In many emergency and critical care situations, having an accurate read on a patient’s blood pressure and hypotension risk is vital for a successful outcome. As blood pressure drops in a patient, the autonomous nervous system sends signals to blood vessels throughout the body telling them to constrict (vasoconstriction), thus raising blood pressure. The measurements from arm cuffs that are commonly used on patients today only provide a late indication of hemodynamic events due to the autoregulatory activities such as vasoconstriction that precede most such events.

Researchers at the University of Michigan have developed a unique wearable sensor, worn on the finger, called the Vascular Tone Monitoring System (VATMOS). This device has the ability to continually measure a new physiological signal–the vascular tone and reactivity of small blood vessels in the finger. Because the smaller blood vessels in the finger respond much faster to signals sent from the brain, the VATMOS detects potential cardiovascular events and hypotension much earlier than the traditional cuff system.

VATMOS connects to any portable device or monitor and has practical applications in dialysis centers, combat situations, emergency rooms, ambulances, and eventually in a patient’s home.

Significant Need

VATMOS portably measures the vascular tone and reactivity of small blood vessels in the finger, which gauge a patient’s physiology and hypotension. Using computational methods, the ring predicts hypotension ranging from 9-108 minutes in advance. This is useful for hemodialysispatients who greatly benefit from constant blood pressure monitoring, as well as in combat and critical care situations.

Competitive Advantage

VATMOS is easily portable, provides continuous hemodynamic monitoring, and predicts hypotension up to 108 minutes in advance. VATMOS also provides more relevant data to physicians, making it a better indicator of patient physiology than current devices such as pulse oximeters.


The team worked with the University of Michigan Office of Tech Transfer and our Commercialization Coach, Ken Spenser, to license VATMOS to New Vital Signs, Inc.