Innovative Gadget Monitors Blood Pressure Levels
Continuous Blood Pressure Monitoring with Ultrasound
Monitoring blood pressure represents a fundamental health measure, yet traditional methods merely provide a fleeting glance through the use of pressure cuffs that constrict arteries. Although continuous monitoring exists, it typically requires invasive insertion of a transducer into the artery. Now, a team from Caltech is working on a new method that could enable continuous blood pressure readings anywhere on the body.
In a study published in July in PNAS Nexus, researchers outlined their technique, called resonance sonomanometry (RSM), which employs ultrasound to assess artery wall dimensions. By utilizing sound waves to locate resonant frequencies, the technique can determine the pressure within these walls based on their tension. This method allows for simultaneous readings of blood pressure without needing calibration, which is a significant advancement over existing non-invasive techniques.
Mechanism of Resonance Sonomanometry
The RSM system utilizes an ultrasound transducer that transmits sound waves at varying frequencies to assess the artery’s dimensions. This vibration causes the arterial walls to oscillate, creating a unique motion pattern that can indicate the resonant frequency. By identifying this frequency, researchers can determine the tension in the artery walls, which is directly tied to the fluid pressure inside.
Tests conducted on models and human subjects demonstrated the effectiveness and precision of this technology. Initial tests were done with a model simulating an artery using rubber tubing, followed by trials on human subjects, including measurements taken from the carotid artery while corroborating results with traditional pressure cuff readings. The technology showed validity on multiple types of arteries, indicating its versatility.
RSM not only provides consistent data throughout the cardiac cycle but is also capable of detecting variations in blood pressure caused by respiration. This technique is particularly promising as it utilizes a non-invasive approach, which avoids issues associated with skin coloration seen in some light-based measurement devices.
Dr. Nick van Terheyden, a digital health leader, emphasizes the importance of ongoing monitoring as opposed to annual readings, calling the new mathematical and physical approach an exciting development. The research team has further established a spin-off company, Esperto Medical, aiming to bring this technology to market. They are developing a compact transducer module designed to fit into wearable devices like armbands and ultimately wrist-worn gadgets.
According to a survey, 92% of consumers interested in wearables would pay a premium for health-related features, with blood pressure tracking being the most sought-after function. The future may see smartwatches continuously monitoring blood pressure, paralleling operations of standard vital sign measurements.