Wearable Wake-up System for CCHS Patients

Abstract

Abstract Congenital Central Hypoventilation Syndrome (CCHS) leads to insufficient breathing especially during sleep. While patients can be ventilated and monitored during the night, adolescents undergo changes in their biorhythm and lifestyle and are at higher risk to inadvertently fall asleep and stop breathing during the day. In this paper, we propose a prototype mobile wake-up device worn behind both ears that constantly measures oxygen saturation and heart rate noninvasively. If a dangerously low level of saturation is detected, it is assumed that the user fell asleep. To wake them, the device issues an acoustic and haptic alarm. The device settings are accessed via a smartphone app. To evaluate the sensor performance, a subject simultaneously wore the prototype behind his ears and a commercial finger pulse oximeter on his hand. Heart rate and blood oxygen saturation were taken for three measurements of few minutes each. Mean absolute error of oxygen saturation was less than 2 % for two data sets and 6.1 %for the third. It is assumed that during this measurement, the device lost contact to the skin. The heart rate measurement showed satisfactory agreement of < 4 % mean average error. In the future, the measurement quality will be improved by calibration and more reliable attachment to the ear and a user study will be conducted in order to evaluate the prototype usability.