2010 年 48 巻 6 号 p. 584-588
We have developed a method of preventing bathing accidents based on the respiratory rate, body motion, and water level. The respiratory waveform could be detected from the RR interval (RRI) of the bathtub electrocardiogram (ECG) . The body motion and water level were detected from the alternating current (AC) and direct current (DC) components of the acceleration signals. The device consisted of an ECG amplifier, accelerometer, Bluetooth module, and personal computer (PC) . The changes in the DC component in terms of the level change when the subject entered the bathtub were used as a trigger to switch the system on. A bathing accident was simulated that involved body motion, submergence, and apnea while taking a bath. The algorithm for detecting accidents was based on the absence of respiration and body motion and a high water level. As a result, the accident could be detected during the period of apnea. The time from accident onset to detection was 18.7 ± 7.3 seconds. It was possible to distinguish relaxation, body motion, submergence, and apnea using the bathtub ECG and an accelerometer. Thus, bathing accidents could be detected at an early stage.