Small blood pressure monitor is your constant buddy

“She wore rings on her fingers and bells on her toes” is a fashion statement in an old song. Today, a “finger ring” devised by MIT that can be worn on the little finger is more practical, though not quite as fashionable. It functions as part of a blood pressure monitor that communicates with what looks like a mini motherboard strapped to your wrist. This small device enables a patient to wear the device 24 hours a day, collecting continuous readings.

Traditional techniques are more cumbersome and only provide a snapshot of the patient’s condition when taken in a doctor’s office or at home. Such readings can result in false numbers, because patients who are uncomfortable in a medical setting may return higher numbers than if they were relaxed. Routine, periodic self-administered readings at home can show more timely trends, but readings may be inaccurate due to the patient’s inability to perform the test appropriately.

The MIT designed device is important because blood pressure can go up and down like a see saw within minutes. High blood pressure, if you don’t already know from all the pill commercials on TV, is linked to stroke, heart attack, and aneurysm, which is an unpleasant bursting of a blood vessel.

The new continuous monitoring device is in the prototype stage, but may be applied later to other uses, including another potentially life-threatening problem called apnea, which occurs during sleep. Apnea has garnered attention lately because the sleeping person who stops breathing more than just momentarily, may wake up dead.

This project was funded by the National Institutes of Health (NIH), National Science Foundation and the Sharp Corporation, and grew out of the Home Automation and Healthcare Consortium, which included MIT faculty members and several companies.

A battery about the size of the one that keeps your watch ticking, keeps the monitor going as it measures how your heart is ticking. As the heart pumps blood, your blood pressure changes. The device measures the resulting pulse at two points along an artery. This method differs from the usual one-site cuff method, and is called pulse wave velocity. The calculated data is transmitted using radio signals or wireless Internet. Your new buddy will allow the doctor to keep closer tabs on your health.