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Cerebral autoregulation

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https://www.readbyqxmd.com/read/29028933/novel-method-for-intraoperative-assessment-of-cerebral-autoregulation-by-paced-breathing
#1
N H Sperna Weiland, J Hermanides, M W Hollmann, B Preckel, W J Stok, J J van Lieshout, R V Immink
Background: Cerebral autoregulation (CA) is the mechanism that maintains constancy of cerebral blood flow (CBF) despite variations in blood pressure (BP). Patients with attenuated CA have been shown to have an increased incidence of peri-operative stroke. Studies of CA in anaesthetized subjects are rare, because a simple and non-invasive method to quantify the integrity of CA is not available. In this study, we set out to improve non-invasive quantification of CA during surgery. For this purpose, we introduce a novel method to amplify spontaneous BP fluctuations during surgery by imposing mechanical positive pressure ventilation at three different frequencies and quantify CA from the resulting BP oscillations...
October 6, 2017: British Journal of Anaesthesia
https://www.readbyqxmd.com/read/29026526/recent-advances-in-cerebral-oximetry-assessment-of-cerebral-autoregulation-with-near-infrared-spectroscopy-myth-or-reality
#2
REVIEW
Anneliese Moerman, Stefan De Hert
In recent years, the feasibility of near-infrared spectroscopy to continuously assess cerebral autoregulation has gained increasing interest. By plotting cerebral oxygen saturation over blood pressure, clinicians can generate an index of autoregulation: the cerebral oximetry index (COx). Successful integration of this monitoring ability in daily critical care may allow clinicians to tailor blood pressure management to the individual patient's need and might prove to be a major step forward in terms of patient outcome...
2017: F1000Research
https://www.readbyqxmd.com/read/29025902/relative-contributions-of-systemic-hemodynamic-variables-to-cerebral-autoregulation-during-orthostatic-stress
#3
Hisao Yoshida, Jason W Hamner, Keita Ishibashi, Can Ozan Tan
Postural changes impair the ability of the cerebrovasculature to buffer against dynamic pressure fluctuations, but the mechanisms underlying this impairment have not been elucidated. We hypothesized that autoregulatory impairment may reflect the impact of static central volume shifts on hemodynamic factors other than arterial pressure (AP). In 14 young volunteers, we assessed the relation of fluctuations in cerebral blood flow (CBF) to those in AP, cardiac output, and CO2, during oscillatory lower body pressure (LBP) (±20 mmHg at 0...
October 12, 2017: Journal of Applied Physiology
https://www.readbyqxmd.com/read/28993802/glycemia-is-related-to-impaired-cerebrovascular-autoregulation-after-severe-pediatric-traumatic-brain-injury-a-retrospective-observational-study
#4
Adam M H Young, Hadie Adams, Joseph Donnelly, Mathew R Guilfoyle, Helen Fernandes, Mathew R Garnett, Marek Czosnyka, Peter Smielewski, Mark Plummer, Shruti Agrawal, Peter J Hutchinson
INTRODUCTION: A strong association exists between hyperglycemia and outcome in pediatric traumatic brain injury (TBI). Herein, we describe observations of serum markers of glucose metabolism in a cohort of pediatric TBI patients and how these variables are related to parameters of intracranial pathophysiology. METHODS: A retrospective analysis was performed on pediatric severe TBI patients admitted to Addenbrookes Hospital Paediatric Intensive Care Unit (PICU) between January 2001 and December 2013...
2017: Frontiers in Pediatrics
https://www.readbyqxmd.com/read/28991702/cerebral-autoregulation-is-preserved-in-multiple-sclerosis-patients
#5
Daniel Ferreira, Pedro Castro, Gonçalo Videira, João Pedro Filipe, Rosa Santos, Maria José Sá, Elsa Azevedo, Pedro Abreu
Multiple sclerosis (MS) is an inflammatory disease that may also be associated with vascular dysfunction. One master component of vascular regulation is cerebral autoregulation (CA). We aimed to investigate the integrity of CA in MS patients and study its relationship with autonomic dysfunction (AD), magnetic-resonance-imaging (MRI) lesion load and hemodynamic parameters. We enrolled 20 relapsing-remitting MS and 20 healthy subjects. CA was assessed by transfer function analysis parameters (coherence, gain and phase), as obtained in the very low, low and high-frequency domains (VLF, LF, HF, respectively)...
October 15, 2017: Journal of the Neurological Sciences
https://www.readbyqxmd.com/read/28979042/cerebral-oximetry-and-autoregulation-during-cardiopulmonary-bypass-a-review
#6
REVIEW
Nousjka P A Vranken, Patrick W Weerwind, Nadia A Sutedja, Ervin E Ševerdija, Paul J C Barenbrug, Jos G Maessen
Postoperative neurological complications (PNCs) following cardiac surgery with cardiopulmonary bypass (CPB) is a detrimental complication, contributing to increased mortality rates and health care costs. To prevent intraoperative cerebral desaturations associated with PNC, continuous brain monitoring using near-infrared spectroscopy has been advocated. However, clear evidence for a defined desaturation threshold requiring intervention during CPB is still lacking. Since cerebral oximetry readings are nonspecific, cerebral tissue oxygenation values need to be interpreted with caution and in the context of all available clinical information...
September 2017: Journal of Extra-corporeal Technology
https://www.readbyqxmd.com/read/28974996/monitoring-pressure-augmentation-in-patients-with-ischemic-penumbra-using-continuous-electroencephalogram-three-cases-and-a-review-of-the-literature
#7
Christopher R Newey, Vikas Gupta, Agnieszka A Ardelt
BACKGROUND: Continuous electroencephalography (CEEG) is a sensitive, noninvasive surrogate monitor of cerebral blood flow (CBF). Changes in CBF can be seen as changes in the frequencies on the CEEG. This case series suggests that increase in CEEG frequencies may be used to detect improved CBF following pressure augmentation such as with treatment of vasospasm from subarachnoid hemorrhage (SAH) or acute thrombosis from ischemic stroke. The application of this observation to clinical decision-making has not been clearly defined and requires further study...
October 2017: Neurohospitalist
https://www.readbyqxmd.com/read/28972197/coherent-averaging-of-pseudorandom-binary-stimuli-is-the-dynamic-cerebral-autoregulatory-response-symmetrical
#8
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
https://www.readbyqxmd.com/read/28949271/pressure-passivity-of-cerebral-mitochondrial-metabolism-is-associated-with-poor-outcome-following-perinatal-hypoxic-ischemic-brain-injury
#9
Subhabrata Mitra, Gemma Bale, David Highton, Roxanna Gunny, Cristina Uria-Avellanal, Alan Bainbridge, Magdalena Sokolska, David Price, Angela Huertas-Ceballos, Giles S Kendall, Judith Meek, Ilias Tachtsidis, Nicola J Robertson
Hypoxic ischemic encephalopathy (HIE) leads to significant morbidity and mortality. Impaired autoregulation after hypoxia-ischaemia has been suggested to contribute further to injury. Thalamic lactate/N-Acetylasperate (Lac/NAA) peak area ratio of > 0.3 on proton ((1)H) magnetic resonance spectroscopy (MRS) is associated with poor neurodevelopment outcome following HIE. Cytochrome-c-oxidase (CCO) plays a central role in mitochondrial oxidative metabolism and ATP synthesis. Using a novel broadband NIRS system, we investigated the impact of pressure passivity of cerebral metabolism (CCO), oxygenation (haemoglobin difference (HbD)) and cerebral blood volume (total haemoglobin (HbT)) in 23 term infants following HIE during therapeutic hypothermia (HT)...
January 1, 2017: Journal of Cerebral Blood Flow and Metabolism
https://www.readbyqxmd.com/read/28933655/cerebrovascular-reactivity-measurement-in-cerebral-small-vessel-disease-rationale-and-reproducibility-of-a-protocol-for-mri-acquisition-and-image-processing
#10
Michael J Thrippleton, Yulu Shi, Gordon Blair, Iona Hamilton, Gordon Waiter, Christian Schwarzbauer, Cyril Pernet, Peter Jd Andrews, Ian Marshall, Fergus Doubal, Joanna M Wardlaw
Background Impaired autoregulation may contribute to the pathogenesis of cerebral small vessel disease. Reliable protocols for measuring microvascular reactivity are required to test this hypothesis and for providing secondary endpoints in clinical trials. Aims To develop and assess a protocol for acquisition and processing of cerebrovascular reactivity by MRI, in subcortical tissue of patients with small vessel disease and minor stroke. Methods We recruited 15 healthy volunteers, testing paradigms using 1- and 3-min 6% CO2 challenges with repeat scanning, and 15 patients with history of minor stroke...
January 1, 2017: International Journal of Stroke: Official Journal of the International Stroke Society
https://www.readbyqxmd.com/read/28925890/the-use-of-hemodynamic-and-cerebral-monitoring-to-study-pharmacodynamics-in-neonates
#11
A Smits, L Thewissen, A Dereymaeker, E Dempsey, A Caicedo, Gunnar Naulaers
BACKGROUND: Drugs acting on the cardiovascular and central nervous system often display relatively fast clinical responses, which may differ in neonates compared to children and adults. Introduction of bedside monitoring tools might be of additional value in the pharmacodynamic (PD) assessment of such drugs in neonates. METHODS: We aim to provide an overview of the frequently used monitoring tools to assess drug effects on the hemodynamic status as well as the cerebral circulation, oxygenation and cerebral metabolism in neonates...
September 18, 2017: Current Pharmaceutical Design
https://www.readbyqxmd.com/read/28912128/aging-modifies-the-effect-of-cardiac-output-on-middle-cerebral-artery-blood-flow-velocity
#12
Anne-Sophie G T Bronzwaer, Jasper Verbree, Wim J Stok, Mat J A P Daemen, Mark A van Buchem, Matthias J P van Osch, Johannes J van Lieshout
An association between cerebral blood flow (CBF) and cardiac output (CO) has been established in young healthy subjects. As of yet it is unclear how this association evolves over the life span. To that purpose, we continuously recorded mean arterial pressure (MAP; finger plethysmography), CO (pulse contour; CO-trek), mean blood flow velocity in the middle cerebral artery (MCAV; transcranial Doppler ultrasonography), and end-tidal CO2 partial pressure (PetCO2) in healthy young (19-27 years), middle-aged (51-61 years), and elderly subjects (70-79 years)...
September 2017: Physiological Reports
https://www.readbyqxmd.com/read/28904458/can-transcranial-color-doppler-spectral-signatures-be-a-novel-biomarker-for-monitoring-cerebrovascular-autoregulation-and-intracranial-pressure-a-speculative-synthesis
#13
Sandhya Mangalore, Kotresh, Rakshith Srinivasa, Alangar Sathyaranjandas Hegde, Rangashetty Srinivasa
BACKGROUND: Trans Cranial Colour Doppler (TCCD) has been extensively used in various neurological and neurosurgical conditions causing severe raise in the intracranial pressure (ICP). MATERIAL AND METHOD: Our study explores the sequential evolution of TCCD flow pattern by correlating with pupillary reactivity, Glasgow coma scale (GCS), and imaging. Our cohort consisted of thirty patients with ten patients in each subgroup admitted to the neuro-Intensive Care Unit (NICU) for various neurological and neurosurgical causes...
July 2017: Annals of Indian Academy of Neurology
https://www.readbyqxmd.com/read/28902182/gestational-age-dependent-relationship-between-cerebral-oxygen-extraction-and-blood-pressure
#14
Zachary A Vesoulis, Steve M Liao, Amit M Mathur
BackgroundPremature infants may lack mature cerebrovascular autoregulatory function and fail to adapt oxygen extraction to decreasing systemic perfusion.MethodsInfants ≤28 weeks of gestational age (GA) were recruited. Systemic oxygen saturation (SpO2), mean arterial blood pressure (MABP), and cerebral saturation (near-infrared spectroscopy, SctO2) were measured continuously over the first 72 h. Resulting data underwent error-processing. For each remaining 10 m window, the mean MABP and fractional tissue oxygen extraction (FTOE) were calculated...
September 13, 2017: Pediatric Research
https://www.readbyqxmd.com/read/28887332/the-cerebro-cardiovascular-response-to-periodic-squat-stand-maneuvers-in-healthy-subjects-a-time-domain-analysis
#15
Sam C Barnes, Naomi Ball, Victoria Joanna Haunton, Thompson G Robinson, Ronney B Panerai
BACKGROUND: Squat-stand maneuvers (SSMs) have been used to improve the coherence of transfer function analysis (TFA) estimates during the assessment of dynamic cerebral autoregulation (dCA). There is a need to understand the influence of peripheral changes resulting from SSMs on cerebral blood flow, which might confound estimates of dCA. METHODS: 29 healthy subjects underwent recordings at rest (5 min standing) and 15 SSMs (0.05Hz). Heart rate (3-lead ECG), end-tidal CO2 (capnography), blood pressure (Finometer), cerebral blood velocity (CBV, transcranial Doppler, MCA) and the angle of the thigh (tilt sensor) were measured continuously...
September 8, 2017: American Journal of Physiology. Heart and Circulatory Physiology
https://www.readbyqxmd.com/read/28884722/-severe-carotid-stenosis-cerebral-autoregulation-in-the-ipsilateral-region
#16
V B Semenyutin, G А Asaturyan, А А Nikiforova, G К Panuntsev, V A Aliev, V B Iblyaminov, A V Savello, А Patzak, K V Laptev, I P Dudanov, О А Pavlov
AIM: To study cerebral autoregulation (CA) in region of the stenotic carotid artery. MATERIAL AND METHODS: The study involved 35 patients with critical stenosis of the carotid arteries, including 24 patients were asymptomatic and 11 patients with symptomatic course. Blood flow velocity in middle cerebral arteries was monitored using Multi Dop X (DWL, Germany) with simultaneous noninvasive systemic blood pressure registration (CNAP, Austria). CA was assessed by calculating the phase shift (PS) between spontaneous oscillations of blood flow velocity and blood pressure within the range of systemic Mayer waves (80-120 mHz)...
2017: Zhurnal Nevrologii i Psikhiatrii Imeni S.S. Korsakova
https://www.readbyqxmd.com/read/28880397/transcranial-doppler-a-stethoscope-for-the-brain-neurocritical-care-use
#17
REVIEW
Chiara Robba, Danilo Cardim, Mypinder Sekhon, Karol Budohoski, Marek Czosnyka
Transcranial Doppler (TCD) ultrasonography is a noninvasive bedside monitoring technique that can evaluate cerebral blood flow hemodynamics in the intracranial arterial vasculature. TCD allows assessment of linear cerebral blood flow velocity, with a high temporal resolution and is inexpensive, reproducible, and portable. The aim of this review is to provide an overview of the most commonly used TCD derived signals and measurements used commonly in neurocritical care. We describe both basic (flow velocity, pulsatility index) and advanced concepts, including critical closing pressure, wall tension, autoregulation, noninvasive intracranial pressure, brain compliance, and cerebrovascular time constant; we also describe the clinical applications of TCD to highlight their utility in the diagnosis and monitoring of cerebrovascular diseases as the "stethoscope for the brain...
September 7, 2017: Journal of Neuroscience Research
https://www.readbyqxmd.com/read/28871418/time-spent-with-impaired-autoregulation-is-linked-with-outcome-in-severe-infant-paediatric-traumatic-brain-injury
#18
Konstantin Hockel, Jennifer Diedler, Felix Neunhoeffer, Ellen Heimberg, Carmen Nagel, Martin U Schuhmann
BACKGROUND: It could be shown in traumatic brain injury (TBI) in adults that the functional status of cerebrovascular autoregulation (AR), determined by the pressure reactivity index (PRx), correlates to and even predicts outcome. We investigated PRx, cerebral perfusion pressure (CPP) and intracranial pressure (ICP) and their correlation to outcome in severe infant and paediatric TBI. METHODS: Seventeen patients (range, 1 day to 14 years) with severe TBI (median GCS at presentation, 4) underwent long-term computerised ICP and mean arterial pressure (MAP) monitoring using dedicated software to determine CPP and PRx and optimal CPP (CPP level where PRx shows best autoregulation) continuously...
September 4, 2017: Acta Neurochirurgica
https://www.readbyqxmd.com/read/28860964/inter-individual-relationships-between-sympathetic-arterial-baroreflex-function-and-cerebral-perfusion-control-in-healthy-males
#19
Trevor Witter, Yu-Chieh Tzeng, Terry O'Donnell, Jessica Kusel, Bridget Walker, Mary Berry, Chloe E Taylor
Maintenance of adequate cerebral perfusion during normal physiological challenges requires integration between cerebral blood flow (CBF) and systemic blood pressure control mechanisms. Previous studies have shown that cardiac baroreflex sensitivity (BRS) is inversely related to some measures of cerebral autoregulation. However, interactions between the sympathetic arterial baroreflex and cerebral perfusion control mechanisms have not been explored. To determine the nature and magnitude of these interactions we measured R-R interval, blood pressure, CBF velocity, and muscle sympathetic nerve activity (MSNA) in 11 healthy young males...
2017: Frontiers in Neuroscience
https://www.readbyqxmd.com/read/28840161/impairment-of-cerebral-autoregulation-in-pediatric-extracorporeal-membrane-oxygenation-associated-with-neuroimaging-abnormalities
#20
Fenghua Tian, Michael Craig Morriss, Lina Chalak, Ramgopal Venkataraman, Chul Ahn, Hanli Liu, Lakshmi Raman
Extracorporeal membrane oxygenation (ECMO) is a life-supporting therapy for critically ill patients with severe respiratory and/or cardiovascular failure. Cerebrovascular impairment can result in hemorrhagic and ischemic complications commonly seen in the patients supported on ECMO. We investigated the degree of cerebral autoregulation impairment during ECMO as well as whether it is predictive of neuroimaging abnormalities. Spontaneous fluctuations of mean arterial pressure (MAP) and cerebral tissue oxygen saturation ([Formula: see text]) were continuously measured during the ECMO run...
October 2017: Neurophotonics
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