404 resources related to Baroreflex
- Topics related to Baroreflex
- IEEE Organizations related to Baroreflex
- Conferences related to Baroreflex
- Periodicals related to Baroreflex
- Most published Xplore authors for Baroreflex
The conference program will consist of plenary lectures, symposia, workshops and invitedsessions of the latest significant findings and developments in all the major fields of biomedical engineering.Submitted papers will be peer reviewed. Accepted high quality papers will be presented in oral and postersessions, will appear in the Conference Proceedings and will be indexed in PubMed/MEDLINE
The CDC is the premier conference dedicated to the advancement of the theory and practice of systems and control. The CDC annually brings together an international community of researchers and practitioners in the field of automatic control to discuss new research results, perspectives on future developments, and innovative applications relevant to decision making, automatic control, and related areas.
The ACC is the annual conference of the American Automatic Control Council (AACC, the U.S. national member organization of the International Federation for Automatic Control (IFAC)). The ACC is internationally recognized as a premier scientific and engineering conference dedicated to the advancement of control theory and practice. The ACC brings together an international community of researchers and practitioners to discuss the latest findings in automatic control. The 2020 ACC technical program will
The 2020 IEEE International Conference on Systems, Man, and Cybernetics (SMC 2020) will be held in Metro Toronto Convention Centre (MTCC), Toronto, Ontario, Canada. SMC 2020 is the flagship conference of the IEEE Systems, Man, and Cybernetics Society. It provides an international forum for researchers and practitioners to report most recent innovations and developments, summarize state-of-the-art, and exchange ideas and advances in all aspects of systems science and engineering, human machine systems, and cybernetics. Advances in these fields have increasing importance in the creation of intelligent environments involving technologies interacting with humans to provide an enriching experience and thereby improve quality of life. Papers related to the conference theme are solicited, including theories, methodologies, and emerging applications. Contributions to theory and practice, including but not limited to the following technical areas, are invited.
The ICASSP meeting is the world's largest and most comprehensive technical conference focused on signal processing and its applications. The conference will feature world-class speakers, tutorials, exhibits, and over 50 lecture and poster sessions.
The IEEE Reviews in Biomedical Engineering will review the state-of-the-art and trends in the emerging field of biomedical engineering. This includes scholarly works, ranging from historic and modern development in biomedical engineering to the life sciences and medicine enabled by technologies covered by the various IEEE societies.
Broad coverage of concepts and methods of the physical and engineering sciences applied in biology and medicine, ranging from formalized mathematical theory through experimental science and technological development to practical clinical applications.
Both general and technical articles on current technologies and methods used in biomedical and clinical engineering; societal implications of medical technologies; current news items; book reviews; patent descriptions; and correspondence. Special interest departments, students, law, clinical engineering, ethics, new products, society news, historical features and government.
IEEE Intelligent Systems, a bimonthly publication of the IEEE Computer Society, provides peer-reviewed, cutting-edge articles on the theory and applications of systems that perceive, reason, learn, and act intelligently. The editorial staff collaborates with authors to produce technically accurate, timely, useful, and readable articles as part of a consistent and consistently valuable editorial product. The magazine serves software engineers, systems ...
Science and technology related to the basic physics and engineering of magnetism, magnetic materials, applied magnetics, magnetic devices, and magnetic data storage. The Transactions publishes scholarly articles of archival value as well as tutorial expositions and critical reviews of classical subjects and topics of current interest.
2010 Annual International Conference of the IEEE Engineering in Medicine and Biology, 2010
Baroreflex regulates arterial pressure by modulating ventricular and vascular properties. We investigated if the framework of circulatory equilibrium that we developed previously (Am J Physiol 2004, 2005) by extending the classic Guyton's framework is capable of predicting baroreflex induced changes in arterial pressure. In animal experiments, we estimated open loop transfer functions of baroreflexly modulated ventricular and vascular properties, synthesized ...
Computers in Cardiology, 2004, 2004
To elicit the effects of considering causality in the study of the interactions between KR interval and systolic pressure (SP) variability, the traditional noncausal crossspectral analysis was compared with a causal method able to separate the two arms of the RR-SP regulatory loop. Estimates of coherence (K) and causal coherences from SP to RR (Ksr) and from RR to SP ...
Proceedings of 18th Annual International Conference of the IEEE Engineering in Medicine and Biology Society, 1996
In this study compared the baroreflex gain (BRG) measured by the spectral method proposed by Robbe (1987) with the standard phenylephrine method in a population of 43 post-infarction patients (mean age/spl plusmn/SD: 52/spl plusmn/8). The agreement between the two techniques was assessed computing the bias (i.e. the mean value of the difference) and the 95% limits of agreement, whereas the ...
Computers in Cardiology 1996, 1996
The authors compared the baroreflex gain (BRG) measured by the phenylephrine technique (Phe-BRG) with BRG measured by the sequence technique (Seq-BRG) in 50 post-myocardial infarction patients (age: 52/spl plusmn/8 years, LVEF: 42/spl plusmn/12%). Correlation analysis was performed to assess the degree of linear relationship between Phe-BRG and Seq-BRG. The agreement was investigated computing the bias and the limits of agreement ...
Computers in Cardiology 2001. Vol.28 (Cat. No.01CH37287), 2001
Presents a new method for noninvasive assessment of baroreceptor sensitivity (BRS). Using this new method, BRS is estimated by linear regression analysis of the instantaneous values of BRS reordered into a logical, ascending sequence. The performance of the new method was compared with measurements of BRS by the traditional bolus phenylephrine method and other well-known non- invasive BRS assessment techniques, ...
Baroreflex regulates arterial pressure by modulating ventricular and vascular properties. We investigated if the framework of circulatory equilibrium that we developed previously (Am J Physiol 2004, 2005) by extending the classic Guyton's framework is capable of predicting baroreflex induced changes in arterial pressure. In animal experiments, we estimated open loop transfer functions of baroreflexly modulated ventricular and vascular properties, synthesized baroreflex induced dynamic changes in arterial pressure using the estimated transfer functions and compared the predicted responses with measured responses. We demonstrated that the predicted baroreflex induced changes in arterial pressure matched reasonable well with those measured. We conclude that the framework of circulatory equilibrium is generalizable under the condition where baroreflex dynamically changes arterial pressure.
To elicit the effects of considering causality in the study of the interactions between KR interval and systolic pressure (SP) variability, the traditional noncausal crossspectral analysis was compared with a causal method able to separate the two arms of the RR-SP regulatory loop. Estimates of coherence (K) and causal coherences from SP to RR (Ksr) and from RR to SP (Krs), and of noncausal (G) and causal (Gsr) baroreflex gain were evaluated at 0.1 Hz in 10 healthy young subjects in the supine position and after head-up tilt. While K was high in both conditions, at rest Ksr was signflcantly lower rhan Krs. After tilt, Ksr increased and Krs decreased signi@antly. With respect to G, Gsr was significantly lower ut rest and comparable afier tilt. Thus, in the supine position the prevalence of non-baroreflex coupling mechanisms led [he traditional approach to overestimate the baroreflex gain, while the tilt-induced activation of the baroreflex control made similar the gain esrimafes.
In this study compared the baroreflex gain (BRG) measured by the spectral method proposed by Robbe (1987) with the standard phenylephrine method in a population of 43 post-infarction patients (mean age/spl plusmn/SD: 52/spl plusmn/8). The agreement between the two techniques was assessed computing the bias (i.e. the mean value of the difference) and the 95% limits of agreement, whereas the degree of linear association has assessed by correlation analysis. The Pearson correlation coefficient was 0.67. The estimated limits of agreement were: -10.5/spl divide/5.5 ms/mmHg with a bias of -1 ms/mmHg (N.S.). As the difference between the two measurements was found to depend on their mean value (which is an estimate of the true BRG), the authors performed the same analysis on the percentage difference. The corresponding limits of agreement were -93.6/spl divide/88.5% with a bias of -2.6%. According to these results. The difference between the two measurements can be almost as large as the BRG of the patient. The authors' conclusion is that the spectral technique can substitute the pharmacological measurement for screening purposes but not in the assessment of patient prognosis where a depressed phenylephrine BRG (<3 ms/mmHg) has an important independent prognostic value.
The authors compared the baroreflex gain (BRG) measured by the phenylephrine technique (Phe-BRG) with BRG measured by the sequence technique (Seq-BRG) in 50 post-myocardial infarction patients (age: 52/spl plusmn/8 years, LVEF: 42/spl plusmn/12%). Correlation analysis was performed to assess the degree of linear relationship between Phe-BRG and Seq-BRG. The agreement was investigated computing the bias and the limits of agreement of the 2 measures and of the percentage difference between the 2 measures. The authors found a moderate degree of linear association (correlation coefficient=0.67). The bias was 2.2 ms/mmHg (p<0.05), indicating that on average, the sequence method gives a higher value for BRG than the phenylephrine test. The agreement was poor, as the limits of agreement were. -7.3+11.7 ms/mmHg. The corresponding percentage values were: 27% for the bias and -67+122% for the limits of agreement. These results indicate that using one method or the other can lead to significantly different results and that the 2 methods can be used as alternatives only for screening purposes.
Presents a new method for noninvasive assessment of baroreceptor sensitivity (BRS). Using this new method, BRS is estimated by linear regression analysis of the instantaneous values of BRS reordered into a logical, ascending sequence. The performance of the new method was compared with measurements of BRS by the traditional bolus phenylephrine method and other well-known non- invasive BRS assessment techniques, such as the "spontaneous sequences" and the "correlated modulus" methods, in 19 subjects. The BRS of the entire population was 8.31/spl plusmn/3.90 ms/mmHg for the phenylephrine method, 8.39/spl plusmn/4.21 ms/mmHg for the new method, and 12.6/spl plusmn/6.72 ms/mmHg for the spontaneous sequences method. However, estimation of BRS using the modulus method was only valid for five subjects (weighted coherence >0.5) with a BRS of 10.41/spl plusmn/4.18 ms/mmHg. The estimates of BRS derived from the four methods were significantly correlated for these five subjects. This result suggests that, with further refinements, the new method may be used for reliable non-invasive estimation of BRS.
In ten healthy volunteers, we assessed the effects produced by 2-min 12% O2breathing on the instantaneous time course of: arterial oxygen saturation (SaO2), respiratory frequency (RF), end-tidal CO2 (ETCO2), R-R intervals (RR), systolic pressure (SP), diastolic pressure (DP), pulse pressure (PP), maximal amplitude of arterial pressure derivative (dmAP), and, estimated by a time frequency distribution, their low frequency powers (LFRR, LFPPand LFdmAP) and high frequency powers of RR (HFRR) and respiration (HFRes) as well as baroreflex sensitivity (BRS) and respiratory sinus arrhythmia sensitivity RSAS) by alpha index. Mean SaO2of 82±2% provoked consistent response patterns in all variables: with 9-s latency, progressive decrease (p<; 0.002) until the end of LFdmAP, LFPP, RR, HFRR, RSAS, dmAP, ETCO2and BRS (36-s latency), and gradual increase (p<; 0.004) of RF; with 108-s latency, a sustained decrease (p<; 0.004) of SP and DP. Hypocapnic hypoxemia provokes: an immediate functional depression shown by gradual reductions of sympathetic and vagal activities that contribute to the progressive fall of RR, RSAS and BRS with unchanged arterial pressure, and, through chemoreflex activation, a progressive increase of RF; and later, via direct vasodilation, a reduction of arterial pressure.
The value of implementing mathematical models in Simulink is demonstrated through an overview of the challenges involved when determining the dynamic response of non-linear systems. This overview is demonstrated by using an example of the baroreceptor nerve (and its response to blood pressure changes) as a non-linear system which can be modelled and simulated in Simulink. The simulated results indicate that a comparison can be made to actual short-term experimental data and simulated data to validate the model. Thereafter, the simulated model can be tested using artificial long-term inputs which infer a non-linear system's dynamic response. This method would be valuable for any research or design where a non-linear physical system's dynamic response would be otherwise experimentally expensive or impossible.
An approach to dynamic scheduling is presented which draws inspiration from a biological control mechanism (the baroreceptor reflex). A simplified model of the reflex is proposed which validates known experimental results, and the nonlinear "scheduling" mechanism is analyzed for applications in automatic control.
Blood pressure variability was found to follow a 1/f behaviour. The aim of the authors' study was to verify whether this phenomenon was associated with a concomitant 1/f modulation of the baroreflex sensitivity. In 8 ambulant subjects, systolic blood pressure and pulse interval were continuously monitored for 24 hours and jointly analysed by a sequential procedure to obtain a dynamic estimation of baroreflex sensitivity over day and night. A single spectrum was estimated via FFT from each 24-h sensitivity profile and the presence of the 1/f pattern was evaluated by fitting such a spectrum by a 1/f curve. The authors' results indicate that the baroreflex sensitivity is characterised by marked and systematic short and long-term changes actually following a 1/f behaviour.<<ETX>>
The baroreflex system is the fastest mechanism in the body to regulate arterial pressure. Because the neural system (i.e., autonomic nervous system) mediates the baroreflex and the system operates under the closed-loop condition, the quantitative dynamic characteristics of the baroreflex system remained unknown until recently despite the fact that a countless number of observational and qualitative studies had been conducted. In order to develop the artificial baroreflex system, i.e., the bionic baroreflex system, we first anatomically isolated the carotid sinuses to open the baroreflex loop and identified the open-loop transfer function of the baroreflex system using white noise pressure perturbations. We found that the baroreflex system is basically a lowpass filter and remarkably linear. As an actuator to implement the bionic baroreflex system, we then stimulated the sympathetic efferent nerves at various parts of the baroreflex loop and identified the transfer functions from the stimulation sites to systemic arterial pressure. We found that the actuator responses can be described remarkably well with linear transfer functions. Since transfer functions of the native baroreflex and of the actuator were identified, the controller that is required to reproduce the native baroreflex transfer function can be easily derived from those transfer functions. To examine the performance of bionic baroreflex system, we implemented it animal models of baroreflex failure. The bionic baroreflex system restored normal arterial pressure regulation against orthostatic stresses that is indistinguishable from the native baroreflex system.
No standards are currently tagged "Baroreflex"