Leman Micro Devices (LMD) recently announced Bluetooth wireless connectivity for its V-Sensor technology. LMD is developing the V-Sensor — short for “vital sign sensor” — for use by smartphone companies. According to an LMD release, the V-Sensor represents the “first medically-accurate measurement of vital signs through low-power single sensor: cuffless and calibration-free.”

We’ve written about Omron’s oscillometric blood pressure watch and Valencell’s in-the-ear BP measurement technologies. Omron’s watch measures blood pressure by inflating an air chamber under the watch. Valencell’s tech employs photoplethysmography (PPG) and inertial sensors. The V-Sensor does not employ either oscillometric or PPG tech. Instead, the V-Sensor measures blood pressure by occluding (blocking) arteries on the tip of the finger. When used with LMD’s e-Checkup app, the V-sensor measures blood pressure, body temperature, pulse rate, respiration rate, and blood oxygen with clinical accuracy, according to LMD.

The V-Sensor measures blood pressure using the Riva-Rocci technique. The Riva-Rocci technique, introduced in 1896 by ScipioneĀ Riva-Rocci, determines systolic blood pressure. Riva-Rocci preceded Nicolai Sergeivich Korotkoff”s 1905 auscultatory technique introduction by 9 years. The Korotkoff method is the common brachial BP cuff reading; it involves listening to the sounds of the blood flow as pressure is lessened. The Korotkoff sounds allow clinicians to measure both systolic and diastolic blood pressure numbers. Recent studies support the Riva-Rocci technique’s accuracy. Research published in the Netherlands Journal of Medicine concluded “Riva-Rocci measurements of systolic blood pressure may be as good as the traditionally used Korotkoff measurements.”

LMD is in the process of obtaining CE and FDA clearance. A company representative stated LMD is currently manufacturing small samples of the V-Sensor for testing by smartphone manufacturers. LMD anticipates the first commercial smartwatch shipments with V-Sensor technology in 2021.