Wearable ultrasound patch can monitor central blood pressure in arteries as deep as four centimetres below the skin
Researchers at University of California (UC), San Diego have developed a stretchy ultrasound patch that can be worn on the skin and provide readings of central blood pressure each time, even while the user is moving. And it can still get a good reading through fatty tissue. It could help people detect cardiovascular problems earlier on and with precision.
Applications include real-time, continuous monitoring of blood pressure changes in patients with heart or lung disease as well as patients who are critically ill or undergoing surgery. The patch uses ultrasound, so it could potentially be used to track other vital signs and physiological signals from places deep inside the body.
Patch can perform test on stationary as well as on moving body
The patch was tested on a male subject who wore it on the forearm, wrist, neck and foot. Tests were performed both while the subject was stationary and during exercise. Recordings collected with the patch were more consistent and precise than recordings from a commercial tonometer. The patch recordings were also comparable to those collected with a traditional ultrasound probe.
Ultrasound waves to record diameter of blood vessel
The patch is a thin sheet of silicone elastomer patterned with what’s called an “island-bridge” structure which is an array of small electronic parts (islands) that are each connected by spring-shaped wires (bridges).
Each island contains electrodes and devices called piezoelectric transducers which produce ultrasound waves when electricity passes through them. The bridges connecting them are made of thin, spring-like copper wires. The island-bridge structure allows the entire patch to conform to the skin and stretch, bend and twist without compromising electronic function.
The patch uses ultrasound waves to record the diameter of a pulsing blood vessel located as deep as four centimetres below the skin. This information then gets translated into a waveform using the customised software. Each peak, valley and notch in the waveform, as well as the overall shape of the waveform, represents a specific activity or event in the heart.
These signals provide a detailed information to doctors assessing a patient’s cardiovascular health. They can be used to predict heart failure, determine if the blood supply is fine, etc.
Well, the team is looking to collaborate with experts in data processing and wireless technologies for the next phase of the project.