scholarly journals Intracortical electrophysiological correlates of blood flow after severe SAH: A multimodality monitoring study

2017 ◽  
Vol 38 (3) ◽  
pp. 506-517 ◽  
Author(s):  
Brandon Foreman ◽  
David Albers ◽  
J Michael Schmidt ◽  
Cristina Maria Falo ◽  
Angela Velasquez ◽  
...  
Keyword(s):  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Delayed Cerebral Ischemia ◽  
Neurovascular Coupling ◽  
Preliminary Evidence ◽  
Secondary Brain Injury ◽  
Poor Grade ◽  
Scalp Eeg ◽  
Rate Of Decline ◽  
Eeg Alpha

Subarachnoid hemorrhage (SAH) is a devastating form of stroke. Approximately one in four patients develop progressive neurological deterioration and silent infarction referred to as delayed cerebral ischemia (DCI). DCI is a complex, multifactorial secondary brain injury pattern and its pathogenesis is not fully understood. We aimed to study the relationship between cerebral blood flow (CBF) and neuronal activity at both the cortex and in scalp using electroencephalography (EEG) in poor-grade SAH patients undergoing multimodality intracranial neuromonitoring. Twenty patients were included, of whom half had DCI median 4.7 days (interquartile range (IQR): 4.0–5.6) from SAH bleed. The rate of decline in regional cerebral blood flow (rCBF) was significant in both those with and without DCI and occurred between days 4 and 7 post-SAH. The scalp EEG alpha-delta ratio declined early in those with DCI. In the group without DCI, CBF and cortical EEG alpha-delta ratio were correlated (r = 0.53; p <  0.01) and in the group without DCI, inverse neurovascular coupling was observed at CPP <  80 mmHg. We found preliminary evidence that as patients enter the period of highest risk for the development of DCI, the absence of neurovascular coupling may act as a possible pathomechanism in the development of ischemia following SAH.

scholarly journals Neurovascular Coupling and Epilepsy: Hemodynamic Markers for Localizing and Predicting Seizure Onset

2007 ◽  
Vol 7 (4) ◽  
pp. 91-94 ◽  
Author(s):  
Theodore H. Schwartz
Keyword(s):  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Neurovascular Coupling ◽  
Epileptic Activity ◽  
Tissue Hypoxia ◽  
Epileptic Focus ◽  
Seizure Onset

Hemodynamic surrogates of epileptic activity are being used to map epileptic foci with PET, SPECT, and fMRI. However, there are few studies of neurovascular coupling in epilepsy. Recent data indicate that cerebral blood flow, although focally increased at the onset of a seizure, may be temporarily inadequate to meet the metabolic demands of both interictal and ictal epileptic events. Transient focal tissue hypoxia and hyperperfusion may be excellent markers for the epileptic focus and may even precede the onset of the ictal event.

Cerebral blood flow and vasoresponsivity within and around cerebral contusions

1996 ◽  
Vol 85 (5) ◽  
pp. 871-876 ◽  
Author(s):  
Mark R. McLaughlin ◽  
Donald W. Marion
Keyword(s):  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Repeated Measures ◽  
Closed Head Injury ◽  
Ct Scanning ◽  
Brain Parenchyma ◽  
Secondary Brain Injury ◽  
Content Type ◽  
Repeated Measures Analysis ◽  
Surrounding Parenchyma

✓ There is increasing evidence that regional ischemia plays a major role in secondary brain injury. Although the cortex underlying subdural hematomas seems particularly vulnerable to ischemia, little is known about the adequacy of cerebral blood flow (CBF) or the vasoresponsivity within the vascular bed of contusions. The authors used the xenon-enhanced computerized tomography (CT) CBF technique to define the CBF and vasoresponsivity of contusions, pericontusional parenchyma, and the remainder of the brain 24 to 48 hours after severe closed head injury in 10 patients: six patients with one contusion and four with two contusions, defined as mixed or high-density lesions on CT scanning. The CBF within the contusions (29.3 ± 16.4 ml/100 g/minute, mean ± standard deviation) was significantly lower than both that found in the adjacent 1-cm perimeter of normal-appearing tissue (42.5 ± 15.8 ml/100 g/minute) and the mean global CBF (52.5 ± 17.5 ml/100 g/minute) (p < 0.004, repeated-measures analysis of variance). A subset of seven patients (10 contusions) also underwent a second Xe-CT CBF study during mild hyperventilation (a PaCO of 24–32 mm Hg). In only two of these 10 contusions was vasoresponsivity less than 1% (range 0%–7.6%); in the rim of normal-appearing pericontusional tissue, it was 0.4% to 9.1%. The authors conclude that CBF within intracerebral contusions is highly variable and is often above 18 ml/100 g/minute, the reported threshold for irreversible ischemia. Intracontusional CBF is significantly reduced relative to surrounding brain parenchyma, and CO2 vasoresponsivity is usually present. In the contusion and the surrounding parenchyma, vasoresponsivity may be nearly three times normal, suggesting hypersensitivity to hyperventilation therapy. Given this possible hypersensitivity and relative hypoperfusion within and around cerebral contusions, these lesions are particularly vulnerable to secondary injury such as that which may be caused by hypotension or aggressive hyperventilation.

Abstract 196: Sanguinate (PEGylated-carboxyhemoglobin-bovine) Improves Cerebral Blood Flow and Oxygen Extraction to Vulnerable Brain Regions in Patients at Risk for Delayed Cerebral Ischemia After Subarachnoid Hemorrhage

Stroke ◽  
2017 ◽  
Vol 48 (suppl_1) ◽  
Author(s):  
Rajat Dhar ◽  
Hemant Misra ◽  
Michael Diringer
Keyword(s):  
At Risk ◽  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Subarachnoid Hemorrhage ◽  
Cerebral Ischemia ◽  
Delayed Cerebral Ischemia ◽  
Brain Regions ◽  
Oxygen Extraction ◽  
Patients At Risk ◽  
Higher Doses

Introduction: Sanguinate is a dual-action oxygen transfer and carbon monoxide-releasing agent with efficacy in animal models of focal brain ischemia and established safety in health volunteers. We performed a dose-escalation study in subarachnoid hemorrhage (SAH) patients at risk for delayed cerebral ischemia (DCI) to evaluate tolerability and explore efficacy in improving cerebral blood flow (CBF) and flow-metabolism balance to vulnerable brain regions. Methods: 12 subjects were studied over three dose tiers: 160mg/kg, 240 mg/kg, and 320 mg/kg, with close safety evaluation prior to proceeding to higher doses. After baseline 15 O-PET measurement of global and regional CBF and oxygen extraction fraction (OEF), Sanguinate was infused over two hours; PET was repeated immediately after and again at 24-hours. Vulnerable brain regions were defined as those with baseline OEF ≥ 0.5. Results: Sanguinate infusion resulted in a significant but transient rise in mean arterial pressure (115±15 to 127±13 mm Hg) that was not dose-dependent. No adverse physiologic or clinical effects were observed with infusion at any dose. Global CBF did not rise significantly after Sanguinate (42.6±7 to 45.9±9 ml/100g/min, p=0.18). However, in the 28% of regions classified as vulnerable, Sanguinate resulted in a significant rise in CBF (42.2±11 to 51.2±18) and reduction in OEF (0.6±0.1 to 0.5±0.11, both p<0.001). The increase in regional CBF was only seen with the two higher doses but OEF improved in all tiers. However, response was attenuated at 24-hours. Conclusions: We safely administered a novel oxygen transport and vasodilating agent to a cohort of patients with SAH. Sanguinate infusion appeared to improve CBF and flow-metabolism balance in vulnerable brain regions and warrants further study in those at-risk for DCI. Higher or repeat dosing may be required for sustained efficacy.

scholarly journals Effect of Hypertonic Saline on Cerebral Blood Flow in Poor-Grade Patients With Subarachnoid Hemorrhage

Stroke ◽  
2003 ◽  
Vol 34 (6) ◽  
pp. 1389-1396 ◽  
Author(s):  
Ming-Yuan Tseng ◽  
Pippa G. Al-Rawi ◽  
John D. Pickard ◽  
Frank A. Rasulo ◽  
Peter J. Kirkpatrick
Keyword(s):  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Subarachnoid Hemorrhage ◽  
Hypertonic Saline ◽  
Poor Grade

scholarly journals Noninvasive Optical Monitoring of Cerebral Blood Flow and EEG Spectral Responses after Severe Traumatic Brain Injury: A Case Report

2021 ◽  
Vol 11 (8) ◽  
pp. 1093
Author(s):  
Chien-Sing Poon ◽  
Benjamin Rinehart ◽  
Dharminder S. Langri ◽  
Timothy M. Rambo ◽  
Aaron J. Miller ◽  
...  
Keyword(s):  
Traumatic Brain Injury ◽  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Brain Injury ◽  
Brain Activity ◽  
Correlation Spectroscopy ◽  
Secondary Brain Injury ◽  
Diffuse Correlation Spectroscopy ◽  
Flow Monitoring ◽  
And Function

Survivors of severe brain injury may require care in a neurointensive care unit (neuro-ICU), where the brain is vulnerable to secondary brain injury. Thus, there is a need for noninvasive, bedside, continuous cerebral blood flow monitoring approaches in the neuro-ICU. Our goal is to address this need through combined measurements of EEG and functional optical spectroscopy (EEG-Optical) instrumentation and analysis to provide a complementary fusion of data about brain activity and function. We utilized the diffuse correlation spectroscopy method for assessing cerebral blood flow at the neuro-ICU in a patient with traumatic brain injury. The present case demonstrates the feasibility of continuous recording of noninvasive cerebral blood flow transients that correlated well with the gold-standard invasive measurements and with the frequency content changes in the EEG data.

Neurovascular Coupling in Seizures

Neuroglia ◽  
2021 ◽  
Vol 2 (1) ◽  
pp. 36-47
Author(s):  
G. Campbell Teskey ◽  
Cam Ha T. Tran
Keyword(s):  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Functional Imaging ◽  
Neurological Disorders ◽  
Seizure Activity ◽  
Current Knowledge ◽  
Imaging Techniques ◽  
Neurovascular Coupling ◽  
Functional Brain Imaging ◽  
Blood Flow Control

Neurovascular coupling is a key control mechanism in cerebral blood flow (CBF) regulation. Importantly, this process was demonstrated to be affected in several neurological disorders, including epilepsy. Neurovascular coupling (NVC) is the basis for functional brain imaging, such as PET, SPECT, fMRI, and fNIRS, to assess and map neuronal activity, thus understanding NVC is critical to properly interpret functional imaging signals. However, hemodynamics, as assessed by these functional imaging techniques, continue to be used as a surrogate to map seizure activity; studies of NVC and cerebral blood flow control during and following seizures are rare. Recent studies have provided conflicting results, with some studies showing focal increases in CBF at the onset of a seizure while others show decreases. In this brief review article, we provide an overview of the current knowledge state of neurovascular coupling and discuss seizure-related alterations in neurovascular coupling and CBF control.

Sign in / Sign up

Export Citation Format

Share Document