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van Bohemen SJ, Rogers JM, Boughton PC, Clarke JL, Valderrama JT, Kyme AZ. Continuous non-invasive estimates of cerebral blood flow using electrocardiography signals: a feasibility study. Biomed Eng Lett 2023; 13:185-195. [PMID: 37124110 PMCID: PMC10130316 DOI: 10.1007/s13534-023-00265-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2022] [Revised: 01/11/2023] [Accepted: 01/22/2023] [Indexed: 02/12/2023] Open
Abstract
AbstractThis paper describes a potential method to detect changes in cerebral blood flow (CBF) using electrocardiography (ECG) signals, measured across scalp electrodes with reference to the same signal across the chest—a metric we term the Electrocardiography Brain Perfusion index (EBPi). We investigated the feasibility of EBPi to monitor CBF changes in response to specific tasks. Twenty healthy volunteers wore a head-mounted device to monitor EBPi and electroencephalography (EEG) during tasks known to alter CBF. Transcranial Doppler (TCD) ultrasound measurements provided ground-truth estimates of CBF. Statistical analyses were applied to EBPi, TCD right middle cerebral artery blood flow velocity (rMCAv) and EEG relative Alpha (rAlpha) data to detect significant task-induced changes and correlations. Breath-holding and aerobic exercise induced highly significant increases in EBPi and TCD rMCAv (p < 0.01). Verbal fluency also increased both measures, however the increase was only significant for EBPi (p < 0.05). Hyperventilation induced a highly significant decrease in TCD rMCAv (p < 0.01) but EBPi was unchanged. Combining all tasks, EBPi exhibited a highly significant, weak positive correlation with TCD rMCAv (r = 0.27, p < 0.01) and the Pearson coefficient between EBPi and rAlpha was r = − 0.09 (p = 0.05). EBPi appears to be responsive to dynamic changes in CBF and, can enable practical, continuous monitoring. CBF is a key parameter of brain health and function but is not easily measured in a practical, continuous, non-invasive fashion. EBPi may have important clinical implications in this context for stroke monitoring and management. Additional studies are required to support this claim.
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Kedarasetti RT, Turner KL, Echagarruga C, Gluckman BJ, Drew PJ, Costanzo F. Functional hyperemia drives fluid exchange in the paravascular space. Fluids Barriers CNS 2020; 17:52. [PMID: 32819402 PMCID: PMC7441569 DOI: 10.1186/s12987-020-00214-3] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2020] [Accepted: 08/09/2020] [Indexed: 12/20/2022] Open
Abstract
The brain lacks a conventional lymphatic system to remove metabolic waste. It has been proposed that directional fluid movement through the arteriolar paravascular space (PVS) promotes metabolite clearance. We performed simulations to examine if arteriolar pulsations and dilations can drive directional CSF flow in the PVS and found that arteriolar wall movements do not drive directional CSF flow. We propose an alternative method of metabolite clearance from the PVS, namely fluid exchange between the PVS and the subarachnoid space (SAS). In simulations with compliant brain tissue, arteriolar pulsations did not drive appreciable fluid exchange between the PVS and the SAS. However, when the arteriole dilated, as seen during functional hyperemia, there was a marked exchange of fluid. Simulations suggest that functional hyperemia may serve to increase metabolite clearance from the PVS. We measured blood vessels and brain tissue displacement simultaneously in awake, head-fixed mice using two-photon microscopy. These measurements showed that brain deforms in response to pressure changes in PVS, consistent with our simulations. Our results show that the deformability of the brain tissue needs to be accounted for when studying fluid flow and metabolite transport.
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Affiliation(s)
- Ravi Teja Kedarasetti
- Center for Neural Engineering, The Pennsylvania State University, University Park, PA, USA
- Department of Engineering Science and Mechanics, The Pennsylvania State University, University Park, PA, USA
| | - Kevin L Turner
- Center for Neural Engineering, The Pennsylvania State University, University Park, PA, USA
- Department of Biomedical Engineering, The Pennsylvania State University, University Park, PA, USA
| | - Christina Echagarruga
- Center for Neural Engineering, The Pennsylvania State University, University Park, PA, USA
- Department of Biomedical Engineering, The Pennsylvania State University, University Park, PA, USA
| | - Bruce J Gluckman
- Center for Neural Engineering, The Pennsylvania State University, University Park, PA, USA
- Department of Engineering Science and Mechanics, The Pennsylvania State University, University Park, PA, USA
- Department of Neurosurgery, The Pennsylvania State University, University Park, PA, USA
- Department of Biomedical Engineering, The Pennsylvania State University, University Park, PA, USA
| | - Patrick J Drew
- Center for Neural Engineering, The Pennsylvania State University, University Park, PA, USA.
- Department of Engineering Science and Mechanics, The Pennsylvania State University, University Park, PA, USA.
- Department of Neurosurgery, The Pennsylvania State University, University Park, PA, USA.
- Department of Biomedical Engineering, The Pennsylvania State University, University Park, PA, USA.
| | - Francesco Costanzo
- Center for Neural Engineering, The Pennsylvania State University, University Park, PA, USA.
- Department of Engineering Science and Mechanics, The Pennsylvania State University, University Park, PA, USA.
- Department of Biomedical Engineering, The Pennsylvania State University, University Park, PA, USA.
- Department of Mathematics, The Pennsylvania State University, University Park, PA, USA.
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Kedarasetti RT, Drew PJ, Costanzo F. Arterial pulsations drive oscillatory flow of CSF but not directional pumping. Sci Rep 2020; 10:10102. [PMID: 32572120 PMCID: PMC7308311 DOI: 10.1038/s41598-020-66887-w] [Citation(s) in RCA: 49] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2020] [Accepted: 05/28/2020] [Indexed: 01/05/2023] Open
Abstract
The brain lacks a traditional lymphatic system for metabolite clearance. The existence of a "glymphatic system" where metabolites are removed from the brain's extracellular space by convective exchange between interstitial fluid (ISF) and cerebrospinal fluid (CSF) along the paravascular spaces (PVS) around cerebral blood vessels has been controversial. While recent work has shown clear evidence of directional flow of CSF in the PVS in anesthetized mice, the driving force for the observed fluid flow remains elusive. The heartbeat-driven peristaltic pulsation of arteries has been proposed as a probable driver of directed CSF flow. In this study, we use rigorous fluid dynamic simulations to provide a physical interpretation for peristaltic pumping of fluids. Our simulations match the experimental results and show that arterial pulsations only drive oscillatory motion of CSF in the PVS. The observed directional CSF flow can be explained by naturally occurring and/or experimenter-generated pressure differences.
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Affiliation(s)
- Ravi Teja Kedarasetti
- Department of Engineering Science and Mechanics, The Pennsylvania State University, University Park, PA, United States
- Center for Neural Engineering, The Pennsylvania State University, University Park, PA, United States
| | - Patrick J Drew
- Department of Engineering Science and Mechanics, The Pennsylvania State University, University Park, PA, United States
- Center for Neural Engineering, The Pennsylvania State University, University Park, PA, United States
- Department of Biomedical Engineering, The Pennsylvania State University, University Park, PA, United States
- Department of Neurosurgery, The Pennsylvania State University, University Park, PA, United States
| | - Francesco Costanzo
- Department of Engineering Science and Mechanics, The Pennsylvania State University, University Park, PA, United States.
- Center for Neural Engineering, The Pennsylvania State University, University Park, PA, United States.
- Department of Biomedical Engineering, The Pennsylvania State University, University Park, PA, United States.
- Department of Mathematics, The Pennsylvania State University, University Park, PA, United States.
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Caballero-Lozada AF, Nanwani KL, Pavón F, Zorrilla-Vaca A, Zorrilla-Vaca C. Clinical Applications of Ultrasonography in Neurocritically Ill Patients. J Intensive Care Med 2020; 36:627-634. [PMID: 32153247 DOI: 10.1177/0885066620905796] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Ultrasonography is part of the multimodal monitoring of the neurocritical patient. Through transcranial color Doppler ultrasound, carotid-color Doppler ultrasound, and ocular ultrasound it is possible to diagnose and monitor a multitude of pathological conditions, such as cerebrovascular events, vasospasm, Terson syndrome, carotid atheromatosis, and brain death. Furthermore, these techniques enable the monitoring of the intracranial pressure, the cerebral perfusion pressure, and the midline deviation, which allows us to understand the patient's neurocritical pathology at their bedside, in a noninvasive way. Although none of these tools have yet been shown to improve patient prognosis, the dissemination of knowledge and management of neurovascular ultrasonography could significantly improve the comprehensive management of neurocritical patients.
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Affiliation(s)
| | - Kapil Laxman Nanwani
- Department of Intensive Medicine, 16268University Hospital La Paz-Cantoblanco-Carlos III, Madrid, Spain
| | - Favio Pavón
- Department of Anaesthesiology, 28006Universidad del Valle, Cali, Colombia
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Kaczynski J, Home R, Shields K, Walters M, Whiteley W, Wardlaw J, Newby DE. Reproducibility of Transcranial Doppler ultrasound in the middle cerebral artery. Cardiovasc Ultrasound 2018; 16:15. [PMID: 30200977 PMCID: PMC6131943 DOI: 10.1186/s12947-018-0133-z] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/16/2018] [Accepted: 07/19/2018] [Indexed: 12/14/2022] Open
Abstract
BACKGROUND Transcranial Doppler ultrasound remains the only imaging modality that is capable of real-time measurements of blood flow velocity and microembolic signals in the cerebral circulation. We here assessed the repeatability and reproducibility of transcranial Doppler ultrasound in healthy volunteers and patients with symptomatic carotid artery stenosis. METHODS Between March and August 2017, we recruited 20 healthy volunteers and 20 patients with symptomatic carotid artery stenosis. In a quiet temperature-controlled room, two 1-h transcranial Doppler measurements of blood flow velocities and microembolic signals were performed sequentially on the same day (within-day repeatability) and a third 7-14 days later (between-day reproducibility). Levels of agreement were assessed by interclass correlation co-efficient. RESULTS In healthy volunteers (31±9 years, 11 male), within-day repeatability of Doppler measurements were 0.880 (95% CI 0.726-0.950) for peak velocity, 0.867 (95% CI 0.700-0.945) for mean velocity, and 0.887 (95% CI 0.741-0.953) for end-diastolic velocity. Between-day reproducibility was similar but lower: 0.777 (95% CI 0.526-0.905), 0.795 (95% CI 0.558-0.913), and 0.674 (95% CI 0.349-0.856) respectively. In patients (72±11 years, 11 male), within-day repeatability of Doppler measurements were higher: 0.926 (95% CI 0.826-0.970) for peak velocity, 0.922 (95% CI 0.817-0.968) for mean velocity, and 0.868 (95% CI 0.701-0.945) for end-diastolic velocity. Similarly, between-day reproducibility revealed lower values: 0.800 (95% CI 0.567-0.915), 0.786 (95% CI 0.542-0.909), and 0.778 (95% CI 0.527-0.905) respectively. In both cohorts, the intra-observer Bland Altman analysis demonstrated acceptable mean measurement differences and limits of agreement between series of middle cerebral artery velocity measurements with very few outliers. In patients, the carotid stenoses were 30-40% (n = 9), 40-50% (n = 6), 50-70% (n = 3) and > 70% (n = 2). No spontaneous embolisation was detected in either of the groups. CONCLUSIONS Transcranial Doppler generates reproducible data regarding the middle cerebral artery velocities. However, larger studies are needed to validate its clinical applicability. TRIAL REGISTRATION ClinicalTrial.gov (ID NCT 03050567), retrospectively registered on 15/05/2017.
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Affiliation(s)
- Jakub Kaczynski
- British Heart Foundation Centre for Cardiovascular Science, University of Edinburgh, Chancellor’s Building, 49 Little France Crescent, Edinburgh, EH16 4SA UK
| | - Rachel Home
- College of Medicine and Veterinary Medicine, University of Edinburgh, 47 Little France Crescent, Edinburgh, EH16 4TJ UK
| | - Karen Shields
- Stroke Unit, Queen Elizabeth University Hospital, 1345 Govan Road, Glasgow, G51 4TF UK
| | - Matthew Walters
- College of Medical, Veterinary and Life Sciences, Wolfson Medical School Building, University of Glasgow, University Avenue, Glasgow, G12 8QQ UK
| | - William Whiteley
- Royal Infirmary of Edinburgh, 51 Little France Crescent, Old Dalkeith Road, Edinburgh, EH16 4SA UK
| | - Joanna Wardlaw
- Royal Infirmary of Edinburgh, 51 Little France Crescent, Old Dalkeith Road, Edinburgh, EH16 4SA UK
| | - David E. Newby
- British Heart Foundation Centre for Cardiovascular Science, University of Edinburgh, Chancellor’s Building, 49 Little France Crescent, Edinburgh, EH16 4SA UK
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Time Course of Cerebrovascular Reactivity in Patients Treated for Unruptured Intracranial Aneurysms: A One-Year Transcranial Doppler and Acetazolamide Follow-Up Study. BIOMED RESEARCH INTERNATIONAL 2018; 2018:6489276. [PMID: 29854773 PMCID: PMC5944219 DOI: 10.1155/2018/6489276] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/08/2017] [Revised: 03/04/2018] [Accepted: 03/21/2018] [Indexed: 11/18/2022]
Abstract
Background Cerebrovascular reactivity (CVR) is often impaired in the early phase after aneurysmal subarachnoid hemorrhage. There is, however, little knowledge about the time course of CVR in patients treated for unruptured intracranial aneurysms (UIA). Methods CVR, assessed by transcranial Doppler and acetazolamide test, was examined within the first postoperative week after treatment for UIA and reexamined one year later. Results Of 37 patients initially assessed, 34 were reexamined after one year. Bilaterally, baseline and acetazolamide-induced blood flow velocities were higher in the postoperative week compared with one year later (p < 0.001). CVR on the ipsilateral side of treatment was lower in the initial examination compared with follow-up (58.9% versus 66.1%, p = 0.04). There was no difference in CVR over time on the contralateral side (63.4% versus 65.0%, p = 0.65). When mean values of right and left sides were considered there was no difference in CVR between exams. Larger aneurysm size was associated with increased change in CVR (p = 0.04), and treatment with clipping was associated with 13.8%-point increased change in CVR compared with coiling (p = 0.03). Conclusion Patients with UIA may have a temporary reduction in CVR on the ipsilateral side after aneurysm treatment. The change in CVR appears more pronounced for larger-sized aneurysms and in patients treated with clipping. We recommend that ipsilateral and contralateral CVR should be assessed separately, as mean values can conceal side-differences.
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Venturelli PM, Brunser AM, Gaete J, Illanes S, López J, Olavarría VV, Reccius A, Brinck P, González F, Cavada G, Lavados PM. Reliability of Hand-Held Transcranial Doppler with M-mode Ultrasound in Middle Cerebral Artery Measurement. J Med Ultrasound 2017; 25:76-81. [PMID: 30065464 PMCID: PMC6029317 DOI: 10.1016/j.jmu.2016.12.001] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2016] [Accepted: 12/06/2016] [Indexed: 11/13/2022] Open
Abstract
Purpose To determine the intra- and interrater agreement of mean flow velocity (MFV) and pulsatility index (PI) measurement in middle cerebral arteries, assessed by transcranial Doppler (TCD) with M-mode. Methods Masked experienced neurosonologists performed TCD with M-mode using handheld probe in healthy adult volunteers. The Bland–Altman method for concordance and intraclass correlation coefficient were used. Results Seventy-seven healthy volunteers and seven raters participated (3 on regular TCD shift and 4 off-shift). The intrarater absolute mean difference between measurements was 5.5 cm/s [95% confidence interval (CI), 4.7–6.3] for MVF and 0.073 (95% CI, 0.063–0.083) for PI. The difference between MFV measurements was significantly higher in off-shift raters (p = 0.015). The interrater absolute mean difference between measurements was 6.5 cm/s (95% CI, 5.5–7.5) for MVF and 0.065 (95% CI, 0.059–0.071) for PI. No influence was found for the middle cerebral artery side, volunteer’s sex, or age, and there was no significant difference between raters. The intraclass correlation coefficient was 82.2% (95% CI 77.8–85.6) and 72.9% (95% CI 67.4–77.6) for MFV and PI, respectively. Conclusions There exists good intra- and interrater agreement in MFV and PI measurements using M-mode TCD. These results support the use of this noninvasive tool and are important for clinical and investigational purposes.
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Affiliation(s)
- Paula Muñoz Venturelli
- Unidad de Neurología Vascular, Servicio de Neurología, Departamento de Neurología y Psiquiatría, Clínica Alemana de Santiago, Facultad de Medicina Clínica Alemana Universidad del Desarrollo, Santiago, Chile.,NMH, The George Institute for Global Health, University of Sydney, Sydney, Australia
| | - Alejandro M Brunser
- Unidad de Neurología Vascular, Servicio de Neurología, Departamento de Neurología y Psiquiatría, Clínica Alemana de Santiago, Facultad de Medicina Clínica Alemana Universidad del Desarrollo, Santiago, Chile
| | - Javier Gaete
- Unidad de Neurología Vascular, Servicio de Neurología, Departamento de Neurología y Psiquiatría, Clínica Alemana de Santiago, Facultad de Medicina Clínica Alemana Universidad del Desarrollo, Santiago, Chile.,Servicio de Neurología, Hospital Clínico de Magallanes, Punta Arenas, Chile
| | - Sergio Illanes
- Unidad de Neurología Vascular, Servicio de Neurología, Departamento de Neurología y Psiquiatría, Clínica Alemana de Santiago, Facultad de Medicina Clínica Alemana Universidad del Desarrollo, Santiago, Chile
| | - Javiera López
- Unidad de Neurología Vascular, Servicio de Neurología, Departamento de Neurología y Psiquiatría, Clínica Alemana de Santiago, Facultad de Medicina Clínica Alemana Universidad del Desarrollo, Santiago, Chile
| | - Verónica V Olavarría
- Unidad de Neurología Vascular, Servicio de Neurología, Departamento de Neurología y Psiquiatría, Clínica Alemana de Santiago, Facultad de Medicina Clínica Alemana Universidad del Desarrollo, Santiago, Chile
| | - Andrés Reccius
- Unidad de Neurología Vascular, Servicio de Neurología, Departamento de Neurología y Psiquiatría, Clínica Alemana de Santiago, Facultad de Medicina Clínica Alemana Universidad del Desarrollo, Santiago, Chile.,Centro de Pacientes Críticos y Departamento de Neurología, Clínica Las Condes, Chile
| | - Pablo Brinck
- Unidad de Neurología Vascular, Servicio de Neurología, Departamento de Neurología y Psiquiatría, Clínica Alemana de Santiago, Facultad de Medicina Clínica Alemana Universidad del Desarrollo, Santiago, Chile
| | - Francisca González
- Unidad de Neurología Vascular, Servicio de Neurología, Departamento de Neurología y Psiquiatría, Clínica Alemana de Santiago, Facultad de Medicina Clínica Alemana Universidad del Desarrollo, Santiago, Chile
| | - Gabriel Cavada
- Departamento Científico Docente, Clínica Alemana de Santiago, Universidad del Desarrollo, Santiago, Chile.,Facultad de Medicina, Universidad de los Ande, Santiago, Chile
| | - Pablo M Lavados
- Unidad de Neurología Vascular, Servicio de Neurología, Departamento de Neurología y Psiquiatría, Clínica Alemana de Santiago, Facultad de Medicina Clínica Alemana Universidad del Desarrollo, Santiago, Chile.,Departamento de Ciencias Neurológicas, Facultad de Medicina, Universidad de Chile, Santiago, Chile
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Transcranial Color Duplex Ultrasound: A Reliable Tool for Cerebral Hemodynamic Assessment in Brain Injuries. J Neurosurg Anesthesiol 2016; 28:159-63. [PMID: 26524419 DOI: 10.1097/ana.0000000000000242] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
BACKGROUND Transcranial color duplex ultrasound (TCCD) is becoming an important tool for cerebral monitoring of brain-injured patients. To date, TCCD reproducibility has been studied in healthy volunteers or patients with subarachnoid hemorrhage and its efficiency in many brain injuries has not been proved. Our aim was to evaluate TCCD interobserver agreement in different brain injuries. PATIENTS AND METHODS We performed a prospective monocentric trial conducted from January 2014 to September 2014 in intensive care unit (ICU) of Saint-Etienne university teaching hospital, France.Brain-damaged patients admitted in ICU were included, excluding those with decompressive craniectomy. Two randomized operators among the ICU medical staff consecutively performed measurements of cerebral blood flow velocities with TCCD. RESULTS One hundred measurements were obtained from 42 patients. Hemodynamic and end-tidal CO2 pressure were similar between both measurement set. The results obtained with the Bland-Altman method showed bias at 0.52 (95% confidence interval [CI], -4.19 to 3.16), 0.53 (95% CI, -1.86 to 2.92), and 0.002 (95% CI, -0.06 to 0.06) for mean velocity, diastolic velocity, and pulsatility index, respectively. The limits of agreement were (-32.4; 31.4), (-20.4; 21.4), (-0.5; 0.5) for mean velocity, diastolic velocity, and pulsatility index, respectively. The Passing and Bablok regression have shown a quasilinear relationship between measurements. CONCLUSIONS We reported the reliability of TCCD interobserver agreement in brain-damaged patients.
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Sadasivan C, Fiorella DJ, Woo HH, Lieber BB. Physical factors effecting cerebral aneurysm pathophysiology. Ann Biomed Eng 2013; 41:1347-65. [PMID: 23549899 DOI: 10.1007/s10439-013-0800-z] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2012] [Accepted: 03/21/2013] [Indexed: 12/21/2022]
Abstract
Many factors that are either blood-, wall-, or hemodynamics-borne have been associated with the initiation, growth, and rupture of intracranial aneurysms. The distribution of cerebral aneurysms around the bifurcations of the circle of Willis has provided the impetus for numerous studies trying to link hemodynamic factors (flow impingement, pressure, and/or wall shear stress) to aneurysm pathophysiology. The focus of this review is to provide a broad overview of such hemodynamic associations as well as the subsumed aspects of vascular anatomy and wall structure. Hemodynamic factors seem to be correlated to the distribution of aneurysms on the intracranial arterial tree and complex, slow flow patterns seem to be associated with aneurysm growth and rupture. However, both the prevalence of aneurysms in the general population and the incidence of ruptures in the aneurysm population are extremely low. This suggests that hemodynamic factors and purely mechanical explanations by themselves may serve as necessary, but never as necessary and sufficient conditions of this disease's causation. The ultimate cause is not yet known, but it is likely an additive or multiplicative effect of a handful of biochemical and biomechanical factors.
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Affiliation(s)
- Chander Sadasivan
- Department of Neurological Surgery, Stony Brook University Medical Center, 100 Nicolls Road, HSC T12, Room 080, Stony Brook, NY 11794-8122, USA
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10
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Staalsø JM, Edsen T, Romner B, Olsen NV. Transcranial Doppler velocimetry in aneurysmal subarachnoid haemorrhage: intra- and interobserver agreement and relation to angiographic vasospasm and mortality. Br J Anaesth 2012; 110:577-85. [PMID: 23257989 DOI: 10.1093/bja/aes458] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND Transcranial Doppler measurements of the middle cerebral artery flow velocity are widely used as an indicator of vasospasm after aneurysmal subarachnoid haemorrhage (SAH). We investigated inter- and intraoperator agreement in SAH patients and healthy volunteers using colour-coded transcranial Doppler (TCCD), with the secondary aim of describing prediction of angiographic vasospasm and mortality. METHODS Sixty patients and 70 healthy controls were each examined in duplicate by alternating operators. A total of 939 measurements divided on 201 examination sets were conducted by four observers. The Bland-Altman limits of agreement (LoA) were calculated using a variance components analysis. Angiography was performed on clinical indication and survival recorded at 30 days. RESULTS Differences between measurements increased with increasing average, and therefore, we analysed log-transformed values. Thus, LoA are given as ratios between measurements. There were no systematic intra- or interobserver differences (bias). The intraobserver LoA was 0.62-1.61 in patients and 0.67-1.50 in controls. However, they were 0.55-1.82 in patients with angiographic vasospasm, whereas in patients without, they were 0.66-1.52. The interobserver LoA was 0.55-1.81 in patients and 0.65-1.55 in controls, while in patients with and without angiographic vasospasm, they were 0.45-2.22 and 0.60-1.67, respectively. Flow velocity measurements day 6-10 were positively associated with 30 day mortality risk (P=0.02, logistic regression). CONCLUSIONS TCCD measurement variability is wider in patient measurements than in controls. This discrepancy can largely be explained by a higher degree of error in patients with angiographic vasospasm. Despite the considerable measurement variability in TCCD, values are predictive of outcome in SAH.
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Affiliation(s)
- J M Staalsø
- Department of Neuroscience and Pharmacology, Faculty of Health, University of Copenhagen, Copenhagen, Denmark
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Levitt MR, Vaidya SS, Mai JC, Hallam DK, Kim LJ, Ghodke BV. Balloon Test Occlusion with the Doppler Velocity Guidewire. J Stroke Cerebrovasc Dis 2012; 21:909.e1-4. [DOI: 10.1016/j.jstrokecerebrovasdis.2011.10.002] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2011] [Revised: 10/06/2011] [Accepted: 10/15/2011] [Indexed: 11/30/2022] Open
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Marshall SA, Nyquist P, Ziai WC. The role of transcranial Doppler ultrasonography in the diagnosis and management of vasospasm after aneurysmal subarachnoid hemorrhage. Neurosurg Clin N Am 2010; 21:291-303. [PMID: 20380971 DOI: 10.1016/j.nec.2009.10.010] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
Transcranial Doppler ultrasonography (TCD) is a tool employed by the neurosurgeon and neurointensivist in the management of vasospasm in the intensive care unit after aneurysmal subarachnoid hemorrhage. A review of the current indications, monitoring parameters, indices, and relevance of modern TCD technology is provided, as well as algorithms for the use of TCD ultrasonography in the management of patients with subarachnoid hemorrhage. Other current uses of TCD ultrasonography are also discussed in the setting of neurocritical care.
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Affiliation(s)
- Scott A Marshall
- Division of Neurosciences Critical Care, Departments of Anesthesiology Critical Care Medicine, Johns Hopkins University School of Medicine, Meyer 8-140, 600 North Wolfe Street, Baltimore, MD 21287, USA.
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McMahon CJ, McDermott P, Horsfall D, Selvarajah JR, King AT, Vail A. The reproducibility of transcranial Doppler middle cerebral artery velocity measurements: Implications for clinical practice. Br J Neurosurg 2009; 21:21-7. [PMID: 17453770 DOI: 10.1080/02688690701210539] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
Use of transcranial Doppler (TCD) to diagnose vasospasm has been criticised. We examined reproducibility of TCD middle cerebral artery (MCA) velocity measurements. Thirty-six healthy adult volunteers were recruited. Four operators, two experienced and two inexperienced, participated. MCA velocity was measured twice by one operator and once by a second operator. Mean (95% limits of agreement) interoperator agreement was 2.4(+/-36.7) cm/s. Experienced vs. inexperienced, inexperienced vs. inexperienced, and experienced vs. experienced operators were -2.8(+/-39.3), -5.6(+/-40.1), 1.8(+/-22.1) cm/s, respectively. Intraoperator agreement across all operators, experienced and inexperienced were -0.5(+/-16.9), -1.6(+/-19.3), 0.7(+/-13.7) cm/s, respectively. Interoperator limits of agreement for experienced operators were almost half that of inexperienced operators. Intraoperator reproducibility was much better, regardless of level of experience, but aberrant results did occur even with experienced operators. If TCD measurements are used to guide management it is essential that operators are adequately trained, and readings repeated before potentially harmful treatments are instituted.
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Affiliation(s)
- C J McMahon
- School of Medicine, Faculty of Medicine and Human Sciences, University of Manchester, and Stroke Services, Hope Hospital, UK
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14
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White H, Venkatesh B. Applications of transcranial Doppler in the ICU: a review. Intensive Care Med 2006; 32:981-94. [PMID: 16791661 DOI: 10.1007/s00134-006-0173-y] [Citation(s) in RCA: 119] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2005] [Accepted: 03/16/2006] [Indexed: 01/09/2023]
Abstract
OBJECTIVE Transcranial Doppler (TCD) ultrasonography is a technique that uses a hand-held Doppler transducer (placed on the surface of the cranial skin) to measure the velocity and pulsatility of blood flow within the intracranial and the extracranial arteries. This review critically evaluates the evidence for the use of TCD in the critical care population. DISCUSSION TCD has been frequently employed for the clinical evaluation of cerebral vasospasm following subarachnoid haemorrhage (SAH). To a lesser degree, TCD has also been used to evaluate cerebral autoregulatory capacity, monitor cerebral circulation during cardiopulmonary bypass and carotid endarterectomies and to diagnose brain death. Technological advances such as M mode, colour Doppler and three-dimensional power Doppler ultrasonography have extended the scope of TCD to include other non-critical care applications including assessment of cerebral emboli, functional TCD and the management of sickle cell disease. CONCLUSIONS Despite publications suggesting concordance between TCD velocity measurements and cerebral blood flow there are few randomized controlled studies demonstrating an improved outcome with the use of TCD monitoring in neurocritical care. Newer developments in this technology include venous Doppler, functional Doppler and use of ultrasound contrast agents.
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Affiliation(s)
- Hayden White
- Queen Elizabeth II Hospital, Department of Anaesthesia, Coopers Plains, QLD, Australia
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15
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Naval NS, Stevens RD, Mirski MA, Bhardwaj A. Controversies in the management of aneurysmal subarachnoid hemorrhage*. Crit Care Med 2006; 34:511-24. [PMID: 16424735 DOI: 10.1097/01.ccm.0000198331.45998.85] [Citation(s) in RCA: 73] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
BACKGROUND The care of patients with aneurysmal subarachnoid hemorrhage has evolved significantly with the advent of new diagnostic and therapeutic modalities. Although it is believed that these advances have contributed to improved outcomes, considerable uncertainty persists regarding key areas of management. OBJECTIVE To review selected controversies in the management of aneurysmal subarachnoid hemorrhage, with a special emphasis on endovascular vs. surgical techniques for securing aneurysms, the diagnosis and therapy of cerebral vasospasm, neuroprotection, antithrombotic and anticonvulsant agents, cerebral salt wasting, and myocardial dysfunction, and to suggest venues for further clinical investigation. DATA SOURCE Search of MEDLINE and Cochrane databases and manual review of article bibliographies. DATA SYNTHESIS AND CONCLUSIONS Many aspects of care in patients with aneurysmal subarachnoid hemorrhage remain highly controversial and warrant further resolution with hypothesis-driven clinical or translational research. It is anticipated that the rigorous evaluation and implementation of such data will provide a basis for improvements in short- and long-term outcomes.
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Affiliation(s)
- Neeraj S Naval
- Division of Neurosciences Critical Care, Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
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16
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Harris AD, Ide K, Poulin MJ, Frayne R. Control of end-tidal PCO2 reduces middle cerebral artery blood velocity variability: implications for physiological neuroimaging. Neuroimage 2005; 29:1272-7. [PMID: 16226042 DOI: 10.1016/j.neuroimage.2005.08.023] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2005] [Revised: 08/09/2005] [Accepted: 08/23/2005] [Indexed: 11/28/2022] Open
Abstract
Breath-by-breath variability of the end-tidal partial pressure of CO2 (Pet(CO2)) has been shown to be associated with cerebral blood flow (CBF) fluctuations. These fluctuations can impact neuroimaging techniques that depend on cerebrovascular blood flow. We hypothesized that controlling Pet(CO2) would reduce CBF variability. Dynamic end-tidal forcing was used to control Pet(CO2) at 1.5 mm Hg above the resting level and to hold the end-tidal partial pressure of oxygen (Pet(O2)) at the resting level. Peak blood velocity in the middle cerebral artery (MCA) was measured by transcranial Doppler ultrasound (TCD) as an index of CBF. Blood velocity parameters and timing features were determined on each waveform and the variance of these parameters was compared between Normal (air breathing) and Forcing (end-tidal gas control) sessions. The variability of all velocity parameters was significantly reduced in the Forcing session. In particular, the variability of the average velocity over the cardiac cycle was decreased by 18.2% (P < 0.001). For the most part, the variability of the timing parameters was unchanged. Thus, we conclude that controlling Pet(CO2) is effective in reducing CBF variability, which would have important implications for physiologic neuroimaging.
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Affiliation(s)
- Ashley D Harris
- Biomedical Engineering Program, University of Calgary, Canada
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17
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Badjatia N, Topcuoglu MA, Buonanno FS, Smith EE, Nogueira RG, Rordorf GA, Carter BS, Ogilvy CS, Singhal AB. Relationship between hyperglycemia and symptomatic vasospasm after subarachnoid hemorrhage*. Crit Care Med 2005; 33:1603-9; quiz 1623. [PMID: 16003069 DOI: 10.1097/01.ccm.0000168054.60538.2b] [Citation(s) in RCA: 114] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
OBJECTIVE To determine the relationship between blood glucose levels (mg/dL) and occurrence of symptomatic vasospasm (VSP) and clinical outcomes after aneurysmal subarachnoid hemorrhage. DESIGN Retrospective observational study of 352 patients with subarachnoid hemorrhage admitted within 48 hrs of ictus between January 1995 and June 2002. SETTING Neurointensive care unit. PATIENTS Adult patients admitted after subarachnoid hemorrhage. INTERVENTIONS None. MEASUREMENTS AND MAIN RESULTS Variables included age; Hunt-Hess classification score; Fisher group; insulin use; infectious disease status; history of diabetes mellitus; and blood glucose values. Poor clinical outcome was defined by a modified Rankin score > or =3, and hyperglycemia was defined by a blood glucose level >140 mg/dL. Mean daily blood glucose values were assessed from admission to development of VSP or day 14. Mean admission blood glucose value, mean inpatient blood glucose value, insulin use, infectious disease status, Hunt-Hess classification score, Fisher group, and history of diabetes mellitus were entered in a Cox proportional hazards model. VSP occurred in 103 (29.2%) of 352 patients. Mean admission blood glucose values (176.6 +/- 40.3 mg/dL vs. 162.3 +/- 47.8 mg/dL; p = .01) and mean inpatient blood glucose values (166.2 +/- 24.7 mg/dL vs. 155.8 +/- 29.7 mg/dL; p = .001) were significantly higher in patients with VSP. Mean inpatient blood glucose value (relative risk, 1.01; 95% confidence interval, 1.0-1.03; p = .04), Hunt-Hess classification score > or =3 (relative risk, 2.23; 95% confidence interval, 1.21-3.99; p = .02), and Fisher group score of 3 (relative risk, 1.28; 95% confidence interval, 1.15-3.1; p = .05) increased the risk for VSP. Hyperglycemia was associated with longer length of stay in the neurointensive care unit (14.5 +/- 7.1 days vs. 11.6 +/- 5.4 days; p < .001) and poor outcome at discharge (modified Rankin score > or =3: 58.9% vs. 18.8%; p < .001). CONCLUSIONS Mean inpatient blood glucose value is associated with the development of VSP and may represent a target for therapy to prevent VSP and improve clinical outcomes.
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Affiliation(s)
- Neeraj Badjatia
- Department of Neurology, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
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18
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Aaslid R. Transcranial Doppler assessment of cerebral vasospasm. EUROPEAN JOURNAL OF ULTRASOUND : OFFICIAL JOURNAL OF THE EUROPEAN FEDERATION OF SOCIETIES FOR ULTRASOUND IN MEDICINE AND BIOLOGY 2002; 16:3-10. [PMID: 12470845 DOI: 10.1016/s0929-8266(02)00045-9] [Citation(s) in RCA: 71] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
This review summarizes the use of transcranial Doppler (TCD) for assessment of cerebral vasospasm. The basic hemodynamic principles are presented, and used as a basis for discussing findings and interpretation methods. The need for additional information and measurements to correctly interpret TCD velocities is analyzed, and the use of a special extracranial Doppler technique is recommended. The advantages and limitations of the 'Lindegaard Index' (LI) are discussed. The recent advances in the use of TCD for cerebral autoregulation testing are opening up a new and promising avenue in diagnosis, monitoring and treatment of cerebral vasospasm.
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Affiliation(s)
- Rune Aaslid
- Department of Neurological Surgery, University of Washington, Seattle, USA.
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Abstract
Cerebral pressure autoregulation, a sensitive homeostatic mechanism important for the control of cerebral blood flow, is impaired by disease pathology and some drugs commonly used during anaesthesia. Therefore, the assessment of cerebral pressure autoregulation can help optimize cerebral blood flow in patients who have suffered neurological insults. In this article, we outline the means available for testing cerebral pressure autoregulation, thus allowing the reader to decide on the best strategy to adopt in their particular operating theatre and intensive care setting.
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Affiliation(s)
- Frank A Rasulo
- Department of Anaesthesia, Addenbrookes Hospital, Cambridge CB2 2QQ, UK
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20
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Bell RD, Benitez RP. Continuous measurement of cerebral blood flow velocity by using transcranial Doppler reveals significant moment-to-moment variability of data in healthy volunteers and in patients. Crit Care Med 2002; 30:712-3. [PMID: 11990945 DOI: 10.1097/00003246-200203000-00042] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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