EMFIT QS heart rate and respiration rate validation

Abstract

Objective: The EMFIT QS (Quantified Sleep) is an unobtrusive monitoring device with a state-of-the-art analysis platform that tracks heart (HR) and respiration rate (RR), as well as heart rate variability, in addition to providing a sleep stage estimation and sleep quality analysis. The device consists of a thin ferroelectret sensor that can be placed underneath a bed mattress and sleep analysis can be overviewed conveniently from the EMFIT QS web interface. With this kind of sensitive and contactless sensor subject's vital signs can be easily monitored without discomfort.Approach: We compared the EMFIT QS HR and RR to those evaluated from the electrocardiogram (ECG) and respiratory inductive plethysmography (RIP) of 33 patients measured in an overnight polysomnography. The Bland-Altman analysis was used for comparison and ±6 heart beats per minute (bpm) and ±4 respiration cycles per minute (rpm) were considered to be acceptable differences. Main results: The 95% limits of agreement (LoA) for the heart rate are -4.4 (CI95%: [-5.8, -4.2]) and 4.4 ( CI95%: [4.3, 5.9]) bpm, whereas the respiration rate LoA are -2.5 (CI95%: [-2.8, -2.4]) and 2.2 (CI95%: [2.1, 2.5]) rpm. Significance: The EMFIT QS measures reliably heart and respiration rate. It can be readily deployed for vital monitoring when a subject is lying in bed e.g. when tracking athletes' night-time recovery or consumers' well-being. It also has potential in telemedicine applications