Accurate Cuffless blood pressure measurement available 24 hours a day

ams announced the release of the first integrated vital signal sensor reference design based on its AS7024. This solution enables fast and accurate cuffless blood pressure measurement 24 hours a day, making it more convenient as it eliminates the need for a cuff.

The new vital signal sensor reference design based on the AS7024 integrates not only hardware such as the AS7024, but also software required for measuring blood pressure, heart rate (HRM), heart rate variability (HRV), and electrocardiograms (ECG). The AS7204 sensor IC integrates three LEDs, a photodiode, an optical front-end and sequencer for HRM, and an analog front-end for ECG in a low-profile 6.1mm x 2.7mm package.

In addition, this reference design enables the measurement of vagal tone and arterial elasticity, as well as skin temperature and skin resistance through an interface with external sensors.

The AS7024 has a small form factor, making it ideal for applications with limited board area such as fitness bands, smartwatches, sports watches, and smart patches, and it enables the expansion of vital signal monitoring applications to various form factors and end-product markets, such as automotive or personal health monitoring.

The AS7024 HRM operates using the industry-proven photoplethysmography (PPG) technique. When light, such as from an LED, is projected onto blood vessels, the reflectivity of the light changes depending on the expansion or contraction of the vessels as blood passes through; the PPG technique measures pulse waves by utilizing these changes in blood flow volume. The electrocardiogram is a standard technique for measuring electrical pulses generated by the heart's sinoatrial node.
The software used in the AS7024 reference design is proprietary technology jointly developed by ams and its partners, which calculates blood pressure by analyzing synchronized HRM and ECG measurements. The blood pressure measurement accuracy of the AS7024 was proven through clinical trials conducted by the Medical University of Graz in Austria based on the IEEE standard for capless wearable devices.

The results measured with this reference design are comparable to reference measurements obtained using conventional surgical blood pressure monitors that use cuffs. When combining over 1,000 measurement results from more than 100 clinical trial participants aged 18 to 65, the AS7024 reference design demonstrated excellent accuracy, showing an error rate of ± 7.5 mmHg or less for systolic blood pressure and ± 5.5 mmHg or less for diastolic blood pressure.

Thomas Riener, Senior Vice President of Color and Spectral Sensing at ams, explained, “The AS7024 reference design and blood pressure measurement algorithm demonstrated superior performance that transcends the realm of personal health monitoring technology. Smart wearable devices utilizing the AS7024 will provide accurate 24-hour blood pressure monitoring capabilities backed by numerous use cases. This not only eliminates the inconvenience and hassle of users having to undergo regular pressure blood pressure measurements but also significantly improves the user experience by allowing continuous measurement of blood pressure, heart rate, and cardiac function in a comfortable and pleasant state during daily activities.”