Noninvasive Monitoring of Vital Signs Based on Highly Sensitive Fiber Optic Mattress

Abstract

A smart mattress based on optical fiber Mach-zender interferometer (OF-MZI) is designed for noninvasive and continuous monitoring of human vital signs. Through arranging the sensing fiber between two elastic covering layers with sandwich structure, the mattress was sensitive to the respiration and heartbeat induced micro-pressure. In the processing terminal, the waveforms of vital signs were demodulated by 3 *3 coupler based differentiate and cross-multiplying method, and then four characteristic indicators including the heart rate, heartbeat amplitude, respiration rate, and respiration amplitude were respectively extracted through feature extraction algorithm, for evaluating the human health condition. Clinical experimental results of eighteen subjects indicate that the mattress system could not only distinguish the activity states of no body, on bed, body movement and off bed, but also contribute to clinical diagnosis of bradycardia, tachycardia, polypnea and apnoea. By adopting Bland-Altman analysis method, good reproducibility and accuracy were confirmed, where the max errors of heart rate and respiration rate are respectively 2 bpm and 1 bpm. Moreover, the responses at different positions of the mattress are identical and the continuous monitoring results in one day are consistent with daily change of vital signs, which proves that the fiber optic mattress has good reliability and stability. Beneficial from high-sensitivity, multiple parameters, long-term continuous monitoring, high comfortability and low cost, the mattress is promising in the early detection and prevention of cardiac and respiratory diseases as a household medical device.Index Terms-smart mattress, optical fiber Machzender interferometer, healthcare monitoring, heartbeat, respiration.

Low-cost plastic optical fiber sensor embedded in mattress for sleep performance monitoring

“…Physiological signals can be obtained with fewer limitations on duration and distance via wireless equipment and remote monitoring technology [1] which makes such technology suitable for monitoring health problems of elderly people living alone. Respiration and heart rate are important physiological signals used for monitoring human health [2]. Long-term and continuous measurement of respiration and heart rate is particularly important for the evaluation of some diseases [3] such as coronary heart disease [4], arrhythmia [5], fatigue [6] and apnea [7].…”

“…Several approaches have been proposed to measure respiration and heart rate using optical fiber sensors, such as fiber Bragg grating (FBG) sensors [25][26][27][28][29], Mach-Zehnder interferometer (MZI) sensors [2] and light intensity modulation POF sensors [30 -32]. FBG and MZI require expensive production machinery and testing instruments and are not suitable for family guardianship due to high cost.…”

Towards Accurate, Cost-Effective, Ultra-Low-Power and Non-Invasive Respiration Monitoring: A Reusable Wireless Wearable Sensor for an Off-the-Shelf KN95 Mask

“…Chest or abdomen movement based approaches measure respiratory rate by sensing the vibrations [14], pressure changes [15][16][17][18][19], displacement changes [20][21][22][23][24][25][26][27][28][29][30][31][32][33], or bioelectrical signals [34,35] caused by chest or abdomen movements during respirations. These approaches can provide respiration monitoring at fixed locations [14][15][16][17][21][22][23][24][25][26][27][28][29][30][31][32], such as specific beds, mattresses, and rooms, or in wearable ways [18][19][20][30][31][32][33][34][35]. However, due to the coupling of respiratory motion and other body movements, reducing the influence of artefacts caused by other body movements i...…”

A Comparison of Alternative Approaches to MR Cardiac Triggering: A Pilot Study at 3 Tesla

“…The advantage of use of optical recording for detection of phases of heart activity in the MRI environment is that the optical instrumentation has high immunity to the artifacts caused by both magnetic and high-frequency electromagnetic fields. Today, the most commonly used types of optical sensors include sensors based on the light interference [39], [40], and Fiber Bragg Grating (FBG) sensors that evaluate changes of light reflected on a grating structure [41]- [44]. The other currently developed type of optical sensor is based on the principle of measuring changes in light output caused by bends of optical fiber [45], [46].…”