Evaluation of reproducibility of spontaneous baroreflex sensitivity at rest and during laboratory tests

Iellamo, Ferdinando; Legramante, Jacopo M.; Raimondi, Gianfranco; Castrucci, Filippo; Massaro, Michele; Peruzzi, G

doi:10.1097/00004872-199609000-00009

Cited by 134 publications

(126 citation statements)

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“…Indices of autonomic circulatory control have been shown by our group and numerous other investigators to be quite stable over time and between study days at baseline conditions in a variety of study populations. 19,[23][24][25] For this reason a time control group was not justified, and the changes in measurements over time can be assumed to be due primarily to drug effects at the different infusion rates. In addition, although the investigators administering the protocol were unblinded and could have been biased in the assignment of sedation scores, the drug infusion scheme was designed to target specific plasma concentrations, rather than titrating to sedation score.…”

Section: Methodsmentioning

confidence: 99%

Autonomic circulatory and cerebrocortical responses during increasing depth of propofol sedation/hypnosis in humans

Lafreniere

Milne

Brunet

et al. 2000

Can J Anesth/J Can Anesth

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Purpose: To describe the relative effects of graded central nervous system (CNS) depression, using increasing propofol infusion rates, on neurovegetative brainstem-mediated circulatory control mechanisms and higher cortical activity in healthy humans.Methods: Propofol was administered using an infusion scheme designed to achieve three target blood concentrations in ten healthy volunteers. Blood propofol concentrations and sedation scores were determined at baseline, during the three propofol infusion levels, and 30 min into the recovery period. Electroencephalographic (EEG) power was measured in three frequency bands to quantify cortical activity, and autonomic heart rate control was quantified using spontaneous baroreflex assessment and power spectral analysis of pulse interval. Results: Sedation scores closely paralleled propofol blood concentrations (0, 0.53 ± 0.34, 1.24 ± 0.21, 3.11 ± 0.80, and 0.96 ± 0.42 µg·mL -1 at baseline, three infusion levels and recovery respectively), and all subjects were unconscious at the deepest level. Indices of autonomic heart rate control were decreased only at the deepest levels of CNS depression, while EEG effects were apparent at all propofol infusion rates. These EEG effects were frequency specific, with power in the beta band being affected at light levels of sedation, and alpha and delta power altered at deeper levels. Conclusions: The results of this study support a relative preservation of neurovegetative circulatory control mechanisms during the early stages of CNS depression using gradually increasing rates of infusion of propofol. Indices of circulatory control did not reliably reflect depth of sedation.Objectif : Décrire les effets relatifs d'une dépression graduée du système nerveux central (SNC) sur les mécanismes d'origine centrale du contrôle neurovégétatif de la circulation, et l'activité corticale supérieure chez des humains sains, en utilisant des perfusions de propofol à vitesses croissantes. Méthode : Le propofol a été administré, chez dix volontaires en santé, selon un schéma de perfusion conçu pour atteindre trois concentrations sanguines cibles. Les concentrations sanguines de propofol et les scores de sédation ont été déterminés au départ, pendant les trois régimes de perfusion de propofol et à 30 min pendant la récupéra-tion. La puissance électroencéphalographique (EEG) a été mesurée selon trois bandes fréquentielles pour quantifier l'activité corticale, et le contrôle autonome de la fréquence cardiaque a été mesuré à l'aide d'une évaluation baroréflexe spontanée et de l'analyse spectrale de la puissance de l'intervalle pulsé.Résultats : Les scores de sédation ont présenté un étroit parallélisme avec les concentrations sanguines de propofol (0; 0,53 ± 0,34, 1,24 ± 0,21; 3,11 ± 0,80, et 0,96 ± 0,42 µg·mL -1 au début, pendant les trois perfusions et la récupération, respectivement), et tous les sujets ont connu un profond sommeil. Les indices de contrôle autonome de la fréquence cardiaque ont diminué seulement au moment de la plus profonde dépression d...

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Section: Methodsmentioning

confidence: 99%

Autonomic circulatory and cerebrocortical responses during increasing depth of propofol sedation/hypnosis in humans

Lafreniere

Milne

Brunet

et al. 2000

Can J Anesth/J Can Anesth

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“…Because S-BRS is partly derived from SBP determination, any estimate of its time evolution is limited by the time evolution of the BP signal. Because S-BRS is reproducible in the short term 15,[23][24][25] and has a predictable evolution in the long term, S-BRS can be considered an intrinsic characteristic of each subject and therefore used in research studies and clinical practice.…”

Section: Figure 1 Correlations Between Age and S-brs At Inclusion (Amentioning

confidence: 99%

Aging Process on Spectrally Determined Spontaneous Baroreflex Sensitivity

et al. 2007

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Abstract-The interindividual age-related decrease in baroreflex sensitivity (BRS) was reported in many cross-sectional studies. However, the long-term intraindividual decrease in BRS has never been confirmed by longitudinal studies. Data obtained from a 5-year prospective study designed to assess the 5-year stress effects on blood pressure (BP) provided the opportunity to assess longitudinal aging process on spectrally determined BRS (S-BRS) using the cross spectral analysis. This analysis was carried out in 205 men aged between 18 and 50 years who had 2 valid beat to beat BP recordings (Finapress) at a mean 5-year interval. At inclusion and at end of follow-up, S-BRS was significantly correlated with age (rϭϪ0. 50, PϽ0.001, rϭϪ0.33, PϽ0.001 respectively). Interestingly, the slopes and the intercepts were not significantly different at a 5-year interval. This result is in favor of the good reproducibility of S-BRS. The attenuation with age of S-BRS was calculated at 3.6% a year. This decrease was slightly higher than the one obtained with the baseline data (2.3% per year). This longitudinal study provided, for the first time, an estimate of the slope of the age-related physiological S-BRS decrease in a mid-aged healthy male population. Our findings reinforce the interest of evaluating spontaneous BRS reported to predict hypertension and cardiovascular events in various populations. Key Words: mental stress Ⅲ baroreflex Ⅲ hypertension Ⅲ blood pressure Ⅲ reproducibility B aroreflex sensitivity (BRS) is a relevant index of the autonomic control of blood pressure (BP). Historically, BRS was determined using drug-induced BP and heart rate (HR) opposite variations. More recently, noninvasive techniques of determining spontaneous BRS have been implemented, 1-3 the spectral method being one of the most popular. The spectral determination of BRS (S-BRS) is a reliable measure of BRS because it has often been reported to be correlated with the pharmacologically determined BRS. 4 -7 S-BRS is easy to determine, and repeated measures are easy to make. Aging process on S-BRS has already been reported in several cross sectional studies. 8 -12 Such studies only report interindividual S-BRS variation with age. Thus, S-BRS has consistently been reported to decrease with age. Physiological aging in men was associated with a marked reduction in baroreflex buffering. A differential aging process on baroreflex buffering BP and cardiovagal baroreflex was reported. 10 The decrease in baroreflex buffering with aging was related to an increase in basal sympathetic nerve activity and to a reduction in systemic Alpha1-adrenergic vascular responsiveness whereas the decrease in cardiovagal baroreflex was related to a decrease in parasympathetic pathways. 10,13 However, to our knowledge, the intraindividual BRS alteration with age has never been reported. For that purpose, we analyzed the S-BRS 5-year aging process in a cohort of 205 healthy young men. This unique data set was extracted from a 5-year follow-up study designed to assess stress ...

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“…14,15 Briefly, the mean slope of spontaneous sequences of consecutive beats characterized by systolic blood pressure (SBP) and RRI changing in the same direction (either increasing, ie, up-sequences or decreasing, ie, down-sequences) was calculated and taken as a measure of the integrated baroreflex sensitivity (BRS). 16 …”

Section: Spontaneous Baroreflex Analysismentioning

confidence: 99%

Baroreflex Buffering of Sympathetic Activation During Sleep

et al. 2004

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Abstract--We examined the effects of sleep microstructure, ie, the cyclic alternating pattern (CAP), on heart rate (HR)-and blood pressure (BP)-regulating mechanisms and on baroreflex control of HR in healthy humans and tested the hypothesis that sympathetic activation occurring in CAP epochs during non-rapid eye movement (non-REM) sleep periods is buffered by the arterial baroreflex. Ten healthy males underwent polysomnography and simultaneous recording of BP, ECG, and respiration. Baroreflex sensitivity (BRS) was calculated by the sequences method. Autoregressive power spectral analysis was used to investigate R-R interval (RRI) and BP variabilities. During overall non-REM sleep, BP decreased and RRI increased in comparison to wakefulness, with concomitant decreases in low-frequency RRI and BP oscillations and increases in high-frequency RRI oscillations. These changes were reversed during REM to wakefulness levels, with the exception of RRI. During CAP, BP increased significantly in comparison to non-CAP and did not differ from REM and wakefulness. The low-frequency component of BP variability was significantly higher during CAP than non-CAP. RRI and its low-frequency spectral component did not differ between CAP and non-CAP. BRS significantly increased during CAP in comparison to non-CAP. BRS was not different during CAP and REM and was greater during both in comparison with the awake state. Even during sleep stages, like non-REM sleep, characterized by an overall vagal predominance, phases of sustained sympathetic activation do occur that resemble that occurring during REM. Throughout the overnight sleep period, the arterial baroreflex acts to buffer surges of sympathetic activation by means of rapid changes in cardiac vagal circuits.

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Evaluation of reproducibility of spontaneous baroreflex sensitivity at rest and during laboratory tests

Cited by 134 publications

References 0 publications

Autonomic circulatory and cerebrocortical responses during increasing depth of propofol sedation/hypnosis in humans

Autonomic circulatory and cerebrocortical responses during increasing depth of propofol sedation/hypnosis in humans

Aging Process on Spectrally Determined Spontaneous Baroreflex Sensitivity

Baroreflex Buffering of Sympathetic Activation During Sleep

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