Abstract:High blood pressure (BP) is a major cardiovascular risk factor that is treatable, yet hypertension awareness and control rates are low. Ubiquitous BP monitoring technology could improve hypertension management, but existing devices require an inflatable cuff and are not compatible with such anytime, anywhere measurement of BP. We extended the oscillometric principle, which is used by most automatic cuff devices, to develop a cuff-less BP monitoring device using a smartphone. As the user presses her/his finger … Show more
“…Above testing results also reveal that our pulse sensing system can measure the blood pressure, as indicated in Figure c. This result is similar to the traditional oscillometric method, in which blood pressure is measured by decreasing the cuff pressure applied on the radial artery . Specifically, the mean arterial pressure (MAP), which is the static pressure of the maximum pulse wave amplitude, is read from the pulse wave envelope directly.…”
Real-time and continuous monitoring of physiological signals is essential for mobile health, which is becoming a popular tool for efficient and convenient medical services. Here, an active pulse sensing system that can detect the weak vibration patterns of the human radial artery is constructed with a sandwich-structure piezoelectret that has high equivalent piezoelectricity. The high precision and stability of the system result in possible medical assessment applications, including the capability to identify common heart problems (such as arrhythmia); the feasibility to conduct pulse palpation measurements similar to well-trained doctors in Traditional Chinese Medicine; and the possibility to measure and read blood pressure.The ORCID identification number(s) for the author(s) of this article can be found under https://doi.org/10.1002/adfm.201803413.imitate the TCM practice for health assessments without well-trained, real doctors. Previously, human pulse waves have been measured using sensors based on different detection mechanisms, such as optics, [16,17] image processing, [15,18,19] acoustics, [20] and pressure means, [21][22][23][24][25][26][27][28][29] etc. Among these, active pressure sensors based on the working principles of piezoelectricity [21][22][23][24] or triboelectricity [7,8] are the more intuitive and sensitive method to detect pulse waves, as these sensors can accurately and directly reflect the weak vibration of the radial artery to better imitate the pulse diagnosis in TCM. Several vertical contact-separation and single-electrode triboelectric pressure sensors have been published to detect human motion and physiological signals, with advantages of thin, flexible, and excellent sensitivity. [30] However, vertical contact-separation devices are composed of two separated parts, which increases the difficulty of assembly and operation in practice. Single-electrode triboelectric sensors have been proposed to address this issue but the exposed residual charges on the sensor surface can be easily leaked. Piezoelectret is flexible, lightweight, and have large and stable equivalent piezoelectric coefficient for high sensitivity. [25] Furthermore, sensors based on piezoelectret materials can alleviate the aforementioned issues in triboelectric sensors to detect physiological signals.In this work, we use an active and flexible pulse wave sensing system based on a fluorinated ethylene propylene (FEP)/Ecoflex/FEP sandwich-structured piezoelectret for piezoelectriclike detections. [25,26,31] Several key features are accomplished from the prototype sensing systems: 1) excellent precision and stability capable of differentiating and classifying pulses from different volunteers coupled with the help of big data analyses; 2) the identification of a common heart problem (arrhythmia) from volunteers who were previously diagnosed in hospitals equipped with advanced and bulky electrocardiogram (ECG) setups; 3) the feasibility in recording and revealing the blood pressure using the pulse sensing system instead of a ...
“…Above testing results also reveal that our pulse sensing system can measure the blood pressure, as indicated in Figure c. This result is similar to the traditional oscillometric method, in which blood pressure is measured by decreasing the cuff pressure applied on the radial artery . Specifically, the mean arterial pressure (MAP), which is the static pressure of the maximum pulse wave amplitude, is read from the pulse wave envelope directly.…”
Real-time and continuous monitoring of physiological signals is essential for mobile health, which is becoming a popular tool for efficient and convenient medical services. Here, an active pulse sensing system that can detect the weak vibration patterns of the human radial artery is constructed with a sandwich-structure piezoelectret that has high equivalent piezoelectricity. The high precision and stability of the system result in possible medical assessment applications, including the capability to identify common heart problems (such as arrhythmia); the feasibility to conduct pulse palpation measurements similar to well-trained doctors in Traditional Chinese Medicine; and the possibility to measure and read blood pressure.The ORCID identification number(s) for the author(s) of this article can be found under https://doi.org/10.1002/adfm.201803413.imitate the TCM practice for health assessments without well-trained, real doctors. Previously, human pulse waves have been measured using sensors based on different detection mechanisms, such as optics, [16,17] image processing, [15,18,19] acoustics, [20] and pressure means, [21][22][23][24][25][26][27][28][29] etc. Among these, active pressure sensors based on the working principles of piezoelectricity [21][22][23][24] or triboelectricity [7,8] are the more intuitive and sensitive method to detect pulse waves, as these sensors can accurately and directly reflect the weak vibration of the radial artery to better imitate the pulse diagnosis in TCM. Several vertical contact-separation and single-electrode triboelectric pressure sensors have been published to detect human motion and physiological signals, with advantages of thin, flexible, and excellent sensitivity. [30] However, vertical contact-separation devices are composed of two separated parts, which increases the difficulty of assembly and operation in practice. Single-electrode triboelectric sensors have been proposed to address this issue but the exposed residual charges on the sensor surface can be easily leaked. Piezoelectret is flexible, lightweight, and have large and stable equivalent piezoelectric coefficient for high sensitivity. [25] Furthermore, sensors based on piezoelectret materials can alleviate the aforementioned issues in triboelectric sensors to detect physiological signals.In this work, we use an active and flexible pulse wave sensing system based on a fluorinated ethylene propylene (FEP)/Ecoflex/FEP sandwich-structured piezoelectret for piezoelectriclike detections. [25,26,31] Several key features are accomplished from the prototype sensing systems: 1) excellent precision and stability capable of differentiating and classifying pulses from different volunteers coupled with the help of big data analyses; 2) the identification of a common heart problem (arrhythmia) from volunteers who were previously diagnosed in hospitals equipped with advanced and bulky electrocardiogram (ECG) setups; 3) the feasibility in recording and revealing the blood pressure using the pulse sensing system instead of a ...
“…Through placement of high density weights on the screen adjacent to the camera, the application derives force (F, grams) from the strain gauge output (V) as F = 443.75 V, where V takes on 400 levels from 0 to 0.83 (firm setting). Like our previous device 6 , the application plots the data as they are recorded to visually guide the finger actuation.Figure 1An iPhone application for cuff-less and calibration-free blood pressure (BP) monitoring via extension of the oscillometric cuff measurement principle. ( a ) Photograph of an oscillometric cuff device and diagram of BP computation from the measured cuff pressure and blood volume oscillations.…”
We developed an iPhone X application to measure blood pressure (BP) via the “oscillometric finger pressing method”. The user presses her fingertip on both the front camera and screen to increase the external pressure of the underlying artery, while the application measures the resulting variable-amplitude blood volume oscillations via the camera and applied pressure via the strain gauge array under the screen. The application also visually guides the fingertip placement and actuation and then computes BP from the measurements just like many automatic cuff devices. We tested the application, along with a finger cuff device, against a standard cuff device. The application yielded bias and precision errors of −4.0 and 11.4 mmHg for systolic BP and −9.4 and 9.7 mmHg for diastolic BP (n = 18). These errors were near the finger cuff device errors. This proof-of-concept study surprisingly indicates that cuff-less and calibration-free BP monitoring may be feasible with many existing and forthcoming smartphones.
“…Wearable devices with continuous monitoring are being used to study a wide range of physiologic measures with daily rhythms (1). Ambulatory blood pressure monitoring, the gold-standard for hypertension diagnosis, or a recently developed cuffless BP monitoring system (42) can be used to test the effect of circadian dosage time on efficacy. In parallel, the development of robust circadian biomarkers will help clinicians administer treatment at optimal times.…”
One Sentence Summary: Bioinformatic analyses on thousands of human tissue samples reveals an enCYCLOPedia of rhythmic gene expression across the body and identifies key translational opportunities for circadian medicine in cardiovascular disease.
Abstract:The discovery that half of the mammalian protein-coding genome is clock-regulated has clear implications for medicine. Indeed, recent studies demonstrate time-of-day impact on therapeutic outcomes in human heart disease and cancer. Yet biological time is rarely given clinical consideration. A key barrier is the absence of information on the what and where of molecular rhythms in the human body. Here, we have applied CYCLOPS, an algorithm designed to reconstruct sample order in the absence of time-of-day information, to the GTEx collection of 632 human donors contributing 4,292 RNA-seq samples from 13 distinct human tissue types. We identify rhythms in expression across the body that persist at the population-level. This includes a set of 'ubiquitous cyclers' comprised of well-established circadian clock factors but also many genes without prior circadian context. Among thousands of tissue-divergent rhythms, we discover a set of genes robustly oscillating in cardiovascular tissue, including key drug targets relevant to heart disease. These results also have implications for genetic studies where circadian variability may have masked genetic influence. It is our hope that the human enCYCLOPedia helps drive the translation of circadian biology into prospective clinical trials in cardiology and many other therapeutic areas.
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