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Carlson AP, Jones T, Zhu Y, Desai M, Alsarah A, Shuttleworth CW. Oxygen-based autoregulation indices associated with clinical outcomes and spreading depolarization in aSAH. MEDRXIV : THE PREPRINT SERVER FOR HEALTH SCIENCES 2024:2024.05.17.24307563. [PMID: 38798620 PMCID: PMC11118627 DOI: 10.1101/2024.05.17.24307563] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2024]
Abstract
Background Impairment in cerebral autoregulation has been proposed as a potentially targetable factor in patients with aneurysmal subarachnoid hemorrhage (aSAH), however there are different continuous measures that can be used to calculate the state of autoregulation. In addition, it has previously been proposed that there may be an association of impaired autoregulation with the occurrence of spreading depolarization (SD) events. Methods Subjects with invasive multimodal monitoring and aSAH were enrolled in an observational study. Autoregulation indices were prospectively calculated from this database as a 10 second moving correlation coefficient between various cerebral blood flow (CBF) surrogates and mean arterial pressure (MAP). In subjects with subdural ECoG (electrocorticography) monitoring, SD was also scored. Associations between clinical outcomes using the mRS (modified Rankin Scale) and occurrence of either isolated or clustered SD was assessed. Results 320 subjects were included, 47 of whom also had ECoG SD monitoring. As expected, baseline severity factors such as mFS and WFNS (World Federation of Neurosurgical Societies scale) were strongly associated with the clinical outcome. SD probability was related to blood pressure in a triphasic pattern with a linear increase in probability below MAP of ∼100mmHg.Autoregulation indices were available for intracranial pressure (ICP) measurements (PRx), PbtO2 from Licox (ORx), perfusion from the Bowman perfusion probe (CBFRx), and cerebral oxygen saturation measured by near infrared spectroscopy (OSRx). Only worse ORx and OSRx were associated with worse clinical outcomes. ORx and OSRx also were found to both increase in the hour prior to SD for both sporadic and clustered SD. Conclusions Impairment in autoregulation in aSAH is associated with worse clinical outcomes and occurrence of SD when using ORx and OSRx. Impaired autoregulation precedes SD occurrence. Targeting the optimal MAP or cerebral perfusion pressure in patients with aSAH should use ORx and/or OSRx as the input function rather than intracranial pressure.
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Svedung Wettervik TM, Hånell A, Howells T, Ronne-Engström E, Lewén A, Enblad P. Individualized Autoregulation-Derived Cerebral Perfusion Targets in Aneurysmal Subarachnoid Hemorrhage: A New Therapeutic Avenue? J Intensive Care Med 2024:8850666241252415. [PMID: 38706245 DOI: 10.1177/08850666241252415] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/07/2024]
Abstract
Background: Cerebral perfusion pressure (CPP) is an important target in aneurysmal subarachnoid hemorrhage (aSAH), but it does not take into account autoregulatory disturbances. The pressure reactivity index (PRx) and the CPP with the optimal PRx (CPPopt) are new variables that may capture these pathomechanisms. In this study, we investigated the effect on the outcome of certain combinations of CPP or ΔCPPopt (actual CPP-CPPopt) with the concurrent autoregulatory status (PRx) after aSAH. Methods: This observational study included 432 aSAH patients, treated in the neurointensive care unit, at Uppsala University Hospital, Sweden. Functional outcome (GOS-E) was assessed 1-year postictus. Heatmaps of the percentage of good monitoring time (%GMT) of PRx/CPP and PRx/ΔCPPopt combinations in relation to GOS-E were created to visualize the association between these variables and outcome. Results: In the heatmap of the %GMT of PRx/CPP, the combination of lower CPP with higher PRx values was more strongly associated with lower GOS-E. The tolerance for lower CPP values increased with lower PRx values until a threshold of -0.50. However, for decreasing PRx below -0.50, there was a gradual reduction in the tolerance for lower CPP. In the heatmap of the %GMT of PRx/ΔCPPopt, the combination of negative ΔCPPopt with higher PRx values was strongly associated with lower GOS-E. In particular, negative ΔCPPopt together with PRx above +0.50 correlated with worse outcomes. In addition, there was a transition toward an unfavorable outcome when PRx went below -0.50, particularly if ΔCPPopt was negative. Conclusions: The PRx levels influenced the association between CPP/ΔCPPopt and outcome. Thus, this variable could be used to individualize a safe CPP-/ΔCPPopt-range.
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Affiliation(s)
| | - Anders Hånell
- Department of Medical Sciences, Section of Neurosurgery, Uppsala University, Uppsala, Sweden
| | - Timothy Howells
- Department of Medical Sciences, Section of Neurosurgery, Uppsala University, Uppsala, Sweden
| | | | - Anders Lewén
- Department of Medical Sciences, Section of Neurosurgery, Uppsala University, Uppsala, Sweden
| | - Per Enblad
- Department of Medical Sciences, Section of Neurosurgery, Uppsala University, Uppsala, Sweden
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Svedung Wettervik T, Howells T, Hånell A, Lewén A, Enblad P. The Optimal pressure reactivity index range is disease-specific: A comparison between aneurysmal subarachnoid hemorrhage and traumatic brain injury. J Clin Monit Comput 2024:10.1007/s10877-024-01168-9. [PMID: 38702589 DOI: 10.1007/s10877-024-01168-9] [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: 02/28/2024] [Accepted: 04/22/2024] [Indexed: 05/06/2024]
Abstract
PURPOSE Impaired cerebral pressure autoregulation is common and detrimental after acute brain injuries. Based on the prevalence of delayed cerebral ischemia in aneurysmal subarachnoid hemorrhage (aSAH) patients compared to traumatic brain injury (TBI), we hypothesized that the type of autoregulatory disturbance and the optimal PRx range may differ between these two conditions. The aim of this study was to determine the optimal PRx ranges in relation to functional outcome following aSAH and TBI, respectively. METHODS In this observational study, 487 aSAH patients and 413 TBI patients, treated in the neurointensive care, Uppsala, Sweden, between 2008 and 2018, were included. The percentage of good monitoring time (%GMT) of PRx was calculated within 8 intervals covering the range from -1.0 to + 1.0, and analyzed in relation to favorable outcome (GOS-E 5 to 8). RESULTS In multiple logistic regressions, a higher %GMTs of PRx in the intervals -1.0 to -0.5 and + 0.75 to + 1.0 were independently associated with a lower rate of favorable outcome in the aSAH cohort. In a similar analysis in the TBI cohort, only positive PRx in the interval + 0.75 to + 1.0 was independently associated with a lower rate of favorable outcome. CONCLUSION Extreme PRx values in both directions were unfavorable in aSAH, possibly as high PRx could indicate proximal vasospasm with exhausted distal vasodilatory reserve, while very negative PRx could reflect myogenic hyperreactivity with suppressed cerebral blood flow. Only elevated PRx was unfavorable in TBI, possibly as pressure passive vessels may be a more predominant pathomechanism in this disease.
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Affiliation(s)
- Teodor Svedung Wettervik
- Department of Medical Sciences, Section of Neurosurgery, Uppsala University, 751 85, Uppsala, Sweden.
| | - Timothy Howells
- Department of Medical Sciences, Section of Neurosurgery, Uppsala University, 751 85, Uppsala, Sweden
| | - Anders Hånell
- Department of Medical Sciences, Section of Neurosurgery, Uppsala University, 751 85, Uppsala, Sweden
| | - Anders Lewén
- Department of Medical Sciences, Section of Neurosurgery, Uppsala University, 751 85, Uppsala, Sweden
| | - Per Enblad
- Department of Medical Sciences, Section of Neurosurgery, Uppsala University, 751 85, Uppsala, Sweden
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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; 0:revneuro-2024-0028. [PMID: 38581271 DOI: 10.1515/revneuro-2024-0028] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [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, 12288 University of New Mexico School of Medicine , MSC10 5615, 1 UNM, Albuquerque, NM, 87131, USA
- Department of Neurosciences, 12288 University of New Mexico School of Medicine , 915 Camino de Salud NE, Albuquerque, NM, 87106, USA
| | - Andrew R Mayer
- 168528 Mind Research Network , 1101 Yale, Blvd, NE, Albuquerque, NM, 87106, USA
| | - Chad Cole
- Department of Neurosurgery, 12288 University of New Mexico School of Medicine , MSC10 5615, 1 UNM, Albuquerque, NM, 87131, USA
| | - Harm J van der Horn
- 168528 Mind Research Network , 1101 Yale, Blvd, NE, Albuquerque, NM, 87106, USA
| | - Joshua Marquez
- 12288 University of New Mexico School of Medicine , 915 Camino de Salud NE, Albuquerque, NM, 87106, USA
| | - Taylor C Stevenson
- Department of Neurosurgery, 12288 University of New Mexico School of Medicine , MSC10 5615, 1 UNM, Albuquerque, NM, 87131, USA
| | - C William Shuttleworth
- Department of Neurosciences, 12288 University of New Mexico School of Medicine , 915 Camino de Salud NE, Albuquerque, NM, 87106, USA
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Eide PK, Ringstad G. Functional analysis of the human perivascular subarachnoid space. Nat Commun 2024; 15:2001. [PMID: 38443374 PMCID: PMC10914778 DOI: 10.1038/s41467-024-46329-1] [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: 04/26/2023] [Accepted: 02/20/2024] [Indexed: 03/07/2024] Open
Abstract
The human subarachnoid space harbors the cerebrospinal fluid, which flows within a landscape of blood vessels and trabeculae. Functional implications of subarachnoid space anatomy remain far less understood. This study of 75 patients utilizes a cerebrospinal fluid tracer (gadobutrol) and consecutive magnetic resonance imaging to investigate features of early (i.e. within 2-3 h after injection) tracer propagation within the subarachnoid space. There is a time-dependent perivascular pattern of enrichment antegrade along the major cerebral artery trunks; the anterior-, middle-, and posterior cerebral arteries. The correlation between time of first enrichment around arteries and early enrichment in nearby cerebral cortex is significant. These observations suggest the existence of a compartmentalized subarachnoid space, where perivascular ensheathment of arteries facilitates antegrade tracer passage towards brain tissue. Periarterial transport is impaired in subjects with reduced intracranial pressure-volume reserve capacity and in idiopathic normal pressure hydrocephalus patients who also show increased perivascular space size.
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Affiliation(s)
- Per Kristian Eide
- Department of Neurosurgery, Oslo University Hospital - Rikshospitalet, Pb 4950 Nydalen, N-0424, Oslo, Norway.
- KG Jebsen Centre for Brain Fluid Research, Institute of Clinical Medicine, Faculty of Medicine, University of Oslo, PB 1072 Blindern, N-0316, Oslo, Norway.
| | - Geir Ringstad
- Department of Radiology, Oslo University Hospital- Rikshospitalet, Pb 4950 Nydalen, N-0424, Oslo, Norway
- Department of Geriatrics and Internal medicine, Sorlandet Hospital, 4838, Arendal, Arendal, Norway
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Chang JJ, Kepplinger D, Metter EJ, Felbaum DR, Mai JC, Armonda RA, Aulisi EF. Pressure reactivity index for early neuroprognostication in poor-grade subarachnoid hemorrhage. J Neurol Sci 2023; 450:120691. [PMID: 37267816 DOI: 10.1016/j.jns.2023.120691] [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: 03/16/2023] [Revised: 05/18/2023] [Accepted: 05/21/2023] [Indexed: 06/04/2023]
Abstract
BACKGROUND Pressure reactivity index (PRx) utilizes moving correlation coefficients from intracranial pressure (ICP) and mean arterial pressures to evaluate cerebral autoregulation. We evaluated patients with poor-grade subarachnoid hemorrhage (SAH), identified their PRx trajectories over time, and identified threshold time points where PRx could be used for neuroprognostication. METHODS Patients with poor-grade SAH were identified and received continuous bolt ICP measurements. Dichotomized outcomes were based on ninety-day modified Rankin scores and disposition. Smoothed PRx trajectories for each patient were created to generate "candidate features" that looked at daily average PRx, cumulative first-order changes in PRx, and cumulative second-order changes in PRx. "Candidate features" were then used to perform penalized logistic regression analysis using poor outcome as the dependent variable. Penalized logistic regression models that maximized specificity for poor outcome were generated over several time periods and evaluated how sensitivities changed over time. RESULTS 16 patients with poor-grade SAH were evaluated. Average PRx trajectories for the good (PRx < 0.25) and poor outcome groups (PRx > 0.5) started diverging at post-ictus day 8. When targeting specificities ≥88% for poor outcome, sensitivities for poor outcome consistently increased to >70% starting at post-ictus days 12-14 with a maximum sensitivity of 75% occurring at day 18. CONCLUSIONS Our results suggest that by using PRx trends, early neuroprognostication in patients with SAH and poor clinical exams may start becoming apparent at post-ictus day 8 and reach adequate sensitivities by post-ictus days 12-14. Further study is required to validate this in larger poor-grade SAH populations.
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Affiliation(s)
- Jason J Chang
- Department of Critical Care Medicine, MedStar Washington Hospital Center, Washington, DC, USA; Department of Neurology, Georgetown University Medical Center, Washington, DC, USA.
| | - David Kepplinger
- Department of Statistics, George Mason University, Fairfax, VA, USA
| | - E Jeffrey Metter
- Department of Neurology, University of Tennessee Health Science Center, Memphis, TN, USA
| | - Daniel R Felbaum
- Department of Neurosurgery, Georgetown University and MedStar Washington Hospital Center, Washington, DC, USA
| | - Jeffrey C Mai
- Department of Neurosurgery, Georgetown University and MedStar Washington Hospital Center, Washington, DC, USA
| | - Rocco A Armonda
- Department of Neurosurgery, Georgetown University and MedStar Washington Hospital Center, Washington, DC, USA
| | - Edward F Aulisi
- Department of Neurosurgery, Georgetown University and MedStar Washington Hospital Center, Washington, DC, USA
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Svedung Wettervik T, Hånell A, Howells T, Ronne Engström E, Lewén A, Enblad P. ICP, CPP, and PRx in traumatic brain injury and aneurysmal subarachnoid hemorrhage: association of insult intensity and duration with clinical outcome. J Neurosurg 2023; 138:446-453. [PMID: 35901752 DOI: 10.3171/2022.5.jns22560] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2022] [Accepted: 05/05/2022] [Indexed: 02/04/2023]
Abstract
OBJECTIVE The primary aim of this study was to determine the combined effect of insult intensity and duration of intracranial pressure (ICP), cerebral perfusion pressure (CPP), and pressure reactivity index (PRx) on outcome measured with the Glasgow Outcome Scale-Extended (GOS-E) in patients with traumatic brain injury (TBI) or aneurysmal subarachnoid hemorrhage (aSAH). METHODS This observational study included all TBI and aSAH patients treated in the neurointensive care unit in Uppsala, Sweden, 2008-2018, with at least 24 hours of ICP monitoring during the first 10 days following injury and available long-term clinical outcome data. ICP, CPP, and PRx insults were visualized as 2D plots to highlight the effects of both insult intensity and duration on patient outcome. RESULTS Of 950 included patients, 436 were TBI and 514 aSAH patients. The TBI patients were younger, more often male, and exhibited worse neurological status at admission, but recovered more favorably than the aSAH patients. There was a transition from good to poor outcome with ICP above 15-20 mm Hg in both TBI and aSAH. The two diagnoses had opposite CPP patterns. In TBI patients, CPP episodes at or below 80 mm Hg were generally favorable, whereas CPP episodes above 80 mm Hg were favorable in the aSAH patients. In the TBI patients there was a transition from good to poor outcome when PRx exceeded zero, but no evident transition was found in the aSAH cohort. CONCLUSIONS The insult intensity and duration plots formulated in this study illustrate the similarities and differences between TBI and aSAH patients. In particular, aSAH patients may benefit from much higher CPP targets than TBI patients.
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Affiliation(s)
| | - Anders Hånell
- Department of Medical Sciences, Section of Neurosurgery, Uppsala University, Uppsala, Sweden
| | - Timothy Howells
- Department of Medical Sciences, Section of Neurosurgery, Uppsala University, Uppsala, Sweden
| | | | - Anders Lewén
- Department of Medical Sciences, Section of Neurosurgery, Uppsala University, Uppsala, Sweden
| | - Per Enblad
- Department of Medical Sciences, Section of Neurosurgery, Uppsala University, Uppsala, Sweden
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8
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Sarigul B, De Macêdo Filho LJM, Hawryluk GWJ. Invasive Monitoring in Traumatic Brain Injury. CURRENT SURGERY REPORTS 2022. [DOI: 10.1007/s40137-022-00332-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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9
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Al-Kawaz M, Cho SM, Gottesman RF, Suarez JI, Rivera-Lara L. Impact of Cerebral Autoregulation Monitoring in Cerebrovascular Disease: A Systematic Review. Neurocrit Care 2022; 36:1053-1070. [PMID: 35378665 DOI: 10.1007/s12028-022-01484-5] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2021] [Accepted: 03/01/2022] [Indexed: 12/16/2022]
Abstract
Cerebral autoregulation (CA) prevents brain injury by maintaining a relatively constant cerebral blood flow despite fluctuations in cerebral perfusion pressure. This process is disrupted consequent to various neurologic pathologic processes, which may result in worsening neurologic outcomes. Herein, we aim to highlight evidence describing CA changes and the impact of CA monitoring in patients with cerebrovascular disease, including ischemic stroke, intracerebral hemorrhage (ICH), and aneurysmal subarachnoid hemorrhage (aSAH). The study was preformed according to the Preferred Reporting Items for Systematic Reviews and Meta-Analysis guidelines. English language publications were identified through a systematic literature conducted in Ovid Medline, PubMed, and Embase databases. The search spanned the dates of each database's inception through January 2021. We selected case-control studies, cohort observational studies, and randomized clinical trials for adult patients (≥ 18 years) who were monitored with continuous metrics using transcranial Doppler, near-infrared spectroscopy, and intracranial pressure monitors. Of 2799 records screened, 48 studies met the inclusion criteria. There were 23 studies on ischemic stroke, 18 studies on aSAH, 5 studies on ICH, and 2 studies on systemic hypertension. CA impairment was reported after ischemic stroke but generally improved after tissue plasminogen activator administration and successful mechanical thrombectomy. Persistent impairment in CA was associated with hemorrhagic transformation, malignant cerebral edema, and need for hemicraniectomy. Studies that investigated large ICHs described bilateral CA impairment up to 12 days from the ictus, especially in the presence of small vessel disease. In aSAH, impairment of CA was associated with angiographic vasospasm, delayed cerebral ischemia, and poor functional outcomes at 6 months. This systematic review highlights the available evidence for CA disruption during cerebrovascular diseases and its possible association with long-term neurological outcome. CA may be disrupted even before acute stroke in patients with untreated chronic hypertension. Monitoring CA may help in establishing individualized management targets in patients with cerebrovascular disease.
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Affiliation(s)
- Mais Al-Kawaz
- Department of Neurosurgery, Icahn School of Medicine at Mount Sinai, New York, NY, USA.
- Department of Neurology, The Johns Hopkins University School of Medicine, Baltimore, MD, USA.
| | - Sung-Min Cho
- Department of Neurology, The Johns Hopkins University School of Medicine, Baltimore, MD, USA
- Department of Anesthesiology and Critical Care Medicine, The Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Rebecca F Gottesman
- Stroke Branch, National Institute of Neurological Disorders and Stroke Intramural Program, National Institutes of Health, Bethesda, MD, USA
| | - Jose I Suarez
- Department of Neurology, The Johns Hopkins University School of Medicine, Baltimore, MD, USA
- Department of Anesthesiology and Critical Care Medicine, The Johns Hopkins University School of Medicine, Baltimore, MD, USA
- Department of Neurosurgery, The Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Lucia Rivera-Lara
- Division of Stroke and Neurocritical Care, Stanford University, Palo Alto, CA, USA
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Lidington D, Wan H, Bolz SS. Cerebral Autoregulation in Subarachnoid Hemorrhage. Front Neurol 2021; 12:688362. [PMID: 34367053 PMCID: PMC8342764 DOI: 10.3389/fneur.2021.688362] [Citation(s) in RCA: 29] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2021] [Accepted: 06/25/2021] [Indexed: 12/28/2022] Open
Abstract
Subarachnoid hemorrhage (SAH) is a devastating stroke subtype with a high rate of mortality and morbidity. The poor clinical outcome can be attributed to the biphasic course of the disease: even if the patient survives the initial bleeding emergency, delayed cerebral ischemia (DCI) frequently follows within 2 weeks time and levies additional serious brain injury. Current therapeutic interventions do not specifically target the microvascular dysfunction underlying the ischemic event and as a consequence, provide only modest improvement in clinical outcome. SAH perturbs an extensive number of microvascular processes, including the “automated” control of cerebral perfusion, termed “cerebral autoregulation.” Recent evidence suggests that disrupted cerebral autoregulation is an important aspect of SAH-induced brain injury. This review presents the key clinical aspects of cerebral autoregulation and its disruption in SAH: it provides a mechanistic overview of cerebral autoregulation, describes current clinical methods for measuring autoregulation in SAH patients and reviews current and emerging therapeutic options for SAH patients. Recent advancements should fuel optimism that microvascular dysfunction and cerebral autoregulation can be rectified in SAH patients.
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Affiliation(s)
- Darcy Lidington
- Department of Physiology, University of Toronto, Toronto, ON, Canada.,Toronto Centre for Microvascular Medicine at the Ted Rogers Centre for Heart Research Translational Biology and Engineering Program, University of Toronto, Toronto, ON, Canada
| | - Hoyee Wan
- Department of Physiology, University of Toronto, Toronto, ON, Canada.,Toronto Centre for Microvascular Medicine at the Ted Rogers Centre for Heart Research Translational Biology and Engineering Program, University of Toronto, Toronto, ON, Canada
| | - Steffen-Sebastian Bolz
- Department of Physiology, University of Toronto, Toronto, ON, Canada.,Toronto Centre for Microvascular Medicine at the Ted Rogers Centre for Heart Research Translational Biology and Engineering Program, University of Toronto, Toronto, ON, Canada.,Heart & Stroke/Richard Lewar Centre of Excellence for Cardiovascular Research, University of Toronto, Toronto, ON, Canada
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Svedung Wettervik T, Howells T, Lewén A, Ronne-Engström E, Enblad P. Temporal Dynamics of ICP, CPP, PRx, and CPPopt in High-Grade Aneurysmal Subarachnoid Hemorrhage and the Relation to Clinical Outcome. Neurocrit Care 2021; 34:390-402. [PMID: 33420669 PMCID: PMC8128752 DOI: 10.1007/s12028-020-01162-4] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2020] [Accepted: 11/18/2020] [Indexed: 12/23/2022]
Abstract
BACKGROUND High intracranial pressure (ICP) and low cerebral perfusion pressure (CPP) may induce secondary brain injury following aneurysmal subarachnoid hemorrhage (aSAH). In the current study, we aimed to determine the temporal incidence of insults above/below certain ICP/CPP thresholds, the role of pressure autoregulation in CPP management (PRx and CPPopt), and the relation to clinical outcome. METHODS In this retrospective study, 242 patients were included with aSAH, who were treated in the neurointensive care unit, Uppsala University Hospital, Sweden, 2008-2018, with ICP monitoring the first 10 days post-ictus. Data from ICP, pressure autoregulation (PRx), CPP, and CPPopt (the CPP with the lowest/optimal PRx) were analyzed the first 10 days. The percentage of good monitoring time (GMT) above/below various ICP and CPP thresholds was calculated, e.g., ICP > 20 mm Hg (%), CPP < 60 mm Hg (%), and ∆CPPopt (CPP-CPPopt) < - 10 mm Hg (%). RESULTS Of the 242 patients, 63 (26%) had favorable (GOS-E 5-8) and 179 (74%) had unfavorable (GOS-E 1-4) outcome at 12 months. Higher proportion (GMT) of ICP insults above 20 mm Hg was most common the first 3 days post-ictus and was then independently associated with unfavorable outcome. CPP gradually increased throughout the 10 days post-ictus, and higher proportion of GMT with CPP < 90 mm Hg was independently associated with unfavorable outcome in the late vasospasm phase (days 6.5-10). PRx was above 0 throughout the 10 days and deteriorated in the late vasospasm phase. Higher values were then independently associated with unfavorable outcome. There was no difference in GMT of CPP deviations from CPPopt between the outcome groups. CONCLUSIONS Avoiding intracranial hypertension early and maintaining a high CPP in the vasospasm phase when the pressure autoregulation is most disturbed may improve clinical outcome after aSAH.
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Affiliation(s)
- Teodor Svedung Wettervik
- Department of Neuroscience, Section of Neurosurgery, Uppsala University, 751 85, Uppsala, Sweden.
| | - Timothy Howells
- Department of Neuroscience, Section of Neurosurgery, Uppsala University, 751 85, Uppsala, Sweden
| | - Anders Lewén
- Department of Neuroscience, Section of Neurosurgery, Uppsala University, 751 85, Uppsala, Sweden
| | - Elisabeth Ronne-Engström
- Department of Neuroscience, Section of Neurosurgery, Uppsala University, 751 85, Uppsala, Sweden
| | - Per Enblad
- Department of Neuroscience, Section of Neurosurgery, Uppsala University, 751 85, Uppsala, Sweden
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12
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Fan BB, Sun XC, Huang ZJ, Yang XM, Guo ZD, He ZH. Hypoperfusion assessed by pressure reactivity index is associated with delayed cerebral ischemia after subarachnoid hemorrhage: an observational study. Chin Neurosurg J 2021; 7:16. [PMID: 33648581 PMCID: PMC7923615 DOI: 10.1186/s41016-021-00231-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2020] [Accepted: 01/02/2021] [Indexed: 11/16/2022] Open
Abstract
Background Dysfunction of cerebral autoregulation is one of the pathophysiological mechanisms that causes delayed cerebral ischemia (DCI) after subarachnoid hemorrhage (SAH). Pressure reactivity index (PRx) have been confirmed to reflect the level of cerebral autoregulation and used to derive optimal cerebral perfusion pressure (CPPopt). The goal of this study is to explore the associations between autoregulation, CPPopt, PRx, and DCI. Methods Continuous intracranial pressure (ICP), arterial blood pressure (ABP), and cerebral perfusion pressure (CPP) signals acquired from 61 aSAH patients were retrospectively analyzed. PRx was calculated and collected by Pneumatic computer system. The CPP at the lowest PRx was determined as the CPPopt. The duration of a hypoperfusion event (dHP) was defined as the cumulative time that the PRx was > 0.3 and the CPP was <CPPopt. The duration of CPP more than 10 mmHg below CPPopt (ΔCPPopt < − 10 mmHg) was also used to assess hypoperfusion. The percent of the time of hypoperfusion by dHP and ΔCPPopt < − 10 mmHg (%dHP and %ΔCPPopt) were compared between DCI group and control group, utilizing univariate and multivariable logistic regression. It was the clinical prognosis at 3 months after hemorrhage that was assessed with the modified Rankin Scale, and logistic regression and ROC analysis were used for predictive power for unfavorable outcomes (mRs 3–5). Results Data from 52 patients were included in the final analysis of 61 patients. The mean %dHP in DCI was 29.23% and 10.66% in control. The mean %ΔCPPopt < − 10 mmHg was 22.28%, and 5.90% in control. The %dHP (p < 0.001) and the %ΔCPPopt < − 10mmHg (p < 0.001) was significantly longer in the DCI group. In multivariate logistic regression model, %ΔCPPopt <− 10 mmHg (p < 0.001) and %dHP (p < 0.001) were independent risk factor for predicting DCI, and %ΔCPPopt <− 10 mmHg (p = 0.010) and %dHP (p = 0.026) were independent risk factor for predicting unfavorable outcomes. Conclusions The increase of duration of hypoperfusion events and duration of CPP below CPPopt over 10 mmHg, evaluated as time of lowered CPP, is highly indicative of DCI and unfavorable outcomes.
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Affiliation(s)
- Bin Bin Fan
- Department of Neurosurgery, The First Affiliated Hospital of Chongqing Medical University, Chongqing, China
| | - Xiao Chuan Sun
- Department of Neurosurgery, The First Affiliated Hospital of Chongqing Medical University, Chongqing, China.
| | - Zhi Jian Huang
- Department of Neurosurgery, The First Affiliated Hospital of Chongqing Medical University, Chongqing, China
| | - Xiao Min Yang
- Department of Neurosurgery, The First Affiliated Hospital of Chongqing Medical University, Chongqing, China
| | - Zong Duo Guo
- Department of Neurosurgery, The First Affiliated Hospital of Chongqing Medical University, Chongqing, China
| | - Zhao Hui He
- Department of Neurosurgery, The First Affiliated Hospital of Chongqing Medical University, Chongqing, China
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Wang J, McDonagh DL, Meng L. Calcium Channel Blockers in Acute Care: The Links and Missing Links Between Hemodynamic Effects and Outcome Evidence. Am J Cardiovasc Drugs 2021; 21:35-49. [PMID: 32410171 DOI: 10.1007/s40256-020-00410-4] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Calcium channel blockers (CCBs) exert profound hemodynamic effects via blockage of calcium flux through voltage-gated calcium channels. CCBs are widely used in acute care to treat concerning, debilitating, or life-threatening hemodynamic changes in many patients. The overall literature suggests that, for systemic hemodynamics, although CCBs decrease blood pressure, they normally increase cardiac output; for regional hemodynamics, although they impair pressure autoregulation, they normally increase organ blood flow and tissue oxygenation. In acute care, CCBs exert therapeutic efficacy or improve outcomes in patients with aneurysmal subarachnoid hemorrhage, acute myocardial infarction and unstable angina, hypertensive crisis, perioperative hypertension, and atrial tachyarrhythmia. However, despite the clear links, there are missing links between the known hemodynamic effects and the reported outcome evidence, suggesting that further studies are needed for clarification. In this narrative review, we aim to discuss the hemodynamic effects and outcome evidence for CCBs, the links and missing links between these two domains, and the directions that merit future investigations.
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Affiliation(s)
- Jin Wang
- Department of Anesthesiology, The Second Affiliated Hospital, Xi'an Jiaotong University, Xi'an, Shaanxi, China
| | - David L McDonagh
- Department of Anesthesiology and Pain Management, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Lingzhong Meng
- Department of Anesthesiology, Yale University School of Medicine, 330 Cedar Street, TMP 3, New Haven, CT, 06520, USA.
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14
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Mechanisms behind altered pulsatile intracranial pressure in idiopathic normal pressure hydrocephalus: role of vascular pulsatility and systemic hemodynamic variables. Acta Neurochir (Wien) 2020; 162:1803-1813. [PMID: 32533412 PMCID: PMC7360648 DOI: 10.1007/s00701-020-04423-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2020] [Accepted: 05/19/2020] [Indexed: 12/15/2022]
Abstract
BACKGROUND The dementia subtype idiopathic normal pressure hydrocephalus (iNPH) has unknown etiology, but one characteristic is elevated intracranial pressure (ICP) wave amplitudes in those individuals who respond with clinical improvement following cerebrospinal fluid (CSF) diversion. To explore the mechanisms behind altered ICP wave amplitudes, we correlated central aortic blood pressure (BP) and ICP waveform amplitudes (intracranial aortic amplitude correlation) and examined how this correlation relates to ICP wave amplitude levels and systemic hemodynamic parameters. METHODS The study included 29 patients with probable iNPH who underwent continuous multi-hour measurement of ICP, radial artery BP, and systemic hemodynamic parameters. The radial artery BP waveforms were used to estimate central aortic BP waveforms, and the intracranial aortic amplitude correlation was determined over consecutive 4-min periods. RESULTS The average intracranial aortic amplitude correlation was 0.28 ± 0.16 at the group level. In the majority of iNPH patients, the intracranial aortic amplitude correlation was low, while in about 1/5 patients, the correlation was rather high (average Pearson correlation coefficient > 0.4). The degree of correlation was hardly influenced by systemic hemodynamic parameters. CONCLUSIONS In about 1/5 iNPH patients of this study, the intracranial aortic amplitude correlation (IAACAORTIC) was rather high (average Pearson correlation coefficient > 0.4), suggesting that cerebrovascular factors to some extent may affect the ICP wave amplitudes in a subset of patients. However, in 14/19 (74%) iNPH patients with elevated ICP wave amplitudes, the intracranial aortic amplitude correlation was low, indicating that the ICP pulse amplitude in most iNPH patients is independent of central vascular excitation, ergo it is modulated by local cerebrospinal physiology. In support of this assumption, the intracranial aortic amplitude correlation was not related to most systemic hemodynamic variables. An exception was found for a subgroup of the patients with high systemic vascular resistance, where there was a correlation.
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15
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Evensen KB, Eide PK. Measuring intracranial pressure by invasive, less invasive or non-invasive means: limitations and avenues for improvement. Fluids Barriers CNS 2020; 17:34. [PMID: 32375853 PMCID: PMC7201553 DOI: 10.1186/s12987-020-00195-3] [Citation(s) in RCA: 62] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2020] [Accepted: 04/19/2020] [Indexed: 12/20/2022] Open
Abstract
Sixty years have passed since neurosurgeon Nils Lundberg presented his thesis about intracranial pressure (ICP) monitoring, which represents a milestone for its clinical introduction. Monitoring of ICP has since become a clinical routine worldwide, and today represents a cornerstone in surveillance of patients with acute brain injury or disease, and a diagnostic of individuals with chronic neurological disease. There is, however, controversy regarding indications, clinical usefulness and the clinical role of the various ICP scores. In this paper, we critically review limitations and weaknesses with the current ICP measurement approaches for invasive, less invasive and non-invasive ICP monitoring. While risk related to the invasiveness of ICP monitoring is extensively covered in the literature, we highlight other limitations in current ICP measurement technologies, including limited ICP source signal quality control, shifts and drifts in zero pressure reference level, affecting mean ICP scores and mean ICP-derived indices. Control of the quality of the ICP source signal is particularly important for non-invasive and less invasive ICP measurements. We conclude that we need more focus on mitigation of the current limitations of today's ICP modalities if we are to improve the clinical utility of ICP monitoring.
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Affiliation(s)
- Karen Brastad Evensen
- Department of Neurosurgery, Oslo University Hospital-Rikshospitalet, P.O. Box 4950, Nydalen, 0424, Oslo, Norway
- Department of Informatics, Faculty of Mathematics and Natural Sciences, University of Oslo, Oslo, Norway
| | - Per Kristian Eide
- Department of Neurosurgery, Oslo University Hospital-Rikshospitalet, P.O. Box 4950, Nydalen, 0424, Oslo, Norway.
- Institute of Clinical Medicine, Faculty of Medicine, University of Oslo, Oslo, Norway.
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Silverman A, Kodali S, Strander S, Gilmore EJ, Kimmel A, Wang A, Cord B, Falcone G, Hebert R, Matouk C, Sheth KN, Petersen NH. Deviation From Personalized Blood Pressure Targets Is Associated With Worse Outcome After Subarachnoid Hemorrhage. Stroke 2019; 50:2729-2737. [PMID: 31495332 PMCID: PMC6756936 DOI: 10.1161/strokeaha.119.026282] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Background and Purpose- Optimal blood pressure (BP) management during the early stages of aneurysmal subarachnoid hemorrhage remains uncertain. Observational studies have found worse outcomes in patients with increased hemodynamic variability, suggesting BP optimization as a potential neuroprotective strategy. In this study, we calculated personalized BP targets at which cerebral autoregulation was best preserved. We analyzed how deviation from these limits correlates with functional outcome. Methods- We prospectively enrolled 31 patients with aneurysmal subarachnoid hemorrhage. Autoregulatory function was continuously measured by interrogating changes in near-infrared spectroscopy (NIRS)-derived tissue oxygenation-a surrogate for cerebral blood flow-as well as intracranial pressure (ICP) in response to changes in mean arterial pressure using time-correlation analysis. The resulting autoregulatory indices were used to identify the upper and lower limit of autoregulation. Percent time that mean arterial pressure exceeded limits of autoregulation was calculated for each patient. Functional outcome was assessed using the modified Rankin Scale at discharge and 90 days. Associations with outcome were analyzed using ordinal multivariate logistic regression. Results- Personalized limits of autoregulation were computed in all patients (age 57.5±13.4, 23F, mean World Federation of Neurological Surgeons 2±1, monitoring time 67.8±50.8 hours). Optimal BP and limits of autoregulation were calculated on average for 89.5±6.7% of the total monitoring period. ICP- and NIRS-derived optimal pressures strongly correlated with one another (P<0.0001). Percent time that mean arterial pressure deviated from limits of autoregulation significantly associated with worse functional outcome at discharge (NIRS, P=0.001; ICP, P=0.004) and 90 days (NIRS, P=0.002; ICP, P=0.003), adjusting separately for age, World Federation of Neurological Surgeons, vasospasm, and delayed cerebral ischemia. Conclusions- Both invasive (ICP) and noninvasive (NIRS) determination of personalized BP targets after aneurysmal subarachnoid hemorrhage is feasible, and these 2 approaches revealed significant collinearity. Furthermore, exceeding individualized limits of autoregulation was associated with poor functional outcomes.
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Affiliation(s)
| | - Sreeja Kodali
- Department of Neurology, Yale Medical School, New Haven, CT
| | | | | | | | - Anson Wang
- Department of Neurology, Yale Medical School, New Haven, CT
| | - Branden Cord
- Department of Neurosurgery, Yale Medical School, New Haven, CT
| | - Guido Falcone
- Department of Neurology, Yale Medical School, New Haven, CT
| | - Ryan Hebert
- Department of Neurosurgery, Yale Medical School, New Haven, CT
| | - Charles Matouk
- Department of Neurosurgery, Yale Medical School, New Haven, CT
| | - Kevin N. Sheth
- Department of Neurology, Yale Medical School, New Haven, CT
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Lu X, Jin G, Chen W, Yu X, Ling F. Depiction of Physiological Homeostasis by Self-Coupled System and Its Significance. Front Physiol 2019; 10:1205. [PMID: 31607948 PMCID: PMC6761279 DOI: 10.3389/fphys.2019.01205] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2019] [Accepted: 09/04/2019] [Indexed: 11/16/2022] Open
Abstract
The negative feedback system (NFS) was regarded as the basic unit of regulation of physiological homeostasis for more than 70 years. However, NFS-based depiction possesses some limitations. The self-coupled system (SCS), a non-stop system in which the output of the current moment becomes the input of the next moment, can also be utilized to depict homeostasis. In SCS-based depiction, all of the related regulatory mechanisms of a homeostasis are regarded as an entity. Then, homeostatic dynamics can be expressed by simple mathematical language. A new disease group was revealed and some useful inferences were obtained through mathematical deduction. They were supported by published studies. SCS-based depiction of homeostasis should be a requisite supplement to medical knowledge systems based on NFS.
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Affiliation(s)
- Xia Lu
- Department of Neurosurgery, Chinese PLA General Hospital and Medical School of Chinese PLA, Beijing, China
- Department of Neurosurgery, Xuanwu Hospital Capital Medical University and China International Institution of Neuroscience, Beijing, China
| | - Guantao Jin
- Advanced School of Art and Humanities, Chinese Academy of Art, Hangzhou, China
| | - Wenjin Chen
- Department of Neurosurgery, Xuanwu Hospital Capital Medical University and China International Institution of Neuroscience, Beijing, China
| | - Xinguang Yu
- Department of Neurosurgery, Chinese PLA General Hospital and Medical School of Chinese PLA, Beijing, China
| | - Feng Ling
- Department of Neurosurgery, Xuanwu Hospital Capital Medical University and China International Institution of Neuroscience, Beijing, China
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19
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Cai J, Fang W, Chen F, Lin Z, Lin Y, Yu L, Yao P, Kang D. Cerebral perfusion pressure threshold to prevent delayed cerebral ischemia after aneurysmal subarachnoid hemorrhage. J Clin Neurosci 2018; 54:29-32. [DOI: 10.1016/j.jocn.2018.04.073] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2017] [Revised: 01/26/2018] [Accepted: 04/30/2018] [Indexed: 11/28/2022]
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Abstract
PURPOSE OF REVIEW Cerebral autoregulation (CA) is a mechanism that maintains cerebral blood flow constant despite fluctuations in systemic arterial blood pressure. This review will focus on recent studies that measured CA non-invasively in acute cerebrovascular events, a feature unique to the transcranial Doppler ultrasound. We will summarize the rationale for CA assessment in acute cerebrovascular disorders and specifically evaluate the existing data on the value of CA measures in relation to clinical severity, guiding management decisions, and prognostication. RECENT FINDINGS Existing data suggest that CA is generally impaired in various cerebrovascular disorders. In patients with small vessel ischemic stroke, CA has been shown to be impaired in both hemispheres, whereas in large territorial strokes, CA impairment has been limited to the affected hemisphere. In these latter patients, impaired CA is also predictive of secondary complications such as hemorrhagic transformation and cerebral edema, hence worse functional outcome. In patients with carotid stenosis, impaired CA may also be associated with a higher ipsilateral hemispheric stroke risk. CA is also strongly linked to outcome in patients with intracranial hemorrhage. In patients with intraparenchymal hemorrhage, CA impairment correlated with clinical and imaging severity, whereas in those with subarachnoid hemorrhage, CA measures have a predictive value for development of delayed cerebral ischemia and radiographic vasospasm. Assessment of CA is increasingly more accessible in acute cerebrovascular disorders and promises to be a valuable measure in guiding hemodynamic management and predicting secondary complication, thus enhancing the care of these patients in the acute setting.
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Affiliation(s)
- Pedro Castro
- Department of Neurology, São João Hospital Center, Porto, Portugal.,Department of Clinical Neurosciences and Mental Health, Faculty of Medicine of University of Porto, Porto, Portugal
| | - Elsa Azevedo
- Department of Neurology, São João Hospital Center, Porto, Portugal.,Department of Clinical Neurosciences and Mental Health, Faculty of Medicine of University of Porto, Porto, Portugal
| | - Farzaneh Sorond
- Department of Neurology, Division of Stroke and Neurocritical, Northwestern University Feinberg School of Medicine, 303 East Chicago Avenue, Ward 12-140, Chicago, IL, 60611, USA.
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22
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Gaasch M, Schiefecker AJ, Kofler M, Beer R, Rass V, Pfausler B, Thomé C, Schmutzhard E, Helbok R. Cerebral Autoregulation in the Prediction of Delayed Cerebral Ischemia and Clinical Outcome in Poor-Grade Aneurysmal Subarachnoid Hemorrhage Patients*. Crit Care Med 2018; 46:774-780. [DOI: 10.1097/ccm.0000000000003016] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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23
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Copplestone S, Welbourne J. A narrative review of the clinical application of pressure reactiviy indices in the neurocritical care unit. Br J Neurosurg 2018; 32:4-12. [PMID: 29298527 DOI: 10.1080/02688697.2017.1416063] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Pressure reactivity indices are used in clinical research as a surrogate marker of the ability of the cerebrovasculature to maintain cerebral autoregulation. The use of pressure reactivity indices in patients with neurological injury represents a potential to move away from population-based physiological targets used in guidelines to individualized physiological targets. The aim of this review is to describe the underlying principles and development of pressure reactivity indices, alongside a critique of how they have been used in clinical research, including their limitations. The primary source literature was identified from a database search of PUBMed and OVID online using the search terms "pressure reactivity index" and "pressure reactivity indices". The evidence base regarding pressure reactivity indices currently remains Level III. Pressure reactivity indices rely on the correlation (-1 to +1) between the arterial blood pressure and intracranial pressure, with negative values indicating intact cerebral autoregulation and positive values indicating dysfunctional cerebral autoregulation. Meaningful data is taken from summary measures and trends. The traumatic brain injury population feature most prominently in the literature. There is limited description of the potential confounding factors that may affect pressure reactivity indices, including physiological parameters and therapeutic interventions. Plotting a pressure reactivity index against a cerebral perfusion pressure can indicate an optimal cerebral perfusion pressure to individualise patient care. There is potential to over interpret optimal cerebral perfusion pressure targets when the values of pressure reactivity indices are close to zero. There is an association between pressure reactivity indices and neurological outcomes, however the use of pressure reactivity indices as a prognostication tool is to be challenged. Average values of cerebral perfusion pressure that are not close to averaged values of optimal cerebral perfusion pressure are also associated with poor outcome. Further research is required to ascertain whether targeting an optimal cerebral perfusion pressure may alter outcome.
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Affiliation(s)
- Stephen Copplestone
- a Advanced trainee in Intensive Care Medicine and Anaesthesia , Plymouth Hospitals NHS Trust , Plymouth , UK
| | - Jessie Welbourne
- b Consultant in Intensive Care Medicine and Neuroanaesthesia, Department of Intensive Care Medicine , Plymouth Hospitals NHS Trust , Plymouth , UK
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25
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Johnson U, Engquist H, Howells T, Nilsson P, Ronne-Engström E, Lewén A, Rostami E, Enblad P. Bedside Xenon-CT Shows Lower CBF in SAH Patients with Impaired CBF Pressure Autoregulation as Defined by Pressure Reactivity Index (PRx). Neurocrit Care 2017; 25:47-55. [PMID: 26842717 DOI: 10.1007/s12028-016-0240-3] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
BACKGROUND Subarachnoid hemorrhage (SAH) is a disease with a high rate of unfavorable outcome, often related to delayed cerebral ischemia (DCI), i.e., ischemic injury that develops days-weeks after onset, with a multifactorial etiology. Disturbances in cerebral pressure autoregulation, the ability to maintain a steady cerebral blood flow (CBF), despite fluctuations in systemic blood pressure, have been suggested to play a role in the development of DCI. Pressure reactivity index (PRx) is a well-established measure of cerebral pressure autoregulation that has been used to study traumatic brain injury, but not extensively in SAH. OBJECTIVE To study the relation between PRx and CBF in SAH patients, and to examine if PRx can be used to predict DCI. METHODS Retrospective analysis of prospectively collected data. PRx was calculated as the correlation coefficient between mean arterial blood pressure (MABP) and intracranial pressure (ICP) in a 5 min moving window. CBF was measured using bedside Xenon-CT (Xe-CT). DCI was diagnosed clinically. RESULTS 47 poor-grade mechanically ventilated patients were studied. Patients with disturbed pressure autoregulation (high PRx values) had lower CBF, as measured by bedside Xe-CT; both in the early (day 0-3) and late (day 4-14) acute phase of the disease. PRx did not differ significantly between patients who developed DCI or not. CONCLUSION In mechanically ventilated and sedated SAH patients, high PRx (more disturbed CBF pressure autoregulation) is associated with low CBF, both day 0-3 and day 4-14 after onset. The role of PRx as a monitoring tool in SAH patients needs further studying.
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Affiliation(s)
- Ulf Johnson
- Department of Neuroscience/Neurosurgery, Uppsala University, Uppsala, Sweden. .,Department of Surgical Sciences/Radiology, Uppsala University, Uppsala, Sweden.
| | - Henrik Engquist
- Department of Neuroscience/Neurosurgery, Uppsala University, Uppsala, Sweden.,Department of Surgical Sciences/Anesthesia and Intensive Care, Uppsala University, Uppsala, Sweden
| | - Tim Howells
- Department of Neuroscience/Neurosurgery, Uppsala University, Uppsala, Sweden
| | - Pelle Nilsson
- Department of Neuroscience/Neurosurgery, Uppsala University, Uppsala, Sweden
| | | | - Anders Lewén
- Department of Neuroscience/Neurosurgery, Uppsala University, Uppsala, Sweden
| | - Elham Rostami
- Department of Neuroscience/Neurosurgery, Uppsala University, Uppsala, Sweden
| | - Per Enblad
- Department of Neuroscience/Neurosurgery, Uppsala University, Uppsala, Sweden
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Wu X, Gao G, Feng J, Mao Q, Jiang J. A Detailed Protocol for Physiological Parameters Acquisition and Analysis in Neurosurgical Critical Patients. J Vis Exp 2017. [PMID: 29155778 DOI: 10.3791/56388] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
Intracranial pressure (ICP) monitoring is now widely used in neurosurgical critical patients. Besides mean ICP value, the ICP derived parameters such as ICP waveform, amplitude of pulse (AMP), the correlation of ICP amplitude and ICP mean (RAP), pressure reactivity index (PRx), ICP and arterial blood pressure (ABP) wave amplitude correlation (IAAC), and so on, can reflect intracranial status, predict prognosis, and can also be used as guidance of proper treatment. However, most of the clinicians focus only on the mean ICP value while ignoring these parameters because of the limitations of the current devices. We have recently developed a multimodality monitoring system to address these drawbacks. This portable, user-friendly system will use a data collecting and storing device to continuously acquire patients' physiological parameters first, i.e., ABP, ICP, and oxygen saturation, and then analyze these physiological parameters. We hope that the multimodality monitoring system will be accepted as a key measure to monitor physiological parameters, to analyze the current clinical status, and to predict the prognosis of the neurosurgical critical patients.
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Affiliation(s)
- Xiang Wu
- Department of Neurosurgery, Renji Hospital, Shanghai Jiaotong University School of Medicine; Shanghai Institute of Head Trauma
| | - Guoyi Gao
- Department of Neurosurgery, Renji Hospital, Shanghai Jiaotong University School of Medicine; Shanghai Institute of Head Trauma;
| | - Junfeng Feng
- Department of Neurosurgery, Renji Hospital, Shanghai Jiaotong University School of Medicine; Shanghai Institute of Head Trauma
| | - Qing Mao
- Department of Neurosurgery, Renji Hospital, Shanghai Jiaotong University School of Medicine; Shanghai Institute of Head Trauma
| | - Jiyao Jiang
- Department of Neurosurgery, Renji Hospital, Shanghai Jiaotong University School of Medicine; Shanghai Institute of Head Trauma
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Robba C, Cardim D, Sekhon M, Budohoski K, Czosnyka M. Transcranial Doppler: a stethoscope for the brain-neurocritical care use. J Neurosci Res 2017; 96:720-730. [PMID: 28880397 DOI: 10.1002/jnr.24148] [Citation(s) in RCA: 60] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2017] [Revised: 06/12/2017] [Accepted: 08/10/2017] [Indexed: 02/03/2023]
Abstract
Transcranial Doppler (TCD) ultrasonography is a noninvasive bedside monitoring technique that can evaluate cerebral blood flow hemodynamics in the intracranial arterial vasculature. TCD allows assessment of linear cerebral blood flow velocity, with a high temporal resolution and is inexpensive, reproducible, and portable. The aim of this review is to provide an overview of the most commonly used TCD derived signals and measurements used commonly in neurocritical care. We describe both basic (flow velocity, pulsatility index) and advanced concepts, including critical closing pressure, wall tension, autoregulation, noninvasive intracranial pressure, brain compliance, and cerebrovascular time constant; we also describe the clinical applications of TCD to highlight their utility in the diagnosis and monitoring of cerebrovascular diseases as the "stethoscope for the brain."
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Affiliation(s)
- Chiara Robba
- Neurocritical Care Unit, Addenbrooke's Hospital, Cambridge University, Box 1, Addenbrooke's Hospital, Cambridge University Hospitals Trust, Hills Road, Cambridge, CB2 0QQ.,Division of Neuroscience, University of Genoa, Genoa, Italy
| | - Danilo Cardim
- Division of Neurosurgery, Department of Clinical Neurosciences, Addenbrooke's Hospital, University of Cambridge, Cambridge, United Kingdom
| | - Mypinder Sekhon
- Division of Critical Care Medicine, Department of Medicine, Vancouver General Hospital, University of British Columbia, Vancouver, British Columbia
| | - Karol Budohoski
- Division of Neurosurgery, Department of Clinical Neurosciences, Addenbrooke's Hospital, University of Cambridge, Cambridge, United Kingdom
| | - Marek Czosnyka
- Division of Neurosurgery, Department of Clinical Neurosciences, Addenbrooke's Hospital, University of Cambridge, Cambridge, United Kingdom
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Johnson U, Engquist H, Lewén A, Howells T, Nilsson P, Ronne-Engström E, Rostami E, Enblad P. Increased risk of critical CBF levels in SAH patients with actual CPP below calculated optimal CPP. Acta Neurochir (Wien) 2017; 159:1065-1071. [PMID: 28361248 PMCID: PMC5425502 DOI: 10.1007/s00701-017-3139-7] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2016] [Accepted: 02/27/2017] [Indexed: 01/23/2023]
Abstract
Background Cerebral pressure autoregulation can be quantified with the pressure reactivity index (PRx), based on the correlation between blood pressure and intracranial pressure. Using PRx optimal cerebral perfusion pressure (CPPopt) can be calculated, i.e., the level of CPP where autoregulation functions best. The relation between cerebral blood flow (CBF) and CPPopt has not been examined. The objective was to assess to which extent CPPopt can be calculated in SAH patients and to investigate CPPopt in relation to CBF. Methods Retrospective study of prospectively collected data. CBF was measured bedside with Xenon-enhanced CT (Xe-CT). The difference between actual CPP and CPPopt was calculated (CPP∆). Correlations between CPP∆ and CBF parameters were calculated with Spearman’s rank order correlation coefficient (rho). Separate calculations were done using all patients (day 0–14 after onset) as well as in two subgroups (day 0–3 and day 4–14). Results Eighty-two patients with 145 Xe-CT scans were studied. Automated calculation of CPPopt was possible in adjunct to 60% of the Xe-CT scans. Actual CPP < CPPopt was associated with higher numbers of low-flow regions (CBF <10 ml/100 g/min) in both the early phase (day 0–3, n = 39, Spearman’s rho = −0.38, p = 0.02) and late acute phase of the disease (day 4–14, n = 35, Spearman’s rho = −0.39, p = 0.02). CPP level per se was not associated with CBF. Conclusions Calculation of CPPopt is possible in a majority of patients with severe SAH. Actual CPP below CPPopt is associated with low CBF.
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Affiliation(s)
- Ulf Johnson
- Department of Neuroscience/Neurosurgery, Uppsala University, S-75185, Uppsala, Sweden.
- Department of Surgical sciences/Radiology, Uppsala University, Uppsala, Sweden.
| | - Henrik Engquist
- Department of Neuroscience/Neurosurgery, Uppsala University, S-75185, Uppsala, Sweden
- Department of Surgical sciences/Anaesthesia and Intensive care, Uppsala University, Uppsala, Sweden
| | - Anders Lewén
- Department of Neuroscience/Neurosurgery, Uppsala University, S-75185, Uppsala, Sweden
| | - Tim Howells
- Department of Neuroscience/Neurosurgery, Uppsala University, S-75185, Uppsala, Sweden
| | - Pelle Nilsson
- Department of Neuroscience/Neurosurgery, Uppsala University, S-75185, Uppsala, Sweden
| | | | - Elham Rostami
- Department of Neuroscience/Neurosurgery, Uppsala University, S-75185, Uppsala, Sweden
| | - Per Enblad
- Department of Neuroscience/Neurosurgery, Uppsala University, S-75185, Uppsala, Sweden
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Abstract
Management of patients with aneurysmal subarachnoid hemorrhage focuses on prevention of rebleeding by early treatment of the aneurysm, as well as detection and management of neurologic and medical complications. Early detection of delayed cerebral ischemia and management of modifiable contributing causes such as vasospasm take a central role, with the goal of preventing irreversible cerebral injury. In efforts to prevent delayed cerebral ischemia, multimodality monitoring has emerged as a promising tool in detecting subclinical physiologic changes before infarction occurs. However, there has been much variability in the utilization of this technology. Recent consensus guidelines discuss the role of multimodality monitoring in acute brain injury. In this review, we evaluate these guidelines and the utility of each modality of multimodality monitoring in aneurysmal subarachnoid hemorrhage.
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O'Rourke MF, O'Brien C, Edelman ER. Arterial Stiffening in Perspective: Advances in Physical and Physiological Science Over Centuries. Am J Hypertens 2016; 29:785-91. [PMID: 27001969 DOI: 10.1093/ajh/hpw019] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2015] [Accepted: 02/05/2016] [Indexed: 11/12/2022] Open
Abstract
Arterial stiffening is not a new issue in medicine or research but was the prime concern of Richard Bright in the early 19th century and of the prominent London physicians and pathologists who tried to unscramble the relationship between kidney, heart, and cerebrovascular disease and hardness of the pulse in the late 19th century. It was of major concern to medical educators including Osler and Mackenzie who were still active in practice 100 years ago. It is all too easy (when dependent on the Internet) to consider arterial stiffness to be a new issue. The terms arterial stiffness, aortic stiffness, or wave reflection do not appear as categories for articles such as this in respectable journals, nor in categories for meetings of specialized physicians. Yet as described in this article, the subject was of interest to clinicians, to investigators such as Harvey in the 17th century, and to physicists who developed laws and principles of elasticity from the study of biological materials including ligaments and arteries. This paper provides a perspective on arterial stiffness from the time of William Harvey and Isaac Newton to the present, with a glance into the future.
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Affiliation(s)
- Michael F O'Rourke
- St Vincent's Clinic University of New South Wales, Victor Chang Cardiac Research Institute, Sydney, New South Wales, Australia;
| | | | - Elazer R Edelman
- Institute for Medical Engineering and Science, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA; Cardiovascular Division, Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, Massachusetts, USA
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31
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Non-invasive estimation of static and pulsatile intracranial pressure from transcranial acoustic signals. Med Eng Phys 2016; 38:477-84. [DOI: 10.1016/j.medengphy.2016.02.009] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2015] [Revised: 02/12/2016] [Accepted: 02/16/2016] [Indexed: 01/05/2023]
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32
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Intracranial Pressure Waveforms are More Closely Related to Central Aortic than Radial Pressure Waveforms: Implications for Pathophysiology and Therapy. ACTA NEUROCHIRURGICA SUPPLEMENT 2016; 122:61-4. [DOI: 10.1007/978-3-319-22533-3_12] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
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33
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Abstract
Pressure autoregulation is an important hemodynamic mechanism that protects the brain against inappropriate fluctuations in cerebral blood flow in the face of changing cerebral perfusion pressure (CPP). Static autoregulation represents how far cerebrovascular resistance changes when CPP varies, and dynamic autoregulation represents how fast these changes happen. Both have been monitored in the setting of neurocritical care to aid prognostication and contribute to individualizing CPP targets in patients. Failure of autoregulation is associated with a worse outcome in various acute neurological diseases. Several studies have used transcranial Doppler ultrasound, intracranial pressure (ICP with vascular reactivity as surrogate measure of autoregulation), and near-infrared spectroscopy to continuously monitor the impact of spontaneous fluctuations in CPP on cerebrovascular physiology and to calculate derived variables of autoregulatory efficiency. Many patients who undergo such monitoring demonstrate a range of CPP in which autoregulatory efficiency is optimal. Management of patients at or near this optimal level of CPP is associated with better outcomes in traumatic brain injury. Many of these studies have utilized the concept of the pressure reactivity index, a correlation coefficient between ICP and mean arterial pressure. While further studies are needed, these data suggest that monitoring of autoregulation could aid prognostication and may help identify optimal CPP levels in individual patients.
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Affiliation(s)
- Marek Czosnyka
- Department of Clinical Neurosciences, Division of Neurosurgery, University of Cambridge, Addenbrooke's Hospital, Box 167, Cambridge, CB2 2QQ, UK,
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34
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Helbok R, Olson DM, Le Roux PD, Vespa P. Intracranial pressure and cerebral perfusion pressure monitoring in non-TBI patients: special considerations. Neurocrit Care 2015; 21 Suppl 2:S85-94. [PMID: 25208677 DOI: 10.1007/s12028-014-0040-6] [Citation(s) in RCA: 59] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
The effect of intracranial pressure (ICP) and the role of ICP monitoring are best studied in traumatic brain injury (TBI). However, a variety of acute neurologic illnesses e.g., subarachnoid hemorrhage, intracerebral hemorrhage, ischemic stroke, meningitis/encephalitis, and select metabolic disorders, e.g., liver failure and malignant, brain tumors can affect ICP. The purpose of this paper is to review the literature about ICP monitoring in conditions other than TBI and to provide recommendations how the technique may be used in patient management. A PubMed search between 1980 and September 2013 identified 989 articles; 225 of which were reviewed in detail. The technique used to monitor ICP in non-TBI conditions is similar to that used in TBI; however, indications for ICP monitoring often are intertwined with the presence of obstructive hydrocephalus and hence the use of ventricular catheters is more frequent. Increased ICP can adversely affect outcome, particularly when it fails to respond to treatment. However, patients with elevated ICP can still have favorable outcomes. Although the influence of ICP-based care on outcome in non-TBI conditions appears less robust than in TBI, monitoring ICP and cerebral perfusion pressure can play a role in guiding therapy in select patients.
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Affiliation(s)
- Raimund Helbok
- Department of Neurology, Neurocritical Care Unit, Innsbruck Medical University, Anichstr. 35, 6020, Innsbruck, Austria,
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35
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Budohoski KP, Czosnyka M, Kirkpatrick PJ. The Role of Monitoring Cerebral Autoregulation After Subarachnoid Hemorrhage. Neurosurgery 2015; 62 Suppl 1:180-4. [PMID: 26181941 DOI: 10.1227/neu.0000000000000808] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Affiliation(s)
- Karol P Budohoski
- Division of Neurosurgery, Department of Clinical Neurosciences, Addenbrooke's Hospital, University of Cambridge, Cambridge, United Kingdom
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36
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Varsos GV, Kasprowicz M, Smielewski P, Czosnyka M. Model-based indices describing cerebrovascular dynamics. Neurocrit Care 2015; 20:142-57. [PMID: 24091657 DOI: 10.1007/s12028-013-9868-4] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
Understanding the dynamic relationship between cerebral blood flow (CBF) and the circulation of cerebrospinal fluid (CSF) can facilitate management of cerebral pathologies. For this reason, various hydrodynamic models have been introduced in order to simulate the phenomena governing the interaction between CBF and CSF. The identification of hydrodynamic models requires an array of signals as input, with the most common of them being arterial blood pressure, intracranial pressure, and cerebral blood flow velocity; monitoring all of them is considered as a standard practice in neurointensive care. Based on these signals, physiological parameters like cerebrovascular resistance, compliances of cerebrovascular bed, and CSF space could then be estimated. Various secondary model-based indices describing cerebrovascular dynamics have been introduced, like the cerebral arterial time constant or critical closing pressure. This review presents model-derived indices that describe cerebrovascular phenomena, the nature of which is both physiological (carbon dioxide reactivity and arterial hypotension) and pathological (cerebral artery stenosis, intracranial hypertension, and cerebral vasospasm). In a neurointensive environment, real-time monitoring of a patient with these indices may be able to provide a detection of the onset of a cerebrovascular phenomenon, which could have otherwise been missed. This potentially "early warning" indicator may then prove to be important for the therapeutic management of the patient.
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Affiliation(s)
- Georgios V Varsos
- Neurosurgical Unit, Department of Clinical Neurosciences, Addenbrooke's Hospital, University of Cambridge, Cambridge, UK,
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37
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Budohoski KP, Guilfoyle M, Helmy A, Huuskonen T, Czosnyka M, Kirollos R, Menon DK, Pickard JD, Kirkpatrick PJ. The pathophysiology and treatment of delayed cerebral ischaemia following subarachnoid haemorrhage. J Neurol Neurosurg Psychiatry 2014; 85:1343-53. [PMID: 24847164 DOI: 10.1136/jnnp-2014-307711] [Citation(s) in RCA: 183] [Impact Index Per Article: 18.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Cerebral vasospasm has traditionally been regarded as an important cause of delayed cerebral ischaemia (DCI) which occurs after aneurysmal subarachnoid haemorrhage, and often leads to cerebral infarction and poor neurological outcome. However, data from recent studies argue against a pure focus on vasospasm as the cause of delayed ischaemic complications. Findings that marked reduction in the incidence of vasospasm does not translate to a reduction in DCI, or better outcomes has intensified research into other possible mechanisms which may promote ischaemic complications. Early brain injury and cell death, blood-brain barrier disruption and initiation of an inflammatory cascade, microvascular spasm, microthrombosis, cortical spreading depolarisations and failure of cerebral autoregulation, have all been implicated in the pathophysiology of DCI. This review summarises the current knowledge about the mechanisms underlying the development of DCI. Furthermore, it aims to describe and categorise the known pharmacological treatment options with respect to the presumed mechanism of action and its role in DCI.
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Affiliation(s)
- Karol P Budohoski
- Division of Neurosurgery, Department of Clinical Neurosciences, Addenbrooke's Hospital, University of Cambridge, Cambridge, UK
| | - Mathew Guilfoyle
- Division of Neurosurgery, Department of Clinical Neurosciences, Addenbrooke's Hospital, University of Cambridge, Cambridge, UK
| | - Adel Helmy
- Division of Neurosurgery, Department of Clinical Neurosciences, Addenbrooke's Hospital, University of Cambridge, Cambridge, UK
| | - Terhi Huuskonen
- Division of Neurosurgery, Department of Clinical Neurosciences, Addenbrooke's Hospital, University of Cambridge, Cambridge, UK Department of Neurosurgery, Kuopio Neurocenter, Kuopio University Hospital, Kuopio, Finland
| | - Marek Czosnyka
- Division of Neurosurgery, Department of Clinical Neurosciences, Addenbrooke's Hospital, University of Cambridge, Cambridge, UK
| | - Ramez Kirollos
- Division of Neurosurgery, Department of Clinical Neurosciences, Addenbrooke's Hospital, University of Cambridge, Cambridge, UK
| | - David K Menon
- Department of Anaesthesiology, Addenbrooke's Hospital, University of Cambridge, Cambridge, UK
| | - John D Pickard
- Division of Neurosurgery, Department of Clinical Neurosciences, Addenbrooke's Hospital, University of Cambridge, Cambridge, UK
| | - Peter J Kirkpatrick
- Division of Neurosurgery, Department of Clinical Neurosciences, Addenbrooke's Hospital, University of Cambridge, Cambridge, UK
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Wang X, Chen JX, Mao Q, Liu YH, You C. Relationship between intracranial pressure and aneurysmal subarachnoid hemorrhage grades. J Neurol Sci 2014; 346:284-7. [PMID: 25245175 DOI: 10.1016/j.jns.2014.09.011] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2014] [Revised: 09/06/2014] [Accepted: 09/08/2014] [Indexed: 02/05/2023]
Abstract
OBJECTIVE Intracranial pressure (ICP) is frequently elevated following aneurysmal subarachnoid hemorrhage (aSAH). In this prospective study, the factors associated with increased ICP and the relationship between ICP and the aSAH grade were evaluated. METHODS Consecutive patients with prospective aSAH were enrolled within 24h after disease onset. Clinical scoring, including the Hunt and Hess scale, the WFNS scale and the Fisher scale, was performed upon admission. Consciousness was evaluated based on the Glasgow Coma Scale, and the subarachnoid hemorrhage volume was determined according to a CT scan. Then, an ICP monitor was placed, and ICP was recorded. The relationship between ICP and the aSAH grade was examined using Spearman correlation coefficients. Additionally, some clinical characteristics of the patients, including age, sex, location and size of the aneurysm, hydrocephalus and rebleeding, were recorded and analyzed. RESULTS A total of 165 patients were enrolled in this study. Of these patients, 111 (67.2%) displayed elevated ICP (≥ 20 mm Hg). The patients who underwent intubation or who experienced rebleeding or hydrocephalus displayed an elevated ICP compared with those who did not (P = 0.002, P = 0.001 and P = 0.008, respectively). There was a positive linear correlation between ICP and both the Hunt and Hess grade and the WFNS grade (correlation coefficients of 0.731 and 0.761, respectively). The correlation between ICP and the Fisher grade was weak according to the correlation coefficient of only 0.093. CONCLUSION ICP following aSAH positively correlates with the patient's consciousness, but no relationship was detected between ICP and the subarachnoid hemorrhage volume.
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Affiliation(s)
- Xiang Wang
- Department of Neurosurgery, West China Hospital of Sichuan University, China
| | - Jin-xiu Chen
- Department of Radiology, Sichuan Cancer Hospital, China
| | - Qing Mao
- Department of Neurosurgery, West China Hospital of Sichuan University, China
| | - Yan-hui Liu
- Department of Neurosurgery, West China Hospital of Sichuan University, China
| | - Chao You
- Department of Neurosurgery, West China Hospital of Sichuan University, China.
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39
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Eide PK, Sorteberg A, Meling TR, Sorteberg W. The effect of baseline pressure errors on an intracranial pressure-derived index: results of a prospective observational study. Biomed Eng Online 2014; 13:99. [PMID: 25052470 PMCID: PMC4125597 DOI: 10.1186/1475-925x-13-99] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2014] [Accepted: 07/17/2014] [Indexed: 11/29/2022] Open
Abstract
Background In order to characterize the intracranial pressure-volume reserve capacity, the correlation coefficient (R) between the ICP wave amplitude (A) and the mean ICP level (P), the RAP index, has been used to improve the diagnostic value of ICP monitoring. Baseline pressure errors (BPEs), caused by spontaneous shifts or drifts in baseline pressure, cause erroneous readings of mean ICP. Consequently, BPEs could also affect ICP indices such as the RAP where in the mean ICP is incorporated. Methods A prospective, observational study was carried out on patients with aneurysmal subarachnoid hemorrhage (aSAH) undergoing ICP monitoring as part of their surveillance. Via the same burr hole in the scull, two separate ICP sensors were placed close to each other. For each consecutive 6-sec time window, the dynamic mean ICP wave amplitude (MWA; measure of the amplitude of the single pressure waves) and the static mean ICP, were computed. The RAP index was computed as the Pearson correlation coefficient between the MWA and the mean ICP for 40 6-sec time windows, i.e. every subsequent 4-min period (method 1). We compared this approach with a method of calculating RAP using a 4-min moving window updated every 6 seconds (method 2). Results The study included 16 aSAH patients. We compared 43,653 4-min RAP observations of signals 1 and 2 (method 1), and 1,727,000 6-sec RAP observations (method 2). The two methods of calculating RAP produced similar results. Differences in RAP ≥0.4 in at least 7% of observations were seen in 5/16 (31%) patients. Moreover, the combination of a RAP of ≥0.6 in one signal and <0.6 in the other was seen in ≥13% of RAP-observations in 4/16 (25%) patients, and in ≥8% in another 4/16 (25%) patients. The frequency of differences in RAP >0.2 was significantly associated with the frequency of BPEs (5 mmHg ≤ BPE <10 mmHg). Conclusions Simultaneous monitoring from two separate, close-by ICP sensors reveals significant differences in RAP that correspond to the occurrence of BPEs. As differences in RAP are of magnitudes that may alter patient management, we do not advocate the use of RAP in the management of neurosurgical patients.
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Affiliation(s)
- Per Kristian Eide
- Department of Neurosurgery, Oslo University Hospital, Rikshospitalet, Oslo, Norway.
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40
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Zweifel C, Dias C, Smielewski P, Czosnyka M. Continuous time-domain monitoring of cerebral autoregulation in neurocritical care. Med Eng Phys 2014; 36:638-45. [DOI: 10.1016/j.medengphy.2014.03.002] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2013] [Revised: 02/24/2014] [Accepted: 03/10/2014] [Indexed: 12/26/2022]
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41
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Lazaridis C, Smielewski P, Steiner LA, Brady KM, Hutchinson P, Pickard JD, Czosnyka M. Optimal cerebral perfusion pressure: are we ready for it? Neurol Res 2013; 35:138-148. [DOI: 10.1179/1743132812y.0000000150] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/30/2023]
Affiliation(s)
- Christos Lazaridis
- Academic Neurosurgical UnitUniversity of Cambridge Clinical School, Cambridge, UK
- Neurosciences Intensive Care UnitMedical University of South Carolina, Charleston, SC, USA
| | - Piotr Smielewski
- Academic Neurosurgical UnitUniversity of Cambridge Clinical School, Cambridge, UK
| | - Luzius A Steiner
- Academic Neurosurgical UnitUniversity of Cambridge Clinical School, Cambridge, UK
- Department of AnesthesiaLausanne University Hospital, Lausanne, Switzerland
| | - Ken M Brady
- Academic Neurosurgical UnitUniversity of Cambridge Clinical School, Cambridge, UK
- Department of Anesthesiology and Pediatrics, Texas Children’s Hospital, Houston, TX, USA
| | - Peter Hutchinson
- Academic Neurosurgical UnitUniversity of Cambridge Clinical School, Cambridge, UK
| | - John D Pickard
- Academic Neurosurgical UnitUniversity of Cambridge Clinical School, Cambridge, UK
| | - Marek Czosnyka
- Academic Neurosurgical UnitUniversity of Cambridge Clinical School, Cambridge, UK
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42
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43
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Eide PK, Sorteberg W. An intracranial pressure-derived index monitored simultaneously from two separate sensors in patients with cerebral bleeds: comparison of findings. Biomed Eng Online 2013; 12:14. [PMID: 23405985 PMCID: PMC3608258 DOI: 10.1186/1475-925x-12-14] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2012] [Accepted: 02/11/2013] [Indexed: 12/29/2022] Open
Abstract
Background In an attempt to characterize the intracranial pressure-volume compensatory reserve capacity, the correlation coefficient (R) between the ICP wave amplitude (A) and the ICP (P) level (RAP) has been applied in the surveillance of neurosurgical patients. However, as the ICP level may become altered by electrostatic discharges, human factors, technical factors and technology issues related to the ICP sensors, erroneous ICP scores may become revealed to the physician, and also become incorporated into the calculated RAP index. To evaluate the problem with regard to the RAP, we compared simultaneous RAP values from two separate ICP signals in the same patient. Materials and Methods We retrieved our recordings in 20 patients with cerebral bleeds wherein the ICP had been recorded simultaneously from two different sensors. Sensor 1 was always a solid sensor while sensor 2 was a solid sensor (Category A), a fluid sensor (Category B), an air-pouch sensor (Category C), or a fibre-optic sensor (Category D). The simultaneous signals were analyzed with automatic identification of the cardiac induced ICP waves, with subsequent determination and comparison of the Pearson correlation coefficient between mean wave amplitude (MWA) and mean ICP (RAP) for 40 6-s time windows every 4-min period. Results A total of 23,056 4-min RAP observations were compared. A difference in RAP ≥0.4 between the two signals was seen in 4% of the observations in Category A-, in 44% of observations in Category B -, in 20% of observations in Category C -, and in 28% of observations in Category D patients, respectively. Moreover, the combination of a RAP of <0.6 in one signal and ≥0.6 in the other was seen in >20% of scores in 3/5 Category A -, in 3/5 Category B -, in 5/7 Category C - and 1/3 Category D patients. Conclusions Simultaneous monitoring of the ICP-derived index RAP from two separate ICP sensors reveals marked differences in the index values. These differences in RAP may be explained by erroneous scoring of the ICP level. This will hamper the usefulness of RAP as a guide in the management of neurosurgical patients.
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Affiliation(s)
- Per Kristian Eide
- Department of Neurosurgery, Oslo University Hospital, Rikshospitalet, and Faculty of Medicine, University of Oslo, Oslo, Norway.
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44
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Abstract
The monitoring of intracranial pressure (ICP) is an important tool in medicine for its ability to portray the brain’s compliance status. The bedside monitor displays the ICP waveform and intermittent mean values to guide physicians in the management of patients, particularly those having sustained a traumatic brain injury. Researchers in the fields of engineering and physics have investigated various mathematical analysis techniques applicable to the waveform in order to extract additional diagnostic and prognostic information, although they largely remain limited to research applications. The purpose of this review is to present the current techniques used to monitor and interpret ICP and explore the potential of using advanced mathematical techniques to provide information about system perturbations from states of homeostasis. We discuss the limits of each proposed technique and we propose that nonlinear analysis could be a reliable approach to describe ICP signals over time, with the fractal dimension as a potential predictive clinically meaningful biomarker. Our goal is to stimulate translational research that can move modern analysis of ICP using these techniques into widespread practical use, and to investigate to the clinical utility of a tool capable of simplifying multiple variables obtained from various sensors.
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Affiliation(s)
- Antonio Di Ieva
- Department of Surgery, Division of Neurosurgery, St. Michael’s Hospital, University of Toronto, Toronto, ON, Canada
- Injury Prevention Research Office, St. Michael’s Hospital, Toronto, ON, Canada
| | - Erika M. Schmitz
- Injury Prevention Research Office, St. Michael’s Hospital, Toronto, ON, Canada
| | - Michael D. Cusimano
- Department of Surgery, Division of Neurosurgery, St. Michael’s Hospital, University of Toronto, Toronto, ON, Canada
- Injury Prevention Research Office, St. Michael’s Hospital, Toronto, ON, Canada
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45
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Eide PK, Bentsen G, Sorteberg AG, Marthinsen PB, Stubhaug A, Sorteberg W. In Reply. Neurosurgery 2012. [DOI: 10.1227/neu.0b013e31825b514e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
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46
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Czosnyka M, Citerio G. Brain compliance: the old story with a new 'et cetera'. Intensive Care Med 2012; 38:925-7. [PMID: 22527086 DOI: 10.1007/s00134-012-2572-6] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2012] [Accepted: 03/27/2012] [Indexed: 11/28/2022]
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