Multimodal Sensor Integration for Unobtrusive Measurement of Blood Pressure-Related Parameters

Monitoring cardiac and respiratory activity, along with the overall physiological state of patients, is crucial in emergency rooms, especially when patients are waiting for further treatment without constant supervision. Unobtrusive sensing technology supports effective patient care by enabling seamless deployment of monitoring systems. This contribution introduces a multi-redundant sensor system for unobtrusive heart activity measurement integrated into an emergency bed. The system includes capacitively coupled electrocardiographic (cECG) electrodes and ballistocardiographic (BCG) sensors in the mattress, and a foot strap with an integrated reflective photoplethysmographic (rPPG) sensor. These sensors provide robust cardiac activity data and enable the extraction of blood pressure-related parameters such as pre-ejection period (PEP), pulse transit time (PTT), and pulse arrival time (PAT). A proof-of-concept study with four healthy volunteers validated the system, showing an RMSE of 0.058 s for RR intervals and 93.6% cardiac activity coverage.