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Carlson AP, Mayer AR, Cole C, van der Horn HJ, Marquez J, Stevenson TC, Shuttleworth CW. Cerebral autoregulation, spreading depolarization, and implications for targeted therapy in brain injury and ischemia. Rev Neurosci 2024; 35:651-678. [PMID: 38581271 PMCID: PMC11297425 DOI: 10.1515/revneuro-2024-0028] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2024] [Accepted: 03/25/2024] [Indexed: 04/08/2024]
Abstract
Cerebral autoregulation is an intrinsic myogenic response of cerebral vasculature that allows for preservation of stable cerebral blood flow levels in response to changing systemic blood pressure. It is effective across a broad range of blood pressure levels through precapillary vasoconstriction and dilation. Autoregulation is difficult to directly measure and methods to indirectly ascertain cerebral autoregulation status inherently require certain assumptions. Patients with impaired cerebral autoregulation may be at risk of brain ischemia. One of the central mechanisms of ischemia in patients with metabolically compromised states is likely the triggering of spreading depolarization (SD) events and ultimately, terminal (or anoxic) depolarization. Cerebral autoregulation and SD are therefore linked when considering the risk of ischemia. In this scoping review, we will discuss the range of methods to measure cerebral autoregulation, their theoretical strengths and weaknesses, and the available clinical evidence to support their utility. We will then discuss the emerging link between impaired cerebral autoregulation and the occurrence of SD events. Such an approach offers the opportunity to better understand an individual patient's physiology and provide targeted treatments.
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Affiliation(s)
- Andrew P. Carlson
- Department of Neurosurgery, University of New Mexico School of Medicine, MSC10 5615, 1 UNM, Albuquerque, NM, 87131, USA
- Department of Neurosciences, University of New Mexico School of Medicine, 915 Camino de Salud NE, Albuquerque, NM, 87106, USA
| | - Andrew R. Mayer
- Mind Research Network, 1101 Yale, Blvd, NE, Albuquerque, NM, 87106, USA
| | - Chad Cole
- Department of Neurosurgery, University of New Mexico School of Medicine, MSC10 5615, 1 UNM, Albuquerque, NM, 87131, USA
| | | | - Joshua Marquez
- University of New Mexico School of Medicine, 915 Camino de Salud NE, Albuquerque, NM, 87106, USA
| | - Taylor C. Stevenson
- Department of Neurosurgery, University of New Mexico School of Medicine, MSC10 5615, 1 UNM, Albuquerque, NM, 87131, USA
| | - C. William Shuttleworth
- Department of Neurosciences, University of New Mexico School of Medicine, 915 Camino de Salud NE, Albuquerque, NM, 87106, USA
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Olsen MH, Riberholt CG, Berg RMG, Møller K. Myths and methodologies: Assessment of dynamic cerebral autoregulation by the mean flow index. Exp Physiol 2024; 109:614-623. [PMID: 38376110 PMCID: PMC10988760 DOI: 10.1113/ep091327] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2023] [Accepted: 01/17/2024] [Indexed: 02/21/2024]
Abstract
The mean flow index-usually referred to as Mx-has been used for assessing dynamic cerebral autoregulation (dCA) for almost 30 years. However, concerns have arisen regarding methodological consistency, construct and criterion validity, and test-retest reliability. Methodological nuances, such as choice of input (cerebral perfusion pressure, invasive or non-invasive arterial pressure), pre-processing approach and artefact handling, significantly influence mean flow index values, and previous studies correlating mean flow index with other established dCA metrics are confounded by inherent methodological flaws like heteroscedasticity, while the mean flow index also fails to discriminate individuals with presumed intact versus impaired dCA (discriminatory validity), and its prognostic performance (predictive validity) across various conditions remains inconsistent. The test-retest reliability, both within and between days, is generally poor. At present, no single approach for data collection or pre-processing has proven superior for obtaining the mean flow index, and caution is advised in the further use of mean flow index-based measures for assessing dCA, as current evidence does not support their clinical application.
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Affiliation(s)
- Markus Harboe Olsen
- Department of Neuroanaesthesiology, The Neuroscience CentreCopenhagen University Hospital − RigshospitaletCopenhagenDenmark
| | - Christian Gunge Riberholt
- Department of Neuroanaesthesiology, The Neuroscience CentreCopenhagen University Hospital − RigshospitaletCopenhagenDenmark
- Department of Brain and Spinal Cord Injury, The Neuroscience CentreCopenhagen University Hospital − RigshospitaletCopenhagenDenmark
| | - Ronan M. G. Berg
- Department of Clinical Physiology and Nuclear MedicineCopenhagen University Hospital − RigshospitaletCopenhagenDenmark
- Centre for Physical Activity ResearchCopenhagen University Hospital − RigshospitaletCopenhagenDenmark
- Department of Biomedical Sciences, Faculty of Health and Medical SciencesUniversity of CopenhagenCopenhagenDenmark
- Neurovascular Research Laboratory, Faculty of Life Sciences and EducationUniversity of South WalesPontypriddUK
| | - Kirsten Møller
- Department of Neuroanaesthesiology, The Neuroscience CentreCopenhagen University Hospital − RigshospitaletCopenhagenDenmark
- Department of Clinical Medicine, Faculty of Health and Medical SciencesUniversity of CopenhagenCopenhagenDenmark
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Vitt JR, Loper NE, Mainali S. Multimodal and autoregulation monitoring in the neurointensive care unit. Front Neurol 2023; 14:1155986. [PMID: 37153655 PMCID: PMC10157267 DOI: 10.3389/fneur.2023.1155986] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2023] [Accepted: 04/04/2023] [Indexed: 05/10/2023] Open
Abstract
Given the complexity of cerebral pathology in patients with acute brain injury, various neuromonitoring strategies have been developed to better appreciate physiologic relationships and potentially harmful derangements. There is ample evidence that bundling several neuromonitoring devices, termed "multimodal monitoring," is more beneficial compared to monitoring individual parameters as each may capture different and complementary aspects of cerebral physiology to provide a comprehensive picture that can help guide management. Furthermore, each modality has specific strengths and limitations that depend largely on spatiotemporal characteristics and complexity of the signal acquired. In this review we focus on the common clinical neuromonitoring techniques including intracranial pressure, brain tissue oxygenation, transcranial doppler and near-infrared spectroscopy with a focus on how each modality can also provide useful information about cerebral autoregulation capacity. Finally, we discuss the current evidence in using these modalities to support clinical decision making as well as potential insights into the future of advanced cerebral homeostatic assessments including neurovascular coupling.
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Affiliation(s)
- Jeffrey R. Vitt
- Department of Neurological Surgery, UC Davis Medical Center, Sacramento, CA, United States
- Department of Neurology, UC Davis Medical Center, Sacramento, CA, United States
| | - Nicholas E. Loper
- Department of Neurological Surgery, UC Davis Medical Center, Sacramento, CA, United States
| | - Shraddha Mainali
- Department of Neurology, Virginia Commonwealth University, Richmond, VA, United States
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Muacevic A, Adler JR. Blood Pressure Control in Traumatic Subdural Hematomas. Cureus 2022; 14:e30654. [PMID: 36439570 PMCID: PMC9685202 DOI: 10.7759/cureus.30654] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2022] [Accepted: 10/25/2022] [Indexed: 01/25/2023] Open
Abstract
Background There is debate over optimal systolic blood pressure (SBP) after traumatic subdural hematoma. Increased SBP has the benefit of increasing cerebral perfusion pressure and limiting the detrimental secondary effects of traumatic brain injury but poses a risk of hematoma expansion. While prior studies have shown that SBP<90mmHg is associated with worsened morbidity and mortality in subdural hematoma patients, clinical guidelines and expert opinion have differing initial SBP goals. The aim of this study is to leverage a large database to determine the effects of two such goals, namely SBP 100-150mmHg versus SBP<180mmHg in this patient population. Methods A de-identified database network (TriNetX Research Network) was used to retrospectively query all patients with a first instance diagnosis of acute traumatic SDH, who also had a recorded GCS, with maintenance of SBP 100-150 within the first 24 hours (cohort 1) versus patients with an SBP<180 (cohort 2). Data came from 68 health care organizations (HCOs) with a total of 105,897,964 patients on 9/1/2022. The primary outcome of interest was mortality within 30 days. Secondary outcomes include gastrostomy tube placement, craniotomy/craniectomy/burr hole drainage, venous thromboembolism, ischemic stroke, myocardial infarction, seizure, falls, cardiac arrest, and acute kidney injury within 30 days. Cohorts were propensity-score matched for confounders. Results After propensity score matching, 1,243 patients were identified in each cohort. Age at index was 57.97+/-23.21 years and 58.28+/-22.35 years for cohorts 1 and 2, respectively. Mortality was seen in 243 patients (19.756%) vs. 209 (16.992%) (OR 1.203, 95% CI (0.98,1.476), p=0.0767) in cohorts 1 and 2, respectively. There was no statistical difference in secondary outcomes. Conclusion The results of this study demonstrate that the primary outcome of mortality at 30 days is not statistically different in acute traumatic SDH patients, whether their SBP is kept at 100-150 or below 180. Likewise, it shows no statistical difference in the subsequent incidence of gastrostomy tube placement, craniotomy/craniectomy/burr holes, venous thromboembolism, ischemic stroke, myocardial infarction, seizure, falls, or acute kidney injury.
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Zeiler FA, Aries M, Czosnyka M, Smieleweski P. Cerebral Autoregulation Monitoring in Traumatic Brain Injury: An Overview of Recent Advances in Personalized Medicine. J Neurotrauma 2022; 39:1477-1494. [PMID: 35793108 DOI: 10.1089/neu.2022.0217] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Impaired cerebral autoregulation (CA) in moderate/severe traumatic brain injury (TBI) has been identified as a strong associate with poor long-term outcomes, with recent data highlighting its dominance over cerebral physiologic dysfunction seen in the acute phase post injury. With advances in bedside continuous cerebral physiologic signal processing, continuously derived metrics of CA capacity have been described over the past two decades, leading to improvements in cerebral physiologic insult detection and development of novel personalized approaches to TBI care in the intensive care unit (ICU). This narrative review focuses on highlighting the concept of continuous CA monitoring and consequences of impairment in moderate/severe TBI. Further, we provide a comprehensive description and overview of the main personalized cerebral physiologic targets, based on CA monitoring, that are emerging as strong associates with patient outcomes. CA-based personalized targets, such as optimal cerebral perfusion pressure (CPPopt), lower/upper limit of regulation (LLR/ULR), and individualized intra-cranial pressure (iICP) are positioned to change the way we care for TBI patients in the ICU, moving away from the "one treatment fits all" paradigm of current guideline-based therapeutic approaches, towards a true personalized medicine approach tailored to the individual patient. Future perspectives regarding research needs in this field are also discussed.
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Affiliation(s)
- Frederick Adam Zeiler
- Health Sciences Centre, Section of Neurosurgery, GB-1 820 Sherbrook Street, Winnipeg, Manitoba, Canada, R3A1R9;
| | - Marcel Aries
- University of Maastricht Medical Center, Department of Intensive Care, Maastricht, Netherlands;
| | - Marek Czosnyka
- university of cambridge, neurosurgery, Canbridge Biomedical Campus, box 167, cambridge, United Kingdom of Great Britain and Northern Ireland, cb237ar;
| | - Peter Smieleweski
- Cambridge University, Neurosurgery, Cambridge, United Kingdom of Great Britain and Northern Ireland;
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Batson C, Froese L, Gomez A, Sainbhi AS, Stein KY, Alizadeh A, Zeiler FA. Impact of Age and Biological Sex on Cerebrovascular Reactivity in Adult Moderate/Severe Traumatic Brain Injury: An Exploratory Analysis. Neurotrauma Rep 2021; 2:488-501. [PMID: 34901944 PMCID: PMC8655816 DOI: 10.1089/neur.2021.0039] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
Age and biological sex are two potential important modifiers of cerebrovascular reactivity post-traumatic brain injury (TBI) requiring close evaluation for potential subgroup responses. The goal of this study was to provide a preliminary exploratory analysis of the impact of age and biological sex on measures of cerebrovascular function in moderate/severe TBI. Forty-nine patients from the prospectively maintained TBI database at the University of Manitoba with archived high-frequency digital cerebral physiology were evaluated. Cerebrovascular reactivity indices were derived as follows: PRx (correlation between intracranial pressure [ICP] and mean arterial pressure [MAP]), PAx (correlation between pulse amplitude of ICP [AMP] and MAP), and RAC (correlation between AMP and cerebral perfusion pressure [CPP]). Time above clinically significant thresholds for each index was calculated over different periods of the acute intensive care unit stay. The association between PRx, PAx, and RAC measures with age was assessed using linear regression, and an age trichotomization scheme (<40, 40-60, >60) using Kruskal-Wallis testing. Similarly, association with biological sex was tested using Mann-Whitney U testing. Biological sex did not demonstrate an impact on any measures of cerebrovascular reactivity. Linear regression between age and PAx and RAC demonstrated a statistically significant positive linear relationship. Median PAx and RAC measures between trichotomized age categories demonstrated statistically significant increases with advancing age. The PRx failed to demonstrate any statistically significant relationship with age in this cohort, suggesting that in elderly patients with controlled ICP, PAx and RAC may be better metrics for detecting impaired cerebrovascular reactivity. Biological sex appears to not be associated with differences in cerebrovascular reactivity in this cohort. The PRx performed the worst in detecting impaired cerebrovascular reactivity in those with advanced age, where PAx and RAC appear to have excelled. Future work is required to validate these findings and explore the utility of different cerebrovascular reactivity indices.
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Affiliation(s)
- Carleen Batson
- Department of Human Anatomy and Cell Science, Department of Surgery, Rady Faculty of Health Sciences, University of Manitoba, Winnipeg, Manitoba, Canada
| | - Logan Froese
- Biomedical Engineering, Faculty of Engineering, University of Manitoba, Winnipeg, Manitoba, Canada
| | - Alwyn Gomez
- Department of Human Anatomy and Cell Science, Department of Surgery, Rady Faculty of Health Sciences, University of Manitoba, Winnipeg, Manitoba, Canada
- Section of Neurosurgery, Department of Surgery, Rady Faculty of Health Sciences, University of Manitoba, Winnipeg, Manitoba, Canada
| | - Amanjyot Singh Sainbhi
- Biomedical Engineering, Faculty of Engineering, University of Manitoba, Winnipeg, Manitoba, Canada
| | - Kevin Y. Stein
- Section of Neurosurgery, Department of Surgery, Rady Faculty of Health Sciences, University of Manitoba, Winnipeg, Manitoba, Canada
| | - Arsalan Alizadeh
- Section of Neurosurgery, Department of Surgery, Rady Faculty of Health Sciences, University of Manitoba, Winnipeg, Manitoba, Canada
| | - Frederick A. Zeiler
- Department of Human Anatomy and Cell Science, Department of Surgery, Rady Faculty of Health Sciences, University of Manitoba, Winnipeg, Manitoba, Canada
- Biomedical Engineering, Faculty of Engineering, University of Manitoba, Winnipeg, Manitoba, Canada
- Section of Neurosurgery, Department of Surgery, Rady Faculty of Health Sciences, University of Manitoba, Winnipeg, Manitoba, Canada
- Centre on Aging, University of Manitoba, Winnipeg, Manitoba, Canada
- Division of Anaesthesia, Department of Medicine, Addenbrooke's Hospital, University of Cambridge, Cambridge, United Kingdom
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