Wearable Cardiorespiratory Monitoring Employing a Multimodal Digital Patch Stethoscope: Estimation of ECG, PEP, LVET and Respiration Using a 55 mm Single-Lead ECG and Phonocardiogram

Abstract

Cardiovascular diseases are the main cause of death worldwide, with sleep disordered breathing being a further aggravating factor. Respiratory illnesses are the third leading cause of death amongst the noncommunicable diseases. The current COVID-19 pandemic, however, also highlights the impact of communicable respiratory syndromes. In the clinical routine, prolonged postanesthetic respiratory instability worsens the patient outcome. Even though early and continuous, long-term cardiorespiratory monitoring has been proposed or even proven to be beneficial in several situations, implementations thereof are sparse. We employed our recently presented, multimodal patch stethoscope to estimate Einthoven electrocardiogram (ECG) Lead I and II from a single 55 mm ECG lead. Using the stethoscope and ECG subsystems, the pre-ejection period (PEP) and left ventricular ejection time (LVET) were estimated. ECG-derived respiration techniques were used in conjunction with a novel, phonocardiogram-derived respiration approach to extract respiratory parameters. Medical-grade references were the SOMNOmedics SOMNO HD TM and Osypka ICON-Core TM . In a study including 10 healthy subjects, we analyzed the performances in the supine, lateral, and prone position. Einthoven I and II estimations yielded correlations exceeding 0.97. LVET and PEP estimation errors were 10% and 21%, respectively. Respiratory rates were estimated with mean absolute errors below 1.2 bpm, and the respiratory signal yielded a correlation of 0.66. We conclude that the estimation of ECG, PEP, LVET, and respiratory parameters is feasible using a wearable, multimodal acquisition device and encourage further research in multimodal signal fusion for respiratory signal estimation.

Wearable Sensing and Telehealth Technology with Potential Applications in the Coronavirus Pandemic

“…Klum et al have reported a wearable stethoscope patch that combines sensing modalities like a MEMS stethoscope, ambient noise sensing, ECG, impedance pneumography and 9-axis actigraphy. The system is able to monitor auscultation continuously without requiring the distribution of sensors over different places of the body [59,60]. To detect wheezing or potentially other adventitious respiratory sounds, Shkel et al implemented a resonant microphone array that could counteract the interference from the heart and external noise sources, thus reducing the digital processing of the acquired signals, reducing power consumption and improving the detection accuracy [61].…”

A Wearable Stethoscope for Long-Term Ambulatory Respiratory Health Monitoring

“…Such an extension can be described as a tapered impedance matching from the source to the load, i.e., to the air microphone, analogous to bell-shaped (or conical) stethoscope heads. Klum et al [ 6 ] propose a method to improve the sensitivity of the system through amplification by coupling a commercial stethoscope diaphragm to an air microphone. However, a simple calculation based on the ratio of the diaphragm surface and the microphone aperture provides a very optimistic result in terms of amplification as some essential basic assumptions of such calculation, namely rigid walls, freely moving piston with zero mass, are practically not fulfilled [ 17 ].…”

“…In this article, we focus on the design and characterization of the sensor module which acquires thoracic sounds. The central element of the sensor module, the acoustic transducer, can either be realized by using an air microphone [ 6 , 7 , 8 ] or a contact microphone [ 9 , 10 , 11 ]. Air microphones (electret condenser microphones and capacitive or piezoelectric MEMS microphones) are commonly inserted into the stethoscope heads [ 8 ] in order to benefit from an optimized mechanical design to guide the pressure waves.…”

Lifestyle Acquired Immunity, Decentralized Intelligent Infrastructures, and Revised Healthcare Expenditures May Limit Pandemic Catastrophe: A Lesson From COVID-19

“…As discussed above, case fatalities were high in developed countries and the cross analysis of NCDs mortality with median age and per capita income also suggested that elderly people with NCDs were more at risk of fatal outcomes. Most incidences of mortality (60-90%) were related to preexisting one or more NCDs (75)(76)(77)(78).…”