The Experts below are selected from a list of 234 Experts worldwide ranked by ideXlab platform
Ramakrishna Mukkamala - One of the best experts on this subject based on the ideXlab platform.
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Estimation of the Total Peripheral Resistance baroreflex impulse response from spontaneous hemodynamic variability.
American journal of physiology. Heart and circulatory physiology, 2007Co-Authors: Xiaoxiao Chen, Jong-kyung Kim, Javier A. Sala-mercado, Robert L. Hammond, Rafat I. Elahi, Tadeusz J. Scislo, Gokul Swamy, Donal S. O'leary, Ramakrishna MukkamalaAbstract:We previously developed a mathematical analysis technique for estimating the static gain values of the arterial Total Peripheral Resistance (TPR) baroreflex (GA) and the cardiopulmonary TPR baroref...
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identification of the Total Peripheral Resistance baroreflex impulse response from spontaneous hemodynamic variability validation by chronic arterial baroreceptor denervation
International Conference of the IEEE Engineering in Medicine and Biology Society, 2007Co-Authors: Xiaoxiao Chen, Jong-kyung Kim, Robert L. Hammond, Tadeusz J. Scislo, Gokul Swamy, Javier A Salamercado, Donal S Oleary, Ramakrishna MukkamalaAbstract:We have previously proposed a technique for estimating the static gain values and impulse response of the arterial and cardiopulmonary Total Peripheral Resistance (TPR) baroreflex by mathematical analysis of beat-to-beat fluctuations in arterial blood pressure, cardiac output, and stroke volume. In this study, we evaluated the technique with respect to spontaneous hemodynamic variability measured from seven conscious dogs before and after chronic arterial baroreceptor denervation. Our results show that the technique correctly predicted the alterations in TPR baroreflex functioning that are known to occur following the baroreceptor denervation.
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Estimation of arterial and cardiopulmonary Total Peripheral Resistance baroreflex gain values: validation by chronic arterial baroreceptor denervation.
American journal of physiology. Heart and circulatory physiology, 2005Co-Authors: Ramakrishna Mukkamala, Jong-kyung Kim, Javier A. Sala-mercado, Robert L. Hammond, Tadeusz J. Scislo, Donal S. O'learyAbstract:Feedback control of Total Peripheral Resistance (TPR) by the arterial and cardiopulmonary baroreflex systems is an important mechanism for short-term blood pressure regulation. Existing methods for...
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identification of the arterial and cardiopulmonary Total Peripheral Resistance baroreflex gain values from spontaneous hemodynamic variability
International Conference of the IEEE Engineering in Medicine and Biology Society, 2005Co-Authors: Ramakrishna Mukkamala, Jong-kyung Kim, Robert L. Hammond, Tadeusz J. Scislo, Javier A Salamercado, Donal S OlearyAbstract:We have previously proposed a potentially non-invasive technique for determining the closed-loop gain values of the arterial and cardiopulmonary Total Peripheral Resistance (TPR) baroreflex systems by mathematical analysis of beat-to-beat fluctuations in arterial blood pressure, cardiac output, and stroke volume. In this paper, we describe an evaluation of the technique with respect to spontaneous hemodynamic variability measured from seven conscious dogs before and after chronic arterial baroreceptor denervation. We report that the technique correctly predicted the expected changes in the TPR baroreflex gain values induced by the baroreceptor denervation
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non invasive identification of the Total Peripheral Resistance baroreflex impulse response from spontaneous hemodynamic variability
Computing in Cardiology Conference, 2005Co-Authors: R Elahi, Ramakrishna MukkamalaAbstract:We propose a novel technique for identifying the impulse response characterizing the Total Peripheral Resistance (TPR) baroreflex by mathematical analysis of spontaneous, beat-to-beat fluctuations in arterial blood pressure, cardiac output, and stroke volume. The technique may therefore provide a complete linear dynamic characterization of the TPR baroreflex during normal, closed-loop conditions from only non-invasive measurements. We then describe a theoretical evaluation of the technique against realistic beat-to-beat variability generated by a cardiovascular simulator whose actual dynamic properties were exactly known. We report that the technique accurately estimated the TPR baroreflex impulse response as well as other key cardiovascular parameters for a range of simulator parameter values
Richard J. Cohen - One of the best experts on this subject based on the ideXlab platform.
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preliminary application of a novel algorithm to monitor changes in pre flight Total Peripheral Resistance for prediction of post flight orthostatic intolerance in astronauts
Acta Astronautica, 2011Co-Authors: Tatsuya J Arai, Kichang Lee, Michael B Stenger, Steven H Platts, Janice V Meck, Richard J. CohenAbstract:Abstract Orthostatic intolerance (OI) is a significant challenge for astronauts after long-duration spaceflight. Depending on flight duration, 20–80% of astronauts suffer from post-flight OI, which is associated with reduced vascular Resistance. This paper introduces a novel algorithm for continuously monitoring changes in Total Peripheral Resistance (TPR) by processing the Peripheral arterial blood pressure (ABP). To validate, we applied our novel mathematical algorithm to the pre-flight ABP data previously recorded from twelve astronauts ten days before launch. The TPR changes were calculated by our algorithm and compared with the TPR value estimated using cardiac output/heart rate before and after phenylephrine administration. The astronauts in the post-flight presyncopal group had lower pre-flight TPR changes (1.66 times) than those in the non-presyncopal group (2.15 times). The trend in TPR changes calculated with our algorithm agreed with the TPR trend calculated using measured cardiac output in the previous study. Further data collection and algorithm refinement are needed for pre-flight detection of OI and monitoring of continuous TPR by analysis of Peripheral arterial blood pressure.
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theoretical considerations in the dynamic closed loop baroreflex and autoregulatory control of Total Peripheral Resistance
American Journal of Physiology-heart and Circulatory Physiology, 2004Co-Authors: Nikolai A Aljuri, Richard J. CohenAbstract:The most important goal of this study is to enhance our understanding of the crucial functional relationships that determine the behavior of the systemic circulation and its underlying physiologica...
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test of dynamic closed loop baroreflex and autoregulatory control of Total Peripheral Resistance in intact and conscious sheep
American Journal of Physiology-heart and Circulatory Physiology, 2004Co-Authors: Nikolai A Aljuri, R.p. Marini, Richard J. CohenAbstract:This is the first study able to examine and delineate the actual actions of the physiological mechanisms responsible for the dynamic couplings between cardiac output (CO), arterial pressure (Pa), r...
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Noninvasive identification of the Total Peripheral Resistance baroreflex
American journal of physiology. Heart and circulatory physiology, 2002Co-Authors: Ramakrishna Mukkamala, Karin Toska, Richard J. CohenAbstract:We propose two identification algorithms for quantitating the Total Peripheral Resistance (TPR) baroreflex, an important contributor to short-term arterial blood pressure (ABP) regulation. Each algorithm analyzes beat-to-beat fluctuations in ABP and cardiac output, which may both be obtained noninvasively in humans. For a theoretical evaluation, we applied both algorithms to a realistic cardiovascular model. The results contrasted with only one of the algorithms proving to be reliable. This algorithm was able to track changes in the static gains of both the arterial and cardiopulmonary TPR baroreflex. We then applied both algorithms to a preliminary set of human data and obtained contrasting results much like those obtained from the cardiovascular model, thereby making the theoretical evaluation results more meaningful. This study suggests that, with experimental testing, the reliable identification algorithm may provide a powerful, noninvasive means for quantitating the TPR baroreflex. This study also provides an example of the role that models can play in the development and initial evaluation of algorithms aimed at quantitating important physiological mechanisms.
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system identification of dynamic closed loop control of Total Peripheral Resistance by arterial and cardiopulmonary baroreceptors
Acta Astronautica, 2001Co-Authors: Nikolai A Aljuri, R.p. Marini, Nenad Bursac, Richard J. CohenAbstract:Prolonged exposure to microgravity in space flight missions (days) impairs the mechanisms responsible for defense of arterial blood pressure (ABP) and cardiac output (CO) against orthostatic stress in the post-flight period. The mechanisms responsible for the observed orthostatic intolerance are not yet completely understood. Additionally, effective counter measures to attenuate this pathophysiological response are not available. The aim of this study was to investigate the ability of our proposed system identification method to predict closed-loop dynamic changes in TPR induced by changes in mean arterial pressure (MAP) and right atrial pressure (RAP). For this purpose we designed and employed a novel experimental animal model for the examination of arterial and cardiopulmonary baroreceptors in the dynamic closed-loop control of Total Peripheral Resistance (TPR), and applied system identification to the analysis of beat-to-beat fluctuations in the measured signals. Grant numbers: NAG5-4989. c 2001. Elsevier Science Ltd. All rights reserved.
Tadeusz J. Scislo - One of the best experts on this subject based on the ideXlab platform.
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Estimation of the Total Peripheral Resistance baroreflex impulse response from spontaneous hemodynamic variability.
American journal of physiology. Heart and circulatory physiology, 2007Co-Authors: Xiaoxiao Chen, Jong-kyung Kim, Javier A. Sala-mercado, Robert L. Hammond, Rafat I. Elahi, Tadeusz J. Scislo, Gokul Swamy, Donal S. O'leary, Ramakrishna MukkamalaAbstract:We previously developed a mathematical analysis technique for estimating the static gain values of the arterial Total Peripheral Resistance (TPR) baroreflex (GA) and the cardiopulmonary TPR baroref...
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identification of the Total Peripheral Resistance baroreflex impulse response from spontaneous hemodynamic variability validation by chronic arterial baroreceptor denervation
International Conference of the IEEE Engineering in Medicine and Biology Society, 2007Co-Authors: Xiaoxiao Chen, Jong-kyung Kim, Robert L. Hammond, Tadeusz J. Scislo, Gokul Swamy, Javier A Salamercado, Donal S Oleary, Ramakrishna MukkamalaAbstract:We have previously proposed a technique for estimating the static gain values and impulse response of the arterial and cardiopulmonary Total Peripheral Resistance (TPR) baroreflex by mathematical analysis of beat-to-beat fluctuations in arterial blood pressure, cardiac output, and stroke volume. In this study, we evaluated the technique with respect to spontaneous hemodynamic variability measured from seven conscious dogs before and after chronic arterial baroreceptor denervation. Our results show that the technique correctly predicted the alterations in TPR baroreflex functioning that are known to occur following the baroreceptor denervation.
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Estimation of arterial and cardiopulmonary Total Peripheral Resistance baroreflex gain values: validation by chronic arterial baroreceptor denervation.
American journal of physiology. Heart and circulatory physiology, 2005Co-Authors: Ramakrishna Mukkamala, Jong-kyung Kim, Javier A. Sala-mercado, Robert L. Hammond, Tadeusz J. Scislo, Donal S. O'learyAbstract:Feedback control of Total Peripheral Resistance (TPR) by the arterial and cardiopulmonary baroreflex systems is an important mechanism for short-term blood pressure regulation. Existing methods for...
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identification of the arterial and cardiopulmonary Total Peripheral Resistance baroreflex gain values from spontaneous hemodynamic variability
International Conference of the IEEE Engineering in Medicine and Biology Society, 2005Co-Authors: Ramakrishna Mukkamala, Jong-kyung Kim, Robert L. Hammond, Tadeusz J. Scislo, Javier A Salamercado, Donal S OlearyAbstract:We have previously proposed a potentially non-invasive technique for determining the closed-loop gain values of the arterial and cardiopulmonary Total Peripheral Resistance (TPR) baroreflex systems by mathematical analysis of beat-to-beat fluctuations in arterial blood pressure, cardiac output, and stroke volume. In this paper, we describe an evaluation of the technique with respect to spontaneous hemodynamic variability measured from seven conscious dogs before and after chronic arterial baroreceptor denervation. We report that the technique correctly predicted the expected changes in the TPR baroreflex gain values induced by the baroreceptor denervation
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mechanisms mediating nts p2x receptor evoked hypotension cardiac output vs Total Peripheral Resistance
American Journal of Physiology-heart and Circulatory Physiology, 2001Co-Authors: Amy M Kitchen, Tadeusz J. Scislo, Heidi L Collins, Stephen E Dicarlo, Donal S OlearyAbstract:We have previously shown that P2x purinoceptor activation in the subpostremal nucleus tractus solitarius (NTS) produces dose-dependent decreases in mean arterial pressure (MAP), heart rate, efferen...
Donal S. O'leary - One of the best experts on this subject based on the ideXlab platform.
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Estimation of the Total Peripheral Resistance baroreflex impulse response from spontaneous hemodynamic variability.
American journal of physiology. Heart and circulatory physiology, 2007Co-Authors: Xiaoxiao Chen, Jong-kyung Kim, Javier A. Sala-mercado, Robert L. Hammond, Rafat I. Elahi, Tadeusz J. Scislo, Gokul Swamy, Donal S. O'leary, Ramakrishna MukkamalaAbstract:We previously developed a mathematical analysis technique for estimating the static gain values of the arterial Total Peripheral Resistance (TPR) baroreflex (GA) and the cardiopulmonary TPR baroref...
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Estimation of arterial and cardiopulmonary Total Peripheral Resistance baroreflex gain values: validation by chronic arterial baroreceptor denervation.
American journal of physiology. Heart and circulatory physiology, 2005Co-Authors: Ramakrishna Mukkamala, Jong-kyung Kim, Javier A. Sala-mercado, Robert L. Hammond, Tadeusz J. Scislo, Donal S. O'learyAbstract:Feedback control of Total Peripheral Resistance (TPR) by the arterial and cardiopulmonary baroreflex systems is an important mechanism for short-term blood pressure regulation. Existing methods for...
Jong-kyung Kim - One of the best experts on this subject based on the ideXlab platform.
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Estimation of the Total Peripheral Resistance baroreflex impulse response from spontaneous hemodynamic variability.
American journal of physiology. Heart and circulatory physiology, 2007Co-Authors: Xiaoxiao Chen, Jong-kyung Kim, Javier A. Sala-mercado, Robert L. Hammond, Rafat I. Elahi, Tadeusz J. Scislo, Gokul Swamy, Donal S. O'leary, Ramakrishna MukkamalaAbstract:We previously developed a mathematical analysis technique for estimating the static gain values of the arterial Total Peripheral Resistance (TPR) baroreflex (GA) and the cardiopulmonary TPR baroref...
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identification of the Total Peripheral Resistance baroreflex impulse response from spontaneous hemodynamic variability validation by chronic arterial baroreceptor denervation
International Conference of the IEEE Engineering in Medicine and Biology Society, 2007Co-Authors: Xiaoxiao Chen, Jong-kyung Kim, Robert L. Hammond, Tadeusz J. Scislo, Gokul Swamy, Javier A Salamercado, Donal S Oleary, Ramakrishna MukkamalaAbstract:We have previously proposed a technique for estimating the static gain values and impulse response of the arterial and cardiopulmonary Total Peripheral Resistance (TPR) baroreflex by mathematical analysis of beat-to-beat fluctuations in arterial blood pressure, cardiac output, and stroke volume. In this study, we evaluated the technique with respect to spontaneous hemodynamic variability measured from seven conscious dogs before and after chronic arterial baroreceptor denervation. Our results show that the technique correctly predicted the alterations in TPR baroreflex functioning that are known to occur following the baroreceptor denervation.
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Estimation of arterial and cardiopulmonary Total Peripheral Resistance baroreflex gain values: validation by chronic arterial baroreceptor denervation.
American journal of physiology. Heart and circulatory physiology, 2005Co-Authors: Ramakrishna Mukkamala, Jong-kyung Kim, Javier A. Sala-mercado, Robert L. Hammond, Tadeusz J. Scislo, Donal S. O'learyAbstract:Feedback control of Total Peripheral Resistance (TPR) by the arterial and cardiopulmonary baroreflex systems is an important mechanism for short-term blood pressure regulation. Existing methods for...
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identification of the arterial and cardiopulmonary Total Peripheral Resistance baroreflex gain values from spontaneous hemodynamic variability
International Conference of the IEEE Engineering in Medicine and Biology Society, 2005Co-Authors: Ramakrishna Mukkamala, Jong-kyung Kim, Robert L. Hammond, Tadeusz J. Scislo, Javier A Salamercado, Donal S OlearyAbstract:We have previously proposed a potentially non-invasive technique for determining the closed-loop gain values of the arterial and cardiopulmonary Total Peripheral Resistance (TPR) baroreflex systems by mathematical analysis of beat-to-beat fluctuations in arterial blood pressure, cardiac output, and stroke volume. In this paper, we describe an evaluation of the technique with respect to spontaneous hemodynamic variability measured from seven conscious dogs before and after chronic arterial baroreceptor denervation. We report that the technique correctly predicted the expected changes in the TPR baroreflex gain values induced by the baroreceptor denervation
