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Cerebral autoregulation

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https://www.readbyqxmd.com/read/28421173/cerebral-autoregulation-brain-injury-and-the-transitioning-premature-infant
#1
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
#2
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
#3
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
#4
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
#5
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
#6
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
#7
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
#8
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
#9
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
#10
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
#11
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
#12
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...
March 30, 2017: Acta Neurochirurgica
https://www.readbyqxmd.com/read/28356297/nitric-oxide-sensitive-guanylyl-cyclase-signaling-affects-co2-dependent-but-not-pressure-dependent-regulation-of-cerebral-blood-flow
#13
Shadi Jahshan, Lior Dayan, Giris Jacob
Cerebrovascular CO2 reactivity is affected by nitric oxide (NO). We tested the hypothesis that sildenafil selectively potentiates NO-cGMP signaling affects CO2 reactivity. Fourteen healthy males (34±2 years) were enrolled in the study. BP, ECG, velocity of cerebral blood flow (CBF, measured by TCD), end tidal CO2 (EtCO2) were assessed at baseline (CO2 ~ 39 mm Hg), during hyperventilation (CO2 ~ 24 mm Hg), hypercapnia (CO2 ~ 46 mm Hg), boluses of phenylephrine (25-200 µg) and during graded head-up tilting (HUT)...
March 29, 2017: American Journal of Physiology. Regulatory, Integrative and Comparative Physiology
https://www.readbyqxmd.com/read/28355608/new-wavelet-neurovascular-bundle-for-bedside-evaluation-of-cerebral-autoregulation-and-neurovascular-coupling-in-newborns-with-hypoxic-ischemic-encephalopathy
#14
Lina F Chalak, Rong Zhang
Neonatal encephalopathy (NE) resulting from birth asphyxia constitutes a major global public health burden for millions of infants every year, and despite therapeutic hypothermia, half of these neonates have poor neurological outcomes. As new neuroprotective interventions are being studied in clinical trials, there is a critical need to establish physiological surrogate markers of therapeutic efficacy, to guide patient selection and/or to modify the therapeutic intervention. The challenge in the field of neonatal brain injury has been the difficulty of clinically discerning NE severity within the short therapeutic window after birth or of analyzing the dynamic aspects of the cerebral circulation in sick NE newborns...
March 30, 2017: Developmental Neuroscience
https://www.readbyqxmd.com/read/28355201/sex-and-age-differences-in-phenylephrine-mechanisms-and-outcomes-after-piglet-brain-injury
#15
Victor Curvello, Hugh Hekierski, John Riley, Monica Vavilala, William M Armstead
BACKGROUND: Traumatic brain injury (TBI) is the leading cause of injury related death in children, with boys and children under 4 having particularly poor outcomes. Cerebral autoregulation is often impaired after TBI, contributing to poor outcome. In prior studies of newborn pigs, phenylephrine (Phe) preferentially protected cerebral autoregulation in females but not males after TBI. We hypothesized that, in contrast to the newborn, Phe prevents impairment of autoregulation and tissue injury following TBI in both sexes of older pigs...
March 29, 2017: Pediatric Research
https://www.readbyqxmd.com/read/28333037/cerebral-hemodynamic-with-intra-aortic-balloon-pump-business-as-usual
#16
Juliana Caldas, Ronney B Panerai, Edson Bor-Seng-Shu, Juliano Almeida, Graziela Ferreira, Ligia Cunha, Ricardo Nogueira, Marcelo Oliveira, Fabio Jatene, Thompson Robinson, Ludhmila Hajjar
Intra-aortic balloon pump (IABP) is commonly used as mechanical support after cardiac surgery or cardiac shock. Although its benefits for cardiac function have been well documented, its effects on cerebral circulation are still controversial. We hypothesized that transfer function analysis (TFA) and continuous estimates of dynamic cerebral autoregulation (CA) provide consistent results in the assessment of cerebral autoregulation in patients with IABP. Continuous recordings of blood pressure (BP, intra-arterial line), end-tidal CO2, heart rate and cerebral blood flow velocity (CBFV, transcranial Doppler) were obtained i) 5 minutes with IABP ratio 1:3, ii) 5 minutes, starting 1 minute with the IABP-ON, and continuing for another 4 minutes without pump assistance (IABP-OFF)...
March 23, 2017: Physiological Measurement
https://www.readbyqxmd.com/read/28325005/dynamic-modeling-of-apnea-induced-concurrent-variations-in-arterial-blood-pressure-and-cerebral-blood-flow-velocity
#17
Raichel Alex, Rong Zhang, Donald E Watenpaugh, Khosrow Behbehani
Obstructive Sleep Apnea (OSA) is characterized by partial (hypopnea) or complete cessation (apnea) of airflow to the lungs during sleep. It has been previously reported that apnea episodes lead to significant rise in instantaneous blood pressure concomitant with a rise in cerebral blood flow velocity, indicating loss of cerebral autoregulation during the episodes. In this study, we have used Auto Regressive Moving Average model (ARMA (na, nb, nk)) to quantify OSA induced dynamic changes in cerebral blood flow velocity (CBFV) with beat to beat blood pressure (BP) as an input...
August 2016: Conference Proceedings: Annual International Conference of the IEEE Engineering in Medicine and Biology Society
https://www.readbyqxmd.com/read/28316994/multiple-factors-involved-in-the-pathogenesis-of-white-matter-lesions
#18
REVIEW
Jing Lin, Dilong Wang, Linfang Lan, Yuhua Fan
White matter lesions (WMLs), also known as leukoaraiosis (LA) or white matter hyperintensities (WMHs), are characterized mainly by hyperintensities on T2-weighted or fluid-attenuated inversion recovery (FLAIR) images. With the aging of the population and the development of imaging technology, the morbidity and diagnostic rates of WMLs are increasing annually. WMLs are not a benign process. They clinically manifest as cognitive decline and the subsequent development of dementia. Although WMLs are important, their pathogenesis is still unclear...
2017: BioMed Research International
https://www.readbyqxmd.com/read/28306631/thermoregulate-autoregulate-and-ventilate-brain-directed-critical-care-for-pediatric-cardiac-arrest
#19
Jonathan E Kurz, Craig M Smith, Mark S Wainwright
PURPOSE OF REVIEW: Cardiac arrest in childhood is associated with a high risk for mortality and poor long-term functional outcome. This review discusses the current evidence for neuroprotective therapies and goals for postarrest care in the context of the pathophysiology of hypoxic-ischemic injury, modalities for neurologic prognostication in these children and potential future monitoring paradigms for maximizing cerebral perfusion in the postarrest period. RECENT FINDINGS: The recent publication of the in-hospital and out-of-hospital Therapeutic Hypothermia After Cardiac Arrest trials demonstrated a lack of statistically significant benefit for the use of postarrest therapeutic hypothermia...
March 16, 2017: Current Opinion in Pediatrics
https://www.readbyqxmd.com/read/28302943/cerebral-hemodynamics-and-metabolism-during-cardiac-arrest-and-cardiopulmonary-resuscitation-using-hyperspectral-near-infrared-spectroscopy
#20
Reyhaneh Nosrati, Steve Lin, Andrew Ramadeen, Dena Monjazebi, Paul Dorian, Vladislav Toronov
BACKGROUND: Maintaining cerebral oxygen delivery and metabolism during cardiac arrest (CA) through resuscitation is essential to improve the survival rate while avoiding brain injury. The effect of CA and cardiopulmonary resuscitation (CPR) on cerebral and muscle oxygen delivery and metabolism is not clearly quantified.Methods and Results:A novel hyperspectral near-infrared spectroscopy (hNIRS) technique was developed and evaluated to measure cerebral oxygen delivery and aerobic metabolism during ventricular fibrillation (VF) CA and CPR in 14 pigs...
March 10, 2017: Circulation Journal: Official Journal of the Japanese Circulation Society
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