Cerebral Oxygen Metabolism after Aneurysmal Subarachnoid Hemorrhage

Previous studies of cerebral oxygen metabolism and extraction in patients with subarachnoid hemorrhage (SAH) have yielded conflicting results. We used positron emission tomography (PET) to measure the regional cerebral metabolic rate for oxygen (rCMRO2), oxygen extraction fraction (rOEF), and cerebral blood flow (rCBF) 16 times in 11 patients with aneurysmal SAH. All studies were performed preoperatively; no patient had hydrocephalus or intracerebral hematoma on brain CT. Eight patients with no arteriographic vasospasm who were studied on days 1–4 post-SAH had a significant 25% reduction in global CMRO2 compared to age-matched controls, and no significant change in global OEF, suggesting a primary reduction in CMRO2 caused by SAH. Four patients studied seven times during arteriographic vasospasm had significantly increased rOEF with unchanged CMRO2 in arterial territories affected by arteriographic vasospasm compared to territories without vasospasm, indicative of cerebral ischemia without infarction. No brain regions studied with PET were infarcted on follow-up CT. We conclude that the initial aneurysm rupture produces a primary reduction in CMRO2, and that subsequent vasospasm causes ischemia.

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PET Quantification of Cerebral Oxygen Metabolism in Small Animals

The Scientific World JOURNAL ◽

10.1155/2014/159103 ◽

2014 ◽

Vol 2014 ◽

pp. 1-7 ◽

Cited By ~ 3

Author(s):

Takashi Temma ◽

Kazuhiro Koshino ◽

Tetsuaki Moriguchi ◽

Jun-ichiro Enmi ◽

Hidehiro Iida

Keyword(s):

Cerebral Blood Volume ◽

Animal Experiments ◽

Oxygen Metabolism ◽

Cerebrovascular Diseases ◽

Oxygen Extraction Fraction ◽

Small Animals ◽

Cerebral Oxygen ◽

Technical Problems ◽

Cerebral Oxygen Metabolism

Understanding cerebral oxygen metabolism is of great importance in both clinical diagnosis and animal experiments because oxygen is a fundamental source of brain energy and supports brain functional activities. Since small animals such as rats are widely used to study various diseases including cerebral ischemia, cerebrovascular diseases, and neurodegenerative diseases, the development of a noninvasivein vivomeasurement method of cerebral oxygen metabolic parameters such as oxygen extraction fraction (OEF) and cerebral metabolic rate of oxygen (CMRO2) as well as cerebral blood flow (CBF) and cerebral blood volume (CBV) has been a priority. Although positron emission tomography (PET) with15O labeled gas tracers has been recognized as a powerful way to evaluate cerebral oxygen metabolism in humans, this method could not be applied to rats due to technical problems and there were no reports of PET measurement of cerebral oxygen metabolism in rats until an15O-O2injection method was developed a decade ago. Herein, we introduce an intravenous administration method using two types of injectable15O-O2and an15O-O2gas inhalation method through an airway placed in the trachea, which enables oxygen metabolism measurements in rats.

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A theoretical framework for estimating cerebral oxygen metabolism changes using the calibrated-BOLD method: Modeling the effects of blood volume distribution, hematocrit, oxygen extraction fraction, and tissue signal properties on the BOLD signal

NeuroImage ◽

10.1016/j.neuroimage.2011.05.077 ◽

2011 ◽

Vol 58 (1) ◽

pp. 198-212 ◽

Cited By ~ 121

Author(s):

Valerie E.M. Griffeth ◽

Richard B. Buxton

Keyword(s):

Blood Volume ◽

Oxygen Metabolism ◽

Theoretical Framework ◽

Oxygen Extraction Fraction ◽

Volume Distribution ◽

Cerebral Oxygen ◽

Bold Signal ◽

Cerebral Oxygen Metabolism ◽

Extraction Fraction ◽

Blood Volume Distribution

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Clinical characteristics and outcome of aneurysmal subarachnoid hemorrhage with intracerebral hematoma

Journal of Neurosurgery ◽

10.3171/2015.10.jns151036 ◽

2016 ◽

Vol 125 (6) ◽

pp. 1344-1351 ◽

Cited By ~ 18

Author(s):

Anthony Wan ◽

Blessing N. R. Jaja ◽

Tom A. Schweizer ◽

R. Loch Macdonald

Keyword(s):

Subarachnoid Hemorrhage ◽

Early Treatment ◽

Aneurysmal Subarachnoid Hemorrhage ◽

Neurological Status ◽

Aneurysm Rupture ◽

Study Data ◽

Intracerebral Hematoma ◽

Pia Mater ◽

Proportional Odds Models ◽

The Brain

OBJECTIVE Intracerebral hematoma (ICH) with subarachnoid hemorrhage (SAH) indicates a unique feature of intracranial aneurysm rupture since the aneurysm is in the subarachnoid space and separated from the brain by pia mater. Broad consensus is lacking regarding the concept that ultra-early treatment improves outcome. The aim of this study is to determine the associative factors for ICH, ascertain the prognostic value of ICH, and investigate how the timing of treatment relates to the outcome of SAH with concurrent ICH. METHODS The study data were pooled from the SAH International Trialists repository. Logistic regression was applied to study the associations of clinical and aneurysm characteristics with ICH. Proportional odds models and dominance analysis were applied to study the effect of ICH on 3-month outcome (Glasgow Outcome Scale) and investigate the effect of time from ictus to treatment on outcome. RESULTS Of the 5362 SAH patients analyzed, 1120 (21%) had concurrent ICH. In order of importance, neurological status, aneurysm location, aneurysm size, and patient ethnicity were significantly associated with ICH. Patients with ICH experienced poorer outcome than those without ICH (OR 1.58; 95% CI 1.37–1.82). Treatment within 6 hours of SAH was associated with poorer outcome than treatment thereafter (adjusted OR 1.67; 95% CI 1.04–2.69). Subgroup analysis with adjustment for ICH volume, location, and midline shift resulted in no association between time from ictus to treatment and outcome (OR 0.99; 95% CI 0.94–1.07). CONCLUSIONS The most important associative factor for ICH is neurological status on admission. The finding regarding the value of ultra-early treatment suggests the need to more robustly reevaluate the concept that hematoma evacuation of an ICH and repair of a ruptured aneurysm within 6 hours of ictus is the most optimal treatment path.

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Quantitative mapping of cerebral oxygen metabolism using breath-hold calibrated fMRI

10.1101/2021.04.08.438939 ◽

2021 ◽

Author(s):

Michael Germuska ◽

Rachael C Stickland ◽

Antonio Maria Chiarelli ◽

Hannah L Chandler ◽

Richard G Wise

Keyword(s):

Blood Flow ◽

Oxygen Metabolism ◽

Oxygen Extraction Fraction ◽

Arterial Oxygen ◽

Breath Holding ◽

Breath Hold ◽

Neural Function ◽

Cerebral Oxygen ◽

Cerebral Oxygen Metabolism

Magnetic resonance imaging (MRI) offers the possibility to non-invasively map the rate of cerebral metabolic oxygen consumption (CMRO2), which is essential for understanding and monitoring neural function in both health and disease. Existing methods of mapping CMRO2, based on respiratory modulation of arterial spin labelling (ASL) and blood oxygen level dependent (BOLD) signals, require lengthy acquisitions and independent modulation of both arterial oxygen and carbon dioxide levels. Here, we present a new simplified method for mapping the rate of cerebral oxygen metabolism that can be performed using a simple breath-holding paradigm. The method incorporates flow-diffusion modelling of oxygen transport and physiological constraints to create a non-linear mapping between the maximum BOLD signal, M, baseline blood flow (CBF0), and CMRO2. A gradient boosted decision tree is used to learn this mapping directly from simulated MRI data. Modelling studies demonstrate that the proposed method is robust to variation in cerebral physiology and metabolism. This new gas-free methodology offers a rapid and pragmatic alternative to existing dual-calibrated methods, removing the need for specialist respiratory equipment and long acquisition times. In-vivo testing of the method, using an 8-minute 45 second protocol of repeated breath-holding, was performed on 15 healthy volunteers, producing quantitative maps of cerebral blood flow (CBF), oxygen extraction fraction (OEF), and CMRO2.

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Concurrent tissue oxymetry and blood flowmetry to assess the effect of drugs on cerebral oxygen metabolism

Biointerface Research in Applied Chemistry ◽

10.33263/briac103.552555 ◽

2020 ◽

Vol 10 (3) ◽

pp. 5552-5555

Keyword(s):

Brain Activity ◽

Oxygen Metabolism ◽

Brain Regions ◽

Cerebral Oxygen ◽

Cerebral Oxygen Metabolism ◽

Cns Depressant ◽

Carbon Dioxide Co2 ◽

Blood Flowmetry ◽

The Brain

An Oxylite/LDF system (Oxford Optronix, UK) driven by a sensor made of optical fibres for the tissue oxygen tension (pO2) and for the Laser Doppler Blood Flow (BF) was implemented. This has allowed pO2 and BF real time measurements in discrete brain areas of anaesthetised rats that were then challenged with exogenous oxygen (O2) and carbon dioxide (CO2). The results gathered were compared with data obtained following treatment with drugs that have excitatory influence upon the brain activity such as amphetamine or with a central nervous system (CNS) depressant such as CI-966. Altogether these experiments support the methodology for in vivo investigation of pharmacological effects on cerebral oxygen metabolism and could provide new understandings on the effects of psychostimulants and anticonvulsants on selected brain regions.

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Cerebral oxygen metabolism monitoring under hypothermia for severe subarachnoid hemorrhage: report of eight cases

Acta Neurologica Scandinavica ◽

10.1034/j.1600-0404.2002.01300.x ◽

2002 ◽

Vol 106 (5) ◽

pp. 314-318 ◽

Cited By ~ 12

Author(s):

T. Nakamura ◽

N. Tatara ◽

K. Morisaki ◽

K. Kawakita ◽

S. Nagao

Keyword(s):

Subarachnoid Hemorrhage ◽

Oxygen Metabolism ◽

Cerebral Oxygen ◽

Cerebral Oxygen Metabolism

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Abstract TP418: Red Blood Cell Transfusion Increases Cerebral Oxygen Delivery After Subarachnoid Hemorrhage Regardless of Hemoglobin Level

Stroke ◽

10.1161/str.48.suppl_1.tp418 ◽

2017 ◽

Vol 48 (suppl_1) ◽

Author(s):

Rajat Dhar ◽

Allyson Zazulia ◽

Tom Videen ◽

Colin P Derdeyn ◽

Michael Diringer

Keyword(s):

At Risk ◽

Subarachnoid Hemorrhage ◽

Oxygen Delivery ◽

Delayed Cerebral Ischemia ◽

Brain Regions ◽

Oxygen Extraction Fraction ◽

Red Blood Cell Transfusion ◽

Cerebral Oxygen ◽

Arterial Blood ◽

Patients At Risk

Introduction: Impaired oxygen delivery (DO 2 ), as a result of reduced cerebral blood flow (CBF), is the hallmark of delayed cerebral ischemia (DCI) following subarachnoid hemorrhage (SAH). Anemia further contributes to reductions in DO 2 and places the brain at risk for infarction. Transfusion, by raising hemoglobin (Hgb) and oxygen content of arterial blood, may be able to reduce the risk of ischemia. However, it is unknown whether an Hgb threshold exists above which CBF will fall sufficient to negate any benefit of transfusion on DO 2 . In this physiologic proof-of-principle study we evaluated whether transfusion improves DO 2 and reduces brain vulnerable to ischemia across a broad range of Hgb values. Methods: 47 SAH patients with/at-risk for DCI with Hgb 7-13 g/dl were transfused 1 unit of red blood cells (RBCs). 15 O-PET imaging was used to measure CBF, DO 2 , and oxygen extraction fraction (OEF) before and after transfusion. Vulnerable brain regions were defined as those with baseline DO 2 < 4.5 ml/100g/min (equivalent to CBF of 25 ml/100g/min at low-normal Hgb). Results: Baseline Hgb was 9.7 g/dl (range 6.9-12.5) and CBF was 43±11 ml/100g/min. After transfusion, Hgb rose by 12% and global DO 2 by 10% (from 5.0 to 5.5 ml/100g/min, p=0.001), with CBF only marginally lower; response to transfusion was not dependent on Hgb level. Transfusion resulted in a greater (16%) rise in DO 2 , associated with a larger reduction in OEF, in vulnerable brain regions (p=0.005 for low vs. normal regions), even after adjusting for Hgb. Number of vulnerable regions was reduced from median 9 to 4 per patient (p=0.005). Conclusions: Transfusion of RBCs to patients at-risk for DCI improves cerebral oxygen delivery, preferentially to vulnerable regions and reduces brain at-risk for ischemia. This physiologic benefit does not appear limited to those with severe anemia but persists to Hgb as high as 13 g/dl. Our findings suggest that restrictive transfusion practices may not be appropriate in this population. Prospective trials are needed to determine if these physiologic benefits outweigh risks of transfusion and translate into clinical prevention of DCI.

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Clinical condition of 120 patients alive at 3 years after poor-grade aneurysmal subarachnoid hemorrhage

Acta Neurochirurgica ◽

10.1007/s00701-021-04725-2 ◽

2021 ◽

Author(s):

Anniina H. Autio ◽

Juho Paavola ◽

Joona Tervonen ◽

Maarit Lång ◽

Terhi J. Huuskonen ◽

...

Keyword(s):

Subarachnoid Hemorrhage ◽

Clinical Condition ◽

Hospice Care ◽

Aneurysmal Subarachnoid Hemorrhage ◽

Blood Clot ◽

Neurointensive Care ◽

Intracerebral Hematoma ◽

Poor Grade ◽

Final Study ◽

Study Population

Abstract Background To study the clinical condition of poor-grade aneurysmal subarachnoid hemorrhage (aSAH) patients alive at 3 years after neurointensive care. Methods Of the 769 consecutive aSAH patients from a defined population (2005–2015), 269 (35%) were in poor condition on admission: 145 (54%) with H&H 4 and 124 (46%) with H&H 5. Their clinical lifelines were re-constructed from the Kuopio Intracranial Aneurysm Database and Finnish nationwide registries. Of the 269 patients, 155 (58%) were alive at 14 days, 125 (46%) at 12 months, and 120 (45%) at 3 years. Results The 120 H&H 4–5 patients alive at 3 years form the final study population. On admission, 73% had H&H 4 but only 27% H&H 5, 59% intracerebral hematoma (ICH; median 22 cm3), and 26% intraventricular blood clot (IVH). The outcome was favorable (mRS 0–1) in 45% (54 patients: ICH 44%; IVH clot 31%; shunt 46%), moderate (mRS 2–3) in 30% (36 patients: ICH 64%; IVH clot 19%; shunt 42%), and unfavorable (mRS 4–5) in 25% (30 patients: ICH 80%; IVH clot 23%; shunt 50%). A total of 46% carried a ventriculoperitoneal shunt. ICH volume was a significant predictor of mRS at 3 years. Conclusions Of poor-grade aSAH patients, 45% were alive at 3 years, even 27% of those extending to pain (H&H 5). Of the survivors, 75% were at least in moderate condition, while only 2.6% ended in hospice care. Consequently, we propose non-selected admission to neurointensive care (1) for a possibility of moderate outcome, and (2), in case of brain death, possibly improved organ donation rates.

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Effect of supplemental dexmedetomidine in interventional embolism on cerebral oxygen metabolism in patients with intracranial aneurysms

Journal of International Medical Research ◽

10.1177/03000605211002960 ◽

2021 ◽

Vol 49 (4) ◽

pp. 030006052110029

Author(s):

Zhang Guo ◽

Weiwei Wang ◽

Dahua Xie ◽

Ruisheng Lin

Keyword(s):

Intracranial Aneurysms ◽

Jugular Vein ◽

Oxygen Metabolism ◽

Cerebral Oxygen ◽

Cerebral Oxygen Metabolism ◽

Time Points ◽

Venous Oxygen Saturation ◽

Group A ◽

Group B ◽

Oxygen Difference

Objective To investigate the effect of supplemental dexmedetomidine in interventional embolism on cerebral oxygen metabolism in patients with intracranial aneurysms. Methods Ninety patients who underwent interventional embolism of intracranial aneurysms were equally divided into Group A and Group B. In Group A, dexmedetomidine was injected intravenously 10 minutes before inducing anesthesia, with a loading dose of 0.6 µg/kg followed by 0.4 µg/kg/hour. Group B received the same amount of normal saline by the same injection method. Heart rate (HR), mean arterial pressure (MAP), arterial–jugular venous oxygen difference [D(a-jv) (O2)], cerebral oxygen extraction [CE (O2)], and intraoperative propofol use were recorded before inducing anesthesia (T0) and at five time points thereafter. Results The amount of propofol in Group A was lower vs Group B. At all five time points after T0, HR, MAP, D(a-jv) (O2), and CE (O2) in Group A were significantly lower vs Group B, with significant differences for jugular venous oxygen saturation (SjvO2) and the oxygen content of the internal jugular vein (CjvO2) between the groups. Conclusion Dexmedetomidine resulted in less intraoperative propofol, lower D(a-jv) (O2) and CE (O2), and improved cerebral oxygen metabolism.

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