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Leth-Olsen M, Døhlen G, Torp H, Nyrnes SA. Cerebral blood flow dynamics during cardiac surgery in infants. Pediatr Res 2024:10.1038/s41390-024-03161-z. [PMID: 38570558 DOI: 10.1038/s41390-024-03161-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/06/2023] [Revised: 12/21/2023] [Accepted: 03/10/2024] [Indexed: 04/05/2024]
Abstract
BACKGROUND In this pilot study, we investigated continuous cerebral blood flow velocity measurements to explore cerebrovascular hemodynamics in infants with congenital heart disease undergoing cardiac surgery. METHODS A non-invasive transfontanellar cerebral Doppler monitor (NeoDoppler) was used to monitor 15 infants (aged eight days to nine months) during cardiac surgery with cardiopulmonary bypass. Numerical and visual analyses were conducted to assess trends and events in Doppler measurements together with standard monitoring equipment. The mean flow index, calculated as the moving Pearson correlation between mean arterial pressure and time averaged velocity, was utilized to evaluate dynamic autoregulation. Two levels of impaired autoregulation were defined (Mean flow index >0.3/0.45), and percentage of time above these limits were calculated. RESULTS High quality recordings were achieved during 90.6% of the monitoring period. There was a significant reduction in time averaged velocity in all periods of cardiopulmonary bypass. All patients showed a high percentage of time with impaired dynamic autoregulation, with Mean flow index >0.3 and 0.45: 73.71% ± 9.06% and 65.16% ± 11.27% respectively. Additionally, the system promptly detected hemodynamic events. CONCLUSION Continuous transfontanellar cerebral Doppler monitoring could become an additional tool in enhancing cerebral monitoring in infants during cardiac surgery. IMPACT This pilot study demonstrates the feasibility of continuous transfontanellar Doppler monitoring of cerebral blood flow velocities during cardiac surgery in infants. It also demonstrates a high proportion of time with impaired cerebral autoregulation during cardiac surgery based on the Mean flow index. Continuous transfontanellar Doppler could become a useful tool to improve cerebral monitoring and provide new pathophysiological insight.
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Affiliation(s)
- Martin Leth-Olsen
- Department of Circulation and Medical Imaging (ISB), Faculty of Medicine and Health Sciences, NTNU-Norwegian University of Science and Technology, Trondheim, Norway.
- Children's Clinic, St Olav's University Hospital, Trondheim, Norway.
| | - Gaute Døhlen
- Department of Pediatric Cardiology, Oslo University Hospital, Oslo, Norway
| | - Hans Torp
- Department of Circulation and Medical Imaging (ISB), Faculty of Medicine and Health Sciences, NTNU-Norwegian University of Science and Technology, Trondheim, Norway
| | - Siri Ann Nyrnes
- Department of Circulation and Medical Imaging (ISB), Faculty of Medicine and Health Sciences, NTNU-Norwegian University of Science and Technology, Trondheim, Norway
- Children's Clinic, St Olav's University Hospital, Trondheim, Norway
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Siddiqi AZ, Froese L, Gomez A, Sainbhi AS, Stein K, Park K, Vakitbilir N, Zeiler FA. The effect of burst suppression on cerebral blood flow and autoregulation: a scoping review of the human and animal literature. Front Physiol 2023; 14:1204874. [PMID: 37351255 PMCID: PMC10282505 DOI: 10.3389/fphys.2023.1204874] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2023] [Accepted: 05/25/2023] [Indexed: 06/24/2023] Open
Abstract
Background: Burst suppression (BS) is an electroencephalography (EEG) pattern in which there are isoelectric periods interspersed with bursts of cortical activity. Targeting BS through anaesthetic administration is used as a tool in the neuro-intensive care unit but its relationship with cerebral blood flow (CBF) and cerebral autoregulation (CA) is unclear. We performed a systematic scoping review investigating the effect of BS on CBF and CA in animals and humans. Methods: We searched MEDLINE, BIOSIS, EMBASE, SCOPUS and Cochrane library from inception to August 2022. The data that were collected included study population, methods to induce and measure BS, and the effect on CBF and CA. Results: Overall, there were 66 studies that were included in the final results, 41 of which examined animals, 24 of which examined humans, and 1 of which examined both. In almost all the studies, BS was induced using an anaesthetic. In most of the animal and human studies, BS was associated with a decrease in CBF and cerebral metabolism, even if the mean arterial pressure remained constant. The effect on CA during periods of stress (hypercapnia, hypothermia, etc.) was variable. Discussion: BS is associated with a reduction in cerebral metabolic demand and CBF, which may explain its usefulness in patients with brain injury. More evidence is needed to elucidate the connection between BS and CA.
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Affiliation(s)
- A. Zohaib Siddiqi
- Department of Medicine, Rady Faculty of Health Sciences, University of Manitoba, Winnipeg, MB, Canada
| | - Logan Froese
- Biomedical Engineering, Faculty of Engineering, University of Manitoba, Winnipeg, MB, Canada
| | - Alwyn Gomez
- Department of Human Anatomy and Cell Science, Rady Faculty of Health Sciences, University of Manitoba, Winnipeg, MB, Canada
| | - Amanjyot Singh Sainbhi
- Biomedical Engineering, Faculty of Engineering, University of Manitoba, Winnipeg, MB, Canada
| | - Kevin Stein
- Biomedical Engineering, Faculty of Engineering, University of Manitoba, Winnipeg, MB, Canada
| | - Kangyun Park
- Undergraduate Medicine, Rady Faculty of Health Sciences, University of Manitoba, Winnipeg, MB, Canada
| | - Nuray Vakitbilir
- Biomedical Engineering, Faculty of Engineering, University of Manitoba, Winnipeg, MB, Canada
| | - Frederick A. Zeiler
- Biomedical Engineering, Faculty of Engineering, University of Manitoba, Winnipeg, MB, Canada
- Department of Human Anatomy and Cell Science, Rady Faculty of Health Sciences, University of Manitoba, Winnipeg, MB, Canada
- Section of Neurosurgery, Department of Surgery, Rady Faculty of Health Sciences, University of Manitoba, Winnipeg, MB, Canada
- Department of Clinical Neuroscience, Karolinska Institute, Stockholm, Sweden
- Division of Anaesthesia, Department of Medicine, Addenbrooke’s Hospital, University of Cambridge, Cambridge, United Kingdom
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Berndt N, Kovács R, Schoknecht K, Rösner J, Reiffurth C, Maechler M, Holzhütter HG, Dreier JP, Spies C, Liotta A. Low neuronal metabolism during isoflurane-induced burst suppression is related to synaptic inhibition while neurovascular coupling and mitochondrial function remain intact. J Cereb Blood Flow Metab 2021; 41:2640-2655. [PMID: 33899556 PMCID: PMC8504408 DOI: 10.1177/0271678x211010353] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Deep anaesthesia may impair neuronal, vascular and mitochondrial function facilitating neurological complications, such as delirium and stroke. On the other hand, deep anaesthesia is performed for neuroprotection in critical brain diseases such as status epilepticus or traumatic brain injury. Since the commonly used anaesthetic propofol causes mitochondrial dysfunction, we investigated the impact of the alternative anaesthetic isoflurane on neuro-metabolism. In deeply anaesthetised Wistar rats (burst suppression pattern), we measured increased cortical tissue oxygen pressure (ptiO2), a ∼35% drop in regional cerebral blood flow (rCBF) and burst-associated neurovascular responses. In vitro, 3% isoflurane blocked synaptic transmission and impaired network oscillations, thereby decreasing the cerebral metabolic rate of oxygen (CMRO2). Concerning mitochondrial function, isoflurane induced a reductive shift in flavin adenine dinucleotide (FAD) and decreased stimulus-induced FAD transients as Ca2+ influx was reduced by ∼50%. Computer simulations based on experimental results predicted no direct effects of isoflurane on mitochondrial complexes or ATP-synthesis. We found that isoflurane-induced burst suppression is related to decreased ATP consumption due to inhibition of synaptic activity while neurovascular coupling and mitochondrial function remain intact. The neurometabolic profile of isoflurane thus appears to be superior to that of propofol which has been shown to impair the mitochondrial respiratory chain.
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Affiliation(s)
- Nikolaus Berndt
- Institute for Imaging Science and Computational Modelling in Cardiovascular Medicine Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin and Berlin Institute of Health, Berlin, Germany
| | - Richard Kovács
- Institute for Neurophysiology, Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin and Berlin Institute of Health, Berlin, Germany
| | - Karl Schoknecht
- Carl-Ludwig-Institute for Physiology, University Leipzig, Leipzig, Germany
| | - Jörg Rösner
- Neuroscience Research Center, Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin and Berlin Institute of Health, Berlin, Germany
| | - Clemens Reiffurth
- Center for Stroke Research Berlin, Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany.,Department of Experimental Neurology, Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany
| | - Mathilde Maechler
- Institute for Neurophysiology, Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin and Berlin Institute of Health, Berlin, Germany
| | - Hermann-Georg Holzhütter
- Institute of Biochemistry, Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin and Berlin Institute of Health, Berlin, Germany
| | - Jens P Dreier
- Center for Stroke Research Berlin, Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany.,Department of Experimental Neurology, Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany.,Department of Neurology, Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany.,Bernstein center for Computational Neuroscience, Charité - Universitätsmedizin, Humboldt-Universität zu Berlin and Technische Universität Berlin, Berlin, Germany.,Einstein Center for Neuroscience, Charité - Universitätsmedizin Berlin, the Freie Universität Berlin, the Humboldt-Universität zu Berlin and the Technische Universität Berlin, Berlin, Germany
| | - Claudia Spies
- Department of Anesthesiology and Intensive Care, Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin and Berlin Institute of Health, Berlin, Germany.,Berlin Institute of Health, Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin and Berlin Institute of Health, Berlin, Germany
| | - Agustin Liotta
- Institute for Neurophysiology, Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin and Berlin Institute of Health, Berlin, Germany.,Department of Experimental Neurology, Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany.,Department of Anesthesiology and Intensive Care, Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin and Berlin Institute of Health, Berlin, Germany.,Berlin Institute of Health, Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin and Berlin Institute of Health, Berlin, Germany
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Zeiler FA, Ercole A, Beqiri E, Cabeleira M, Aries M, Zoerle T, Carbonara M, Stocchetti N, Smielewski P, Czosnyka M, Menon DK. Cerebrovascular reactivity is not associated with therapeutic intensity in adult traumatic brain injury: a CENTER-TBI analysis. Acta Neurochir (Wien) 2019; 161:1955-1964. [PMID: 31240583 PMCID: PMC6704258 DOI: 10.1007/s00701-019-03980-8] [Citation(s) in RCA: 40] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2019] [Accepted: 06/11/2019] [Indexed: 02/03/2023]
Abstract
BACKGROUND Impaired cerebrovascular reactivity in adult traumatic brain injury (TBI) is known to be associated with poor outcome. However, there has yet to be an analysis of the association between the comprehensively assessed intracranial hypertension therapeutic intensity level (TIL) and cerebrovascular reactivity. METHODS Using the Collaborative European Neuro Trauma Effectiveness Research in TBI (CENTER-TBI) high-resolution intensive care unit (ICU) cohort, we derived pressure reactivity index (PRx) as the moving correlation coefficient between slow-wave in ICP and mean arterial pressure, updated every minute. Mean daily PRx, and daily % time above PRx of 0 were calculated for the first 7 days of injury and ICU stay. This data was linked with the daily TIL-Intermediate scores, including total and individual treatment sub-scores. Daily mean PRx variable values were compared for each TIL treatment score via mean, standard deviation, and the Mann U test (Bonferroni correction for multiple comparisons). General fixed effects and mixed effects models for total TIL versus PRx were created to display the relation between TIL and cerebrovascular reactivity. RESULTS A total of 249 patients with 1230 ICU days of high frequency physiology matched with daily TIL, were assessed. Total TIL was unrelated to daily PRx. Most TIL sub-scores failed to display a significant relationship with the PRx variables. Mild hyperventilation (p < 0.0001), mild hypothermia (p = 0.0001), high levels of sedation for ICP control (p = 0.0001), and use vasopressors for CPP management (p < 0.0001) were found to be associated with only a modest decrease in mean daily PRx or % time with PRx above 0. CONCLUSIONS Cerebrovascular reactivity remains relatively independent of intracranial hypertension therapeutic intensity, suggesting inadequacy of current TBI therapies in modulating impaired autoregulation. These findings support the need for investigation into the molecular mechanisms involved, or individualized physiologic targets (ICP, CPP, or Co2) in order to treat dysautoregulation actively.
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Affiliation(s)
- Frederick A. Zeiler
- Division of Anaesthesia, Addenbrooke’s Hospital, University of Cambridge, Cambridge, UK
- Department of Surgery, Rady Faculty of Health Sciences, University of Manitoba, Winnipeg, MB R3A 1R9 Canada
- Brain Physics Laboratory, Division of Neurosurgery, Department of Clinical Neurosciences, Addenbrooke’s Hospital, University of Cambridge, Cambridge, UK
- Department of Human Anatomy and Cell Science, Rady Faculty of Health Sciences, University of Manitoba, Winnipeg, Canada
- Department of Biomedical Engineering, Faculty of Engineering, University of Manitoba, Winnipeg, Canada
| | - Ari Ercole
- Division of Anaesthesia, Addenbrooke’s Hospital, University of Cambridge, Cambridge, UK
| | - Erta Beqiri
- Brain Physics Laboratory, Division of Neurosurgery, Department of Clinical Neurosciences, Addenbrooke’s Hospital, University of Cambridge, Cambridge, UK
| | - Manuel Cabeleira
- Brain Physics Laboratory, Division of Neurosurgery, Department of Clinical Neurosciences, Addenbrooke’s Hospital, University of Cambridge, Cambridge, UK
| | - Marcel Aries
- Department of Intensive Care, Maastricht UMC, Maastricht, Netherlands
| | - Tommaso Zoerle
- Neuro ICU Fondazione IRCCS Cà Granda Ospedale Maggiore Policlinico, Milan, Italy
| | - Marco Carbonara
- Neuro ICU Fondazione IRCCS Cà Granda Ospedale Maggiore Policlinico, Milan, Italy
| | - Nino Stocchetti
- Neuro ICU Fondazione IRCCS Cà Granda Ospedale Maggiore Policlinico, Milan, Italy
- Department of Physiopathology and Transplantation, Milan University, Milan, Italy
| | - Peter Smielewski
- Brain Physics Laboratory, Division of Neurosurgery, Department of Clinical Neurosciences, Addenbrooke’s Hospital, University of Cambridge, Cambridge, UK
| | - Marek Czosnyka
- Brain Physics Laboratory, Division of Neurosurgery, Department of Clinical Neurosciences, Addenbrooke’s Hospital, University of Cambridge, Cambridge, UK
- Institute of Electronic Systems, Warsaw University of Technology, Warsaw, Poland
| | - David K. Menon
- Division of Anaesthesia, Addenbrooke’s Hospital, University of Cambridge, Cambridge, UK
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6
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Niu B, Fang Y, Miao JM, Yu Y, Cao F, Chen HX, Zhang ZG, Mei W, Tian YK. Minimal alveolar concentration of sevoflurane for induction of isoelectric electroencephalogram in middle-aged adults. Br J Anaesth 2013; 112:72-8. [PMID: 23975567 DOI: 10.1093/bja/aet280] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
BACKGROUND We determined the minimal alveolar concentration (MAC) of sevoflurane inducing an isoelectric EEG in 50% of adult subjects (MACie). METHODS We included 31 middle-aged subjects; 30 subjects finished the study protocol and received sevoflurane at preselected concentrations according to a modified Dixon 'up-and-down' design starting at 1.7 vol% with 0.2 vol% steps size. General anaesthesia was induced and maintained with sevoflurane; tracheal intubation was facilitated with cisatracurium. After a period of 30 min before skin incision, the state of isoelectric EEG was considered as significant when a burst suppression ratio of 100% lasted for >1 min. The haemodynamic responses to skin incision and the vasopressor requirement to maintain stable haemodynamic status were also analysed according to the EEG state. RESULTS MACie was 3.5% (95% confidence interval, 3.4-3.7%) in middle-aged subjects. When compared with subjects not in isoelectric EEG state, subjects in isoelectric EEG state received more phenylephrine to maintain stable haemodynamics (10 of 10 compared with 7 of 20 subjects, P=0.001) and experienced less sympathetic responses to skin incision (1 of 10 compared with 11 of 20 subjects, P=0.024). CONCLUSIONS MACie for sevoflurane was ∼2.1 times MAC for immobilization in phenobarbital premedicated middle-aged adults. Sevoflurane-induced isoelectric EEG state is associated with significant cardiovascular depression but reduced haemodynamic responses to skin incision.
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Affiliation(s)
- B Niu
- Department of Anaesthesiology and Pain Medicine, Tongji Hospital
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7
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Blood pressure regulation IX: cerebral autoregulation under blood pressure challenges. Eur J Appl Physiol 2013. [PMID: 23737006 DOI: 10.1007/s00421‐013‐2667‐y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
Cerebral autoregulation (CA) is integral to the delicate process of maintaining stable cerebral perfusion and brain tissue oxygenation against changes in arterial blood pressure. The last four decades has seen dramatic advances in understanding CA physiology, and the role that CA might play in the causation and progression of disease processes that affect the cerebral circulation such as stroke. However, the translation of these basic scientific advances into clinical practice has been limited by the maintenance of old constructs and because there are persistent gaps in our understanding of how this vital vascular mechanism should be quantified. In this review, we re-evaluate relevant studies that challenge established paradigms about how the cerebral perfusion pressure and blood flow are related. In the context of blood pressure being a major haemodynamic challenge to the cerebral circulation, we conclude that: (1) the physiological properties of CA remain inconclusive, (2) many extant methods for CA characterisation are based on simplistic assumptions that can give rise to misleading interpretations, and (3) robust evaluation of CA requires thorough consideration not only of active vasomotor function, but also the unique properties of the intracranial environment.
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8
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Tzeng YC, Ainslie PN. Blood pressure regulation IX: cerebral autoregulation under blood pressure challenges. Eur J Appl Physiol 2013; 114:545-59. [PMID: 23737006 PMCID: PMC3929776 DOI: 10.1007/s00421-013-2667-y] [Citation(s) in RCA: 153] [Impact Index Per Article: 13.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2013] [Accepted: 05/21/2013] [Indexed: 12/11/2022]
Abstract
Cerebral autoregulation (CA) is integral to the delicate process of maintaining stable cerebral perfusion and brain tissue oxygenation against changes in arterial blood pressure. The last four decades has seen dramatic advances in understanding CA physiology, and the role that CA might play in the causation and progression of disease processes that affect the cerebral circulation such as stroke. However, the translation of these basic scientific advances into clinical practice has been limited by the maintenance of old constructs and because there are persistent gaps in our understanding of how this vital vascular mechanism should be quantified. In this review, we re-evaluate relevant studies that challenge established paradigms about how the cerebral perfusion pressure and blood flow are related. In the context of blood pressure being a major haemodynamic challenge to the cerebral circulation, we conclude that: (1) the physiological properties of CA remain inconclusive, (2) many extant methods for CA characterisation are based on simplistic assumptions that can give rise to misleading interpretations, and (3) robust evaluation of CA requires thorough consideration not only of active vasomotor function, but also the unique properties of the intracranial environment.
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Affiliation(s)
- Yu-Chieh Tzeng
- Cardiovascular Systems Laboratory, Centre for Translational Physiology, University of Otago, 23A Mein Street, PO Box 7343, Wellington South, New Zealand,
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Abstract
Temperature fluctuations significantly impact neurological injuries in intensive care units. As the benefits of therapeutic hypothermia continue to unfold, many of these discoveries are generated by studies in animal models undergoing experimental procedures under the influence of anesthetics. We studied the effect of induced hypothermia on neural electrophysiological signals of an uninjured brain in a rodent model while under isoflurane. Fourteen rats were divided into 2 groups (n=7 each), on the basis of electrode placement at either frontal-occipital or primary somatosensory cortical locations. Neural signals were recorded during normothermia (T=36.5 to 37.5°C), mild hypothermia (T=32 to 34°C), and hyperthermia (T=38.5 to 39.5°C). The burst-suppression ratio was used to evaluate electroencephalography (EEG), and amplitude-latency analysis was used to assess somatosensory-evoked potentials (SSEPs). Hypothermia was characterized by an increased burst-suppression ratio (mean±SD) of 0.58±0.06 in hypothermia versus 0.16±0.13 in normothermia, P<0.001 in frontal-occipital; and 0.30±0.13 in hypothermia versus 0.04±0.04 in normothermia, P=0.006 in somatosensory. There was potentiation of SSEP (2.89±1.24 times the normothermic baseline in hypothermia, P=0.02) and prolonged peak latency (N10: 10.8±0.4 ms in hypothermia vs. 9.1±0.3 ms in normothermia; P15: 16.2±0.8 ms in hypothermia vs. 13.7±0.6 ms in normothermia; P<0.001), whereas hyperthermia was primarily marked by shorter peak latencies (N10: 8.6±0.2 ms, P15: 12.6±0.4 m; P<0.001). In the absence of brain injury in a rodent model, hypothermia induces significant increase to the SSEP amplitude while increasing SSEP latency. Hypothermia also suppressed EEGs at different regions of the brain by different degrees. The changes to SSEP and EEG are both reversible with subsequent rewarming.
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Lee JK, Blaine Easley R, Brady KM. Neurocognitive monitoring and care during pediatric cardiopulmonary bypass-current and future directions. Curr Cardiol Rev 2011; 4:123-39. [PMID: 19936287 PMCID: PMC2779352 DOI: 10.2174/157340308784245766] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/17/2007] [Revised: 12/17/2007] [Accepted: 12/21/2007] [Indexed: 11/22/2022] Open
Abstract
Neurologic injury in patients with congenital heart disease remains an important source of morbidity and mortality. Advances in surgical repair and perioperative management have resulted in longer life expectancies for these patients. Current practice and research must focus on identifying treatable risk factors for neurocognitive dysfunction, advancing methods for perioperative neuromonitoring, and refining treatment and care of the congenital heart patient with potential neurologic injury. Techniques for neuromonitoring and future directions will be discussed.
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Affiliation(s)
- Jennifer K Lee
- Departments of Anesthesiology/Critical Care Medicine and Pediatrics, Johns Hopkins Medical Institutions, Baltimore, MD, USA
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Reinsfelt B, Westerlind A, Ricksten SE. The effects of sevoflurane on cerebral blood flow autoregulation and flow-metabolism coupling during cardiopulmonary bypass. Acta Anaesthesiol Scand 2011; 55:118-23. [PMID: 21039354 DOI: 10.1111/j.1399-6576.2010.02324.x] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
BACKGROUND previous studies on non-cardiac surgical patients have shown that cerebral pressure-flow autoregulation and cerebral flow-metabolism coupling are maintained with sevoflurane. The effects of sevoflurane on cerebral blood flow (CBF) autoregulation and flow-metabolism coupling during cardiopulmonary bypass (CPB) have not been studied previously. METHODS the effects of sevoflurane-induced burst suppression, monitored with electroencephalography (EEG), on cerebral blood flow velocity (CBFV), cerebral oxygen extraction (COE) and flow autoregulation, were studied in 16 patients undergoing cardiac surgery. The experimental procedure was performed during non-pulsatile CPB with mild hypothermia (34 degreesC) in fentanyl/droperidol-anesthetized patients. Middle cerebral artery transcranial Doppler flow velocity, right jugular vein bulb oxygen saturation and jugular venous pressure were measured continuously. Autoregulation was tested during changes in the mean arterial pressure (40-90 mmHg), induced by sodium nitroprusside and norepinephrine before (control), and during additional sevoflurane administration, in a dose that resulted in an EEG burst-suppression level of 4-6/min. RESULTS sevoflurane, at an inspired concentration of 3.36 ± 0.03%, induced a 17% decrease in CBFV (P<0.05) and a 22% decrease in COE (P<0.05) compared with the control. The slope of the positive relationship between CBFV and cerebral perfusion pressure was steeper with sevoflurane (p<0.01) compared with control measurements, as was the slope of the negative relationship between cpp and coe (p<0.01). CONCLUSION burst-suppression doses of sevoflurane exert an intrinsic cerebral vasodilatory effect, which impairs CBF autoregulation during mildly hypothermic CPB. Furthermore, during sevoflurane administration, CBF is in excess relative to oxygen demand, indicating a partial loss of the cerebral flow-metabolism coupling.
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Affiliation(s)
- B Reinsfelt
- Department of Cardiothoracic Anaesthesia and Intensive Care, Sahlgrenska University Hospital, Gothenburg, Sweden
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Calvo Vecino JM, Abad Gurumeta A, Garrido Reche E, Chao Novo K, Orts Castro A, Tomás Lachos J. [Transcranial Doppler ultrasound, bispectral index, and electroencephalographic monitoring of entropy during pediatric total intravenous anesthesia]. REVISTA ESPANOLA DE ANESTESIOLOGIA Y REANIMACION 2010; 57:621-629. [PMID: 22283014 DOI: 10.1016/s0034-9356(10)70298-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
BACKGROUND AND OBJECTIVE Transcranial Doppler ultrasound is a noninvasive technique for monitoring the velocity of blood flow in the main intracranial arteries, particularly those in the circle of Willis. Our aim was to assess whether changes in cerebral arterial blood flow in anesthetized pediatric patients detected by pulsed Doppler ultrasound correlate with changes in the bispectral (BIS) index and electroencephalographic state and response entropy (ES and ER, respectively). MATERIAL AND METHODS Prospective, blinded observational study of 36 pediatric patients (age range, 5 to 11 years) under total intravenous anesthesia for minor surgical procedures. Propofol and fentanyl were used for induction; propofol and remifentanil in continuous perfusion and a single dose of cisatracurium were used for maintenance. In all patients we monitored hemodynamic and respiratory patterns, gases, temperature, and hypnosis (BIS, ES and ER) as well as cerebral blood flow estimated by pulsed Doppler ultrasound in the middle cerebral artery. Raw data were subjected to statistical smoothing. The resistance index, pulsatility index, mean velocity, and estimated baseline cerebral blood flow were calculated from the Doppler sonogram. We then studied the correlations between the Doppler-derived values and BIS, ES, ER, fraction of end-tidal carbon dioxide, and temperature. The variables were entered into logistic regression. RESULTS The pattern at induction indicated high resistance (low mean velocities and high pulsatility indexes) until the lowest BIS and ES values of 31 and 29, respectively, were reached. During maintenance, the Doppler sonogram pattern was slower (normalization of the pulsatility index, the resistance index, and mean velocity). Changes in flow and absolute entropy and BIS values were statistically correlated (Pearson's r values > or = 0.91); there was 95.6% agreement between Doppler values and BIS and agreement between BIS and ES values of 35-45. On awakening, flow velocities approached baseline values when BIS and ES rose to between 90 and 98. The estimated cerebral blood flow underwent fluctuations coinciding with an approximately concomitant increase or decrease in BIS (r > 0.95); the response of BIS was slightly delayed by no more than a minute but there was no corresponding response of entropy measurements. CONCLUSIONS We report Doppler ultrasound patterns during anesthesia with propofol. Systems for monitoring hypnosis could be considered indirect measurements of cerebral blood flow; BIS measurements are more sensitive to flow change. Transcranial Doppler ultrasound facilitates the observation of changes in blood flow that occur at different levels of hypnosis during anesthesia.
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Affiliation(s)
- J M Calvo Vecino
- Servicio de Anestesiología y Reanimación, Complejo Hospitalario de Vallecas, Hospital Infanta Leonor, Vallecas, Madrid.
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Abad Gurumeta A, Calvo Vecino JM, Abad Motos A, Olidén Gutiérrez L, García Alvarez R, Nieto Moreno A. [Transcranial Doppler ultrasound, bispectral index, and electroencephalographic monitoring of entropy during sevoflurane anesthesia in children]. REVISTA ESPANOLA DE ANESTESIOLOGIA Y REANIMACION 2010; 57:630-638. [PMID: 22283015 DOI: 10.1016/s0034-9356(10)70299-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
BACKGROUND AND OBJECTIVE Transcranial Doppler ultrasound is a noninvasive technique for monitoring the velocity of blood flow in the main intracranial arteries, particularly those in the circle of Willis. Our aim was to assess whether changes in cerebral arterial blood flow in pediatric patients under sevoflurane anesthesia demonstrated by pulsed Doppler ultrasound correlate with changes in the bispectral (BIS) index and electroencephalographic state and response entropy (ES and ER, respectively). MATERIAL AND METHODS Prospective, blinded observational study of 36 pediatric patients (age range, 5 to 11 years; ASA physical status classification, 1-2) under sevoflurane anesthesia for minor surgical procedures. Anesthesia was induced with sevoflurane and maintained with 2.5% sevoflurane in an inspired oxygen fraction of 50% in air. A continuous perfusion of remifentanil was provided for analgesia. In all patients we monitored hemodynamic and respiratory patterns, gases, temperature, and hypnosis (BIS, ES and ER) as well as cerebral blood flow estimated by pulsed Doppler ultrasound in the middle cerebral artery. The resistance index, pulsatility index, mean velocity, and estimated baseline cerebral blood flow were calculated from the Doppler sonogram. Correlations (Pearson's r) were calculated between BIS, ES, ER, the pulsatility index, resistance index, mean flow velocity, estimated cerebral blood flow, fraction of end-tidal carbon dioxide, and temperature. A regression model was constructed. RESULTS Induction caused a pattern of high velocity (elevated mean velocity and normal or reduced pulsatility index) until the lowest BIS and ES values of 31 and 29, respectively, were reached. During maintenance, the Doppler sonogram pattern was slower (normalization of the pulsatility index, the resistance index, and mean velocity). Changes in flow and absolute entropy and BIS values were statistically correlated (Pearson's r values > or = 0.91); there was 95.6% agreement between Doppler values and BIS and agreement between BIS and ES values of 35 to 45. On awakening, flow velocities approached baseline values when BIS and ES rose to between 90 and 98. The estimated cerebral blood flow underwent fluctuations coinciding with an approximately concomitant increase or decrease in BIS (r > 0.95); the BIS response occurred with a slight delay of no more than a minute. The entropy measurements did not reflect the fluctuations. CONCLUSIONS We show Doppler ultrasound patterns during anesthetic induction with sevoflurane. Systems for monitoring hypnosis could be considered indirect measurements of cerebral blood flow; BIS measurements are more sensitive to change. Transcranial Doppler ultrasound facilitates the observation of changes in blood flow that occur at different levels of hypnosis during anesthesia.
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Affiliation(s)
- A Abad Gurumeta
- Servicio de Anestesiología y Reanimación del Hospital Infanta Sofía, Madrid
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Calderon-Arnulphi M, Alaraj A, Amin-Hanjani S, Mantulin WW, Polzonetti CM, Gratton E, Charbel FT. Detection of cerebral ischemia in neurovascular surgery using quantitative frequency-domain near-infrared spectroscopy. J Neurosurg 2007; 106:283-90. [PMID: 17410713 DOI: 10.3171/jns.2007.106.2.283] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
OBJECT There is great value in monitoring for signs of ischemia during neurovascular procedures. Current intraoperative monitoring techniques provide real-time feedback with limited accuracy. Quantitative frequency-domain near-infrared spectroscopy (Q-NIRS) allows measurement of tissue oxyhemoglobin (HbO2), deoxyhemoglobin (HHb), and total hemoglobin (tHb) concentrations and brain tissue oxygen saturation (SO2), which could be useful when monitoring for evidence of intraoperative ischemia. METHODS Using Q-NIRS, the authors monitored 25 neurovascular procedures including aneurysm clip placement, arteriovenous malformation resection, carotid endarterectomy, superficial temporal artery-middle cerebral artery (MCA) bypass surgery, external carotid artery-MCA bypass surgery, encephaloduromyosynangiosis, and balloon occlusion testing. The Q-NIRS technology provides measurable cerebral oxygenation values independent from those of the scalp tissue. Thus, alterations in the variables measured with Q-NIRS quantitatively reflect cerebral tissue perfusion. Bilateral monitoring was performed in all cases. Five of the patients exhibited evidence of clinical ischemic events during the procedures. One patient suffered blood loss with systemic hypotension and developed diffuse brain edema intraoperatively, one patient suffered an ischemic event intraoperatively and developed an occipital stroke postoperatively, and one patient showed slowing on electroencephalography intraoperatively during carotid clamping; in two patients balloon occlusion testing failed. In all cases of ischemic events occurring during the procedure, Q-NIRS monitoring showed a decrease in HbO2, tHb, and SO2, and an increase in HHb. CONCLUSIONS . Quantitative frequency-domain near-infrared spectroscopy provides quantifiable and continuous real-time information about brain oxygenation and hemodynamics in a noninvasive manner. This continuous intraoperative oxygenation monitoring is a promising method for detecting ischemic events during neurovascular procedures.
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Affiliation(s)
- Mateo Calderon-Arnulphi
- Department of Neurosurgery, University of Illinois at Chicago Medical Center, Chicago 60612, USA
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