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Cerebral autoregulation

Daniel Silva de Azevedo, Angela Salomao Macedo Salinet, Marcelo de Lima Oliveira, Manoel Jacobsen Teixeira, Edson Bor-Seng-Shu, Ricardo de Carvalho Nogueira
Cerebral microcirculation is gradually compromised during sepsis, with significant reductions in the function of capillaries and blood perfusion in small vessels. Transcranial Doppler ultrasound (TCD) has been used to assess cerebral circulation in a typical clinical setting. This study was to systematically review TCD studies, assess their methodological quality, and identify trends that can be associated with the temporal evolution of sepsis and its clinical outcome. A meta-analysis of systematic reviews was conducted according to the PRISMA statement...
October 18, 2016: Journal of Clinical Monitoring and Computing
Nolan S Hartkamp, Reinoud P H Bokkers, M J P van Osch, Gert J de Borst, Jeroen Hendrikse
BACKGROUND AND PURPOSE: To assess the effect of unilateral large vessel disease upon the cerebral hemodynamic autoregulatory status in the basal ganglia of patients with steno-occlusive internal carotid artery (ICA) disease. MATERIALS AND METHODS: Twenty-five healthy volunteers and 38 patients with a unilateral symptomatic steno-occlusive ICA lesion and were investigated; 20 with a stenosis >50% and 18 with an occlusion. Cerebral blood flow (CBF) and cerebrovascular reactivity (CVR) were assessed with pseudo-continuous arterial spin labeling (ASL) magnetic resonance (MR) imaging before and after administration of acetazolamide...
October 12, 2016: Journal of Neuroradiology. Journal de Neuroradiologie
Charles L Francoeur, Stephan A Mayer
For patients who survive the initial bleeding event of a ruptured brain aneurysm, delayed cerebral ischemia (DCI) is one of the most important causes of mortality and poor neurological outcome. New insights in the last decade have led to an important paradigm shift in the understanding of DCI pathogenesis. Large-vessel cerebral vasospasm has been challenged as the sole causal mechanism; new hypotheses now focus on the early brain injury, microcirculatory dysfunction, impaired autoregulation, and spreading depolarization...
October 14, 2016: Critical Care: the Official Journal of the Critical Care Forum
Sarah E Bigby, Jennifer E Carter, Sébastien Bauquier, Thierry Beths
Anesthesia protocols for patients with intracranial lesions need to provide hemodynamic stability, preserve cerebrovascular autoregulation, avoid increases in intracranial pressure, and facilitate a rapid recovery. Propofol total intravenous anesthesia (TIVA) maintains cerebral blood flow autoregulation and is considered superior to inhalant agents as an anesthetic protocol for patients with intracranial lesions. A propofol-based TIVA subsequent to premedication with medetomidine and diazepam was used in a king penguin ( Aptenodytes patagonicus ) undergoing magnetic resonance imaging of the brain after a new onset of seizures...
September 2016: Journal of Avian Medicine and Surgery
Utpal S Bhalala, Elumalai Appachi, Muhammad Ali Mumtaz
Many known risk factors for adverse cardiovascular and neurological outcomes in children with congenital heart defects (CHD) are not modifiable; however, the temperature and blood flow during cardiopulmonary bypass (CPB), are two risk factors, which may be altered in an attempt to improve long-term neurological outcomes. Deep hypothermic circulatory arrest, traditionally used for aortic arch repair, has been associated with short-term and long-term neurologic sequelae. Therefore, there is a rising interest in using moderate hypothermia with selective antegrade cerebral blood flow on CPB during aortic arch repair...
2016: Frontiers in Pediatrics
(no author information available yet)
[This corrects the article DOI: 10.1371/journal.pone.0161408.].
2016: PloS One
Roberta Rosas Petrocinio, Elga Dias Gomes
BACKGROUND: High altitude retinopathy (HAR) includes a number of diseases related to high altitude such as acute mountain sickness (AMS), high altitude pulmonary edema (HAPE) and high altitude cerebral edema (HACE). High altitude retinopathy is mainly characterized by retinal hemorrhages, usually sparing the macular region, a condition specifically known as high altitude retinal hemorrhages (HARH). The pathogenesis of HARH is unclear. Many studies show that lack of oxygen causes an inadequate autoregulation of retinal circulation, causing vascular incompetence...
2016: Aerospace Medicine and Human Performance
Xavier Waltz, Andrew E Beaudin, Patrick J Hanly, Georgios D Mitsis, Marc J Poulin
Cerebral autoregulation (CA) impairment may contribute to the increased risk of stroke associated with obstructive sleep apnea (OSA). It is unknown if impaired CA is further exacerbated by isocapnic-hypoxia and whether it is improved by treatment of OSA with continuous positive airway pressure (CPAP). CA was assessed during wakefulness in 53 OSA patients (50.3 ± 9.3 years) and 21 controls (49.8 ± 8.6 years) at baseline and following a minimum of 1 month of effective CPAP therapy (OSA patients, n = 40)...
September 20, 2016: Journal of Physiology
Cristina Fuente Mora, Jose-Alberto Palma, Horacio Kaufmann, Lucy Norcliffe-Kaufmann
Familial dysautonomia is an inherited autonomic disorder with afferent baroreflex failure. We questioned why despite low blood pressure standing, surprisingly few familial dysautonomia patients complain of symptomatic hypotension or have syncope. Using transcranial Doppler ultrasonography of the middle cerebral artery, we measured flow velocity (mean, peak systolic, and diastolic), area under the curve, pulsatility index, and height of the dictrotic notch in 25 patients with familial dysautonomia and 15 controls...
September 9, 2016: Journal of Cerebral Blood Flow and Metabolism
Wojciech Weigl, Daniel Milej, Dariusz Janusek, Stanisław Wojtkiewicz, Piotr Sawosz, Michał Kacprzak, Anna Gerega, Roman Maniewski, Adam Liebert
We present an overview of the wide range of potential applications of optical methods for monitoring traumatic brain injury. The MEDLINE database was electronically searched with the following search terms: "traumatic brain injury," "head injury," or "head trauma," and "optical methods," "NIRS," "near-infrared spectroscopy," "cerebral oxygenation," or "cerebral oximetry." Original reports concerning human subjects published from January 1980 to June 2015 in English were analyzed. Fifty-four studies met our inclusion criteria...
September 7, 2016: Journal of Cerebral Blood Flow and Metabolism
Valerie Y Chock, Laura A Rose, Jeanet V Mante, Rajesh Punn
BACKGROUND: Near-infrared spectroscopy (NIRS) may assist with characterization of a hemodynamically significant patent ductus arteriosus (hsPDA) by measuring cerebral and renal saturation (Csat and Rsat) levels. We hypothesized that Csat and Rsat in preterm infants with an hsPDA would be decreased compared to those with no PDA or non-significant PDA. METHODS: This non a-priori designed study retrospectively investigated clinical and ECHO characteristics of preterm infants <29 weeks gestation who underwent routine NIRS monitoring...
September 7, 2016: Pediatric Research
Rosa Maria Cerbo, Simona Orcesi, Luigia Scudeller, Martina Borellini, Carolina Croci, Claudia Ravelli, Giulia Masa, Piermichele Paolillo, Paolo Manzoni, Umberto Balottin, Mauro Stronati
Objective We aimed at assessing the association between superior vena cava flow (SVCf), regional (cerebral) tissue oxygen saturation (rSO2), and cerebral fractional oxygen extraction (CFOE) during the first 48 hours of life and 2-years neurodevelopmental outcome of very low-birth-weight infants (VLBW). Methods We prospectively studied 60 VLBW infants admitted to our neonatal intensive care unit; rSO2 was continuously monitored with near-infrared spectroscopy during the first 48 hours of life, SVCf was measured at 4 to 6, 12, 24, and 48 hours, and CFOE was calculated...
September 2016: American Journal of Perinatology
Roberto De Simone, Angelo Ranieri, Vincenzo Bonavita
Two critical functions for the control of intracranial fluids dynamics are carried on the venous side of the perfusion circuit: the first is the avoidance of cortical veins collapse during the physiological increases of cerebrospinal fluid (CSF) pressure in which they are immersed. The second, is the generation of an abrupt venous pressure drop at the confluence of the cortical veins with the dural sinuses that is required to allow a CSF outflow rate balanced with its production. There is evidence that both of these effects are ensured by a Starling resistor mechanism (a fluid dynamic construct that governs the flow in collapsible tubes exposed to variable external pressure) acting at the confluence of cortical veins in the dural sinus...
September 6, 2016: Panminerva Medica
Aileen Schroeter, Joanes Grandjean, Felix Schlegel, Bechara J Saab, Markus Rudin
Previously, we reported widespread bilateral increases in stimulus-evoked functional magnetic resonance imaging signals in mouse brain to unilateral sensory paw stimulation. We attributed the pattern to arousal-related cardiovascular changes overruling cerebral autoregulation thereby masking specific signal changes elicited by local neuronal activity. To rule out the possibility that interhemispheric neuronal communication might contribute to bilateral functional magnetic resonance imaging responses, we compared stimulus-evoked functional magnetic resonance imaging responses to unilateral hindpaw stimulation in acallosal I/LnJ, C57BL/6, and BALB/c mice...
September 5, 2016: Journal of Cerebral Blood Flow and Metabolism
Thomas Tovedal, Mark Lubberink, Arvid Morell, Sergio Estrada, Sandeep S V Golla, Gunnar Myrdal, Rickard P F Lindblom, Stefan Thelin, Jens Sörensen, Gunnar Antoni, Fredrik Lennmyr
BACKGROUND: Perfusion strategies during aortic surgery usually comprise hypothermic circulatory arrest (HCA), often combined with selective antegrade cerebral perfusion (SACP) or retrograde cerebral perfusion. Cerebral blood flow (CBF) is a fundamental parameter for which the optimal level has not been clearly defined. We sought to determine the CBF at a pump flow level of 6 mL/kg/min, previously shown likely to provide adequate SACP at 20°C in pigs. METHODS: Repeated positron emission tomography (PET) scans were used to quantify the CBF and glucose metabolism throughout HCA and SACP including cooling and rewarming...
September 1, 2016: Annals of Thoracic Surgery
Adi Tsalach, Eliahu Ratner, Stas Lokshin, Zmira Silman, Ilan Breskin, Nahum Budin, Moshe Kamar
Cerebral autoregulation is a mechanism which maintains constant cerebral blood flow (CBF) despite changes in mean arterial pressure (MAP). Assessing whether this mechanism is intact or impaired and determining its boundaries is important in many clinical settings, where primary or secondary injuries to the brain may occur. Herein we describe the development of a new ultrasound tagged near infra red light monitor which tracks CBF trends, in parallel, it continuously measures blood pressure and correlates them to produce a real time autoregulation index...
2016: PloS One
Saeid Taheri, Jin Yu, Hong Zhu, Mark S Kindy
BACKGROUND: Cerebral ionic homeostasis impairment, especially Ca2+, has been observed in Alzheimer's disease (AD) and also with hypertension. Hypertension and AD both have been implicated in impaired cerebral autoregulation. However, the relationship between the ionic homeostasis impairment in AD and hypertension and cerebral blood flow (CBF) autoregulation is not clear. OBJECTIVE: To test the hypothesis that a high-salt diet regimen influences the accumulation of amyloid-β (Aβand CBF) and CBF, exacerbates cognitive decline, and increases the propensity to AD...
October 4, 2016: Journal of Alzheimer's Disease: JAD
Alexander Seiler, Ralf Deichmann, Waltraud Pfeilschifter, Elke Hattingen, Oliver C Singer, Marlies Wagner
PURPOSE: Quantitative T2'-mapping detects regional changes of the relation of oxygenated and deoxygenated hemoglobin (Hb) by using their different magnetic properties in gradient echo imaging and might therefore be a surrogate marker of increased oxygen extraction fraction (OEF) in cerebral hypoperfusion. Since elevations of cerebral blood volume (CBV) with consecutive accumulation of Hb might also increase the fraction of deoxygenated Hb and, through this, decrease the T2'-values in these patients we evaluated the relationship between T2'-values and CBV in patients with unilateral high-grade large-artery stenosis...
2016: PloS One
Andreas Oldag, Jens Neumann, Michael Goertler, Hermann Hinrichs, Hans-Jochen Heinze, Andreas Kupsch, Catherine M Sweeney-Reed, Klaus Kopitzki
The measurement of autoregulatory delay by near-infrared spectroscopy (NIRS) has been proposed as an alternative technique to assess cerebral autoregulation, which is routinely assessed via transcranial Doppler sonography (TCD) in most centers. Comparitive studies of NIRS and TCD, however, are largely missing. We investigated whether cerebrovascular reserve (CVR), as assessed via TCD, correlates with the delay of the autoregulatory response to changes in arterial blood pressure (ABP) as assessed by NIRS, i...
November 2016: Journal of Neurology
Sandor Viski, Miklos Orosz, Katalin Reka Czuriga-Kovacs, Maria Tunde Magyar, Laszlo Csiba, Laszlo Olah
BACKGROUND: Alcohol is a known triggering factor for orthostatic dysfunction, increasing the risk of neurally-mediated syncope. Since orthostatic tolerance may be affected by both systemic and cerebral hemodynamic changes, our aim was to investigate the acute effects of alcohol on cerebral vasoreactivity measured during the head-up tilt (HUT) test in 20 healthy subjects. METHODS: Mean arterial blood pressure (mBP), heart rate, and flow parameters in both middle cerebral arteries (MCAs) were continuously recorded in the supine and during a 10-minute HUT positions before and after alcohol intake...
September 15, 2016: Journal of the Neurological Sciences
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