Continuous, Non-invasive and Cuff-free Blood Pressure Monitoring System

This paper presents a continuous and non-invasive blood pressure monitoring system, which can measure the blood pressure without the use of a inflatable cuff. A wearable IEEE 802.15.4-based Wireless Body Sensor Network (WBSN) composed by a photoplethysmographic (PPG) sensor node located on the forehead, and an electrocardiographic sensor node located on the chest, is used to measure the propagation time of the pressure wave from the chest to the forehead. This propagation time is related with the user blood pressure through a mathematical model, which is solved by the WBSN without sending raw signals from the sensors to a more complex device, such as a laptop or cell phone. On-node processing and blood pressure cuff-free estimation allow reducing energy consumption, while the location of the sensor nodes provides the user with a complete freedom of movement. After evaluating the system, experimental results show that the proposed system has the potential for constantly and non-invasively measuring the blood pressure of a person during daily activities.