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Bonfanti M, Lorini FL, Zangari R, Bonanomi E, Farina A, Pezzetti G, Gerevini S, Aresi S, Dell'Avanzo G, Micheli F, Lanterna LA, Biroli F, Gritti P. Intracranial Pressure Thresholds for Cerebral Autoregulation Impairment: Age-Stratified Analysis of Ultra-Low-Frequency Pressure Reactivity Index (UL-PRx) in Traumatic Brain Injury. Neurocrit Care 2024:10.1007/s12028-024-02056-5. [PMID: 39009939 DOI: 10.1007/s12028-024-02056-5] [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: 03/20/2024] [Accepted: 06/21/2024] [Indexed: 07/17/2024]
Abstract
BACKGROUND The study investigated the effectiveness of low-frequency sampling in detecting alterations in cerebrovascular reactivity (CVR) associated with changes in intracranial pressure (ICP) in patients with traumatic brain injury (TBI) across different age groups. The primary objective was to investigate an ICP threshold that indicates a decrease in CVR as evidenced by a significant increase in the ultra-low-frequency pressure reactivity index (UL-PRx). Additionally, the study aimed to develop an age-based categorization method for patients with TBI to investigate the differences between these ICP thresholds in different age groups. METHODS In this retrospective analysis, data from 263 patients with TBI were prospectively collected. ICP and mean arterial pressure were extracted from the hospital database at 5-min intervals. Demographic details, clinical presentation, computed tomography scans, neurosurgical interventions, and 12-months outcome were recorded. ICP versus UL-PRx values were categorized into ICP bins and graphically represented with boxplots for each age group, illustrating how as ICP values rise, there is a bin (age-tailored ICP [AT-ICP]) beyond which UL-PRx shows a sudden increase, indicating CVR loss. Homogeneous age groups were established to obtain a consistent AT-ICP threshold. The discriminatory ability of the AT-ICP thresholds was compared with the guideline-recommended thresholds by calculating the area under the Receiver Operating Characteristic curve of the ICP-derived indices (dose above threshold, and the hourly dosage above threshold). RESULTS Age groups 0-5, 6-20, 21-60, 61-70, and 71-85 years were the best age subdivisions, corresponding to AT-ICP thresholds of 20, 30, 35, 25, and 30 mmHg, respectively. The AT-ICP thresholds exhibited better discriminative ability compared with the guideline-recommended thresholds. CONCLUSIONS The AT-ICP thresholds offer a novel approach for estimating CVR impairment and the developed method represents an alternative solution to address the age stratification issue in patients with TBI.
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Affiliation(s)
- Marco Bonfanti
- FROM Research Foundation- ETS, Papa Giovanni XXIII Hospital, Piazza OSM 1, 24129, Bergamo, Italy.
| | - Ferdinando Luca Lorini
- Department of Anesthesia and Critical Care Medicine, Papa Giovanni XXIII Hospital, Bergamo, Italy
| | - Rosalia Zangari
- FROM Research Foundation- ETS, Papa Giovanni XXIII Hospital, Piazza OSM 1, 24129, Bergamo, Italy
| | - Ezio Bonanomi
- Department of Anesthesia and Critical Care Medicine, Papa Giovanni XXIII Hospital, Bergamo, Italy
| | - Alessia Farina
- Department of Anesthesia and Critical Care Medicine, Papa Giovanni XXIII Hospital, Bergamo, Italy
| | - Giulio Pezzetti
- Department of Neuroradiology, Papa Giovanni XXIII Hospital, Bergamo, Italy
| | - Simonetta Gerevini
- Department of Neuroradiology, Papa Giovanni XXIII Hospital, Bergamo, Italy
| | - Silvia Aresi
- Department of Anesthesia and Critical Care Medicine, Papa Giovanni XXIII Hospital, Bergamo, Italy
| | - Giacomo Dell'Avanzo
- Department of Anesthesia and Critical Care Medicine, Papa Giovanni XXIII Hospital, Bergamo, Italy
| | - Fabio Micheli
- Department of Anesthesia and Critical Care Medicine, Papa Giovanni XXIII Hospital, Bergamo, Italy
| | | | - Francesco Biroli
- FROM Research Foundation- ETS, Papa Giovanni XXIII Hospital, Piazza OSM 1, 24129, Bergamo, Italy
| | - Paolo Gritti
- Department of Anesthesia and Critical Care Medicine, Papa Giovanni XXIII Hospital, Bergamo, Italy
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Svedung Wettervik T, Hånell A, Lewén A, Enblad P. Should Patients with Traumatic Brain Injury with Significant Contusions be Treated with Different Neurointensive Care Targets? Neurocrit Care 2024:10.1007/s12028-024-01954-y. [PMID: 38506969 DOI: 10.1007/s12028-024-01954-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2023] [Accepted: 02/01/2024] [Indexed: 03/22/2024]
Abstract
BACKGROUND Patients with traumatic brain injury (TBI) with large contusions make up a specific TBI subtype. Because of the risk of brain edema worsening, elevated cerebral perfusion pressure (CPP) may be particularly dangerous. The pressure reactivity index (PRx) and optimal cerebral perfusion pressure (CPPopt) are new promising perfusion targets based on cerebral autoregulation, but they reflect the global brain state and may be less valid in patients with predominant focal lesions. In this study, we aimed to investigate if patients with TBI with significant contusions exhibited a different association between PRx, CPP, and CPPopt in relation to functional outcome compared to those with small/no contusions. METHODS This observational study included 385 patients with moderate to severe TBI treated at a neurointensive care unit in Uppsala, Sweden. The patients were classified into two groups: (1) significant contusions (> 10 mL) and (2) small/no contusions (but with extra-axial or diffuse injuries). The percentage of good monitoring time (%GMT) with intracranial pressure > 20 mm Hg; PRx > 0.30; CPP < 60 mm Hg, within 60-70 mm Hg, or > 70 mm Hg; and ΔCPPopt less than - 5 mm Hg, ± 5 mm Hg, or > 5 mm Hg was calculated. Outcome (Glasgow Outcome Scale-Extended) was assessed after 6 months. RESULTS Among the 120 (31%) patients with significant contusions, a lower %GMT with CPP between 60 and 70 mm Hg was independently associated with unfavorable outcome. The %GMTs with PRx and ΔCPPopt ± 5 mm Hg were not independently associated with outcome. Among the 265 (69%) patients with small/no contusions, a higher %GMT of PRx > 0.30 and a lower %GMT of ΔCPPopt ± 5 mm Hg were independently associated with unfavorable outcome. CONCLUSIONS In patients with TBI with significant contusions, CPP within 60-70 mm Hg may improve outcome. PRx and CPPopt, which reflect global cerebral pressure autoregulation, may be useful in patients with TBI without significant focal brain lesions but seem less valid for those with large contusions. However, this was an observational, hypothesis-generating study; our findings need to be validated in prospective studies before translating them into clinical practice.
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Affiliation(s)
- Teodor Svedung Wettervik
- 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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Risinger Liljegren A, Brorsson C, Karlsson M, Koskinen LOD, Sundström N. Cerebrovascular Pressure Reactivity Measures: Index Comparison and Clinical Outcome in Patients With Traumatic Brain Injury Treated According to an Intracranial Pressure-Focused Management: Rejection of the Null Hypothesis. Neurotrauma Rep 2023; 4:848-856. [PMID: 38156075 PMCID: PMC10754344 DOI: 10.1089/neur.2023.0074] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2023] Open
Abstract
The aim was to investigate whether the pressure reactivity indices PRx, long-PRx (L-PRx), and pressure reactivity (PR) are interchangeable as measures of vascular reactivity, and whether they correlate with clinical outcome when an intracranial pressure (ICP)-targeted treatment regimen is applied in patients with traumatic brain injury (TBI). Patients with TBI (n = 29) that arrived at the hospital within 24 h of injury were included. PRx and L-PRx were derived from Pearson correlations between mean arterial pressure (MAP) and ICP over a short- and long-time interval. PR was the regression coefficient between the hourly mean values of ICP and MAP. Indices were compared to each other, parameters at admission, and outcome assessed by the extended Glasgow Outcome Scale-Extended (GOSE) at 6 and 12 months. PRx and L-PRx had the strongest correlation with each other (R = 0.536, p < 0.01). A correlation was also noted between L-PRx and PR (R = 0.475, p < 0.01), but not between PRx and PR. A correlation was found between age and PRx (R = 0.482, p = 0.01). No association with outcome for any of the indices was found. PRx/L-PRx and L-PRx/PR were moderately correlated with each other. Age was associated with PRx. None of the indices correlated with outcome when our ICP treatment regime was applied. Part of our null hypothesis, that the three indices are associated with outcome, must be rejected. There was, however, an association between some of the indices. To further understand the relation of treatment regimes and pressure reactivity indices, a larger, randomized study is warranted.
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Affiliation(s)
- Axel Risinger Liljegren
- Department of Clinical Science-Neurosciences, Radiation Physics, Biomedical Engineering, Umeå University, Umeå, Sweden
| | - Camilla Brorsson
- Department of Surgery and Perioperative Sciences, Radiation Physics, Biomedical Engineering, Umeå University, Umeå, Sweden
| | - Marcus Karlsson
- Department of Radiation Sciences, Radiation Physics, Biomedical Engineering, Umeå University, Umeå, Sweden
| | - Lars-Owe D. Koskinen
- Department of Clinical Science-Neurosciences, Radiation Physics, Biomedical Engineering, Umeå University, Umeå, Sweden
| | - Nina Sundström
- Department of Radiation Sciences, Radiation Physics, Biomedical Engineering, Umeå University, Umeå, Sweden
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Dias C, de Castro A, Gaio R, Silva R, Pereira E, Monteiro E. Lung Injury Risk in Traumatic Brain Injury Managed With Optimal Cerebral Perfusion Pressure Guided-Therapy. J Crit Care Med (Targu Mures) 2023; 9:97-105. [PMID: 37593249 PMCID: PMC10429626 DOI: 10.2478/jccm-2023-0009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2022] [Accepted: 01/31/2023] [Indexed: 08/19/2023] Open
Abstract
Introduction Management of traumatic brain injury (TBI) has to counterbalance prevention of secondary brain injury without systemic complications, namely lung injury. The potential risk of developing acute respiratory distress syndrome (ARDS) leads to therapeutic decisions such as fluid balance restriction, high PEEP and other lung protective measures, that may conflict with neurologic outcome. In fact, low cerebral perfusion pressure (CPP) may induce secondary ischemic injury and mortality, but disproportionate high CPP may also increase morbidity and worse lung compliance and hypoxia with the risk of developing ARDS and fatal outcome. The evaluation of cerebral autoregulation at bedside and individualized (optimal CPP) CPPopt-guided therapy, may not only be a relevant measure to protect the brain, but also a safe measure to avoid systemic complications. Aim of the study We aimed to study the safety of CPPopt-guided-therapy and the risk of secondary lung injury association with bad outcome. Methods and results Single-center retrospective analysis of 92 severe TBI patients admitted to the Neurocritical Care Unit managed with CPPopt-guided-therapy by PRx (pressure reactivity index). During the first 10 days, we collected data from blood gas, ventilation and brain variables. Evolution along time was analyzed using linear mixed-effects regression models. 86% were male with mean age 53±21 years. 49% presented multiple trauma and 21% thoracic trauma. At hospital admission, median GCS was 7 and after 3-months GOS was 3. Monitoring data was CPP 86±7mmHg, CPP-CPPopt -2.8±10.2mmHg and PRx 0.03±0.19. The average PFratio (PaO2/FiO2) was 305±88 and driving pressure 15.9±3.5cmH2O. PFratio exhibited a significant quadratic dependence across time and PRx and driving pressure presented significant negative association with PFRatio. CPP and CPPopt did not present significant effect on PFratio (p=0.533; p=0.556). A significant positive association between outcome and the difference CPP-CPPopt was found. Conclusion Management of TBI using CPPopt-guided-therapy was associated with better outcome and seems to be safe regarding the development of secondary lung injury.
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Affiliation(s)
- Celeste Dias
- Faculty of Medicine, University of Porto, Porto, Portugal
- University Hospital Centre São João, PortoPortugal
| | | | - Rita Gaio
- Faculty of Mathematics, University of Porto, Porto, Portugal
- Centre of Mathematics of the University of Porto, Porto, Portugal
| | - Ricardo Silva
- Faculty of Mathematics, University of Porto, Porto, Portugal
| | | | - Elisabete Monteiro
- Faculty of Medicine, University of Porto, Porto, Portugal
- University Hospital Centre São João, PortoPortugal
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Agrawal S, Placek MM, White D, Daubney E, Cabeleira M, Smielewski P, Czosnyka M, Young A, Watson S, Maw A, Hutchinson PJ. Studying Trends of Auto-Regulation in Severe Head Injury in Paediatrics (STARSHIP): protocol to study cerebral autoregulation in a prospective multicentre observational research database study. BMJ Open 2023; 13:e071800. [PMID: 36898758 PMCID: PMC10008199 DOI: 10.1136/bmjopen-2023-071800] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 03/12/2023] Open
Abstract
INTRODUCTION Studying cerebral autoregulation, particularly PRx (Pressure Reactivity Index), is commonly employed in adult traumatic brain injury (TBI) and gives real-time information about intracranial pathophysiology, which can help in patient management. Experience in paediatric TBI (PTBI) is limited to single-centre studies despite disproportionately higher incidence of morbidity and mortality in PTBI than in adult TBI. PROJECT We describe the protocol to study cerebral autoregulation using PRx in PTBI. The project called Studying Trends of Auto-Regulation in Severe Head Injury in Paediatrics is a multicentre prospective ethics approved research database study from 10 centres across the UK. Recruitment started in July 2018 with financial support from local/national charities (Action Medical Research for Children, UK). METHODS AND ANALYSIS The first phase of the project is powered to detect optimal thresholds of PRx associated with favourable outcome in PTBI by recruiting 135 patients (initial target of 3 years which has changed to 5 years due to delays related to COVID-19 pandemic) from 10 centres in the UK with outcome follow-up to 1-year postictus. The secondary objectives are to characterise patterns of optimal cerebral perfusion pressure in PTBI and compare the fluctuations in these measured parameters with outcome. The goal is to create a comprehensive research database of a basic set of high-resolution (full waveforms resolution) neuromonitoring data in PTBI for scientific use. ETHICS AND DISSEMINATION Favourable ethical approval has been provided by Health Research Authority, Southwest-Central Bristol Research Ethics Committee (Ref: 18/SW/0053). Results will be disseminated via publications in peer-reviewed medical journals and presentations at national and international conferences. TRIAL REGISTRATION NUMBER NCT05688462.
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Affiliation(s)
- Shruti Agrawal
- Department of Paediatrics, Cambridge University, Cambridge, UK
- Paediatric Intensive Care, Cambridge University Hospitals NHS Foundation Trust, Cambridge, UK
| | - Michal M Placek
- Department of Clinical Neurosciences, University of Cambridge, Cambridge, UK
| | - Deborah White
- Paediatric Intensive Care, Cambridge University Hospitals NHS Foundation Trust, Cambridge, UK
| | - Esther Daubney
- Paediatric Intensive Care, Cambridge University Hospitals NHS Foundation Trust, Cambridge, UK
| | - Manuel Cabeleira
- Department of Mechanical Engineering, University College London, London, UK
| | - Peter Smielewski
- Department of Clinical Neurosciences, University of Cambridge, Cambridge, UK
| | - Marek Czosnyka
- Department of Paediatrics, Cambridge University, Cambridge, UK
| | - Adam Young
- Department of Clinical Neurosciences, University of Cambridge, Cambridge, UK
| | - Suzanna Watson
- Paediatric Neuropsychology, Cambridge Centre for Paediatric Neuropsychological Rehabilitation, Cambridge, UK
- Centre for Child Development, Cambridge University Hospitals NHS Foundation Trust, Cambridge, UK
| | - Anna Maw
- Paediatric Neurologi, Cambridge University Hospitals NHS Foundation Trust, Cambridge, UK
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Neurotrauma and Intracranial Pressure Management. Crit Care Clin 2023; 39:103-121. [DOI: 10.1016/j.ccc.2022.08.002] [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]
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Marini CP, McNelis J, Petrone P. Multimodality Monitoring and Goal-Directed Therapy for the Treatment of Patients with Severe Traumatic Brain Injury: A Review for the General and Trauma Surgeon. Curr Probl Surg 2021; 59:101070. [DOI: 10.1016/j.cpsurg.2021.101070] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2021] [Accepted: 10/04/2021] [Indexed: 11/28/2022]
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8
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Marini CP, McNelis J, Petrone P. In Brief. Curr Probl Surg 2021. [DOI: 10.1016/j.cpsurg.2021.101071] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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9
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Svedung Wettervik T, Howells T, Hillered L, Rostami E, Lewén A, Enblad P. Autoregulatory or Fixed Cerebral Perfusion Pressure Targets in Traumatic Brain Injury: Determining Which Is Better in an Energy Metabolic Perspective. J Neurotrauma 2021; 38:1969-1978. [PMID: 33504257 DOI: 10.1089/neu.2020.7290] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Current guidelines in traumatic brain injury (TBI) recommend a cerebral perfusion pressure (CPP) within the fixed interval of 60-70 mm Hg. However, the autoregulatory, optimal CPP target (CPPopt) might yield better cerebral blood flow (CBF) regulation. In this study, we investigated fixed versus autoregulatory CPP targets in relation to cerebral energy metabolism and clinical outcome after TBI. Ninety-eight non-craniectomized patients with severe TBI treated in the neurointensive care unit, Uppsala University Hospital, Sweden, 2008-2018, were included. Data from cerebral microdialysis (MD), intracranial pressure (ICP), pressure autoregulation, CPP and CPPopt55-15 (a variant of CPPopt based on filtered slow waves from 15-55 sec range) were analyzed the first 10 days. The good monitoring time (GMT %) below/within/above the fixed and autoregulatory CPP targets were calculated. CPPopt55-15 was >70 mm Hg 74% of the time the first 10 days. Higher GMT (%) ΔCPPopt55-15 ± 10 mm Hg correlated with lower lactate/pyruvate ratio (LPR) on day 1 and lower cerebral glycerol on days 6-10, and predicted favorable clinical outcome. Higher GMT (%) CPP within 60-70 mm Hg correlated with lower cerebral glucose on days 2-10 and higher LPR on days 6-10, but predicted favorable clinical outcome. Higher GMT (%) CPP >70 mm Hg had the opposite associations; that is, with higher cerebral glucose and lower LPR, but unfavorable clinical outcome. Autoregulatory CPP targets may be beneficial, because patients with CPP values close to the optimal CPP had both better cerebral energy metabolism and better clinical outcome, but this needs to be evaluated in randomized trials.
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Affiliation(s)
| | - Timothy Howells
- Department of Neuroscience, Section of Neurosurgery, Uppsala University, Uppsala, Sweden
| | - Lars Hillered
- Department of Neuroscience, Section of Neurosurgery, Uppsala University, Uppsala, Sweden
| | - Elham Rostami
- Department of Neuroscience, Section of Neurosurgery, Uppsala University, Uppsala, Sweden
| | - Anders Lewén
- Department of Neuroscience, Section of Neurosurgery, Uppsala University, Uppsala, Sweden
| | - Per Enblad
- Department of Neuroscience, Section of Neurosurgery, Uppsala University, Uppsala, Sweden
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10
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Riemann L, Beqiri E, Younsi A, Czosnyka M, Smielewski P. Predictive and Discriminative Power of Pressure Reactivity Indices in Traumatic Brain Injury. Neurosurgery 2020; 87:655-663. [PMID: 32171019 DOI: 10.1093/neuros/nyaa039] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2019] [Accepted: 12/28/2019] [Indexed: 11/15/2022] Open
Abstract
BACKGROUND Dysfunctional cerebral blood flow autoregulation plays a crucial role in the secondary damage after traumatic brain injury. The pressure reactivity index (PRx) can be used to monitor dynamic cerebral blood flow autoregulation indirectly. OBJECTIVE To test different versions of the long pressure reactivity index (LPRx), which is based on minute-by-minute data and calculated over extended time windows, and to study their predictive ability and examine whether "long" and "short" pressure reactivity indices could improve predictive power. METHODS PRx and 3 versions of the LPRx calculated over 20-, 60-, and 240-min time windows were assessed in relation to outcome at 6 mo in 855 patients with traumatic brain injury. Predictive power and discriminative ability of indices were evaluated using area under the operator curves and determination of critical thresholds. PRx and LPR indices were combined to evaluate whether LPR indices could improve outcome prediction by adding information about static components of autoregulation. RESULTS Correlation of each LPRx with the PRx decreased with increased time windows. LPR indices performed successively worse in their predictive and discriminative ability from 20-min to 240-min time frames. PRx had a significantly higher predictive ability compared to each LPRx. Combining LPRx and PRx did not lead to an improvement of predictive power compared to the PRx alone. CONCLUSION The critical threshold and predictive value of the PRx for unfavorable outcome and mortality have been confirmed in one of the largest so far published patient cohorts. LPRx performed significantly worse, and its discriminative and predictive abilities decreased with an increasing calculation window.
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Affiliation(s)
- Lennart Riemann
- Department of Neurosurgery, Heidelberg University Hospital, Heidelberg, Germany.,Brain Physics Laboratory, Division of Neurosurgery, Department of Clinical Neurosciences, University of Cambridge, Cambridge, United Kingdom
| | - Erta Beqiri
- Brain Physics Laboratory, Division of Neurosurgery, Department of Clinical Neurosciences, University of Cambridge, Cambridge, United Kingdom.,Department of Physiopathology and Transplantation, Milan University, Milan, Italy
| | - Alexander Younsi
- Department of Neurosurgery, Heidelberg University Hospital, Heidelberg, Germany
| | - Marek Czosnyka
- Brain Physics Laboratory, Division of Neurosurgery, Department of Clinical Neurosciences, University of Cambridge, Cambridge, United Kingdom.,Institute of Electronic Systems, Warsaw University of Technology, Warsaw, Poland
| | - Peter Smielewski
- Brain Physics Laboratory, Division of Neurosurgery, Department of Clinical Neurosciences, University of Cambridge, Cambridge, United Kingdom
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Svedung Wettervik T, Howells T, Enblad P, Lewén A. Temporal Neurophysiological Dynamics in Traumatic Brain Injury: Role of Pressure Reactivity and Optimal Cerebral Perfusion Pressure for Predicting Outcome. J Neurotrauma 2019; 36:1818-1827. [DOI: 10.1089/neu.2018.6157] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Affiliation(s)
- Teodor Svedung Wettervik
- Department of Neuroscience, Section of Neurosurgery, Uppsala University, Uppsala University Hospital, Uppsala, Sweden
| | - Timothy Howells
- Department of Neuroscience, Section of Neurosurgery, Uppsala University, Uppsala University Hospital, Uppsala, Sweden
| | - Per Enblad
- Department of Neuroscience, Section of Neurosurgery, Uppsala University, Uppsala University Hospital, Uppsala, Sweden
| | - Anders Lewén
- Department of Neuroscience, Section of Neurosurgery, Uppsala University, Uppsala University Hospital, Uppsala, Sweden
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12
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Kramer AH, Couillard PL, Zygun DA, Aries MJ, Gallagher CN. Continuous Assessment of "Optimal" Cerebral Perfusion Pressure in Traumatic Brain Injury: A Cohort Study of Feasibility, Reliability, and Relation to Outcome. Neurocrit Care 2019; 30:51-61. [PMID: 29987688 DOI: 10.1007/s12028-018-0570-4] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
BACKGROUND Guidelines recommend maintaining cerebral perfusion pressure (CPP) between 60 and 70 mmHg in patients with severe traumatic brain injury (TBI), but acknowledge that optimal CPP may vary depending on cerebral blood flow autoregulation. Previous retrospective studies suggest that targeting CPP where the pressure reactivity index (PRx) is optimized (CPPopt) may be associated with improved recovery. METHODS We performed a retrospective cohort study involving TBI patients who underwent PRx monitoring to assess issues of feasibility relevant to future interventional studies: (1) the proportion of time that CPPopt could be detected; (2) inter-observer variability in CPPopt determination; and (3) agreement between manual and automated CPPopt estimates. CPPopt was determined for consecutive 6-h epochs during the first week following TBI. Sixty PRx-CPP tracings were randomly selected and independently reviewed by six critical care professionals. We also assessed whether greater deviation between actual CPP and CPPopt (ΔCPP) was associated with poor outcomes using multivariable models. RESULTS In 71 patients, CPPopt could be manually determined in 985 of 1173 (84%) epochs. Inter-observer agreement for detectability was moderate (kappa 0.46, 0.23-0.68). In cases where there was consensus that it could be determined, agreement for the specific CPPopt value was excellent (weighted kappa 0.96, 0.91-1.00). Automated CPPopt was within 5 mmHg of manually determined CPPopt in 93% of epochs. Lower PRx was predictive of better recovery, but there was no association between ΔCPP and outcome. Percentage time spent below CPPopt increased over time among patients with poor outcomes (p = 0.03). This effect was magnified in patients with impaired autoregulation (defined as PRx > 0.2; p = 0.003). CONCLUSION Prospective interventional clinical trials with regular determination of CPPopt and corresponding adjustment of CPP goals are feasible, but measures to maximize consistency in CPPopt determination are necessary. Although we could not confirm a clear association between ΔCPP and outcome, time spent below CPPopt may be particularly harmful, especially when autoregulation is impaired.
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Affiliation(s)
- Andreas H Kramer
- Department of Critical Care Medicine, University of Calgary, Calgary, Canada. .,Department of Clinical Neurosciences, University of Calgary, Calgary, Canada.
| | - Philippe L Couillard
- Department of Critical Care Medicine, University of Calgary, Calgary, Canada.,Department of Clinical Neurosciences, University of Calgary, Calgary, Canada
| | - David A Zygun
- Department of Critical Care Medicine, University of Alberta, Edmonton, Canada
| | - Marcel J Aries
- Department of Intensive Care, University of Maastricht, Maastricht, The Netherlands
| | - Clare N Gallagher
- Department of Clinical Neurosciences, University of Calgary, Calgary, Canada
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Is There a Relationship Between Optimal Cerebral Perfusion Pressure-Guided Management and PaO 2/FiO 2 Ratio After Severe Traumatic Brain Injury? ACTA NEUROCHIRURGICA. SUPPLEMENT 2018. [PMID: 29492533 DOI: 10.1007/978-3-319-65798-1_13] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/19/2023]
Abstract
OBJECTIVE Severe traumatic brain injury (TBI) management has been associated with adult respiratory distress syndrome (ARDS) in previous literature. We aimed to investigate the relationships between optimal CPP-guided management, ventilation parameters over time and outcome after severe TBI. MATERIALS AND METHODS We performed retrospective analysis of recorded data from 38 patients admitted to the NCCU after severe TBI, managed with optimal cerebral perfusion pressure (CPPopt)-guided therapy, calculated using pressure reactivity index (PRx). All patients were sedated and ventilated with lung protective criteria (Peep > 5, tidal volume 6-8 ml/kg and airway pressure < 30 cmH2O). RESULTS Daily mean CPPopt varied between a minimum of 84 mmHg and a maximum of 91 mmHg with an all period mean value of 88 mmHg. The mean value for the difference between CPP and CPPopt was -1.9 mmHg. Daily mean P/F ratio decreased and varied between 253 and 387 with an all-period mean of 294 mmHg. During the 10 days of recording data, five patients (13%) developed criteria of severe ARDS, but only two patients died due to severe ARDS (5%). PaO2/FiO2 (P/F) ratio did not correlate with CPPopt, but showed a strong correlation with tidal volume (p = 0.000) and driving pressure (p = 0.000). CONCLUSIONS Although CPPopt-guided therapy may induce a decrease in P/F ratio over time during the first 10 days, we could not find an association with worst outcome, which may be influenced by lung protective ventilation strategies and preservation of cerebral autoregulation.
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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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Rubenstein R, Chang B, Yue JK, Chiu A, Winkler EA, Puccio AM, Diaz-Arrastia R, Yuh EL, Mukherjee P, Valadka AB, Gordon WA, Okonkwo DO, Davies P, Agarwal S, Lin F, Sarkis G, Yadikar H, Yang Z, Manley GT, Wang KKW, Cooper SR, Dams-O'Connor K, Borrasso AJ, Inoue T, Maas AIR, Menon DK, Schnyer DM, Vassar MJ. Comparing Plasma Phospho Tau, Total Tau, and Phospho Tau-Total Tau Ratio as Acute and Chronic Traumatic Brain Injury Biomarkers. JAMA Neurol 2017; 74:1063-1072. [PMID: 28738126 DOI: 10.1001/jamaneurol.2017.0655] [Citation(s) in RCA: 157] [Impact Index Per Article: 22.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Importance Annually in the United States, at least 3.5 million people seek medical attention for traumatic brain injury (TBI). The development of therapies for TBI is limited by the absence of diagnostic and prognostic biomarkers. Microtubule-associated protein tau is an axonal phosphoprotein. To date, the presence of the hypophosphorylated tau protein (P-tau) in plasma from patients with acute TBI and chronic TBI has not been investigated. Objective To examine the associations between plasma P-tau and total-tau (T-tau) levels and injury presence, severity, type of pathoanatomic lesion (neuroimaging), and patient outcomes in acute and chronic TBI. Design, Setting, and Participants In the TRACK-TBI Pilot study, plasma was collected at a single time point from 196 patients with acute TBI admitted to 3 level I trauma centers (<24 hours after injury) and 21 patients with TBI admitted to inpatient rehabilitation units (mean [SD], 176.4 [44.5] days after injury). Control samples were purchased from a commercial vendor. The TRACK-TBI Pilot study was conducted from April 1, 2010, to June 30, 2012. Data analysis for the current investigation was performed from August 1, 2015, to March 13, 2017. Main Outcomes and Measures Plasma samples were assayed for P-tau (using an antibody that specifically recognizes phosphothreonine-231) and T-tau using ultra-high sensitivity laser-based immunoassay multi-arrayed fiberoptics conjugated with rolling circle amplification. Results In the 217 patients with TBI, 161 (74.2%) were men; mean (SD) age was 42.5 (18.1) years. The P-tau and T-tau levels and P-tau-T-tau ratio in patients with acute TBI were higher than those in healthy controls. Receiver operating characteristic analysis for the 3 tau indices demonstrated accuracy with area under the curve (AUC) of 1.000, 0.916, and 1.000, respectively, for discriminating mild TBI (Glasgow Coma Scale [GCS] score, 13-15, n = 162) from healthy controls. The P-tau level and P-tau-T-tau ratio were higher in individuals with more severe TBI (GCS, ≤12 vs 13-15). The P-tau level and P-tau-T-tau ratio outperformed the T-tau level in distinguishing cranial computed tomography-positive from -negative cases (AUC = 0.921, 0.923, and 0.646, respectively). Acute P-tau levels and P-tau-T-tau ratio weakly distinguished patients with TBI who had good outcomes (Glasgow Outcome Scale-Extended GOS-E, 7-8) (AUC = 0.663 and 0.658, respectively) and identified those with poor outcomes (GOS-E, ≤4 vs >4) (AUC = 0.771 and 0.777, respectively). Plasma samples from patients with chronic TBI also showed elevated P-tau levels and a P-tau-T-tau ratio significantly higher than that of healthy controls, with both P-tau indices strongly discriminating patients with chronic TBI from healthy controls (AUC = 1.000 and 0.963, respectively). Conclusions and Relevance Plasma P-tau levels and P-tau-T-tau ratio outperformed T-tau level as diagnostic and prognostic biomarkers for acute TBI. Compared with T-tau levels alone, P-tau levels and P-tau-T-tau ratios show more robust and sustained elevations among patients with chronic TBI.
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Affiliation(s)
- Richard Rubenstein
- Laboratory of Neurodegenerative Diseases and CNS Biomarker Discovery, Departments of Neurology and Physiology/Pharmacology, State University of New York Downstate Medical Center, Brooklyn
| | - Binggong Chang
- Laboratory of Neurodegenerative Diseases and CNS Biomarker Discovery, Departments of Neurology and Physiology/Pharmacology, State University of New York Downstate Medical Center, Brooklyn
| | - John K Yue
- Brain and Spinal Injury Center, San Francisco General Hospital, San Francisco, California
| | - Allen Chiu
- Laboratory of Neurodegenerative Diseases and CNS Biomarker Discovery, Departments of Neurology and Physiology/Pharmacology, State University of New York Downstate Medical Center, Brooklyn
| | - Ethan A Winkler
- Brain and Spinal Injury Center, San Francisco General Hospital, San Francisco, California.,Department of Neurological Surgery, University of California, San Francisco
| | - Ava M Puccio
- Department of Neurosurgery, University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania
| | | | - Esther L Yuh
- Brain and Spinal Injury Center, San Francisco General Hospital, San Francisco, California.,Department of Radiology, University of California, San Francisco
| | - Pratik Mukherjee
- Brain and Spinal Injury Center, San Francisco General Hospital, San Francisco, California.,Department of Radiology, University of California, San Francisco
| | - Alex B Valadka
- Department of Neurosurgery, Virginia Commonwealth University, Richmond
| | - Wayne A Gordon
- Department of Rehabilitation Medicine, Icahn School of Medicine at Mount Sinai, New York, New York
| | - David O Okonkwo
- Department of Neurosurgery, University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania
| | - Peter Davies
- Litwin-Zucker Center for Research in Alzheimer's Disease, Feinstein Institute for Medical Research, Manhasset, New York
| | - Sanjeev Agarwal
- Department of Orthopedic Surgery and Rehabilitation Medicine, State University of New York Downstate Medical Center, Brooklyn
| | - Fan Lin
- Program for Neurotrauma, Neuroproteomics, and Biomarker Research, Department of Emergency Medicine, Psychiatry and Chemistry, University of Florida, Gainesville
| | - George Sarkis
- Program for Neurotrauma, Neuroproteomics, and Biomarker Research, Department of Emergency Medicine, Psychiatry and Chemistry, University of Florida, Gainesville.,Department of Chemistry, Faculty of Science, Alexandria University, Ibrahimia, Alexandria, Egypt
| | - Hamad Yadikar
- Program for Neurotrauma, Neuroproteomics, and Biomarker Research, Department of Emergency Medicine, Psychiatry and Chemistry, University of Florida, Gainesville.,Department of Biochemistry, Kuwait University, Khadiya, Kuwait
| | - Zhihui Yang
- Program for Neurotrauma, Neuroproteomics, and Biomarker Research, Department of Emergency Medicine, Psychiatry and Chemistry, University of Florida, Gainesville
| | - Geoffrey T Manley
- Brain and Spinal Injury Center, San Francisco General Hospital, San Francisco, California.,Department of Neurological Surgery, University of California, San Francisco
| | - Kevin K W Wang
- Program for Neurotrauma, Neuroproteomics, and Biomarker Research, Department of Emergency Medicine, Psychiatry and Chemistry, University of Florida, Gainesville
| | | | - Shelly R Cooper
- Department of Psychology, Washington University, St Louis, Missouri
| | - Kristen Dams-O'Connor
- Department of Rehabilitation Medicine, Icahn School of Medicine at Mount Sinai, New York, New York
| | - Allison J Borrasso
- Department of Neurosurgery, University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania
| | - Tomoo Inoue
- Brain and Spinal Injury Center, San Francisco General Hospital, San Francisco, California.,Department of Neurological Surgery, University of California, San Francisco
| | - Andrew I R Maas
- Department of Neurosurgery, Antwerp University Hospital, Edegem, Belgium
| | - David K Menon
- Departments of Anesthesia and Neurocritical Care, University of Cambridge, Cambridge, England
| | | | - Mary J Vassar
- Brain and Spinal Injury Center, San Francisco General Hospital, San Francisco, California.,Department of Neurological Surgery, University of California, San Francisco
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Zeiler FA, Donnelly J, Calviello L, Smielewski P, Menon DK, Czosnyka M. Pressure Autoregulation Measurement Techniques in Adult Traumatic Brain Injury, Part II: A Scoping Review of Continuous Methods. J Neurotrauma 2017; 34:3224-3237. [PMID: 28699412 DOI: 10.1089/neu.2017.5086] [Citation(s) in RCA: 59] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
A scoping review of the literature was performed systematically on commonly described continuous autoregulation measurement techniques in adult traumatic brain injury (TBI) to provide an overview of methodology and comprehensive reference library of the available literature for each technique. Five separate small systematic reviews were conducted for each of the continuous techniques: pressure reactivity index (PRx), laser Doppler flowmetry (LDF), near infrared spectroscopy (NIRS) techniques, brain tissue oxygen tension (PbtO2), and thermal diffusion (TD) techniques. Articles from MEDLINE, BIOSIS, EMBASE, Global Health, Scopus, Cochrane Library (inception to December 2016), and reference lists of relevant articles were searched. A two-tier filter of references was conducted. The literature base identified from the individual searches was limited, except for PRx. The total number of articles using each of the five searched techniques for continuous autoregulation in adult TBI were: PRx (28), LDF (4), NIRS (9), PbtO2 (10), and TD (8). All continuous techniques described in adult TBI are based on moving correlation coefficients. The premise behind the calculation of these moving correlation coefficients focuses on the impact of slow fluctuations in either mean arterial pressure (MAP) or cerebral perfusion pressure (CPP) on some indirect measure of cerebral blood flow (CBF), such as: intracranial pressure (ICP), LDF, NIRS signals, PbtO2, or TD CBF. The thought is the correlation between a hemodynamic driving factor, such as MAP or CPP, and a surrogate for CBF or cerebral perfusion sheds insight on the state of cerebral autoregulation. Both PRx and NIRS indices were validated experimentally against the "gold standard" static autoregulatory curve (Lassen curve) at least around the lower threshold of autoregulation. The PRx has the largest literature base supporting the association with patient outcome. Various methods of continuous autoregulation assessment are described within the adult TBI literature. Many studies exist on these various indices, suggesting an association between their values and patient morbidity/death.
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Affiliation(s)
- Frederick A Zeiler
- 1 Division of Anaesthesia, Addenbrooke's Hospital, University of Cambridge , Cambridge, United Kingdom .,2 Section of Neurosurgery, Department of Surgery, University of Manitoba , Winnipeg, Manitoba, Canada .,3 Clinician Investigator Program, University of Manitoba , Winnipeg, Manitoba, Canada
| | - Joseph Donnelly
- 4 Section of Brain Physics, Division of Neurosurgery, Addenbrooke's Hospital, University of Cambridge , Cambridge, United Kingdom
| | - Leanne Calviello
- 4 Section of Brain Physics, Division of Neurosurgery, Addenbrooke's Hospital, University of Cambridge , Cambridge, United Kingdom
| | - Peter Smielewski
- 4 Section of Brain Physics, Division of Neurosurgery, Addenbrooke's Hospital, University of Cambridge , Cambridge, United Kingdom
| | - David K Menon
- 1 Division of Anaesthesia, Addenbrooke's Hospital, University of Cambridge , Cambridge, United Kingdom
| | - Marek Czosnyka
- 4 Section of Brain Physics, Division of Neurosurgery, Addenbrooke's Hospital, University of Cambridge , Cambridge, United Kingdom
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17
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Adams H, Donnelly J, Czosnyka M, Kolias AG, Helmy A, Menon DK, Smielewski P, Hutchinson PJ. Temporal profile of intracranial pressure and cerebrovascular reactivity in severe traumatic brain injury and association with fatal outcome: An observational study. PLoS Med 2017; 14:e1002353. [PMID: 28742817 PMCID: PMC5526498 DOI: 10.1371/journal.pmed.1002353] [Citation(s) in RCA: 53] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/09/2017] [Accepted: 06/12/2017] [Indexed: 01/01/2023] Open
Abstract
BACKGROUND Both intracranial pressure (ICP) and the cerebrovascular pressure reactivity represent the dysregulation of pathways directly involved in traumatic brain injury (TBI) pathogenesis and have been used to inform clinical management. However, how these parameters evolve over time following injury and whether this evolution has any prognostic importance have not been studied. METHODS AND FINDINGS We analysed the temporal profile of ICP and pressure reactivity index (PRx), examined their relation to TBI-specific mortality, and determined if the prognostic relevance of these parameters was affected by their temporal profile using mixed models for repeated measures of ICP and PRx for the first 240 hours from the time of injury. A total of 601 adults with TBI, admitted between September 2002 to January 2016, and with high-resolution continuous monitoring from a single centre, were studied. At 6 months postinjury, 133 (19%) patients had a fatal outcome; of those, 88 (78%) died from nonsurvivable TBI or brain death. The difference in mean ICP between those with a fatal outcome and functional survivors was only significant for the first 168 hours after injury (all p < 0.05). For PRx, those patients with a fatal outcome also had a higher (more impaired) PRx throughout the first 120 hours after injury (all p < 0.05). The separation of ICP and PRx was greatest in the first 72 hours after injury. Mixed models demonstrated that the explanatory power of the PRx decreases over time; therefore, the prognostic weight assigned to PRx should similarly decrease. However, the ability of ICP to predict a fatal outcome remained relatively stable over time. As control of ICP is the central purpose of TBI management, it is likely that some of the information that is reflected in the natural history of ICP changes is no longer apparent because of therapeutic intervention. CONCLUSIONS We demonstrated the temporal evolution of ICP and PRx and their relationship with fatal outcome, indicating a potential early prognostic and therapeutic window. The combination of dynamic monitoring variables and their time profile improved prediction of outcome. Therefore, time-driven dynamic modelling of outcome in patients with severe TBI may allow for more accurate and clinically useful prediction models. Further research is needed to confirm and expand on these findings.
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Affiliation(s)
- Hadie Adams
- Division of Neurosurgery, Department of Clinical Neuroscience, Addenbrooke's Hospital, University of Cambridge, Cambridge, United Kingdom
| | - Joseph Donnelly
- Division of Neurosurgery, Department of Clinical Neuroscience, Addenbrooke's Hospital, University of Cambridge, Cambridge, United Kingdom
| | - Marek Czosnyka
- Division of Neurosurgery, Department of Clinical Neuroscience, Addenbrooke's Hospital, University of Cambridge, Cambridge, United Kingdom.,Institute of Electronic Systems, Warsaw University of Technology, Warsaw, Poland
| | - Angelos G Kolias
- Division of Neurosurgery, Department of Clinical Neuroscience, Addenbrooke's Hospital, University of Cambridge, Cambridge, United Kingdom
| | - Adel Helmy
- Division of Neurosurgery, Department of Clinical Neuroscience, Addenbrooke's Hospital, University of Cambridge, Cambridge, United Kingdom
| | - David K Menon
- Department of Anaesthesia, Addenbrooke's Hospital, University of Cambridge, Cambridge, United Kingdom
| | - Peter Smielewski
- Division of Neurosurgery, Department of Clinical Neuroscience, Addenbrooke's Hospital, University of Cambridge, Cambridge, United Kingdom
| | - Peter J Hutchinson
- Division of Neurosurgery, Department of Clinical Neuroscience, Addenbrooke's Hospital, University of Cambridge, Cambridge, United Kingdom
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18
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Nordström CH, Koskinen LO, Olivecrona M. Aspects on the Physiological and Biochemical Foundations of Neurocritical Care. Front Neurol 2017; 8:274. [PMID: 28674514 PMCID: PMC5474476 DOI: 10.3389/fneur.2017.00274] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2017] [Accepted: 05/29/2017] [Indexed: 12/25/2022] Open
Abstract
Neurocritical care (NCC) is a branch of intensive care medicine characterized by specific physiological and biochemical monitoring techniques necessary for identifying cerebral adverse events and for evaluating specific therapies. Information is primarily obtained from physiological variables related to intracranial pressure (ICP) and cerebral blood flow (CBF) and from physiological and biochemical variables related to cerebral energy metabolism. Non-surgical therapies developed for treating increased ICP are based on knowledge regarding transport of water across the intact and injured blood-brain barrier (BBB) and the regulation of CBF. Brain volume is strictly controlled as the BBB permeability to crystalloids is very low restricting net transport of water across the capillary wall. Cerebral pressure autoregulation prevents changes in intracranial blood volume and intracapillary hydrostatic pressure at variations in arterial blood pressure. Information regarding cerebral oxidative metabolism is obtained from measurements of brain tissue oxygen tension (PbtO2) and biochemical data obtained from intracerebral microdialysis. As interstitial lactate/pyruvate (LP) ratio instantaneously reflects shifts in intracellular cytoplasmatic redox state, it is an important indicator of compromised cerebral oxidative metabolism. The combined information obtained from PbtO2, LP ratio, and the pattern of biochemical variables reveals whether impaired oxidative metabolism is due to insufficient perfusion (ischemia) or mitochondrial dysfunction. Intracerebral microdialysis and PbtO2 give information from a very small volume of tissue. Accordingly, clinical interpretation of the data must be based on information of the probe location in relation to focal brain damage. Attempts to evaluate global cerebral energy state from microdialysis of intraventricular fluid and from the LP ratio of the draining venous blood have recently been presented. To be of clinical relevance, the information from all monitoring techniques should be presented bedside online. Accordingly, in the future, the chemical variables obtained from microdialysis will probably be analyzed by biochemical sensors.
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Affiliation(s)
| | - Lars-Owe Koskinen
- Department of Clinical Neuroscience, Division of Neurosurgery, Umeå University, Umeå, Sweden
| | - Magnus Olivecrona
- Faculty of Health and Medicine, Department of Anesthesia and Intensive Care, Section for Neurosurgery Örebro University Hospital, Örebro University, Örebro, Sweden
- Department for Medical Sciences, Örebro University, Örebro, Sweden
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19
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Detection of Impaired Cerebral Autoregulation Using Selected Correlation Analysis: A Validation Study. COMPUTATIONAL AND MATHEMATICAL METHODS IN MEDICINE 2017; 2017:8454527. [PMID: 28255331 PMCID: PMC5307252 DOI: 10.1155/2017/8454527] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/26/2016] [Revised: 01/02/2017] [Accepted: 01/09/2017] [Indexed: 01/08/2023]
Abstract
Multimodal brain monitoring has been utilized to optimize treatment of patients with critical neurological diseases. However, the amount of data requires an integrative tool set to unmask pathological events in a timely fashion. Recently we have introduced a mathematical model allowing the simulation of pathophysiological conditions such as reduced intracranial compliance and impaired autoregulation. Utilizing a mathematical tool set called selected correlation analysis (sca), correlation patterns, which indicate impaired autoregulation, can be detected in patient data sets (scp). In this study we compared the results of the sca with the pressure reactivity index (PRx), an established marker for impaired autoregulation. Mean PRx values were significantly higher in time segments identified as scp compared to segments showing no selected correlations (nsc). The sca based approach predicted cerebral autoregulation failure with a sensitivity of 78.8% and a specificity of 62.6%. Autoregulation failure, as detected by the results of both analysis methods, was significantly correlated with poor outcome. Sca of brain monitoring data detects impaired autoregulation with high sensitivity and sufficient specificity. Since the sca approach allows the simultaneous detection of both major pathological conditions, disturbed autoregulation and reduced compliance, it may become a useful analysis tool for brain multimodal monitoring data.
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20
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Goodson CM, Rosenblatt K, Rivera-Lara L, Nyquist P, Hogue CW. Cerebral Blood Flow Autoregulation in Sepsis for the Intensivist: Why Its Monitoring May Be the Future of Individualized Care. J Intensive Care Med 2016; 33:63-73. [PMID: 27798314 DOI: 10.1177/0885066616673973] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Cerebral blood flow (CBF) autoregulation maintains consistent blood flow across a range of blood pressures (BPs). Sepsis is a common cause of systemic hypotension and cerebral dysfunction. Guidelines for BP management in sepsis are based on historical concepts of CBF autoregulation that have now evolved with the availability of more precise technology for its measurement. In this article, we provide a narrative review of methods of monitoring CBF autoregulation, the cerebral effects of sepsis, and the current knowledge of CBF autoregulation in sepsis. Current guidelines for BP management in sepsis are based on a goal of maintaining mean arterial pressure (MAP) above the lower limit of CBF autoregulation. Bedside tools are now available to monitor CBF autoregulation continuously. These data reveal that individual BP goals determined from CBF autoregulation monitoring are more variable than previously expected. In patients undergoing cardiac surgery with cardiopulmonary bypass, for example, the lower limit of autoregulation varied between a MAP of 40 to 90 mm Hg. Studies of CBF autoregulation in sepsis suggest patients frequently manifest impaired CBF autoregulation, possibly a result of BP below the lower limit of autoregulation, particularly in early sepsis or with sepsis-associated encephalopathy. This suggests that the present consensus guidelines for BP management in sepsis may expose some patients to both cerebral hypoperfusion and cerebral hyperperfusion, potentially resulting in damage to brain parenchyma. The future use of novel techniques to study and clinically monitor CBF autoregulation could provide insight into the cerebral pathophysiology of sepsis and offer more precise treatments that may improve functional and cognitive outcomes for survivors of sepsis.
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Affiliation(s)
- Carrie M Goodson
- 1 Division of Pulmonary and Critical Care Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Kathryn Rosenblatt
- 2 Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD, USA.,3 Department of Anesthesiology and Critical Care Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Lucia Rivera-Lara
- 2 Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD, USA.,3 Department of Anesthesiology and Critical Care Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Paul Nyquist
- 2 Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD, USA.,3 Department of Anesthesiology and Critical Care Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Charles W Hogue
- 4 Department of Anesthesiology, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA
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21
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Fantini S, Sassaroli A, Tgavalekos KT, Kornbluth J. Cerebral blood flow and autoregulation: current measurement techniques and prospects for noninvasive optical methods. NEUROPHOTONICS 2016; 3:031411. [PMID: 27403447 PMCID: PMC4914489 DOI: 10.1117/1.nph.3.3.031411] [Citation(s) in RCA: 216] [Impact Index Per Article: 27.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/04/2016] [Accepted: 05/10/2016] [Indexed: 05/23/2023]
Abstract
Cerebral blood flow (CBF) and cerebral autoregulation (CA) are critically important to maintain proper brain perfusion and supply the brain with the necessary oxygen and energy substrates. Adequate brain perfusion is required to support normal brain function, to achieve successful aging, and to navigate acute and chronic medical conditions. We review the general principles of CBF measurements and the current techniques to measure CBF based on direct intravascular measurements, nuclear medicine, X-ray imaging, magnetic resonance imaging, ultrasound techniques, thermal diffusion, and optical methods. We also review techniques for arterial blood pressure measurements as well as theoretical and experimental methods for the assessment of CA, including recent approaches based on optical techniques. The assessment of cerebral perfusion in the clinical practice is also presented. The comprehensive description of principles, methods, and clinical requirements of CBF and CA measurements highlights the potentially important role that noninvasive optical methods can play in the assessment of neurovascular health. In fact, optical techniques have the ability to provide a noninvasive, quantitative, and continuous monitor of CBF and autoregulation.
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Affiliation(s)
- Sergio Fantini
- Tufts University, Department of Biomedical Engineering, 4 Colby Street, Medford, Massachusetts 02155, United States
| | - Angelo Sassaroli
- Tufts University, Department of Biomedical Engineering, 4 Colby Street, Medford, Massachusetts 02155, United States
| | - Kristen T. Tgavalekos
- Tufts University, Department of Biomedical Engineering, 4 Colby Street, Medford, Massachusetts 02155, United States
| | - Joshua Kornbluth
- Tufts University School of Medicine, Department of Neurology, Division of Neurocritical Care, 800 Washington Street, Box #314, Boston, Massachusetts 02111, United States
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22
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Parameter Optimization for Selected Correlation Analysis of Intracranial Pathophysiology. COMPUTATIONAL AND MATHEMATICAL METHODS IN MEDICINE 2015; 2015:652030. [PMID: 26693250 PMCID: PMC4677033 DOI: 10.1155/2015/652030] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/13/2015] [Revised: 10/20/2015] [Accepted: 10/25/2015] [Indexed: 11/17/2022]
Abstract
Recently we proposed a mathematical tool set, called selected correlation analysis, that reliably detects positive and negative correlations between arterial blood pressure (ABP) and intracranial pressure (ICP). Such correlations are associated with severe impairment of the cerebral autoregulation and intracranial compliance, as predicted by a mathematical model. The time resolved selected correlation analysis is based on a windowing technique combined with Fourier-based coherence calculations and therefore depends on several parameters. For real time application of this method at an ICU it is inevitable to adjust this mathematical tool for high sensitivity and distinct reliability. In this study, we will introduce a method to optimize the parameters of the selected correlation analysis by correlating an index, called selected correlation positive (SCP), with the outcome of the patients represented by the Glasgow Outcome Scale (GOS). For that purpose, the data of twenty-five patients were used to calculate the SCP value for each patient and multitude of feasible parameter sets of the selected correlation analysis. It could be shown that an optimized set of parameters is able to improve the sensitivity of the method by a factor greater than four in comparison to our first analyses.
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23
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Visualizing secondary brain insults: does the emperor have new clothes? Intensive Care Med 2015; 41:1324-6. [PMID: 26077057 DOI: 10.1007/s00134-015-3858-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2015] [Accepted: 04/30/2015] [Indexed: 10/23/2022]
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24
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Lang EW, Kasprowicz M, Smielewski P, Santos E, Pickard J, Czosnyka M. Short pressure reactivity index versus long pressure reactivity index in the management of traumatic brain injury. J Neurosurg 2015; 122:588-94. [DOI: 10.3171/2014.10.jns14602] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
OBJECT
The pressure reactivity index (PRx) correlates with outcome after traumatic brain injury (TBI) and is used to calculate optimal cerebral perfusion pressure (CPPopt). The PRx is a correlation coefficient between slow, spontaneous changes (0.003–0.05 Hz) in intracranial pressure (ICP) and arterial blood pressure (ABP). A novel index—the so-called long PRx (L-PRx)—that considers ABP and ICP changes (0.0008–0.008 Hz) was proposed.
METHODS
The authors compared PRx and L-PRx for 6-month outcome prediction and CPPopt calculation in 307 patients with TBI. The PRx- and L-PRx–based CPPopt were determined and the predictive power and discriminant abilities were compared.
RESULTS
The PRx and L-PRx correlation was good (R = 0.7, p < 0.00001; Spearman test). The PRx, age, CPP, and Glasgow Coma Scale score but not L-PRx were significant fatal outcome predictors (death and persistent vegetative state). There was a significant difference between the areas under the receiver operating characteristic curves calculated for PRx and L-PRx (0.61 ± 0.04 vs 0.51 ± 0.04; z-statistic = −3.26, p = 0.011), which indicates a better ability by PRx than L-PRx to predict fatal outcome. The CPPopt was higher for L-PRx than for PRx, without a statistical difference (median CPPopt for L-PRx: 76.9 mm Hg, interquartile range [IQR] ± 10.1 mm Hg; median CPPopt for PRx: 74.7 mm Hg, IQR ± 8.2 mm Hg). Death was associated with CPP below CPPopt for PRx (χ2 = 30.6, p < 0.00001), and severe disability was associated with CPP above CPPopt for PRx (χ2 = 7.8, p = 0.005). These relationships were not statistically significant for CPPopt for L-PRx.
CONCLUSIONS
The PRx is superior to the L-PRx for TBI outcome prediction. Individual CPPopt for L-PRx and PRx are not statistically different. Deviations between CPP and CPPopt for PRx are relevant for outcome prediction; those between CPP and CPPopt for L-PRx are not. The PRx uses the entire B-wave spectrum for index calculation, whereas the L-PRX covers only one-third of it. This may explain the performance discrepancy.
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Affiliation(s)
| | - Magdalena Kasprowicz
- 2Institute of Biomedical Engineering and Instrumentation, Wroclaw University of Technology, Wroclaw, Poland; and
| | - Peter Smielewski
- 3Department of Neurosurgery, Addenbrooke's Hospital, University of Cambridge, United Kingdom
| | - Edgar Santos
- 4Department of Neurosurgery, University of Heidelberg, Germany
| | - John Pickard
- 3Department of Neurosurgery, Addenbrooke's Hospital, University of Cambridge, United Kingdom
| | - Marek Czosnyka
- 3Department of Neurosurgery, Addenbrooke's Hospital, University of Cambridge, United Kingdom
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