Applications of the bi-layer thin film sensor system for registering cardio-respiratory activity

A novel bi-layer thin film sensor system was used for accurately registering physiological parameters associated with body movements, such as cardiac and respiratory activities. The bi-layer curvature sensor system can provide additional medical information about the cardiac activity of the patient by mapping the five characteristic waves of the normal heartbeat rate (P, Q, R, S and T wave). This system was also used for registering physiological parameters such as the monitoring of lung ventilation which can give a range of information about the patients health (normal respiration patterns, deep inhalation/exhalation and apnoea), easily distinguishable in the output signal. The bi-layer thin films used consist of a magnetic layer and a non-magnetic counter layer that is utilized to enhance the changes in the relative permeability of the material caused by tensile or compressive stresses during bending. The measuring system is based on a personal computer in conjunction with the LabVIEW® graphical programming package. The nature of this configuration provides the necessary features for sensor signal acquisition, analysis and data presentation. The results from the sensor application on patients demonstrate that this system can provide a robust, cost effective solution to monitoring cardio-respiratory activity with minimum inconvenience to the patient, which is necessary for prolonged, undisturbed monitoring.