Measurement of Blood Pressure Using an Arterial Pulsimeter Equipped with a Hall Device

To measure precise blood pressure (BP) and pulse rate without using a cuff, we have developed an arterial pulsimeter consisting of a small, portable apparatus incorporating a Hall device. Regression analysis of the pulse wave measured during testing of the arterial pulsimeter was conducted using two equations of the BP algorithm. The estimated values of BP obtained by the cuffless arterial pulsimeter over 5 s were compared with values obtained using electronic or liquid mercury BP meters. The standard deviation between the estimated values and the measured values for systolic and diastolic BP were 8.3 and 4.9, respectively, which are close to the range of values of the BP International Standard. Detailed analysis of the pulse wave measured by the cuffless radial artery pulsimeter by detecting changes in the magnetic field can be used to develop a new diagnostic algorithm for BP, which can be applied to new medical apparatus such as the radial artery pulsimeter

Development of pulse diagnostic devices in Korea

AbstractIn Korean medicine, pulse diagnosis is one of the important methods for determining the health status of a patient. For over 40 years, electromechanical pulse diagnostic devices have been developed to objectify and quantify pulse diagnoses. In this paper, we review previous research and development for pulse diagnostic devices according to various fields of study: demand analysis and current phase, literature studies, sensors, actuators, systems, physical quantity studies, clinical studies, and the U-health system. We point out some confusing issues that have been naively accepted without strict verification: original pressure pulse waveform and derivative pressure pulse waveform, pressure signals and other signal types, and minutely controlled pressure exertion issues. We then consider some technical and clinical issues to achieve the development of a pulse diagnostic device that is appropriate both technically and in terms of Korean medicine. We hope to show the history of pulse diagnostic device research in Korea and propose a proper method to research and develop these devices

Power Estimation for Wearable Piezoelectric Energy Harvester

The aim of this research work is to estimate the amount of electricity produced to power up wearable devices using a piezoelectric actuator, as an alternative to external power supply. A prototype of the device has been designed to continuously rotate a piezoelectric actuator mounted on a cantilever beam. A MATLAB® simulation was done to predict the amount of power harvested from human kinetic energy. Further simulation was conducted using COMSOL Multiphysics® to model a cantilever beam with piezoelectric layer. With the base excitation and the presence of tip mass at the beam, the natural frequencies and mode shapes have been analyzed to improve the amount of energy harvested. In this work, it was estimated that a maximum amount of power that could be generated is 250 μW with up to 5.5V DC output. The outcome from this research works will aid in optimising the design of the energy harvester. This research work provides optimistic possibility in harvesting sufficient energy required for wearable devices

An Asynchronous Multi-Sensor Micro Control Unit for Wireless Body Sensor Networks (WBSNs)

In this work, an asynchronous multi-sensor micro control unit (MCU) core is proposed for wireless body sensor networks (WBSNs). It consists of asynchronous interfaces, a power management unit, a multi-sensor controller, a data encoder (DE), and an error correct coder (ECC). To improve the system performance and expansion abilities, the asynchronous interface is created for handshaking different clock domains between ADC and RF with MCU. To increase the use time of the WBSN system, a power management technique is developed for reducing power consumption. In addition, the multi-sensor controller is designed for detecting various biomedical signals. To prevent loss error from wireless transmission, use of an error correct coding technique is important in biomedical applications. The data encoder is added for lossless compression of various biomedical signals with a compression ratio of almost three. This design is successfully tested on a FPGA board. The VLSI architecture of this work contains 2.68-K gate counts and consumes power 496-μW at 133-MHz processing rate by using TSMC 0.13-μm CMOS process. Compared with the previous techniques, this work offers higher performance, more functions, and lower hardware cost than other micro controller designs

A comparison of the haemodynamic and cardic autonomic responses following an acute bout of isometric wall squat and isometric handgrip exercise

Purpose. Isometric exercise (IE) training has been shown to be effective at reducing resting blood pressure (BP). However, there is a lack of clarity as to which IE modality is more effective at reducing resting BP. Acute responses following a single session of IE have been shown to predict long-term training adaptions. It was hypothesised that when using a comparative workload, exercises that recruit more muscle mass have a greater proclivity to induce transient reductions in BP than those that use smaller amounts of muscle mass. To test this hypothesis, the current study set out to compare the acute haemodynamic and autonomic responses following a single session of isometric wall squat (IWS) and isometric handgrip (IHG). Method. Twenty-six sedentary participants performed a single IWS and IHG session comprised of 4 x 2-min contractions, with 2-min rest, at 95 HRpeak and 30% MVC, respectively. Total power spectral density of HR variability and associated low-frequency and high-frequency power spectral components were recorded in absolute and normalized units before, during, and 10-min and 1hour after each IE session. Heart rate (HR) was recorded via electrocardiography and baroreceptor reflex sensitivity via the sequence method. Continuous BP was recorded via the vascular unloading technique and stroke volume and cardiac output (Q̇) via impedance cardiography. Total peripheral resistance (TPR) was calculated according to Ohm’s law. The change from baseline for each variable was used for comparative analysis. Results. During IE, there was a significantly greater increase in systolic BP, diastolic BP, mean BP, HR and Q̇ in the IWS condition (all P= <0.001). There was also significantly less TPR during IWS exercise (P= 0.006). During the 10-min recovery window, there was a significantly greater reduction in systolic BP, diastolic BP, mean BP (all P= 0.005) and TPR (P= <0.001). There were no differences in any autonomic variables during recovery, and no differences in any variables 1-hour post exercise. Conclusion. Isometric wall squat exercise produces a greater cardiovascular response during exercise, with a greater reduction in BP and TPR during a 10-min recovery period. These acute responses may be mechanistically linked to the chronic reductions in resting BP reported after IE training interventions

Updates of Wearing Devices (WDs) In Healthcare, And Disease Monitoring

 With the rising pervasiveness of growing populace, aging and chronic illnesses consistently rising medical services costs, the health care system is going through a crucial change from the conventional hospital focused system to an individual-focused system. Since the twentieth century, wearable sensors are becoming widespread in medical care and biomedical monitoring systems, engaging consistent estimation of biomarkers for checking of the diseased condition and wellbeing, clinical diagnostics and assessment in biological fluids like saliva, blood, and sweat. Recently, the improvements have been centered around electrochemical and optical biosensors, alongside advances with the non-invasive monitoring of biomarkers, bacteria and hormones, etc. Wearable devices have created with a mix of multiplexed biosensing, microfluidic testing and transport frameworks incorporated with flexible materials and body connections for additional created wear ability and effortlessness. These wearables hold guarantee and are fit for a higher understanding of the relationships between analyte focuses inside the blood or non-invasive biofluids and feedback to the patient, which is fundamentally significant in ideal finding, therapy, and control of diseases. In any case, cohort validation studies and execution assessment of wearable biosensors are expected to support their clinical acceptance. In the current review, we discussed the significance, highlights, types of wearables, difficulties and utilizations of wearable devices for biological fluids for the prevention of diseased conditions and real time monitoring of human wellbeing. In this, we sum up the different wearable devices that are developed for health care monitoring and their future potential has been discussed in detail

The Speed of Waves : Measuring the velocity of pressure pulse waves traveling through peripheral blood vessels

Worldwide, cardiovascular diseases (CVDs) are the number one cause of death. Therefore, there is a strong and urgent need for an easy and quick prognostic indicator of this disease to support early diagnosis. The gold standard for determining arterial stiffness is measuring the pulse wave velocity (PWV), which is the speed of the pressure pulse traveling through the moving blood. The goal of this Ph.D. study was to develop and validate a non-invasive, photoplethysmography (PPG)-based device for peripheral measurement of the PWV on the finger. To this aim a novel sensor, called “Multi Photodiode Array” (‘MPA’), was designed for peripheral, non-invasive PWV measurements. Next, the MPA was shown to deliver reliable and accurate PWV measurements with a deviation below 3% within clinically relevant ranges. During the course of the research it was observed that the MPA positioning on the finger could strongly affect the quality of the PWV measurements. Therefore, an explorative study was conducted to find the optimal use condition of the MPA. The final clinical study showed that the MPA could be placed easily, rapidly, and consistently, irrespective of the volunteer whose PWV was measured, and delivered reliable and repeatable results. Overall, the results in this thesis suggest that the novel PPG-based MPA allows accurate and reliable PWV measurements within clinically relevant ranges. In the future, the MPA may substantially simplify PWV measurements and enable long-term monitoring of vascular health, which will contribute to improving prevention, diagnosis and treatment of CVD

Intraocular Pressure and Ocular Hypertension

Primary open-angle glaucoma (POAG) is a multi-factorial progressive optic neuropathy characterized by retinal ganglion cell degeneration and progressive visual field loss which, if left untreated, may lead to blindness. Increased intraocular pressure (IOP) is considered to be the main risk factor for developing POAG, and its reduction has been shown to correlate with a decrease in glaucoma incidence and progression. Considering that fewer than 10% of the subjects with ocular hypertension (OHT) will develop morphological and/or functional glaucomatous damage within 5 years if not treated, glaucoma causes and molecular changes leading to ocular tissue damage in glaucoma are still largely unknown. The contemporary treatment of POAG is mainly oriented towards reducing IOP; the importance of the IOP reduction in other types of glaucoma, such as the “normal pressure glaucoma”, is still discussed. The IOP value is maintained by balancing the amount of fluid contained within the anterior and posterior chambers of the eye; our comprehension of the mechanisms underlying the secretion and active and passive outflow of the aqueous humor is extremely important for improving the treatment of glaucoma. Innovative pharmacological approaches, and laser and surgical procedures aiming to reduce IOP, have been developed in recent years. This book provides a compendium of topics regarding IOP, aqueous humor dynamics, tonometry, and medical and surgical techniques developed to reduce the IOP in subjects with ocular hypertension or glaucoma