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Single cuff noninvasive blood pressure (BP) measurements performed manually or automatically are subject to errors. We developed an experimental system that uses two cuffs in order to improve accuracy of noninvasive BP measurement. This study concentrated on a novel determination of diastolic BP using wrist cuff pulse waveforms and arm cuff pressures. The method was compared with the oscillometric...Show More
Manual and automatic blood pressure (BP) measurement methods have accuracy problems. This paper describes a new method that uses two cuffs to improve accuracy of BP measurement. A specially designed dual-cuff experimental system was used to acquire and process data from the two cuffs. The arm cuff provided cuff pressures (CP) and cuff arterial pulse waveforms. The arm cuff pulse pressure waveforms...Show More
Shortcomings of single cuff blood pressure devices have led to research of devices with more than one cuff for improved accuracy. We assessed two devices that use two cuffs and one device that uses three cuffs. The devices with two cuffs use one occluding arm cuff and one cuff that detects pulses that pass past the occluding cuff. The device with three cuffs uses pulse delay time. The advantages a...Show More
It is well known that non-invasive blood pressure measurements significantly underestimate true systolic blood pressure (SBP), and overestimate diastolic blood pressure (DBP). The aetiology for these errors has not yet been fully established. This study aimed to investigate the accuracy of Korotkoff sounds for detection of SBP and DBP points as used in brachial cuff sphygmomanometry. Brachial cuff...Show More
This paper presents a new principle for noninvasive blood pressure measurements through a modified volume-oscillometric technique that eliminates an inflatable pressure cuff, and instead takes advantage of natural hydrostatic pressure changes caused by raising and lowering the subject's arm. This new methodology provides the distinct advantage of using an absolute gauge pressure reference for meas...Show More
Home blood pressure monitors will play increasingly important role in 21st century healthcare. Improvements in their accuracy and reliability will be necessary. In this paper we described their function and suggested several improvements. The improvements include static accuracy check, a public database of cuff pulse waves, utilization of cuff pulse waves for several hemodynamic variables, and wid...Show More
The aim of this study was to examine the effect on distal arteries of external pressure, applied by upper arm sphygmomanometer cuff. Photoplethysmographic (PPG) signals were measured on the index fingers of 44 healthy male subjects, during the slow decrease of cuff air pressure. For each pulse the ratio of PPG amplitude to its baseline (AM/BL) and its time delay (/spl Delta/TD) relative to the con...Show More
Single cuff automatic blood pressure (BP) measurements are subject to errors because the BP values are based on statistical estimation rather than on physiological principles. We developed a dual cuff experimental system that uses an arm cuff and a wrist cuff. The wrist cuff function is similar to auscultation. This study concentrated on the determination of systolic, diastolic and mean BP using t...Show More
A new method of measuring blood pressure (BP) is presented. This technique involves automatic analysis of the wideband external pulse (WEP) recorded by a pressure sensor positioned over the brachial artery during standard BP cuff deflation. Three distinct components of this "K" or "WEP" signal can be defined: K1, K2, and K3 [1]. Each component has a different shape and "appearance/disappearance" p...Show More
Cuff pulse waves together with cuff pressure are essential in modern automatic blood pressure (BP) devices. Most methods for BP determination employ cuff wave amplitudes. Physiological features of cuff waves have been neglected. In this study we described the origin of amplitude based approach to automatic BP determination. The cuff waves are commonly called oscillations and the methods for BP det...Show More
Objective: Intradialytic haemodynamic instability is a significant clinical problem, leading to end-organ ischaemia and contributing to morbidity and mortality in haemodialysis patients. Non-invasive continuous blood pressure monitoring is not currently part of routine practice but may aid detection and prevention of significant falls in blood pressure during dialysis. Brachial blood pressure is c...Show More
Objective. Development and testing of cuffless blood pressure (BP) devices requires methods to increase and decrease BP. This is also required by cuffless BP validation standards. Pharmacological interventions, whilst successful, are not always feasible for all subpopulations or research settings. Non-pharmacological approaches for increasing BP are available, however, methods for decreasing BP ar...Show More
The most commonly used oscillometric upper-arm (UA) blood pressure (BP) monitors are not convenient enough for ambulatory BP monitoring, given the large size of the arm cuff and the compression of UA during the measurement. Finger-worn oscillometric BP devices featuring miniaturized finger cuff have been developed and researched as an alternative solution to the UA-based measurement, yet the relia...Show More
This work presents a new technique for the noninvasive measurement of systolic blood pressure (sBP), mean blood pressure (mBP) and diastolic blood pressure (dBP) using photo-plethysmographic (PPG) sensors when an artery is exposed to an external pressure. Two sets of experiments were performed: a first study combining PPG with an oscillometric device and the second combining PPG with a force/press...Show More
Pressure data acquired from a blood pressure cuff during a blood pressure test are the starting point of noninvasive, single cuff blood pressure determination. Most blood pressure devices on the market use the single cuff method. This paper describes acquisition, analog and digital processing, and storage of raw data from a blood pressure cuff during gradual cuff deflation. Raw data from 30 arm cu...Show More
Objective: Most automatic cuff blood pressure (BP) measurement devices are based on oscillometry. These devices estimate BP from the envelopes of the cuff pressure oscillations using fixed ratios. The values of the fixed ratios represent population averages, so the devices may only be accurate in subjects with normal BP levels. The objective was to develop and demonstrate the validity of a patient...Show More
Ubiquitous blood pressure (BP) monitoring is needed to improve hypertension detection and control and is becoming feasible due to recent technological advances such as in wearable sensing. Pulse transit time (PTT) represents a well-known potential approach for ubiquitous BP monitoring. The goal of this review is to facilitate the achievement of reliable ubiquitous BP monitoring via PTT. We explain...Show More
Mean arterial pressure (MAP) is the pressure in the arteries averaged over time. Oscillometric blood pressure (BP) monitors determine the value of MAP by processing arterial pulses in the cuff. Cuff pressure at the point of largest pulse amplitude is equal to MAP. The oscillometric determination of MAP is subject to errors resulting from wave reflections and stroke volume variability. We developed...Show More
This paper presents an automated system for testing of oscillometric blood pressure devices. The designed and implemented system includes three measurement channels. One of the measurement channels is based on the usage of a miniature pressure sensor and appropriate pneumatic circuit connected to the cuff tube of the tested oscillometric device. The second channel based on EMFIT sensor is used for...Show More
In this paper, we developed a wireless blood pressure monitoring system which provides a useful tool for users to measure and manage their daily blood pressure values. This system includes an ARM-based blood pressure monitor with a ZigBee wireless transmission module and a PC-based management unit with graphic user interface and database. The wireless blood pressure monitor can measure the blood p...Show More
The importance of home blood pressure (BP) monitoring has been emphasized for achieving effective hypertension management. Currently, the most popular non-invasive BP monitors for home use are the upper-arm cuff-style oscillometric devices which determine BP from the cuff pressure oscillations during the cuff inflation/deflation induced by the pulsatile blood flow in the compressed arteries. Howev...Show More
For the noninvasive and accurate measurement of instantaneous blood pressure (BP) in the radial artery, the performance of a device based on the principle of volume-compensation was assessed by comparison with simultaneous measurement of direct (invasive) radial artery pressure in nine healthy subjects. Bias and precision of systolic BP (SBP) and diastolic BP (DBP) derived from Bland-Altman plots ...Show More
Central blood pressure (cBP) is an important indicator of the load on the heart. Because cBP is difficult to measure directly, indirect methods have been developed. We investigated suitability of blood pressure cuff pulse waves for estimation of cBP and additional hemodynamic variables. Waves obtained from arm cuff and from wrist cuff were compared.Show More
Flexible pressure sensors have been extensively studied for the development of wearable healthcare technologies, specifically in cardiovascular monitoring. Herein, we have reported a mesoscale-featured capacitive pressure sensor for monitoring blood pressure and pulse rate. The sensor is fabricated using a silicone elastomer by sandwiching in the flexible electrodes to make a skin-attachable weara...Show More
This paper proposes a new calibration method for arterial blood pressure (BP) estimation using pulse transit time (PTT). Different from the traditional calibration methods, this new approach features a fast and convenient procedure by modeling the effects on distal arteries of external pressure applied by upper arm cuff. Two rounds of experiments (about two months apart) were conducted on eleven h...Show More