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Physiological Measurement

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https://www.readbyqxmd.com/read/28930098/bioimpedance-technology-for-detection-of-thoracic-injury
#1
Ruben Buendia, Stefan Candefjord, Benjamin Sanchez, Hans Granhed, Bengt-Arne Sjöqvist, Per Örtenwall, Eva-Corina Caragounis
Thoracic trauma is one of the most common and lethal types of injury, causing over a quarter of traumatic deaths. Severe thoracic injuries are often occult and difficult to diagnose in the field. There is a need for a point-of-care diagnostic device for severe thoracic injuries in the prehospital setting. Electrical bioimpedance (EBI) is non-invasive, portable, rapid and easy to use technology that can provide objective and quantitative diagnostic information for the prehospital environment. Here, we evaluated the performance of EBI to detect thoracic injuries...
September 20, 2017: Physiological Measurement
https://www.readbyqxmd.com/read/28930095/robust-and-practical-non-invasive-estimation-of-local-arterial-wave-speed-and-mean-blood-velocity-waveforms
#2
Remi Kowalski, Richard Beare, Marie Willemet, Jordi Alastruey, Joseph J Smolich, Michael M H Cheung, Jonathan P Mynard
Local arterial wave speed, a surrogate of vessel stiffness, can be estimated via the pressure-velocity (PU) and diameter-velocity (ln(D)U) loop methods. These assume negligible early-systolic reflected waves (RWes) and require measurement of cross-sectionally averaged velocity (U<sub>mean</sub>), which itself is a valuable quantity related to volumetric blood flow. However, RWes may not always be negligible and routine Doppler ultrasound typically provides maximum velocity waveforms or estimates of mean velocity subject to various errors (U<sub>raw</sub>)...
September 20, 2017: Physiological Measurement
https://www.readbyqxmd.com/read/28901946/design-of-semg-assembly-to-detect-external-anal-sphincter-activity-a-proof-of-concept
#3
Arsam Shiraz, Brian Leaker, Charles Alexander Mosse, Eskinder Solomon, Michael Craggs, Andreas Demosthenous
Conditional trans-rectal stimulation of the pudendal nerve could provide a viable solution to treat hyperreflexive bladder in spinal cord injury. A set threshold of the amplitude estimate of the external anal sphincter surface electromyography (sEMG) may be used as the trigger signal. The efficacy of such a device should be tested in a large scale clinical trial. As such a probe should remain in situ for several hours while patients attend to their daily routine, the recording electrodes should be designed to be large enough to maintain good contact while observing design constraints...
September 13, 2017: Physiological Measurement
https://www.readbyqxmd.com/read/28885987/theoretical-and-experimental-comparison-of-lag-based-and-time-based-exponential-moving-average-models-of-qt-hysteresis
#4
Vincent Jacquemet, Hugo Gravel, Daniel Curnier, Alain Vinet
In the electrocardiogram, adaptation of the QT interval to variations in heart rate is not instantaneous. Quantification of this hysteresis phenomenon relies on mathematical models describing the relation between the RR and QT time series.These models reproduce hysteresis through an effective RR interval computed as a linear combination of the history of past RR intervals. This filter depends on a time constant parameter that may be used as biomarker. The most common hysteresis model is based on an autoregressive filter with an impulse response that decreases exponentially with the beat number (lag-based model)...
September 8, 2017: Physiological Measurement
https://www.readbyqxmd.com/read/28885986/estimation-of-baroreflex-sensitivity-by-the-bivariate-phase-rectified-signal-averaging-method-a-comparison-with-the-phenylephrine-method
#5
Roberto Maestri, Maria Teresa La Rovere, Grzegorz Raczak, Ludmiła Danilowicz-Szymanowicz, Gian Domenico Pinna
Background A novel technique to assess spontaneous baroreflex sensitivity (BRS) by bivariate phase-rectified signal averaging (PRSA-BRS) has been recently proposed and its independent prognostic power demonstrated. This method, however, has never been compared with the Phenyleprine test (Phe-BRS), commonly regarded as the reference method in clinical and research applications. Methods In 192 heart failure (HF) and 41 post-myocardial infarction (post-MI) patients we compared PRSA-BRS with Phe-BRS, assessing both association and agreement...
September 8, 2017: Physiological Measurement
https://www.readbyqxmd.com/read/28872457/feature-clustering-of-intracranial-pressure-time-series-for-an-alarm-function-estimation-in-traumatic-brain-injury
#6
Michal Teplan, Ivan Bajla, Roman Rosipal, Martin Rusnák
The guidelines for the management of Traumatic Brain Injury (TBI) recommend that IntraCranial Presure (ICP) should be monitored in all salvageable patients with severe TBI, albeit this quantity cannot identify the specific mechanisms of pressure elevation. The conventional application of ICP monitoring consists merely in acquisition of ICP values in discrete time and their comparison to the established ICP threshold. The excess of this threshold triggers the special emergency treatment protocol...
September 5, 2017: Physiological Measurement
https://www.readbyqxmd.com/read/28871074/acoustics-of-snoring-and-automatic-snore-sound-detection-in-children
#7
Mustafa Cavusoglu, Christian Poets, Michael Urschitz
Acoustic analyses of snoring sounds have been efficiently used to objectively assess snoring and to apply in various clinical problems for adult patients. Such studies require highly automatized tools to analyze the whole night sleep sound recordings to extract clinically relevant snore related statistics. The existing techniques and software for adults are not efficiently applicable to snoring sounds in pediatric patients basically because of different acoustic signal properties. In this paper, we present a broad range of acoustic characterization of snoring sounds in children (N=38) in comparison to adult (N=30) patients...
September 5, 2017: Physiological Measurement
https://www.readbyqxmd.com/read/28869423/advanced-analyses-of-physiological-signals-in-the-neonatal-intensive-care-unit
#8
Jacqueline Huvanandana, Cindy Thamrin, Mark Tracy, Murray Hinder, Chinh Nguyen, Alistair L McEwan
Management and monitoring of infants within the neonatal intensive care unit (NICU) represents a unique challenge. It involves an array of life-threatening diseases, procedures with potentially lifelong impacts, co-morbidities associated with preterm birth and risk of infection from prolonged exposure to the hospital environment. With the integration of monitoring systems and increasing accessibility of high-resolution data, there is a growing interest in the utility of advanced data analyses in predictive monitoring and characterising patterns of disease...
September 4, 2017: Physiological Measurement
https://www.readbyqxmd.com/read/28869420/improved-ultrasound-transducer-positioning-by-fetal-heart-location-estimation-during-doppler-based-heart-rate-measurements
#9
Paul Hamelmann, Rik Vullings, Lars Schmitt, Alexander Franciscus Kolen, Massimo Mischi, Judith O E H Van Laar, Jan W M Bergmans
Doppler Ultrasound (US) is the most commonly applied method to measure the fetal heart rate (fHR). When the fetal heart is not properly located within the ultrasonic beam, fHR measurements often fail. As a consequence, clinical staff needs to reposition the US transducer on the maternal abdomen, which can be a time consuming and tedious task. In this article, a method is presented to aid clinicians with the positioning of the US transducer to produce robust fHR measurements. A maximum likelihood estimation (MLE) algorithm is developed, which provides information on fetal heart location using the power of the Doppler signals received in the individual elements of a standard US transducer for fHR recordings...
September 4, 2017: Physiological Measurement
https://www.readbyqxmd.com/read/28857749/direct-means-of-obtaining-cavi-sub-0-sub-a-corrected-cardio-ankle-vascular-stiffness-index-cavi-from-conventional-cavi-measurements-or-their-underlying-variables
#10
Bart Spronck, Michal Mestanik, Ingrid Tonhajzerova, Alexander Jurko, Tomas Jurko, Alberto P Avolio, Mark Butlin
<b>Objective</b> Cardio-ankle vascular index (CAVI) as measured using the VaSera device (CAVI<sub>VS</sub>, Fukuda Denshi), has been proposed as a stiffness index that does not depend on blood pressure. We have recently shown theoretically that CAVI<sub>VS</sub> still exhibits blood pressure dependence, and proposed the corrected index, CAVI<sub>0</sub>. The present study aims to establish a method of calculating CAVI<sub>0</sub> either (i) from VaSera-reported values of cardiac-brachial and brachial-ankle pulse transit times (tb and tba, respectively) and blood pressure, or (ii) directly from CAVI<sub>VS</sub>...
August 31, 2017: Physiological Measurement
https://www.readbyqxmd.com/read/28857748/effects-of-fatigue-and-recovery-on-electromechanical-delay-during-isokinetic-muscle-actions
#11
Cory M Smith, Terry J Housh, Ethan C Hill, Joshua L Keller, Glen O Johnson, Richard J Schmidt
Examine muscle-specific differences and the effects of fatigue and recovery on electromechanical delay (EMD) during maximal isokinetic muscle actions. Approach: Thirteen men performed maximal isokinetic knee extension muscle actions at 60ºs-1, pretest, posttest, and after 5-min of recovery from 25 maximal isokinetic knee extensions. The onsets of the electromyographic, mechanomyographic, and force signals were used to identify EMD measures from the vastus lateralis (VL), vastus medialis (VM), and rectus femoris (RF)...
August 31, 2017: Physiological Measurement
https://www.readbyqxmd.com/read/28857747/investigation-of-cerebral-venous-outflow-in-microgravity
#12
Angelo Taibi, Giacomo Gadda, Mauro Gambaccini, Erica Menegatti, Francesco Sisini, Paolo Zamboni
The gravitational gradient is the major component to face when considering the physiology of venous return and there is a growing interest in understanding the mechanisms ensuring the heart filling in the absence of gravity for astronauts who perform long-term space missions. The purpose of the Drain Brain project was to monitor the cerebral venous outflow of the crew member during an experiment on the International Space Station, so as to study the compensatory mechanisms that facilitate this essential physiological action in subjects living in a microgravity environment...
August 31, 2017: Physiological Measurement
https://www.readbyqxmd.com/read/28836507/detection-of-atrial-fibrillation-using-an-earlobe-photoplethysmographic-sensor
#13
Thomas Conroy, Jairo Hernandez Guzman, Burr Hall, Gill Tsouri, Jean-Phillippe Couderc
Atrial Fibrillation (AF) is the most common cardiac arrhythmia in the world, associated with increased risk of thromboembolic events and an increased mortality rate. In addition, a significant portion of AF patients are asymptomatic. Current AF diagnostic methods, often including a body surface electrocardiogram or implantable loop recorder, are both expensive and invasive and offer limited access within the general community. Objective We tested the feasibility of the detection of AF using photoplethysmographic signal acquired from an inexpensive, non-invasive earlobe photoplethysmographic sensor...
August 24, 2017: Physiological Measurement
https://www.readbyqxmd.com/read/28832339/coherent-normalization-for-i-in-vivo-i-measurements-of-gadolinium-in-bone
#14
Zaid Keldani, Michelle L Lord, Fiona E McNeill, David R Chettle, James L Gräfe
Recent evidence of gadolinium (Gd) deposition in bones of healthy individuals who have previously received Gd-based contrast agents (GBCAs) for MRI, has led to a demand for in vivo measurement techniques. The technique of x-ray fluorescence (XRF) provides a low risk and painless method to assess Gd deposition in bone, and has the potential to be a useful clinical tool. However, interpatient variability creates a challenge while performing in vivo measurements. We explored the use of coherent normalization, which involves normalizing the Gd K x-rays to the coherent scattered gamma-ray from the excitation source, for bone Gd measurements through a series of phantom-based experiments and Monte Carlo simulations...
August 23, 2017: Physiological Measurement
https://www.readbyqxmd.com/read/28812984/modelling-the-effects-of-quinidine-disopyramide-and-e-4031-on-short-qt-syndrome-variant-3-in-the-human-ventricles
#15
Cunjin Luo, Kuanquan Wang, Henggui Zhang
Short QT syndrome (SQTS) is an inherited cardiac channelopathy, but at present little information is available on its pharmacological treatment. SQT3 variant (linked to the inward rectifier potassium current IK1) of SQTS, results from a gain-of-function mutation (Kir2.1 D172N) in the KCNJ2-encoded channels, which is associated with ventricular fibrillation (VF). Using biophysically-detailed human ventricular computer models, this study investigated the potential effects of quinidine, disopyramide, and E-4031 on SQT3...
August 16, 2017: Physiological Measurement
https://www.readbyqxmd.com/read/28737503/directional-connectivity-in-the-eeg-is-able-to-discriminate-wakefulness-from-nrem-sleep
#16
Giulia Lioi, Steven L Bell, David C Smith, David M Simpson
A reliable measure of consciousness is of great interest for various clinical applications including sleep studies and the assessment of depth of anaesthesia. A number of measures of consciousness based on the EEG have been proposed in the literature and tested in studies of dreamless sleep, general anaesthesia and disorders of consciousness. However, reliability has remained a persistent challenge. Despite considerable theoretical and experimental effort, the neural mechanisms underlying consciousness remain unclear, but connectivity between brain regions is thought to be disrupted, impairing information flow...
July 24, 2017: Physiological Measurement
https://www.readbyqxmd.com/read/28696334/recent-advances-in-heart-sound-analysis
#17
Gari D Clifford, Chengyu Liu, Benjamin E Moody, José Millet Roig, Samuel E Schmidt, Qiao Li, Ikaro Silva, Roger G Mark
Heart sounds have been widely studied and have been demonstrated to have value for detecting pathologies in clinical applications. Over the last few decades, the use of heart sound signals has become increasingly uncommon and its practice in modern medicine somewhat diminished, although research into automated analysis has continued. Unfortunately, a comparative analyses of algorithms in the literature have been hindered by the lack of high-quality, rigorously validated, and standardized open databases of heart sound recordings...
July 11, 2017: Physiological Measurement
https://www.readbyqxmd.com/read/28671872/camera-based-assessment-of-arterial-stiffness-and-wave-reflection-parameters-from-neck-micro-motion
#18
Andreia Vieira Moço, Luis Albert Zavala Mondragon, Wenjin Wang, Sander Stuijk, Gerard de Haan
The feasibility of camera-based extraction of the carotid distension waveforms offers the prospect of a user-friendly alternative to Laser Doppler Velocimetry (LDV) or accelerometry-based systems. Upon supplementary calibration of vessel wall displacement to arterial pressure, our system may also be an appealing alternative to applanation tonometry for extracting cardiac-related features from the central pulse pressure waveform. This paper describes the application of camera-based micro-motion imaging to extract health-related features from the contour of the carotid displacement waveform...
July 3, 2017: Physiological Measurement
https://www.readbyqxmd.com/read/28665293/an-original-piecewise-model-for-computing-energy-expenditure-from-accelerometer-and-heart-rate-signals
#19
Hector Manuel Romero-Ugalde, Mael Garnotel, Maeva Doron, Pierre Jallon, Guillaume Charpentier, Sylvia Franc, Erik Huneker, Chantal Simon, Stephane Bonnet
Activity Energy Expenditure (EE) plays an important role in healthcare, therefore, accurate EE measures are required. Currently available reference EE acquisition methods, such as doubly labeled water and indirect calorimetry, are complex, expensive, uncomfortable, and/or difficult to apply on real time. To overcome these drawbacks, the goal of this paper is to propose a model for computing EE in real time (minute-by-minute) from heart rate and accelerometer signals. Approach: The proposed model, which consists of an original branched model, uses heart rate signals for computing EE on moderate to vigorous physical activities and a linear combination of heart rate and counts per minute for computing EE on light to moderate physical activities...
June 30, 2017: Physiological Measurement
https://www.readbyqxmd.com/read/28752824/the-feasibility-of-in-vivo-detection-of-lanthanum-using-a-241-am-k-x-ray-fluorescence-system
#20
Joanna Nguyen, Zaid Keldani, Eric Da Silva, Ana Pejović-Milić, James L Gräfe
OBJECTIVE: Lanthanum (La) is commonly used in phosphate binders in the form of lanthanum carbonate in patients with end-stage kidney disease undergoing hemodialysis treatments. With this administration, there is the potential for La storage in the body with bone being the main site of concern. However, the long-term effects of residual La in the body on bone health are not yet known. In this work, we investigate the feasibility of using a K x-ray fluorescence (K-XRF) spectroscopy system to measure bone La in vivo...
August 21, 2017: Physiological Measurement
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