Abstract
Daily monitoring of health condition at bathroom is important for early detection and prevention of accident. We developed a non-conscious monitoring system for electrocardiogram, ECG, respiration, and drowning using bathtub-installed electrodes. However, the system had some drawbacks such as the subject's stress and fear for the visible electrodes and the corrosion of electrodes. To resolve these drawbacks, we have newly developed a fully non-conscious and maintenance-free monitoring system using the capacitively-coupled invisible electrodes. The electrodes with amplifiers were fixed to the rear surface of bathtub wall near the subject's right scapula and left foot. The capacitive coupling could be made between the electrodes and the water through the insulating material of fiber reinforced plastics of the bathtub wall. In two healthy male subjects, the ECG obtained from the present system and the electrodes directly attached to the body surface were simultaneously measured. From the results, it is demonstrated that the bathtub monitor can accurately measure the R-R intervals and those fluctuations by the respiration, being useful means for detecting the health condition in the bathtub.
