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Physiological Measurement

Lukas Peter Mileder, Tessa Mueller, Nariae Baik-Schneditz, Jasmin Pansy, Bernhard Schwaberger, Corinna Binder-Heschl, Berndt Urlesberger, Gerhard Pichler
In neonates, a patent ductus arteriosus (DA) may be associated with severe complications. We used near-infrared spectroscopy (NIRS) with venous occlusion to investigate the influence of an open DA on peripheral muscle oxygenation/perfusion in preterm neonates. Approach: We analyzed secondary outcome parameters collected as part of prospective observational studies. NIRS measurements were performed between the first and third day of life. Arterial oxygen saturation (SaO2) and heart rate (HR) were monitored by pulse oximetry on the ipsilateral foot...
November 21, 2017: Physiological Measurement
Martina Valente, Michal Javorka, Alberto Porta, Vlasta Bari, Jana Krohova, Barbora Czippelova, Zuzana Turianikova, Giandomenico Nollo, Luca Faes
A defining feature of physiological systems under the neuroautonomic regulation is their dynamical complexity. The most common approach to assess physiological complexity from short-term recordings, i.e. to compute the rate of entropy generation of an individual system by means of measures of conditional entropy (CE), does not consider that complexity may change when the investigated system is part of a network of physiological interactions. This study aims at extending the concept of short-term complexity towards the perspective of network physiology, defining multivariate CE measures whereby multiple physiological processes are accounted for in the computation of entropy rates...
November 14, 2017: Physiological Measurement
Kertin Jost, Sebastian Scherer, Chiara De Angelis, Marcel Buechler, Alexandre N Datta, Philippe C Cattin, Urs Frey, Bela Suki, Sven M Schulzke
Characterizing heart rate variability (HRV) in neonates has gained increased attention and is helpful in quantifying maturation and risk of sepsis in preterm infants. Raw data used to derive HRV in a clinical setting commonly contain noise from motion artifacts. Thoracic surface electromyography (sEMG) potentially allows for pre-emptive removal of motion artifacts and subsequent detection of interbeat interval (IBI) of heart rate to calculate HRV. We tested the feasibility of sEMG in preterm infants to exclude noisy raw data and to derive IBI for HRV analysis...
November 9, 2017: Physiological Measurement
Yang Wang, Zhiwen Liu, Shaodong Ma
This paper proposes an unobtrusive blood pressure (BP) measurement system design with motion artifact (MA) compensation strategy as a potential surrogate to the traditional cuff-based sphygmomanometer for self-monitoring in less restricted environment. Approach: A dual-channel photoplethysmographic signal acquisition system is designed and implemented for the cuff-less BP measurement based on peripheral pulse transit time (PPTT) acquired from the forearm and wrist. Comprised of motion decision, singular spectrum analysis, PPTT calculation and BP measurement, a novel approach is proposed to realize BP measurement with suppressing MA interference...
November 9, 2017: Physiological Measurement
Fabian Braun, Martin Proença, Mathieu Lemay, Mattia Bertschi, Andy Adler, Jean-Philippe Thiran, Josep Sola
<i>Objective</i>: Electrical impedance tomography (EIT) shows potential for radiation-free and non-invasive hemodynamic monitoring. However, many factors degrade the accuracy and repeatability of these measurements. Our goal is to estimate the impact of this variability on EIT-based monitoring of two important central hemodynamic parameters: stroke volume (SV) and pulmonary artery pressure (PAP). <i>Approach</i>: We performed simulations on a 4D (3D + t) bioimpedance model of a human volunteer to study the influence of four potential confounding factors (electrode belt displacement, electrode detachment, changes in hematocrit and lung air volume) on the performance of EIT-based SV and PAP estimation...
November 3, 2017: Physiological Measurement
Rajiv Ranganathan, Rui Wang, Bo Dong, Subir Biswas
OBJECTIVE: Movement impairments such as those due to stroke often result in the nervous system adopting atypical movements to compensate for movement deficits. Monitoring these compensatory patterns is critical for improving functional outcomes during rehabilitation. The purpose of this study was to test the feasibility and validity of a wearable sensor system for detecting compensatory trunk kinematics during activities of daily living. APPROACH: Participants with no history of neurological impairments performed reaching and manipulation tasks with their upper extremity, and their movements were recorded by a wearable sensor system and validated using a motion capture system...
November 3, 2017: Physiological Measurement
Supreeth Prajwal Shashikumar, Qiao Li, Gari D Clifford, Shamim Nemati
Sepsis, a dysregulated immune-mediated host response to infection, is the leading cause of morbidity and mortality in critically ill patients. Indices of heart rate variability and complexity (such as entropy) have been proposed as surrogate markers of Neuro-immune system dysregulation with diseases such as sepsis. However, these indices only provide an average, one dimensional description of complex neuro-physiological interactions. We propose a novel multiscale network construction and analysis method for multivariate physiological time series, and demonstrate its utility for early prediction of sepsis...
November 1, 2017: Physiological Measurement
Evan P Pasha, Takashi Tarumi, Andreana P Haley, Hirofumi Tanaka
INTRODUCTION: We determined if transcranial color-coded Doppler derived hemodynamics are associated with MRI based cerebral blood flow (CBF) in regions clinically important to dementia in healthy middle-aged adults. METHODS: In thirty subjects (18m/12f; age=52±1 years), blood flow velocity (BFV) and cerebrovascular conductance (CVC) were measured with transcranial color-coded Doppler (TCCD) at the middle cerebral artery (MCA) and cerebral blood flow (CBF) was assessed with arterial spin labeled perfusion MRI...
November 1, 2017: Physiological Measurement
Tomasz Sobiech, Teodor Buchner, Paweł Krzesiński, Grzegorz Gielerak
To quantify symptoms of cardiorespiratory interaction in a group of 41 healthy subjects performing a subset of Ewing battery of tests. Approach: We measure empirical distribution of cardiorespiratory coupling time (RI), defined as time from the inspiration onset to the R peaks in the ECG. Study protocol is a subset of Ewing battery of tests. Respiratory function was measured with a thoracic belt and the heart rate was obtained from a two channel ECG measurement. Both series of fiducial points were determined using custom software...
October 27, 2017: Physiological Measurement
Shaoxiong Sun, Wouter Peeters, Rick Bezemer, Xi Long, Igor Paulussen, Ronald M Aarts, Gerrit Jan Noordergraaf
Arterial pulse pressure variation (PPV) is widely used for predicting fluid responsiveness and supporting fluid management in the operating room and intensive care unit. Available PPV algorithms have been typically validated for fluid responsiveness during episodes of hemodynamic stability. Yet, little is known about the performance of PPV algorithms during surgery, where fast changes of the blood pressure may affect the robustness of the presented PPV value. This work provides a comprehensive understanding of how various existing algorithmic designs affect the robustness of the presented PPV value during surgery, and proposes additional processing for the pulse pressure signal before calculating PPV...
October 24, 2017: Physiological Measurement
Nabeel P M, Jayaraj Joseph, Mohanasankar Sivaprakasam
<i>Objective:</i> A novel photoplethysmograph (PPG) probe employs dual photodiodes excited using single infrared light source was developed for local Pulse Wave Velocity (PWV) measurement. The potential use of proposed system in cuffless Blood Pressure (BP) techniques was demonstrated. <i>Approach:</i> Initial validation measurements were performed on a phantom using a reference method. Further, an in-vivo study was carried out in 35 volunteers (age = 28 ± 4.5 years). Carotid local PWV, carotid to finger Pulse Transit Time (PTT<sub>R</sub>) and Pulse Arrival Time at the carotid artery (PAT<sub>C</sub>) were simultaneously measured...
October 23, 2017: Physiological Measurement
Carl A Shiffman
A retrospective analysis of the electrical impedances of 154 normal subjects measured over the past decade shows that "scaling" of the Nyquist plots for human thigh muscles is a property shared by healthy thigh musculature, irrespective of subject and the length of muscle segment. Here the term scaling signifies the near and sometimes "perfect" coalescence of the separate X vs R plots into one "reduced" Nyquist plot by the simple expedient of dividing R and X by Xm , the value of X at the reactance maximum...
October 18, 2017: Physiological Measurement
Reza Sameni, Esmaeil Seraj
The instantaneous phase (IP) and instantaneous frequency (IF) of the electroencephalogram (EEG) are considered as notable complements for the EEG spectrum. The calculation of these parameters commonly includes narrow-band filtering, followed by the calculation of the signal's analytical form. The calculation of the IP and IF is highly susceptible to the filter parameters and background noise level, especially in low analytical signal amplitudes. The objective of this study is to propose a robust statistical framework for EEG IP/IF estimation and analysis...
October 16, 2017: Physiological Measurement
László Hejjel
Accurate pulse rate detection is essential for reliable pulse rate variability analysis. On the other hand, minimizing the sampling frequency is essential to reduce the amounts of data and computational needs, and consequently power consumption of mobile/wearable devices extending their operating hours. Determining variability of physiological parameters needs a new paradigm since there is a limited possibility of calculating an average eliminating random error of measurement. Finding the optimal sampling rate depends on the actual investigation, the expected variability and variability-changes of the study-population...
October 12, 2017: Physiological Measurement
Ahyoung Choi, Hangsik Shin
In his Comment, Hejjel argued that some contents previously published by us were inappropriate for statistical analysis of pulse rate variability due to high inter-individual dispersion. He also claimed that data collection over five minutes for short-term HRV analysis and data collection for an abnormal range of people were required. In order to give our perspective on these issues, we will discuss and clarify some of the existing literature and our own work on this subject, underlining the difference between electrocardiogram and photoplethysmogram...
October 12, 2017: Physiological Measurement
Emmanuel Katsogridakis, David M Simpson, Glen Bush, Lingke Fan, Anthony A Birch, Robert Allen, John F Potter, Ronney B Panerai
Previous studies on cerebral autoregulation have shown the existence of hemispheric symmetry, which may be altered in stroke and traumatic brain injury. There is a paucity of data however on whether the response is symmetrical between those disturbances that cause cerebral hyperperfusion, to those that cause hypoperfusion. Our aim was to investigate whether the responses of cerebral autoregulation to haemodynamic stimuli of different directions are symmetrical. Approach: Using a previously described assessment method, we employed coherent averaging of the cerebral blood flow velocity (CBFV) responses to thigh cuff inflation and deflation, as driven by pseudorandom binary sequences, whilst simultaneously altering the inspired CO2...
October 3, 2017: Physiological Measurement
Tommaso Mauri, Marta Lazzeri, Giacomo Bellani, Alberto Zanella, Giacomo Grasselli
As precision medicine is becoming standard of care to select tailored rather than average treatments, physiological measurements might represent the first step to apply personalized therapy in the intensive care unit (ICU). Systematic assessment of respiratory mechanics in patients with the acute respiratory distress syndrome (ARDS) could represent a step towards this direction for two main reasons. On the one hand, respiratory mechanics are a powerful physiological method to understand the severity of this syndrome in each single patient...
October 2, 2017: Physiological Measurement
Fiona E McNeill, Mandy Fisher, David R Chettle, Mike Inskip, Norm Healey, Riina Bray, Colin E Webber, William I Manton, Leonora Marro, Tye E Arbuckle
A study, conducted in Toronto, Canada, between 2009 and 2011, measured the bone lead concentrations of volunteers aged 1 to 82 years using in vivo x-ray fluorescence (XRF) technology. Bone lead levels were lower compared to Ontario in vivo XRF studies from the early 1990s. In adults, the slope of tibia lead content versus age was reduced by 36 to 56%, i.e., bone lead levels for a given age group were approximately half compared to the same age group 17 years prior. Further, bone lead levels of individuals fell over that time period...
October 2, 2017: Physiological Measurement
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
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
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