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Cerebral autoregulation

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https://www.readbyqxmd.com/read/28522231/large-amount-of-cannabis-ingestion-resulting-in-spontaneous-intracerebral-hemorrhage-a-case-report
#1
Kunakorn Atchaneeyasakul, Luis F Torres, Amer M Malik
Although multiple cases of cannabis-associated ischemic stroke have been reported, there are only 2 reported cases of hemorrhagic stroke with an associated cerebral vasoconstriction. To our knowledge, we present the first case of basal ganglia hemorrhage after a large-volume oral ingestion of cannabis without other identified risk factors. In our case, cerebral digital subtraction angiography within 24 hours of presentation did not reveal vasoconstriction leading to a possible alternative explanation for hemorrhagic stroke, including cannabis-induced transient arterial hypertension and autoregulation disruption...
May 15, 2017: Journal of Stroke and Cerebrovascular Diseases: the Official Journal of National Stroke Association
https://www.readbyqxmd.com/read/28497934/cerebral-autoregulation-monitoring-in-acute-traumatic-brain-injury-what-s-the-evidence
#2
Leanne A Calviello, Joseph Donnelly, Frederick A Zeiler, Eric P Thelin, Peter Smielewski, Marek Czosnyka
Cerebral autoregulation is conceptualized as a vascular self-regulatory mechanism within the brain. Controlled by elusive relationships between various biophysical processes, it functions to protect the brain against potential damages caused by sudden changes in cerebral perfusion pressures and flow. Following events such as traumatic brain injuries (TBI), autoregulation may be compromised, potentially leading to an unfavorable outcome. In spite of its complexity, autoregulation has been able to be quantified non-invasively within the neuro-critical care setting with the aid of transcranial Doppler...
May 12, 2017: Minerva Anestesiologica
https://www.readbyqxmd.com/read/28486883/monitoring-of-optimal-cerebral-perfusion-pressure-in-traumatic-brain-injured-patients-using-a-multi-window-weighting-algorithm
#3
Xiuyun Liu, Natasha M Maurits, Marcel J H Aries, Marek Czosnyka, Ari Ercole, Joseph Donnelly, Danilo Cardim, Dong-Joo Kim, Celeste Dias, Manuel Cabeleira, Peter Smieleweski
Methods to identify an autoregulation guided 'optimal' cerebral perfusion pressure (CPPopt) for traumatic brain injury patients (TBI) have been reported through several studies. An important drawback of existing methodology is that CPPopt can be calculated only in approximately 50-60% of the monitoring time. In this study, we hypothesized that the CPPopt yield and the continuity can be improved significantly through application of a multi-window and weighting calculation algorithm, without adversely affecting preservation of its prognostic value...
May 9, 2017: Journal of Neurotrauma
https://www.readbyqxmd.com/read/28479402/tight-neurovascular-coupling-in-the-spinal-cord-during-nociceptive-stimulation-in-intact-and-spinal-rats
#4
Mathieu Piché, Thierry Paquette, Hugues Leblond
Functional magnetic resonance imaging (fMRI) is based on neurovascular coupling, which allows inferring neuronal activity from hemodynamic changes. Spinal fMRI has been used to examine pain processes, although spinal neurovascular coupling has never been investigated. In addition, fluctuations in mean arterial pressure (MAP) occur during nociceptive stimulation and this may affect neurovascular coupling. The objective of this study was to examine neurovascular coupling in the rat spinal cord during nociceptive stimulation while MAP was manipulated by cervical spinal transection, which prevents nociception-related MAP increases...
May 4, 2017: Neuroscience
https://www.readbyqxmd.com/read/28475214/the-angiotensin-ii-receptor-type-1b-is-the-primary-sensor-of-intraluminal-pressure-in-cerebral-artery-smooth-muscle-cells
#5
Paulo W Pires, Eun-A Ko, Harry A T Pritchard, Michael Rudokas, Evan Yamasaki, Scott Earley
Myogenic vasoconstriction, which reflects the intrinsic ability of smooth muscle cells to contract in response to increases in intraluminal pressure, is critically important for the autoregulation of blood flow. In SMC from cerebral arteries, increasing intraluminal pressure engages a signalling cascade that stimulates cation influx through transient receptor potential (TRP) melastatin 4 (TRPM4) channels to cause membrane depolarization and vasoconstriction. Substantial evidence indicates that the angiotensin II receptor type 1 (AT1 R) is inherently mechanosensitive and initiates this signalling pathway...
May 5, 2017: Journal of Physiology
https://www.readbyqxmd.com/read/28471439/relationships-between-cerebral-autoregulation-and-markers-of-kidney-and-liver-injury-in-neonatal-encephalopathy-and-therapeutic-hypothermia
#6
J K Lee, J Perin, C Parkinson, M O'Connor, M M Gilmore, M Reyes, J Armstrong, J M Jennings, F J Northington, R Chavez-Valdez
OBJECTIVE: We studied whether cerebral blood pressure autoregulation and kidney and liver injuries are associated in neonatal encephalopathy (NE). STUDY DESIGN: We monitored autoregulation of 75 newborns who received hypothermia for NE in the neonatal intensive care unit to identify the mean arterial blood pressure with optimized autoregulation (MAPOPT). Autoregulation parameters and creatinine, aspartate aminotransferase (AST) and alanine aminotransferase (ALT) were analyzed using adjusted regression models...
May 4, 2017: Journal of Perinatology: Official Journal of the California Perinatal Association
https://www.readbyqxmd.com/read/28463046/the-influence-of-hyperthermia-on-intracranial-pressure-cerebral-oximetry-and-cerebral-metabolism-in-traumatic-brain-injury
#7
Lena Nyholm, Tim Howells, Anders Lewén, Lars Hillered, Per Enblad
BACKGROUND: Hyperthermia is a common secondary insult in traumatic brain injury (TBI). The aim was to evaluate the relationship between hyperthermia and intracranial pressure (ICP), and if intracranial compliance and cerebral blood flow (CBF) pressure autoregulation affected that relationship. The relationships between hyperthermia and cerebral oximetry (BtipO2) and cerebral metabolism were also studied. METHODS: A computerized multimodality monitoring system was used for data collection at the neurointensive care unit...
May 2, 2017: Upsala Journal of Medical Sciences
https://www.readbyqxmd.com/read/28443830/paco-sub-2-sub-measurement-in-cerebral-haemodynamics-face-mask-or-nasal-cannulae
#8
Jatinder Singh Minhas, Thompson Robinson, Ronney Panerai
Objective PaCO2 affects cerebral blood flow (CBF) and its regulatory mechanisms, but the effects of CO2 measurement technique on cerebrovascular parameters are unknown. In order to determine if the two most commonly used approaches, face mask (FM) or nasal cannulae (NC), are interchangeable or not, we tested the hypothesis that the use of FM versus NC does not lead to significant differences in CO2-related systemic and cerebrovascular parameters. Approach Recordings of CBF velocity (CBFV), blood pressure (BP), heart rate, and end-tidal CO2 (EtCO2) were performed in 42 subjects during normocapnia (FM or NC) and 5% CO2 inhalation (FM) or hyperventilation (NC)...
April 26, 2017: Physiological Measurement
https://www.readbyqxmd.com/read/28421173/cerebral-autoregulation-brain-injury-and-the-transitioning-premature-infant
#9
REVIEW
Zachary A Vesoulis, Amit M Mathur
Improvements in clinical management of the preterm infant have reduced the rates of the two most common forms of brain injury, such as severe intraventricular hemorrhage and white matter injury, both of which are contributory factors in the development of cerebral palsy. Nonetheless, they remain a persistent challenge and are associated with a significant increase in the risk of adverse neurodevelopment outcomes. Repeated episodes of ischemia-reperfusion represent a common pathway for both forms of injury, arising from discordance between systemic blood flow and the innate regulation of cerebral blood flow in the germinal matrix and periventricular white matter...
2017: Frontiers in Pediatrics
https://www.readbyqxmd.com/read/28416148/alterations-in-autonomic-cerebrovascular-control-after-spinal-cord-injury
#10
Dong-Il Kim, Can Ozan Tan
Among chronic cardiovascular and metabolic sequelae of spinal cord injury (SCI) is an up-to four-fold increase in the risk of ischemic and hemorrhagic stroke, suggesting that individuals with SCI cannot maintain stable cerebral perfusion. In able-bodied individuals, the cerebral vasculature is able to regulate cerebral perfusion in response to swings in arterial pressure (cerebral autoregulation), blood gases (cerebral vasoreactivity), and neural metabolic demand (neurovascular coupling). This ability depends, at least partly, on intact autonomic function, but high thoracic and cervical spinal cord injuries result in disruption of sympathetic and parasympathetic cerebrovascular control...
April 4, 2017: Autonomic Neuroscience: Basic & Clinical
https://www.readbyqxmd.com/read/28411965/dynamic-cerebral-autoregulation-assessment-using-extracranial-internal-carotid-artery-doppler-ultrasonography
#11
Nai-Fang Chi, Hsiao-Lun Ku, Chen-Yen Wang, Yanhui Liu, Lung Chan, Ying-Chin Lin, Chung-Kang Peng, Vera Novak, Han-Hwa Hu, Chaur-Jong Hu
Transcranial Doppler ultrasonography of the middle cerebral artery (MCA) is frequently used to assess dynamic cerebral autoregulation (dCA); however, this is difficult in patients with poor temporal bone windows. In the study described here, we investigated the agreement and sensitivity of dCA indices determined from the extracranial internal carotid artery (ICA) and those determined from the MCA. Measurements for 32 stroke patients and 59 controls were analyzed. Measurement of the mean flow correlation index (Mx) and transfer function analysis based on spontaneous blood pressure fluctuation were simultaneously performed for the extracranial ICA and MCA...
April 12, 2017: Ultrasound in Medicine & Biology
https://www.readbyqxmd.com/read/28404769/a-decrease-in-blood-pressure-is-associated-with-unfavorable-outcome-in-patients-undergoing-thrombectomy-under-general-anesthesia
#12
Kilian M Treurniet, Olvert A Berkhemer, Rogier V Immink, Hester F Lingsma, Vivian M C Ward-van der Stam, Markus W Hollmann, Jaap Vuyk, Wim H van Zwam, Aad van der Lugt, Robert J van Oostenbrugge, Diederik W J Dippel, Jonathan M Coutinho, Yvo B W E M Roos, Henk A Marquering, Charles B L M Majoie
BACKGROUND: Up to two-thirds of patients are either dependent or dead 3 months after thrombectomy for acute ischemic stroke (AIS). Loss of cerebral autoregulation may render patients with AIS vulnerable to decreases in mean arterial pressure (MAP). OBJECTIVE: To determine whether a fall in MAP during intervention under general anesthesia (GA) affects functional outcome. METHODS: This subgroup analysis included patients from the MR CLEAN trial treated with thrombectomy under GA...
April 12, 2017: Journal of Neurointerventional Surgery
https://www.readbyqxmd.com/read/28403909/clinical-pathophysiology-of-hypoxic-ischemic-brain-injury-after-cardiac-arrest-a-two-hit-model
#13
REVIEW
Mypinder S Sekhon, Philip N Ainslie, Donald E Griesdale
Hypoxic ischemic brain injury (HIBI) after cardiac arrest (CA) is a leading cause of mortality and long-term neurologic disability in survivors. The pathophysiology of HIBI encompasses a heterogeneous cascade that culminates in secondary brain injury and neuronal cell death. This begins with primary injury to the brain caused by the immediate cessation of cerebral blood flow following CA. Thereafter, the secondary injury of HIBI takes place in the hours and days following the initial CA and reperfusion. Among factors that may be implicated in this secondary injury include reperfusion injury, microcirculatory dysfunction, impaired cerebral autoregulation, hypoxemia, hyperoxia, hyperthermia, fluctuations in arterial carbon dioxide, and concomitant anemia...
April 13, 2017: Critical Care: the Official Journal of the Critical Care Forum
https://www.readbyqxmd.com/read/28401995/orthostatic-dizziness-in-parkinson-s-disease-is-attributed-to-cerebral-hypoperfusion-a-transcranial-doppler-study
#14
Jinse Park, Hee-Tae Kim, Kang Min Park, Sam Yeol Ha, Sung Eun Kim, Kyong Jin Shin, Si Eun Kim, Wooyoung Jang, Ji Sun Kim, Jinyoung Youn, Engsoek Oh, Suyeon Park
OBJECTIVES: Orthostatic hypotension (OH) is controversially regarded as the cause of orthostatic dizziness in Parkinson's disease (PD). We sought to evaluate whether cerebral autoregulation is an alternative cause for orthostatic dizziness in PD patients, using transcranial Doppler monitoring during head-up tilting. METHODS: Forty-five PD patients with dizziness, 13 PD patients without dizziness, and 10 age-matched healthy controls were enrolled. Participants were divided into the following four groups: patients with dizziness and OH (group 1, n = 22), patients with dizziness but no OH (n = 23, group 2), patients without dizziness (n = 11, group 3), and age-matched healthy controls (n = 10, group 4)...
April 12, 2017: Journal of Clinical Ultrasound: JCU
https://www.readbyqxmd.com/read/28397372/k-channel-impairment-determines-sex-and-age-differences-in-epinephrine-mediated-outcomes-after-brain-injury
#15
William M Armstead, John Riley, Monica S Vavilala
Traumatic brain injury (TBI) is the leading cause of injury-related death in children, with boys and children under 4 years having particularly poor outcomes. Activation of ATP- and calcium-sensitive (KATP and KCa ) channels produces cerebrovasodilation and contributes to autoregulation, both of which are impaired after TBI, contributing to poor outcomes. Upregulation of the c-Jun-terminal kinase (JNK) isoform of mitogen-activated protein kinase produces K channel function impairment after CNS injury. Vasoactive agents can be used to normalize cerebral perfusion pressure...
April 11, 2017: Journal of Neuroscience Research
https://www.readbyqxmd.com/read/28392777/efficacy-of-cerebral-autoregulation-in-early-ischemic-stroke-predicts-smaller-infarcts-and-better-outcome
#16
Pedro Castro, Jorge Manuel Serrador, Isabel Rocha, Farzaneh Sorond, Elsa Azevedo
BACKGROUND AND PURPOSE: Effective cerebral autoregulation (CA) may protect the vulnerable ischemic penumbra from blood pressure fluctuations and minimize neurological injury. We aimed to measure dynamic CA within 6 h of ischemic stroke (IS) symptoms onset and to evaluate the relationship between CA, stroke volume, and neurological outcome. METHODS: We enrolled 30 patients with acute middle cerebral artery IS. Within 6 h of IS, we measured for 10 min arterial blood pressure (Finometer), cerebral blood flow velocity (transcranial Doppler), and end-tidal-CO2...
2017: Frontiers in Neurology
https://www.readbyqxmd.com/read/28385097/cerebral-perfusion-pressure-insults-and-associations-with-outcome-in-adult-traumatic-brain-injury
#17
Fabian Giza, Geert Meyfroidt, Ian Piper, Giuseppe Citerio, Iain Chambers, Per Enblad, Pelle Nilsson, Bart Feyen, Philippe Jorens, Andrew Maas, Martin Ulrich Schuhmann, Rob Donald, Laura Moss, Greet Van den Berghe, Bart Depreitere
The definition of cerebral perfusion pressure (CPP) secondary insults in severe traumatic brain injury remains unclear. The purpose of the present study is to visualize the association of intensity and duration of episodes below or above cerebral perfusion pressure thresholds and outcome. The analysis was based on prospectively collected minute-by-minute intracranial pressure (ICP) and blood pressure data and outcome from 259 adult patients. The relationship of episodes of CPP below or above a certain threshold for certain duration with the 6-month Glasgow Outcome Score was visualized, separately for episodes of active or deficient autoregulation (AR)...
April 7, 2017: Journal of Neurotrauma
https://www.readbyqxmd.com/read/28384837/the-impact-of-integrated-evaluation-of-hemodynamics-on-management-of-preterm-infants-with-late-onset-compromised-systemic-circulation
#18
Reem Amer, Reem Kalash, Mary M Seshia, Yasser N Elsayed
Objectives To study the impact of integrated evaluation of hemodynamics (IEH), using targeted neonatal echocardiography (TNE), cerebral regional tissue oxygenation (crRTO), and fractional oxygen extraction (FOE), using near-infrared spectroscopy (NIRS) on the management of infants with late-onset compromised systemic circulation (LCSC), and evaluation of the hemodynamic characteristics. Study Design Retrospective cohort study comparing infants with LCSC who underwent IEH (April 2014 to May 2016) with an earlier EPOCH who did not undergo IEH (January 2012 to March 2014)...
April 6, 2017: American Journal of Perinatology
https://www.readbyqxmd.com/read/28383324/cerebral-autoregulation-oriented-therapy-at-the-bedside-a-comprehensive-review
#19
Lucia Rivera-Lara, Andres Zorrilla-Vaca, Romergryko G Geocadin, Ryan J Healy, Wendy Ziai, Marek A Mirski
This comprehensive review summarizes the evidence regarding use of cerebral autoregulation-directed therapy at the bedside and provides an evaluation of its impact on optimizing cerebral perfusion and associated functional outcomes. Multiple studies in adults and several in children have shown the feasibility of individualizing mean arterial blood pressure and cerebral perfusion pressure goals by using cerebral autoregulation monitoring to calculate optimal levels. Nine of these studies examined the association between cerebral perfusion pressure or mean arterial blood pressure being above or below their optimal levels and functional outcomes...
April 6, 2017: Anesthesiology
https://www.readbyqxmd.com/read/28361248/increased-risk-of-critical-cbf-levels-in-sah-patients-with-actual-cpp-below-calculated-optimal-cpp
#20
Ulf Johnson, Henrik Engquist, Anders Lewén, Tim Howells, Pelle Nilsson, Elisabeth Ronne-Engström, Elham Rostami, Per Enblad
BACKGROUND: Cerebral pressure autoregulation can be quantified with the pressure reactivity index (PRx), based on the correlation between blood pressure and intracranial pressure. Using PRx optimal cerebral perfusion pressure (CPPopt) can be calculated, i.e., the level of CPP where autoregulation functions best. The relation between cerebral blood flow (CBF) and CPPopt has not been examined. The objective was to assess to which extent CPPopt can be calculated in SAH patients and to investigate CPPopt in relation to CBF...
June 2017: Acta Neurochirurgica
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