Wearable sensor system on chest for continuous measurement of blood pressure and other vital signs

Abstract

Wearable health devices for continuous recording of heart rate (HR) and respiration are a common practice in wellness measurement applications. Typically, these can provide information such as health status and fitness level in daily life. At present, techniques that can provide all vital signals simultaneously, including blood pressure (BP), and validated for clinical accuracy, are lacking. One reason for this is that wearable sensors typically measure the signals from peripherals which are highly influenced by peripheral changes in blood circulation but also cause movement disturbances to recorder signals.In this paper, we present a wearable multimodal sensor system that allows continuous measurement of HR, respiration, and BP oscillations. All sensor elements are enclosed in a single, small-sized unit, which is placed on the chest above the sternum, ensuring monitoring of central BP oscillations. The device has been tested with voluntary subjects (adults and children) in various settings: in static positions, during sleep and in different physiological tasks. In addition, accuracy of the continuous BP measurement was tested against golden standard cuff based continuous BP monitor device, Finometer. We observed that the correlation of BP estimation with the reference had a Pearson’s coefficient in the range of 0.67 to 0.82 (mean 0.76). Both HR and breathing patterns were accurately followed as well. We present the technical solutions used in the sensors’ design, with an emphasis on the novel method to quantify BP from chest movements caused by cardiac activity. Furthermore, we discuss the advantages and challenges of the presented solution, and its feasibility for vital signals monitoring in both home and ambulatory environment.