An Internet of Medical Things System to Increase Continuous Positive Airway Pressure Usage in Patients with Sleep-Disordered Breathing

Obstructive sleep apnea (OSA) is a highly prevalent sleep disorder associated with increased daytime sleepiness and cardiovascular risk. Continuous positive airway pressure (CPAP), requiring a pressure-generating device connected via tubing to a mask during sleep, is an efective treatment. However, patients’ adherence to CPAP is often suboptimal. Behavioural interventions are efective in improving adherence to CPAP. We aimed to provide proof of principle for the operation of a low-cost, self-standing, internet-based system to measure and promote adherence to CPAP. The system is composed of triaxial acceleration sensors attached to the CPAP mask and to the wrist, able to record CPAP usage information, and a mobile app that collects such information and, thorough a chatbot, feeds back to the patient to improve adherence to treatment. The mask subsystem identifes time periods when the mask is put on based on relatively high values of the ratio between acceleration spectral power at frequencies < 0.35 Hz vs. 0.35–2 Hz over 1-min windows. Accuracy in identifcation may be increased taking account of the surges in the standard deviation of wrist accelerations over 1-min windows that accompany putting on and taking of the mask. The whole system can represent a unique tool capable of monitoring and improving patients’ adherence to CPAP treatment. Its main strength lies in its simplicity, low cost, and independence from the specifc CPAP device and mask employed.