OfficeBP: noninvasive continuous blood pressure monitoring based on PPT in office environment

Blood pressure (BP), as a crucial vital sign of human beings, reflects the physical state of the cardiovascular system. Currently, blood pressure is mainly measured by collecting the changes in pressure in the vessel using cuff-sensors. It is a manual operation and cannot achieve continuous BP monitoring. In this work, we developed OfficeBP, a novel non-intrusive BP monitoring system for a typical office environment. OfficeBP relies on measuring the pulse transit time (PTT) between the pulse propagate from arterial proximal to the distal site on once heartbeat. For calculating the PTT, the user's face and thumb fingertip are regarded as the start and end points respectively. A twin-channel PPG sensing system is presented, that is, the fingertip pulse recording photoplethysmography (PPG) is obtained by a low-cost photoelectric sensor integrated with a mouse. Using image processing the face pulse is acquired by remote-PPG (rPPG) that based on a commercial off-the-shelf camera collecting facial video frames. OfficeBP was evaluated on 11 participants in different working conditions including the external illumination factor and personal internal factors, and achieved RMSE result of diastolic blood pressure 4.81 mmHg, systolic blood pressure 5.35 mmHg, demonstrate the feasibility of the system in an office environment.