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Nogueira RC, Aries M, Minhas JS, H Petersen N, Xiong L, Kainerstorfer JM, Castro P. Review of studies on dynamic cerebral autoregulation in the acute phase of stroke and the relationship with clinical outcome. J Cereb Blood Flow Metab 2022; 42:430-453. [PMID: 34515547 PMCID: PMC8985432 DOI: 10.1177/0271678x211045222] [Citation(s) in RCA: 24] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
Acute stroke is associated with high morbidity and mortality. In the last decades, new therapies have been investigated with the aim of improving clinical outcomes in the acute phase post stroke onset. However, despite such advances, a large number of patients do not demonstrate improvement, furthermore, some unfortunately deteriorate. Thus, there is a need for additional treatments targeted to the individual patient. A potential therapeutic target is interventions to optimize cerebral perfusion guided by cerebral hemodynamic parameters such as dynamic cerebral autoregulation (dCA). This narrative led to the development of the INFOMATAS (Identifying New targets FOr Management And Therapy in Acute Stroke) project, designed to foster interventions directed towards understanding and improving hemodynamic aspects of the cerebral circulation in acute cerebrovascular disease states. This comprehensive review aims to summarize relevant studies on assessing dCA in patients suffering acute ischemic stroke, intracerebral haemorrhage, and subarachnoid haemorrhage. The review will provide to the reader the most consistent findings, the inconsistent findings which still need to be explored further and discuss the main limitations of these studies. This will allow for the creation of a research agenda for the use of bedside dCA information for prognostication and targeted perfusion interventions.
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Affiliation(s)
- Ricardo C Nogueira
- Neurology Department, School of Medicine, Hospital das Clinicas, University of São Paulo, São Paulo, Brazil.,Department of Neurology, Hospital Nove de Julho, São Paulo, Brazil
| | - Marcel Aries
- Department of Intensive Care, University of Maastricht, Maastricht University Medical Center+, School for Mental Health and Neuroscience (MHeNS), Maastricht, The Netherlands
| | - Jatinder S Minhas
- Cerebral Haemodynamics in Ageing and Stroke Medicine (CHiASM) Research Group, Department of Cardiovascular Sciences, NIHR Leicester Biomedical Research Centre, Glenfield Hospital, Leicester, UK
| | - Nils H Petersen
- Department of Neurology, Yale University School of Medicine, New Haven, USA
| | - Li Xiong
- Department of Medicine & Therapeutics, The Chinese University of Hong Kong, Hong Kong, China
| | - Jana M Kainerstorfer
- Department of Biomedical Engineering, Carnegie Mellon University, Pittsburgh, USA.,Neuroscience Institute, Carnegie Mellon University, Pittsburgh, USA
| | - Pedro Castro
- Department of Neurology, Faculty of Medicine of University of Porto, Centro Hospitalar Universitário de São João, Porto, Portugal
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Caldwell HG, Carr JMJR, Minhas JS, Swenson ER, Ainslie PN. Acid-base balance and cerebrovascular regulation. J Physiol 2021; 599:5337-5359. [PMID: 34705265 DOI: 10.1113/jp281517] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2021] [Accepted: 10/19/2021] [Indexed: 12/22/2022] Open
Abstract
The regulation and defence of intracellular pH is essential for homeostasis. Indeed, alterations in cerebrovascular acid-base balance directly affect cerebral blood flow (CBF) which has implications for human health and disease. For example, changes in CBF regulation during acid-base disturbances are evident in conditions such as chronic obstructive pulmonary disease and diabetic ketoacidosis. The classic experimental studies from the past 75+ years are utilized to describe the integrative relationships between CBF, carbon dioxide tension (PCO2 ), bicarbonate (HCO3 - ) and pH. These factors interact to influence (1) the time course of acid-base compensatory changes and the respective cerebrovascular responses (due to rapid exchange kinetics between arterial blood, extracellular fluid and intracellular brain tissue). We propose that alterations in arterial [HCO3 - ] during acute respiratory acidosis/alkalosis contribute to cerebrovascular acid-base regulation; and (2) the regulation of CBF by direct changes in arterial vs. extravascular/interstitial PCO2 and pH - the latter recognized as the proximal compartment which alters vascular smooth muscle cell regulation of CBF. Taken together, these results substantiate two key ideas: first, that the regulation of CBF is affected by the severity of metabolic/respiratory disturbances, including the extent of partial/full acid-base compensation; and second, that the regulation of CBF is independent of arterial pH and that diffusion of CO2 across the blood-brain barrier is integral to altering perivascular extracellular pH. Overall, by realizing the integrative relationships between CBF, PCO2 , HCO3 - and pH, experimental studies may provide insights to improve CBF regulation in clinical practice with treatment of systemic acid-base disorders.
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Affiliation(s)
- Hannah G Caldwell
- Centre for Heart, Lung and Vascular Health, School of Health and Exercise Sciences, University of British Columbia, Okanagan, Kelowna, Canada
| | - Jay M J R Carr
- Centre for Heart, Lung and Vascular Health, School of Health and Exercise Sciences, University of British Columbia, Okanagan, Kelowna, Canada
| | - Jatinder S Minhas
- Cerebral Haemodynamics in Ageing and Stroke Medicine (CHiASM) Research Group, NIHR Leicester Biomedical Research Centre, University of Leicester, Leicester, UK
| | - Erik R Swenson
- Pulmonary, Critical Care and Sleep Medicine Division, University of Washington, and VA Puget Sound Healthcare System, Seattle, WA, USA
| | - Philip N Ainslie
- Centre for Heart, Lung and Vascular Health, School of Health and Exercise Sciences, University of British Columbia, Okanagan, Kelowna, Canada
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Ince J, Mankoo AS, Kadicheeni M, Swienton D, Panerai RB, Robinson TG, Minhas JS. Cerebrovascular tone and resistance measures differ between healthy control and patients with acute intracerebral haemorrhage: exploratory analyses from the BREATHE-ICH study. Physiol Meas 2021; 42. [PMID: 33853052 DOI: 10.1088/1361-6579/abf7da] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2020] [Accepted: 04/14/2021] [Indexed: 11/12/2022]
Abstract
Objective.Cerebral autoregulation impairment in acute neurovascular disease is well described. The recent BREATHE-ICH study demonstrated improvements in dynamic cerebral autoregulation, by hypocapnia generated by hyperventilation, in the acute period following intracranial haemorrhage (ICH). This exploratory analysis of the BREATHE-ICH dataset aims to examine the differences in hypocapnic responses between healthy controls and patients with ICH, and determine whether haemodynamic indices differ between baseline and hypocapnic states.Approach.Acute ICH patients were recruited within 48 h of onset and healthy volunteers were recruited from a university setting. Transcranial Doppler measurements of the middle cerebral artery were obtained at baseline and then a hyperventilation intervention was used to induce hypocapnia. Patients with ICH were then followed up at 10-14 D post-event for repeated measurements.Main results.Data from 43 healthy controls and 12 patients with acute ICH met the criteria for statistical analysis. In both normocapnic and hypocapnic conditions, significantly higher critical closing pressure and resistance area product were observed in patients with ICH. Furthermore, critical closing pressure changes were observed to be sustained at 10-14 D follow up. During both the normocapnic and hypocapnic states, reduced autoregulation index was observed bilaterally in patients with ICH, compared to healthy controls.Significance.Whilst this exploratory analysis was limited by a small, non-age matched sample, significant differences between ICH patients and healthy controls were observed in factors associated with cerebrovascular tone and resistance. These differences suggest underlying cerebral autoregulation changes in ICH, which may play a pivotal role in the morbidity and mortality associated with ICH.
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Affiliation(s)
- Jonathan Ince
- Department of Cardiovascular Sciences, University of Leicester, United Kingdom
| | - Alex S Mankoo
- Department of Cardiovascular Sciences, University of Leicester, United Kingdom
| | - Meeriam Kadicheeni
- Department of Cardiovascular Sciences, University of Leicester, United Kingdom
| | - David Swienton
- Department of Radiology, University Hospitals of Leicester NHS Trust, Leicester, United Kingdom
| | - Ronney B Panerai
- Department of Cardiovascular Sciences, University of Leicester, United Kingdom.,NIHR Leicester Biomedical Research Centre, British Heart Foundation Cardiovascular Research Centre, Glenfield Hospital, Leicester, United Kingdom
| | - Thompson G Robinson
- Department of Cardiovascular Sciences, University of Leicester, United Kingdom.,NIHR Leicester Biomedical Research Centre, British Heart Foundation Cardiovascular Research Centre, Glenfield Hospital, Leicester, United Kingdom
| | - Jatinder S Minhas
- Department of Cardiovascular Sciences, University of Leicester, United Kingdom.,NIHR Leicester Biomedical Research Centre, British Heart Foundation Cardiovascular Research Centre, Glenfield Hospital, Leicester, United Kingdom
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Optimal Hemodynamic Parameters for Brain-injured Patients in the Clinical Setting: A Narrative Review of the Evidence. J Neurosurg Anesthesiol 2021; 34:288-299. [PMID: 33443353 DOI: 10.1097/ana.0000000000000752] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2020] [Accepted: 12/07/2020] [Indexed: 11/25/2022]
Abstract
Defining optimal hemodynamic targets for brain-injured patients is a challenging undertaking. The physiological interference observed in various intracranial pathologies can have varying effects on cerebral physiology at different time points. This narrative review provides an overview of cerebral autoregulatory physiology and common misconceptions, and examines the physiological considerations and clinical evidence for determining optimal hemodynamic parameters in acutely brain-injured patients with relevance to modern neuroanesthesia and neurocritical care practice.
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Caldas JR, Passos RDH, Robinson TG, Panerai RB, Minhas JS. Intensive care management of arterial carbon dioxide in acute intracerebral haemorrhage: Case report of influences on cerebral haemodynamics. ULTRASOUND (LEEDS, ENGLAND) 2020; 28:260-265. [PMID: 36959898 PMCID: PMC10028384 DOI: 10.1177/1742271x20903753] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/05/2019] [Accepted: 01/06/2020] [Indexed: 11/15/2022]
Abstract
Intracerebral haemorrhage is relatively common and has devastating consequences. Furthermore, non-invasive and invasive strategies to manage raised intracranial pressure remain limited and associated with high morbidity and mortality. We report a case of a 72-year-old male with intracerebral haemorrhage with ventricular extension, hydrocephalus and intracranial hypertension, who was evaluated by transcranial Doppler ultrasound and optic nerve sheath diameter. This case demonstrates that beyond pharmacological and surgical interventions, simple manipulation of arterial carbon dioxide has the propensity to improve cerebral haemodynamic parameters. Our results demonstrate the negative effects of hypercapnia on cerebral autoregulation and the benefits of having transcranial Doppler ultrasound available in the intensive care unit point of care.
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Affiliation(s)
- Juliana R Caldas
- Escola Bahiana de Medicina e Saúde Pública, Universidade de
Salvador, UNIFACS, Critical Care Unit, Hospital São Rafael Salvador, Salvador,
Brazil
- Juliana R Caldas, Escola Bahiana de Medicina
e Saude Publica Salvador, Salvador 40050-420 Brazil.
| | | | - Thompson G Robinson
- Department of Cardiovascular Sciences, University of Leicester,
Leicester, UK
- NIHR Leicester Biomedical Research Centre, Leicester, UK
| | - Ronney B Panerai
- Department of Cardiovascular Sciences, University of Leicester,
Leicester, UK
- NIHR Leicester Biomedical Research Centre, Leicester, UK
| | - Jatinder S Minhas
- Department of Cardiovascular Sciences, University of Leicester,
Leicester, UK
- NIHR Leicester Biomedical Research Centre, Leicester, UK
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Minhas JS, Panerai RB, Swienton D, Robinson TG. Feasibility of improving cerebral autoregulation in acute intracerebral hemorrhage (BREATHE-ICH) study: Results from an experimental interventional study. Int J Stroke 2019; 15:627-637. [DOI: 10.1177/1747493019873690] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Background Cerebral autoregulation is impaired in a multitude of neurological conditions. Increasingly, clinical studies are correlating the nature of this impairment with prognostic markers. In acute intracerebral hemorrhage, impairment of cerebral autoregulation has been associated with worsening clinical outcomes including poorer Glasgow Coma Score and larger hematoma volume. Hypocapnia has been shown to improve cerebral autoregulation despite concerns over hypoperfusion and consequent ischemic risks, and it is therefore hypothesized that hypocapnia (via hyperventilation) in acute intracerebral hemorrhage may improve cerebral autoregulation and consequently clinical outcome. Aims To assess the feasibility and acceptability of the first cerebral autoregulation-targeted intervention in acute intracerebral hemorrhage utilizing a simple bed-side hyperventilatory maneuver. Methods Twelve patients with acute intracerebral hemorrhage within 48 h of onset were enrolled. The experimental setup measured cerebral blood flow velocity (transcranial Doppler), blood pressure (Finometer), and end-tidal CO2 (EtCO2, capnography) at baseline, and in response to hypocapnia (−5 mmHg below baseline) achieved via a 90-s hyperventilatory maneuver. Cerebral autoregulation was evaluated with transfer function analysis and autoregulatory index calculations. Results We observed tolerance to the protocol in a cohort of mild (National Institutes of Health Scale 4) supratentorial intracerebral hemorrhage patients with small volume hematomas without intraventricular extension. Importantly, a significant difference was noted between ipsilateral autoregulatory index at baseline 4.8 (1.7) and autoregulatory index during hypocapnic intervention 7.0 (0.8) (p = 0.0004), reflecting improved cerebral autoregulation, though a dose-dependent effect of EtCO2 on autoregulatory index was not observed. Conclusions In this small study, there was no observed effect on 14-day death and disability in recruited participants. This is the first report of improvement in cerebral autoregulation in acute intracerebral hemorrhage using a non-invasive interventional maneuver, through induction of hypocapnia via hyperventilation. ClinicalTrials.gov Identifier: NCT03324321 URL: https://clinicaltrials.gov/ct2/show/NCT03324321
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Affiliation(s)
- Jatinder S Minhas
- Cerebral Haemodynamics in Ageing and Stroke Medicine (CHIASM) Research Group, Department of Cardiovascular Sciences, University of Leicester, Leicester, UK
| | - Ronney B Panerai
- Cerebral Haemodynamics in Ageing and Stroke Medicine (CHIASM) Research Group, Department of Cardiovascular Sciences, University of Leicester, Leicester, UK
- National Institute for Health Research Leicester Biomedical Research Centre, University of Leicester, Leicester, UK
| | - David Swienton
- Department of Radiology, University Hospitals of Leicester, Leicester, UK
| | - Thompson G Robinson
- Cerebral Haemodynamics in Ageing and Stroke Medicine (CHIASM) Research Group, Department of Cardiovascular Sciences, University of Leicester, Leicester, UK
- National Institute for Health Research Leicester Biomedical Research Centre, University of Leicester, Leicester, UK
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Do acute stroke patients develop hypocapnia? A systematic review and meta-analysis. J Neurol Sci 2019; 402:30-39. [DOI: 10.1016/j.jns.2019.04.038] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2019] [Revised: 04/12/2019] [Accepted: 04/29/2019] [Indexed: 12/14/2022]
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Minhas JS, Kennedy C, Robinson TG, Panerai RB. Different strategies to initiate and maintain hyperventilation: their effect on continuous estimates of dynamic cerebral autoregulation. Physiol Meas 2019; 40:015003. [PMID: 30577035 DOI: 10.1088/1361-6579/aafab6] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
OBJECTIVE Capnography is a key monitoring intervention in several neurologically vulnerable clinical states. Cerebral autoregulation (CA) describes the ability of the cerebrovascular system to maintain a near constant cerebral blood flow throughout fluctuations in systemic arterial blood pressure, with the partial pressure of arterial carbon dioxide known to directly influence CA. Previous work has demonstrated dysautoregulation lasting around 30 s prior to the anticipated augmentation of hyperventilation-associated hypocapnia. In order assess to potential benefit of hypocapnic interventions in an acute stroke setting, minimisation of dysregulation is paramount. APPROACH Hyperventilation strategies to induce and maintain hypocapnia were performed in 61 healthy participants, effects on temporal estimates of dynamic cerebral autoregulation (autoregulation index, ARI) were assessed to validate the most effective strategy for inducing and maintaining hypocapnia. MAIN RESULTS The extent of initial decrease was significantly smaller in the continuous metronome strategy compared to the delayed metronome and voluntary strategies (▵ARI 0.33 ± 1.18, 2.80 ± 3.33 and 3.69 ± 2.79 respectively, p < 0.017). SIGNIFICANCE The use of a continuous metronome to induce hypocapnia rather than the sudden inception of an auditory stimulus appears to reduce the initial decrease in autoregulatory capacity seen in previous studies. Dysautoregulation can be minimised by continuous metronome use during hyperventilation-induced hypocapnia. This advancement in understanding of the behaviour of CA during hypocapnia permits safer delivery of CA targeted interventions, particularly in neurologically vulnerable patient populations.
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Affiliation(s)
- Jatinder S Minhas
- Department of Cardiovascular Sciences, Cerebral Haemodynamics in Ageing and Stroke Medicine (CHIASM) Cardiovascular Sciences Research Group, University of Leicester, Leicester, United Kingdom. Department of Cardiovascular Sciences, University of Leicester, Leicester LE2 7LX, United Kingdom. Author to whom any correspondence should be addressed
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Minhas JS, Panerai RB, Robinson TG. Sex differences in cerebral haemodynamics across the physiological range of PaCO 2. Physiol Meas 2018; 39:105009. [PMID: 30256215 DOI: 10.1088/1361-6579/aae469] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
OBJECTIVE Cerebral blood flow (CBF) is influenced by changes in arterial CO2 (PaCO2). Recently, cerebral haemodynamic parameters were demonstrated to follow a four parameter logistic curve offering simultaneous assessment of dCA and CO2 vasoreactivity. However, the effects of sex on cerebral haemodynamics have yet to be described over a wide range of PaCO2. APPROACH CBF velocity (CBFV, transcranial Doppler), blood pressure (BP, Finometer) and end-tidal CO2 (EtCO2, capnography) were measured in healthy volunteers at baseline, and in response to hypo- (-5 mmHg and -10 mmHg below baseline) and hypercapnia (5% and 8% CO2), applied in random order. MAIN RESULTS Forty-five subjects (19 male, 26 female, mean age 37.5 years) showed significant differences between males and females in CBFV (50.9 ± 10.4 versus 61.5 ± 12.3 cm · s-1, p = 0.004), EtCO2 (39.2 ± 2.8 versus 36.9 ± 3.0 mmHg, p = 0.005), RAP (1.16 ± 0.23 versus 0.94 ± 0.40 mmHg cm · s-1, p = 0.005) and systolic BP (125.2 ± 8.0 versus 114.6 ± 12.4 mmHg, p = 0.0372), respectively. Significant differences between sexes were observed in the four logistic parameters: y min, y max, k (exponential coefficient) and x (EtCO2 level) across the haemodynamic variables. Significant differences included the CBFV-EtCO2 and ARI-EtCO2 relationship; ARImin (p = 0.036) and CBFVmax (p = 0.001), respectively. Furthermore, significant differences were observed for both CrCPmin (p = 0.045) and CrCPmax (p = 0.005) and RAPmin (p < 0.001) and RAPmax (p < 0.001). SIGNIFICANCE This is the first study to examine sex individually within the context of a multi-level CO2 protocol. The demonstration that the logistic curve parameters are influenced by sex, highlights the need to take into account sex differences between participants in both physiological and clinical studies.
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Affiliation(s)
- J S Minhas
- Cerebral Haemodynamics in Ageing and Stroke Medicine (CHIASM) Research Group, Department of Cardiovascular Sciences, University of Leicester, Leicester, United Kingdom. Author to whom any correspondence should be addressed
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Abstract
PURPOSE OF REVIEW Neurophysiology is a complex network of cellular, electrical, and vascular systems which function to maximize neuronal functioning and brain performance. The brain exists in a closed system made up of parenchyma, cerebrospinal fluid, and blood with any increase in volume leading to a corresponding decrease in one of the components. Once these compensatory mechanisms are exhausted, there is a precipitous increase in the intracranial pressure leading to decreases in cerebral perfusion and resulting ischemia. The cerebral vasculature has significant control over the total volume of blood and regional flow throughout the brain via autoregulation. Through this process, blood flow is tightly regulated to prevent fluctuations and is coupled precisely with metabolic demand. Moreover, oxygen delivery and aerobic respiration are essential for proper brain functioning and can become deranged in various disease states leading to cellular injury and death. RECENT FINDINGS Ongoing trials have provided evidence that in addition to targeted therapy for intracranial pressure monitoring, optimizing brain tissue oxygenation and cerebral autoregulation may lead to improved clinical outcomes. An understanding of neurophysiology is not only essential for treating patients suffering from intracranial injury but also for the development of novel monitoring and therapeutic techniques.
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