scholarly journals Age-Related Changes in Spontaneous Oscillations Assessed by Wavelet Transform of Cerebral Oxygenation and Arterial Blood Pressure Signals

2013 ◽  
Vol 33 (5) ◽  
pp. 692-699 ◽  
Author(s):  
Zengyong Li ◽  
Ming Zhang ◽  
Qing Xin ◽  
Site Luo ◽  
Ruofei Cui ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Wavelet Transform ◽  
Arterial Blood Pressure ◽  
Cerebral Oxygenation ◽  
Oxygenation Index ◽  
Elderly Subjects ◽  
Arterial Blood ◽  
Age Related ◽  
Spontaneous Oscillations ◽  
Young Subjects

The study aims to assess the spontaneous oscillations in elderly subjects based on the wavelet transform of cerebral oxygenation (CO) and arterial blood pressure (ABP) signals. Continuous recordings of near-infrared spectroscopy (NIRS) and ABP signals were obtained from simultaneous measurements in 20 young subjects (age: 27.3 ± 7.1 years) and 15 elderly subjects (age: 70.8 ± 5.1 years) at rest. Using spectral analysis based on wavelet transform, five frequency intervals were identified (I, 0.005 to 0.02 Hz; II, 0.02 to 0.06 Hz; III, 0.06 to 0.15 Hz; IV, 0.15 to 0.40 Hz; and V, 0.40 to 2.0 Hz). The average amplitudes of the Δ[HbO2] and tissue oxygenation index in intervals I to V and the relative amplitudes in intervals IV and V were significantly lower in elderly subjects than in young subjects ( P < 0.05). In addition, the relative amplitudes of the ABP in interval I were significantly lower in elderly subjects than in young subjects ( P = 0.016). The present findings suggest the presence of a cerebrovascular degenerative process caused by aging. Spontaneous oscillations in the CO could be used as an indicator of cerebrovascular changes and could be used to identify the risk for cerebrovascular degenerative processes.

Effect of ‘Autonomic Blockade’ on Cardiac β-Adrenergic Chronotropic Responsiveness in Healthy Young, Healthy Elderly and Endurance-Trained Elderly Subjects

1994 ◽  
Vol 87 (3) ◽  
pp. 297-302 ◽  
Author(s):  
G. A. Ford ◽  
O. F. W. James
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Geometric Mean ◽  
Cardiovascular Responses ◽  
The Elderly ◽  
Elderly Subjects ◽  
Healthy Elderly ◽  
Age Related ◽  
Autonomic Blockade ◽  
Young Subjects

1. Cardiac chronotropic responses to isoprenaline are reduced with ageing in man. It is unclear whether this is due to reduced cardiac β-adrenergic sensitivity or to age-associated differences in reflex cardiovascular responses to the vasodilatory effects of isoprenaline. Age-associated changes in physical activity are also reported to influence β-adrenergic sensitivity. 2. The aim of the present study was to determine the contribution of alterations in reflex changes in parasympathetic and sympathetic influences and physical fitness to the age-associated reduction in cardiac chronotropic responses to β-adrenergic agonists. 3. The effect of ‘autonomic blockade’ with atropine (40 μg/kg intravenously) and clonidine (4 μg/kg intravenously) on blood pressure, heart rate and chronotropic responses to intravenous bolus isoprenaline doses was determined in eight healthy young (mean age 21 years), nine healthy elderly (72 years) and 10 endurance-trained elderly (69 years) subjects. 4. Elderly subjects had a reduced increase in heart rate after atropine (young, 49 ± 9 beats/min; elderly, 36 ± 5 beats/min; endurance-trained elderly, 34 ± 12 beats/min; P < 0.01) and did not demonstrate the transient increase in systolic blood pressure after clonidine observed in young subjects (young, 11 ± 10 mmHg; elderly, −12 ± 16 mmHg; endurance-trained elderly, −18 ± 11 mmHg; P < 0.01). 5. Cardiac chronotropic sensitivity to isoprenaline after ‘autonomic blockade’ increased in the young but decreased in the elderly subjects. The isoprenaline dose that increased heart rate by 25 beats/min before and after autonomic blockade' was: young, before 1.6 μg, after 2.8 μg, P < 0.01 (geometric mean, paired test); elderly, before 6.9 μg, after 3.6 μg, P < 0.05; endurance-trained elderly, before 5.9 μg, after 4.0 μg, P < 0.05. Cardiac chronotropic sensitivity to isoprenaline was significantly reduced in elderly compared with young subjects before (P < 0.01) but was similar after (P = 0.09) ‘autonomic blockade’. Chronotropic sensitivity did not differ between healthy and endurance-trained elderly subjects before or after ‘autonomic blockade’. 6. The age-associated reduction in cardiac chronotropic responses to bolus isoprenaline is primarily due to an age-related reduction in the influence of reflex cardiovascular responses on heart rate and not to an age-related reduction in cardiac β-adrenergic sensitivity. Endurance training is not associated with altered β-adrenergic chronotropic sensitivity in the elderly. The transient pressor response to intravenously administered clonidine may be lost in ageing man.

scholarly journals Effects of β-adrenergic receptor agonists on drinking and arterial blood pressure in young and old rats

2011 ◽  
Vol 300 (4) ◽  
pp. R1001-R1008 ◽  
Author(s):  
Robert L. Thunhorst ◽  
Connie L. Grobe ◽  
Terry G. Beltz ◽  
Alan Kim Johnson
Keyword(s):  
Blood Pressure ◽  
Arterial Blood Pressure ◽  
Adrenergic Receptors ◽  
Adrenergic Receptor ◽  
Aged Rats ◽  
Middle Aged ◽  
Young Rats ◽  
Arterial Blood ◽  
Age Related ◽  
Old Rats

These experiments examined water-drinking and arterial blood pressure responses to β-adrenergic receptor activation in young (4 mo), “middle-aged” adult (12 mo), and old (29 mo) male rats of the Brown-Norway strain. We used isoproterenol to simultaneously activate β1- and β2-adrenergic receptors, salbutamol to selectively activate β2-adrenergic receptors, and the combination of isoproterenol and the β2-adrenergic receptor antagonist ICI 118,551 to stimulate only β1-adrenergic receptors. Animals received one of the drug treatments, and water drinking was measured for 90 min. About 1 wk later, animals received the same drug treatment for measurement of arterial blood pressure responses for 90 min. In some rats, levels of renin and aldosterone secretion in response to isoproterenol or salbutamol were measured in additional tests. Old and middle-aged rats drank significantly less after isoproterenol than did young rats and also had greater reductions in arterial blood pressure. Old and middle-aged rats drank significantly less after salbutamol than did young rats, although reductions in arterial blood pressure were equivalent across the ages. The β2-adrenergic antagonist ICI 118,551 abolished drinking after isoproterenol and prevented most of the observed hypotension. Renin secretion after isoproterenol and salbutamol was greater in young rats than in middle-aged rats, and wholly absent in old rats. Aldosterone secretion was reduced in old rats compared with young and middle-aged rats after treatment with isoproterenol, but not after treatment with salbutamol. In conclusion, there are age-related differences in β-adrenergic receptor-mediated drinking that can be explained only in part by age-related differences in renin secretion after β-adrenergic receptor stimulation.

scholarly journals Detection of Onset, Systolic Peak and Dicrotic Notch in Arterial Blood Pressure Pulses

2017 ◽  
Vol 50 (7-8) ◽  
pp. 170-176 ◽  
Author(s):  
Omkar Singh ◽  
Ramesh Kumar Sunkaria
Keyword(s):  
Blood Pressure ◽  
Wavelet Transform ◽  
Arterial Blood Pressure ◽  
Pressure Pulse ◽  
Data Set ◽  
Dicrotic Notch ◽  
Arterial Blood ◽  
Comparison Results ◽  
Empirical Wavelet Transform ◽  
Pressure Pulses

In this paper, we proposed an effective method for detecting fiducial points in arterial blood pressure pulses. An arterial blood pressure pulse normally consists of onset, systolic peak and dicrotic notch. Detection of fiducial points in blood pressure pulses is a critical task and has many potential applications. The proposed method employs empirical wavelet transform for locating the systolic peak and onset of blood pressure pulse. The proposed method first estimates the fundamental frequency of blood pressure pulse using empirical wavelet transform and utilizes the combination of the blood pressure pulse and the estimated frequency for locating onset and systolic peak. For dicrotic notch detection, it utilizes the first-order difference of blood pressure pulse. The algorithm was validated on various open-source databases and was tested on a data set containing 12,230 beats. Two benchmark parameters such as sensitivity and positive predictivity were used for the performance evaluation. The comparison results for accuracy of the detection of systolic peak, onset and dicrotic notch are reported. The proposed method attained a sensitivity and positive predictivity of 99.95% and 99.97%, respectively, for systolic peaks. For onsets, it attained a sensitivity and predictivity of 99.88% and 99.92%, respectively. For dicrotic notches, a sensitivity and positive predictivity of 98.98% and 98.81% were achieved, respectively.

scholarly journals Risk profile and hemodynamic characteristics in young subjects with high normal arterial blood pressure

2015 ◽  
Vol 47 (3) ◽  
pp. 9
Author(s):  
Julia Georgieva Nikolova ◽  
Mariana Bacelova ◽  
Petar Hrischev ◽  
Margarita Hadjieva ◽  
Petar Nikolov ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Arterial Blood Pressure ◽  
Risk Profile ◽  
Arterial Blood ◽  
Hemodynamic Characteristics ◽  
Young Subjects

scholarly journals Optic Nerve Head Blood Flow Autoregulation during Changes in Arterial Blood Pressure in Healthy Young Subjects

PLoS ONE ◽  
2013 ◽  
Vol 8 (12) ◽  
pp. e82351 ◽  
Author(s):  
Agnes Boltz ◽  
Reinhard Told ◽  
Katarzyna J. Napora ◽  
Stefan Palkovits ◽  
René M. Werkmeister ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Blood Flow ◽  
Optic Nerve ◽  
Arterial Blood Pressure ◽  
Optic Nerve Head ◽  
Arterial Blood ◽  
Young Subjects

APPLICATION OF THE DISCRETE WAVELET TRANSFORM FOR THE ROBUST DETECTION OF THE IMPULSIVE INCIDENCES: APPLICATION TO ARTERIAL BLOOD PRESSURE CHARACTERISTIC EVENTS DETECTION–DELINEATION

2011 ◽  
Vol 09 (05) ◽  
pp. 813-842 ◽  
Author(s):  
MOHAMMAD R. HOMAEINEZHAD ◽  
MOHAMMAD AGHAEE ◽  
HAMID NAJJARAN TOOSI ◽  
ALI GHAFFARI ◽  
REZA RAHMANI
Keyword(s):  
Blood Pressure ◽  
Wavelet Transform ◽  
Discrete Wavelet Transform ◽  
Arterial Blood Pressure ◽  
False Alarm Probability ◽  
Discrete Wavelet ◽  
Robust Detection ◽  
Dicrotic Notch ◽  
Arterial Blood ◽  
Events Detection

The major focus of this study is to describe the structure of a solution designed for robustly detecting and delineating the arterial blood pressure (ABP) signal events. To meet this end, first, the original ABP signal is pre-processed by application of à trous discrete wavelet transform (DWT) for extracting several dyadic scales. Then, a fixed sample size sliding window is moved on the appropriately selected scale and in each slid, six features namely as summation of the nonlinearly amplified Hilbert transform, summation of absolute first-order differentiation, summation of absolute second-order differentiation, curve length, area and variance of the excerpted segment are calculated. Then, all feature trends are normalized and utilized to construct a newly proposed principal components analyzed geometric index (PCAGI) (to be used as the segmentation decision statistic (DS)) by application of a linear orthonormal projection. After application of an adaptive-nonlinear transformation for making the DS baseline stationary, the histogram parameters of the enhanced DS are used to regulate the α-level Neyman–Pearson classifier for false alarm probability (FAP)-bounded delineation of the ABP events. In order to illustrate the capabilities of the presented algorithm, it was applied to all 18 subjects of the MIT-BIH Polysomnographic Database (359,000 beats) and the end-systolic and end-diastolic locations of the ABP signal as well as dicrotic notch pressure were extracted and values of sensitivity and positive predictivity Se = 99.86% and P+ = 99.95% were obtained for the detection of all ABP events. High robustness against measurement noises, acceptable detection-delineation accuracy of the ABP events in the presence of severe heart valvular and arrhythmic dysfunctions within a tolerable computational burden (processing time) and having no parameters dependency to the acquisition sampling frequency can be mentioned as the important merits and capabilities of the proposed PCAGI-based ABP events detection-segmentation algorithm.

Cerebral Oxygenation Non Invasive Monitoring in Traumatic Brain Injury - A Pilot Study

2017 ◽  
Vol 71 (2) ◽  
pp. 113-118
Author(s):  
Vesna Durnev ◽  
Venko Filipce ◽  
Aleksandra Gavrilovska Brzanov ◽  
Maja Mojsova Mijovska ◽  
Marina Temelkovska Stevanovska
Keyword(s):  
Blood Pressure ◽  
Arterial Blood Pressure ◽  
Brain Injuries ◽  
Cerebral Oxygenation ◽  
Traumatic Brain Injuries ◽  
Cerebral Oxygen ◽  
Invasive Monitoring ◽  
Non Invasive ◽  
Arterial Blood ◽  
Hemodynamic Profile

Abstract Introduction. Cerebral oxymetry obtained with Near Infrared Spectroscopy (NIRS) provides noninvasive monitoring of microvasculature in the brain allowing for early recognition and preventive treatment of impaired cerebral oxygenation in traumatic brain injuries. Optimizing cerebral oxygenation is advocated to improve outcome in traumatic brain injured (TBI) hence the goal of this study was to determine the benefit of non invasive monitoring of cerebral oxygenation. Methods. Noninvasive monitoring was conducted in fifteen patients with traumatic brain injury. The values and changes in cerebral oxymetry were analyzed and compared with others tracked parameters: Glasgow Coma Scale on admission to determine the severity of traumatic brain injuries, systolic arterial blood pressure, mean arterial blood pressure, pulse oxymetry, and regular laboratory test. Regional cerebral oxygenation was measured using cerebral oxymetar INVOS 5100 Somanetics®. Results. According to obtained data, we noticed that any change in hemodynamic profile directly influenced the regional cerebral oxygen saturation. Higher changes in values of 15 % and more from basal ones correlate with unfavorable outcome as neurologic sequels. Decreased values of rSO2 in our study were rectified with several simple interventions. In our cases parameter which was most prominent cause for disturbed rSO2 was decreased mean arterial blood pressure. Conclusion. Stable hemodynamic profile leads to optimized cerebral oxygenation. Monitoring the regional oxygen saturation influenced by several factors is important step for forehanded detection of adverse secondary brain injuries. NIRS technology as monitoring system has potential to have diagnostic value and enable right therapeutic decisions and consequently better prognosis in TBI. Continued study of the benefits of cerebral oxygen monitoring is warranted.

Spontaneous oscillations of arterial blood pressure, cerebral and peripheral blood flow in healthy and comatose subjects

1999 ◽  
Vol 21 (7) ◽  
pp. 665-669 ◽  
Author(s):  
Erhard W. Lang ◽  
Rolf R. Dieh ◽  
Lars Timmermann ◽  
Ralf Baron ◽  
Giinther Deusch ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Blood Flow ◽  
Arterial Blood Pressure ◽  
Peripheral Blood ◽  
Peripheral Blood Flow ◽  
Arterial Blood ◽  
Spontaneous Oscillations
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