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Ziółkowski A, Pudełko A, Kazimierska A, Uryga A, Czosnyka Z, Kasprowicz M, Czosnyka M. Peak appearance time in pulse waveforms of intracranial pressure and cerebral blood flow velocity. Front Physiol 2023; 13:1077966. [PMID: 36685171 PMCID: PMC9846027 DOI: 10.3389/fphys.2022.1077966] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2022] [Accepted: 12/08/2022] [Indexed: 01/05/2023] Open
Abstract
The shape of the pulse waveforms of intracranial pressure (ICP) and cerebral blood flow velocity (CBFV) typically contains three characteristic peaks. It was reported that alterations in cerebral hemodynamics may influence the shape of the pulse waveforms by changing peaks' configuration. However, the changes in peak appearance time (PAT) in ICP and CBFV pulses are only described superficially. We analyzed retrospectively ICP and CBFV signals recorded in traumatic brain injury patients during decrease in ICP induced by hypocapnia (n = 11) and rise in ICP during episodes of ICP plateau waves (n = 8). All three peaks were manually annotated in over 48 thousand individual pulses. The changes in PAT were compared between periods of vasoconstriction (expected during hypocapnia) and vasodilation (expected during ICP plateau waves) and their corresponding baselines. Correlation coefficient (rS) analysis between mean ICP and mean PATs was performed in each individual recording. Vasodilation prolonged PAT of the first peaks of ICP and CBFV pulses and the third peak of CBFV pulse. It also accelerated PAT of the third peak of ICP pulse. In contrast, vasoconstriction shortened appearance time of the first peaks of ICP and CBFV pulses and the second peak of ICP pulses. Analysis of individual recordings demonstrated positive association between changes in PAT of all three peaks in the CBFV pulse and mean ICP (rS range: 0.32-0.79 for significant correlations). Further study is needed to test whether PAT of the CBFV pulse may serve as an indicator of changes in ICP-this may open a perspective for non-invasive monitoring of alterations in mean ICP.
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Affiliation(s)
- Arkadiusz Ziółkowski
- Department of Biomedical Engineering, Faculty of Fundamental Problems of Technology, Wroclaw University of Science and Technology, Wroclaw, Poland
| | - Agata Pudełko
- Department of Biomedical Engineering, Faculty of Fundamental Problems of Technology, Wroclaw University of Science and Technology, Wroclaw, Poland
| | - Agnieszka Kazimierska
- Department of Biomedical Engineering, Faculty of Fundamental Problems of Technology, Wroclaw University of Science and Technology, Wroclaw, Poland
| | - Agnieszka Uryga
- Department of Biomedical Engineering, Faculty of Fundamental Problems of Technology, Wroclaw University of Science and Technology, Wroclaw, Poland
| | - Zofia Czosnyka
- Brain Physics Laboratory, Division of Neurosurgery, Department of Clinical Neurosciences, Addenbrooke’s Hospital, University of Cambridge, Cambridge, United Kingdom
| | - Magdalena Kasprowicz
- Department of Biomedical Engineering, Faculty of Fundamental Problems of Technology, Wroclaw University of Science and Technology, Wroclaw, Poland,*Correspondence: Magdalena Kasprowicz,
| | - Marek Czosnyka
- Brain Physics Laboratory, Division of Neurosurgery, Department of Clinical Neurosciences, Addenbrooke’s Hospital, University of Cambridge, Cambridge, United Kingdom,Institute of Electronic Systems, Faculty of Electronics and Information Technology, Warsaw University of Technology, Warsaw, Poland
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Hanalioglu D, Burrows BT, Adelson PD, Appavu B. Cerebrovascular dynamics after pediatric traumatic brain injury. Front Physiol 2023; 14:1093330. [PMID: 36875032 PMCID: PMC9981944 DOI: 10.3389/fphys.2023.1093330] [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: 11/08/2022] [Accepted: 02/07/2023] [Indexed: 02/19/2023] Open
Abstract
Objective: We aimed to investigate model-based indices of cerebrovascular dynamics after pediatric traumatic brain injury (TBI) using transcranial Doppler ultrasound (TCD) integrated into multimodality neurologic monitoring (MMM). Methods: We performed a retrospective analysis of pediatric TBI patients undergoing TCD integrated into MMM. Classic TCD characteristics included pulsatility indices and systolic, diastolic and mean flow velocities of the bilateral middle cerebral arteries. Model-based indices of cerebrovascular dynamics included the mean velocity index (Mx), compliance of the cerebrovascular bed (Ca), compliance of the cerebrospinal space (Ci), arterial time constant (TAU), critical closing pressure (CrCP) and diastolic closing margin (DCM). Classic TCD characteristics and model-based indices of cerebrovascular dynamics were investigated in relation to functional outcomes and intracranial pressure (ICP) using generalized estimating equations with repeated measures. Functional outcomes were assessed using the Glasgow Outcome Scale-Extended Pediatrics score (GOSE-Peds) at 12 months, post-injury. Results: Seventy-two separate TCD studies were performed on twenty-five pediatric TBI patients. We identified that reduced Ci (estimate -5.986, p = 0.0309), increased CrCP (estimate 0.081, p < 0.0001) and reduced DCM (estimate -0.057, p = 0.0179) were associated with higher GOSE-Peds scores, suggestive of unfavorable outcome. We identified that increased CrCP (estimate 0.900, p < 0.001) and reduced DCM (estimate -0.549, p < 0.0001) were associated with increased ICP. Conclusion: In an exploratory analysis of pediatric TBI patients, increased CrCP and reduced DCM and Ci are associated with unfavorable outcomes, and increased CrCP and reduced DCM are associated with increased ICP. Prospective work with larger cohorts is needed to further validate the clinical utility of these features.
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Affiliation(s)
- Damla Hanalioglu
- Department of Neurosciences, Barrow Neurological Institute at Phoenix Children's Hospital, Phoenix, AZ, United States
| | - Brian T Burrows
- Department of Neurosciences, Barrow Neurological Institute at Phoenix Children's Hospital, Phoenix, AZ, United States
| | - P David Adelson
- Department of Neurosciences, Barrow Neurological Institute at Phoenix Children's Hospital, Phoenix, AZ, United States.,Department of Child Health, University of Arizona College of Medicine-Phoenix, Phoenix, AZ, United States
| | - Brian Appavu
- Department of Neurosciences, Barrow Neurological Institute at Phoenix Children's Hospital, Phoenix, AZ, United States.,Department of Child Health, University of Arizona College of Medicine-Phoenix, Phoenix, AZ, United States
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Liang Y, Mo P, Yang X, He Y, Zhang W, Zeng X, Xie L, Gao Q. Estimation of critical closing pressure using intravascular blood pressure of the common carotid artery. Med Eng Phys 2022; 102:103759. [DOI: 10.1016/j.medengphy.2022.103759] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2021] [Revised: 01/01/2022] [Accepted: 01/14/2022] [Indexed: 10/19/2022]
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Intracranial pulse pressure waveform analysis using the higher harmonics centroid. Acta Neurochir (Wien) 2021; 163:3249-3258. [PMID: 34387744 PMCID: PMC8599247 DOI: 10.1007/s00701-021-04958-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2021] [Accepted: 07/25/2021] [Indexed: 11/30/2022]
Abstract
Background The pulse waveform of intracranial pressure (ICP) is its distinctive feature almost always present in the clinical recordings. In most cases, it changes proportionally to rising ICP, and observation of these changes may be clinically useful. We introduce the higher harmonics centroid (HHC) which can be defined as the center of mass of harmonics of the ICP pulse waveform from the 2nd to 10th, where mass corresponds to amplitudes of these harmonics. We investigate the changes in HHC during ICP monitoring, including isolated episodes of ICP plateau waves. Material and methods Recordings from 325 patients treated between 2002 and 2010 were reviewed. Twenty-six patients with ICP plateau waves were identified. In the first step, the correlation between HHC and ICP was examined for the entire monitoring period. In the second step, the above relation was calculated separately for periods of elevated ICP during plateau wave and the baseline. Results For the values averaged over the whole monitoring period, ICP (22.3 ± 6.9 mm Hg) correlates significantly (R = 0.45, p = 0.022) with HHC (3.64 ± 0.46). During the ICP plateau waves (ICP increased from 20.9 ± 6.0 to 53.7 ± 9.7 mm Hg, p < 10−16), we found a significant decrease in HHC (from 3.65 ± 0.48 to 3.21 ± 0.33, p = 10−5). Conclusions The good correlation between HHC and ICP supports the clinical application of pressure waveform analysis in addition to the recording of ICP number only. Mean ICP may be distorted by a zero drift, but HHC remains immune to this error. Further research is required to test whether a decline in HHC with elevated ICP can be an early warning sign of intracranial hypertension, whether individual breakpoints of correlation between ICP and its centroid are of clinical importance.
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Change in Blood Flow Velocity Pulse Waveform during Plateau Waves of Intracranial Pressure. Brain Sci 2021; 11:brainsci11081000. [PMID: 34439619 PMCID: PMC8391497 DOI: 10.3390/brainsci11081000] [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: 07/01/2021] [Revised: 07/22/2021] [Accepted: 07/27/2021] [Indexed: 11/16/2022] Open
Abstract
A reliable method for non-invasive detection of dangerous intracranial pressure (ICP) elevations is still unavailable. In this preliminary study, we investigate quantitatively our observation that superimposing waveforms of transcranial Doppler blood flow velocity (FV) and arterial blood pressure (ABP) may help in non-invasive identification of ICP plateau waves. Recordings of FV, ABP and ICP in 160 patients with severe head injury (treated in the Neurocritical Care Unit at Addenbrookes Hospital, Cambridge, UK) were reviewed retrospectively. From that cohort, we identified 18 plateau waves registered in eight patients. A “measure of dissimilarity” (Dissimilarity/Difference Index, DI) between ABP and FV waveforms was calculated in three following steps: 1. fragmentation of ABP and FV signal according to cardiac cycle; 2. obtaining the normalised representative ABP and FV cycles; and finally; 3. assessing their difference, represented by the area between both curves. DI appeared to discriminate ICP plateau waves from baseline episodes slightly better than conventional pulsatility index did: area under ROC curve 0.92 vs. 0.90, sensitivity 0.81 vs. 0.69, accuracy 0.88 vs. 0.84, respectively. The concept of DI, if further tested and improved, might be used for non-invasive detection of ICP plateau waves.
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Cerebrovascular Impedance During Hemodynamic Change in Rabbits: A Pilot Study. ACTA NEUROCHIRURGICA. SUPPLEMENT 2021. [PMID: 33839859 DOI: 10.1007/978-3-030-59436-7_53] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register]
Abstract
INTRODUCTION Cerebrovascular impedance describes the relationship between pulsatile changes in arterial blood pressure (ABP) and cerebral blood flow (CBF). It is commonly defined by modulus and phase shift derived from Fourier spectra of ABP and CBF velocity (CBFV) signals under mostly steady-state conditions. The aim of this work was to assess heartbeat-to-heartbeat cerebrovascular impedance at heart rate frequency during controlled changes in mean ABP and intracranial pressure (ICP). MATERIAL AND METHODS Recordings of ABP in the femoral artery, transcranial Doppler CBFV in the basilar artery, and subarachnoid ICP were obtained from anesthetized rabbits with induced arterial hypotension (n = 8 rabbits), arterial hypertension (n = 5), or intracranial hypertension (n = 7). Modulus of cerebrovascular impedance (|Z|) was estimated from amplitudes of ABP and CBFV. Phase shift of cerebrovascular impedance (PS) was estimated from time-frequency (TF) representations of phase shift between ABP and CBFV overlaid with a time-variant mask based on the fundamental frequency of ABP. RESULTS Both |Z| and PS increased with increasing mean ABP. |Z| decreased with increasing mean ICP, but no change was observed in PS. CONCLUSIONS The combined beat-to-beat and TF approach allows for the estimation of cerebrovascular impedance during transient hemodynamic changes. |Z| and PS follow the pattern of changes in CPP.
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Plateau Waves of Intracranial Pressure: Methods for Automatic Detection and Prediction. ACTA NEUROCHIRURGICA. SUPPLEMENT 2021. [PMID: 33839853 DOI: 10.1007/978-3-030-59436-7_47] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/01/2023]
Abstract
Plateau waves are recurrent phenomena observed in traumatic brain injury (TBI) patients, characterised by an increase in intracranial pressure (ICP) above 40 mmHg combined with an almost zero arterial blood pressure (ABP) variation and, hence, a decrease in cerebral perfusion pressure (CPP). A raised ICP for a long period of time, namely plateau waves, can lead to a secondary brain injury. Due to the impaired cerebral autoregulation mechanism these TBI patients present, they are admitted to neurocritical care units (NCCUs) to be under continuous multimodal monitoring, which allows a correct diagnosis for each patient. Plateau waves can end naturally by activating a vasoconstriction mechanism which decreases the amount of blood available in the brain. Alternatively, the phenomenon can end with therapeutic treatment.In this sense, the present study consists in the development of an algorithm capable of automatically detecting plateau waves using offline data, i.e. data already collected from patients. This creates an extra tool which allows for faster detection of events to assist their identification and final diagnosis. Despite the additional steps that can be included to improve the algorithm, the results show good performance, and thus it may be applied in NCCUs.
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Moraes L, Yelicich B, Noble M, Biestro A, Puppo C. Impacts of a Pressure Challenge on Cerebral Critical Closing Pressure and Effective Cerebral Perfusion Pressure in Patients with Traumatic Brain Injury. ACTA NEUROCHIRURGICA. SUPPLEMENT 2021; 131:11-16. [PMID: 33839809 DOI: 10.1007/978-3-030-59436-7_3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
INTRODUCTION Cerebral critical closing pressure (CrCP) comprises intracranial pressure (ICP) and arteriolar wall tension (WT). It is the arterial blood pressure (ABP) at which small vessels close and circulation stops. We hypothesized that the increase in WT secondary to a systemic hypertensive challenge would lead to an increase in CrCP and that the "effective" cerebral perfusion pressure (CPPeff; calculated as ABP - CrCP) would give more complete information than the "conventional" cerebral perfusion pressure (CPP; calculated as ABP - ICP). OBJECTIVE This study aimed to compare CrCP, CPP, and CPPeff changes during a hypertensive challenge in patients with a severe traumatic brain injury. PATIENTS AND METHODS Data on ABP, ICP, and cerebral blood flow velocity, measured by transcranial Doppler ultrasound, were acquired simultaneously for 30 min both basally and during a hypertensive challenge. An impedance-based CrCP model was used. RESULTS The following values are expressed as median (interquartile range). There were 11 patients, aged 29 (14) years. CPP increased from 73 (17) to 102 (26) mmHg (P ≤ 0.001). ICP did not change. CrCP changed from 23 (11) to 27 (10) mmHg (P ≤ 0.001). WT increased from 7 (5) to 11 (7) mmHg (P ˂ 0.005). CPPeff changed less than CPP. CONCLUSION The CPP change was greater than the CPPeff change, mainly because CrCP increased simultaneously with the WT increase as a result of the autoregulatory response. CPPeff provides information about the real driving force generating blood movement.
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Affiliation(s)
- Leandro Moraes
- Intensive Care Unit, Hospital de Clinicas, Universidad de la Republica, Montevideo, Uruguay
| | - Bernardo Yelicich
- Intensive Care Unit, Hospital de Clinicas, Universidad de la Republica, Montevideo, Uruguay
| | - Mayda Noble
- Intensive Care Unit, Hospital de Clinicas, Universidad de la Republica, Montevideo, Uruguay
| | - Alberto Biestro
- Intensive Care Unit, Hospital de Clinicas, Universidad de la Republica, Montevideo, Uruguay
| | - Corina Puppo
- Intensive Care Unit, Hospital de Clinicas, Universidad de la Republica, Montevideo, Uruguay.
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Trofimova KA, Agarkova DI, Trofimov AO, Abashkin AY, Bragin DE. Cerebral Critical Closing Pressure in Concomitant Traumatic Brain Injury and Intracranial Hematomas. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2021; 1339:33-38. [DOI: 10.1007/978-3-030-78787-5_5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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Kaczmarska K, Uryga A, Placek MM, Calviello L, Kasprowicz M, Varsos GV, Czosnyka Z, Koźniewska E, Sierzputowski T, Koszewski W, Czosnyka M. Critical closing pressure during experimental intracranial hypertension: comparison of three calculation methods. Neurol Res 2020; 42:387-397. [DOI: 10.1080/01616412.2020.1733323] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Affiliation(s)
- Katarzyna Kaczmarska
- Department of Neurosurgery, Mossakowski Medical Research Centre, Polish Academy of Sciences, Warsaw, Poland
- Institute of Electronic Systems, Faculty of Electronics and Information Technology, Warsaw University of Technology, Warsaw, Poland
| | - Agnieszka Uryga
- Department of Biomedical Engineering, Faculty of Fundamental Problems of Technology, Wroclaw University of Science and Technology, Wroclaw, Poland
| | - Michał M. Placek
- Department of Biomedical Engineering, Faculty of Fundamental Problems of Technology, Wroclaw University of Science and Technology, Wroclaw, Poland
- Division of Neurosurgery, Department of Clinical Neurosciences, University of Cambridge, Cambridge, UK
| | - Leanne Calviello
- Division of Neurosurgery, Department of Clinical Neurosciences, University of Cambridge, Cambridge, UK
| | - Magdalena Kasprowicz
- Department of Biomedical Engineering, Faculty of Fundamental Problems of Technology, Wroclaw University of Science and Technology, Wroclaw, Poland
| | - Georgios V. Varsos
- Division of Neurosurgery, Department of Clinical Neurosciences, University of Cambridge, Cambridge, UK
| | - Zofia Czosnyka
- Division of Neurosurgery, Department of Clinical Neurosciences, University of Cambridge, Cambridge, UK
| | - Ewa Koźniewska
- Department of Neurosurgery, Mossakowski Medical Research Centre, Polish Academy of Sciences, Warsaw, Poland
| | | | - Waldemar Koszewski
- Department of Neurosurgery, Second Faculty of Medicine, Medical University of Warsaw, Warsaw, Poland
| | - Marek Czosnyka
- Institute of Electronic Systems, Faculty of Electronics and Information Technology, Warsaw University of Technology, Warsaw, Poland
- Division of Neurosurgery, Department of Clinical Neurosciences, University of Cambridge, Cambridge, UK
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O’Brien NF, Lovett ME, Chung M, Maa T. Non-invasive estimation of cerebral perfusion pressure using transcranial Doppler ultrasonography in children with severe traumatic brain injury. Childs Nerv Syst 2020; 36:2063-2071. [PMID: 31996979 PMCID: PMC7223617 DOI: 10.1007/s00381-020-04524-7] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/19/2019] [Accepted: 01/25/2020] [Indexed: 12/31/2022]
Abstract
OBJECTIVE To identify if cerebral perfusion pressure (CPP) can be non-invasively estimated by either of two methods calculated using transcranial Doppler ultrasound (TCD) parameters. DESIGN Retrospective review of previously prospectively gathered data. SETTING Pediatric intensive care unit in a tertiary care referral hospital. PATIENTS Twenty-three children with severe traumatic brain injury (TBI) and invasive intracranial pressure (ICP) monitoring in place. INTERVENTIONS TCD evaluation of the middle cerebral arteries was performed daily. CPP at the time of the TCD examination was recorded. For method 1, estimated cerebral perfusion pressure (CPPe) was calculated as: CPPe = MAP × (diastolic flow (Vd)/mean flow (Vm)) + 14. For method 2, critical closing pressure (CrCP) was identified as the intercept point on the x-axis of the linear regression line of blood pressure and flow velocity parameters. CrCP/CPPe was then calculated as MAP-CrCP. MEASUREMENTS AND MAIN RESULTS One hundred eight paired measurements were available. Using patient averaged data, correlation between CPP and CPPe was significant (r = 0.78, p = < 0.001). However, on Bland-Altman plots, bias was 3.7 mmHg with 95% limits of agreement of - 17 to + 25 for CPPe. Using patient averaged data, correlation between CPP and CrCP/CPPe was significant (r = 0.59, p = < 0.001), but again bias was high at 11 mmHg with wide 95% limits of agreement of - 15 to + 38 mmHg. CONCLUSIONS CPPe and CrCP/CPPe do not have clinical value to estimate the absolute CPP in pediatric patients with TBI.
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Affiliation(s)
- Nicole F O’Brien
- Division of Critical Care Medicine, Department of Pediatrics, Nationwide Children’s Hospital, The Ohio State University, 700 Children’s Drive, Columbus, OH 43205 USA
| | - Marlina E. Lovett
- Division of Critical Care Medicine, Department of Pediatrics, Nationwide Children’s Hospital, The Ohio State University, 700 Children’s Drive, Columbus, OH 43205 USA
| | - Melissa Chung
- Division of Neurology, Department of Pediatrics, Nationwide Children’s Hospital, The Ohio State University, 700 Children’s Drive, Columbus, OH 43205 USA
| | - Tensing Maa
- Division of Critical Care Medicine, Department of Pediatrics, Nationwide Children’s Hospital, The Ohio State University, 700 Children’s Drive, Columbus, OH 43205 USA
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Observed and calculated cerebral critical closing pressure are highly correlated in preterm infants. Pediatr Res 2019; 86:242-246. [PMID: 31003233 PMCID: PMC6658334 DOI: 10.1038/s41390-019-0403-y] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/08/2018] [Revised: 04/04/2019] [Accepted: 04/11/2019] [Indexed: 11/28/2022]
Abstract
BACKGROUND Cerebrovascular critical closing pressure (CrCP) is the arterial blood pressure (ABP) at which cerebral blood flow ceases. Preterm ABP is low and close to CrCP. The diastolic closing margin (diastolic ABP minus CrCP) has been associated with intraventricular hemorrhage in preterm infants. CrCP is estimated from middle cerebral artery cerebral blood flow velocity (CBFV) and ABP waveforms. However, these estimations have not been validated due to a lack of gold standard. Direct observation of the CrCP in preterm infants with hypotension is an opportunity to validate synchronously estimated CrCP. METHODS ABP and CBFV tracings were obtained from 24 extremely low birth weight infants. Recordings where diastolic CBFV was zero were identified. The gold standard CrCP was delineated using piecewise regression of ABP and CBFV values paired by rank ordering and then estimated using a published formula. The measured and estimated values were compared using linear regression and Bland-Altman analysis. RESULTS Linear regression showed a high degree of correlation between measured and calculated CrCP (r2 = 0.93). CONCLUSIONS This is the first study to validate a calculated CrCP by comparing it to direct measurements of CrCP from preterm infants when ABP is lower than CrCP.
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Calviello LA, de Riva N, Donnelly J, Czosnyka M, Smielewski P, Menon DK, Zeiler FA. Relationship Between Brain Pulsatility and Cerebral Perfusion Pressure: Replicated Validation Using Different Drivers of CPP Change. Neurocrit Care 2018; 27:392-400. [PMID: 28547321 PMCID: PMC5700211 DOI: 10.1007/s12028-017-0404-9] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Background Determination of relationships between transcranial Doppler (TCD)-based spectral pulsatility index (sPI) and pulse amplitude (AMP) of intracranial pressure (ICP) in 2 groups of severe traumatic brain injury (TBI) patients (a) displaying plateau waves and (b) with unstable mean arterial pressure (MAP). Methods We retrospectively reviewed patients with severe TBI and continuous TCD monitoring displaying either plateau waves or unstable MAP from 1992 to 1998. We utilized linear and nonlinear regression techniques to describe both cohorts: cerebral perfusion pressure (CPP) versus AMP, CPP versus sPI, mean ICP versus ICP AMP, mean ICP versus sPI, and AMP versus sPI. Results Nonlinear regression techniques were employed to analyze the relationships with CPP. In plateau wave and unstable MAP patients, CPP versus sPI displayed an inverse nonlinear relationship (R2 = 0.820 vs. R2 = 0.610, respectively), with the CPP versus sPI relationship best modeled by the following function in both cases: PI = a + (b/CPP). Similarly, in both groups, CPP versus AMP displayed an inverse nonlinear relationship (R2 = 0.610 vs. R2 = 0.360, respectively). Positive linear correlations were displayed in both the plateau wave and unstable MAP cohorts between: ICP versus AMP, ICP versus sPI, AMP versus sPI. Conclusions There is an inverse relationship through nonlinear regression between CPP versus AMP and CPP versus sPI display. This provides evidence to support a previously-proposed model of TCD pulsatility index. ICP shows a positive linear correlation with AMP and sPI, which is also established between AMP and sPI. Electronic supplementary material The online version of this article (doi:10.1007/s12028-017-0404-9) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Leanne A. Calviello
- Division of Neurosurgery, Department of Clinical Neurosciences, Addenbrooke’s Hospital, University of Cambridge, Cambridge, UK
| | - Nicolás de Riva
- Division of Neuroanesthesia, Department of Anesthesiology, Hospital Clinic, Universitat de Barcelona, Barcelona, Spain
| | - Joseph Donnelly
- Division of Neurosurgery, Department of Clinical Neurosciences, Addenbrooke’s Hospital, University of Cambridge, Cambridge, UK
| | - Marek Czosnyka
- Division of Neurosurgery, Department of Clinical Neurosciences, Addenbrooke’s Hospital, University of Cambridge, Cambridge, UK
| | - Peter Smielewski
- Division of Neurosurgery, Department of Clinical Neurosciences, Addenbrooke’s Hospital, University of Cambridge, Cambridge, UK
| | - David K. Menon
- Division of Anesthetics, Addenbrooke’s Hospital, University of Cambridge, Cambridge, UK
- Neurosciences Critical Care Unit, Addenbrooke’s Hospital, Cambridge, UK
- Queens’ College, Cambridge, UK
- National Institute for Health Research, Cambridge, UK
| | - Frederick A. Zeiler
- Division of Anesthetics, Addenbrooke’s Hospital, University of Cambridge, Cambridge, UK
- Section of Neurosurgery, Department of Surgery, Rady Faculty of Health Sciences, University of Manitoba, Winnipeg, Canada
- Clinician Investigator Program, University of Manitoba, Winnipeg, Canada
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Vasopressors Do Not Influence Cerebral Critical Closing Pressure During Systemic Inflammation Evoked by Experimental Endotoxemia and Sepsis in Humans. Shock 2018; 49:529-535. [DOI: 10.1097/shk.0000000000001003] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
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Comparison of Two Algorithms for Analysis of Perfusion Computed Tomography Data for Evaluation of Cerebral Microcirculation in Chronic Subdural Hematoma. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2017. [PMID: 27526170 DOI: 10.1007/978-3-319-38810-6_53] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register]
Abstract
The aim of this work was comparison of two algorithms of perfusion computed tomography (PCT) data analysis for evaluation of cerebral microcirculation in the perifocal zone of chronic subdural hematoma (CSDH). Twenty patients with CSDH after polytrauma were included in the study. The same PCT data were assessed quantitatively in cortical brain region beneath the CSDH (zone 1), and in the corresponding contralateral brain hemisphere (zone 2) without and with the use of perfusion calculation mode excluding vascular pixel 'Remote Vessels' (RV); 1st and 2nd analysis method, respectively. Comparison with normal values for perfusion indices in the zone 1 in the 1st analysis method showed a significant (p < 0.01) increase in CBV and CBF, and no significant increase in MTT and TTP. Use of the RV mode (2nd analysis method) showed no statistically reliable change of perfusion parameters in the microcirculatory blood flow of the 2nd zone. Maintenance of microcirculatory blood flow perfusion reflects the preservation of cerebral blood flow autoregulation in patients with CSDH.
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Cerebral Critical Closing Pressure: Is the Multiparameter Model Better Suited to Estimate Physiology of Cerebral Hemodynamics? Neurocrit Care 2017; 25:446-454. [PMID: 27389005 DOI: 10.1007/s12028-016-0288-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
BACKGROUND Cerebral critical closing pressure (CrCP) is the level of arterial blood pressure (ABP) at which small brain vessels close and blood flow stops. This value is always greater than intracranial pressure (ICP). The difference between CrCP and ICP is explained by the tone of the small cerebral vessels (wall tension). CrCP value is used in several dynamic cerebral autoregulation models. However, the different methods for calculation of CrCP show frequent negative values. These findings are viewed as a methodological limitation. We intended to evaluate CrCP in patients with severe traumatic brain injury (TBI) with a new multiparameter impedance-based model and compare it with results found earlier using a transcranial Doppler (TCD)-ABP pulse waveform-based method. METHODS Twelve severe TBI patients hospitalized during September 2005-May 2007. Ten men, mean age 32 years (16-61). Four had decompressive craniectomies (DC); three presented anisocoria. Patients were monitored with TCD cerebral blood flow velocity (FV), invasive ABP, and ICP. Data were acquired at 50 Hz with an in-house developed data acquisition system. We compared the earlier studied "first harmonic" method (M1) results with results from a new recently developed (M2) "multiparameter method." RESULTS M1: In seven patients CrCP values were negative, reaching -150 mmHg. M2: All positive values; only one lower than ICP (ICP 60 mmHg/ CrCP 57 mmHg). There was a significant difference between M1 and M2 values (M1 < M2) and between ICP and M2 (M2 > ICP). CONCLUSION M2 results in positive values of CrCP, higher than ICP, and are physiologically interpretable.
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The Ontogeny of Cerebrovascular Pressure Autoregulation in Premature Infants. ACTA NEUROCHIRURGICA. SUPPLEMENT 2017; 122:151-5. [PMID: 27165897 DOI: 10.1007/978-3-319-22533-3_31] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Our objective was to quantify cerebrovascular autoregulation as a function of gestational age (GA) and across the phases of the cardiac cycle. One hundred eighty-six premature infants, with a GA range of 23-33 weeks, were monitored using umbilical artery catheters and transcranial Doppler insonation of middle cerebral artery flow velocity (FV) for 1-h sessions over the first week of life. Autoregulation was quantified as a moving correlation coefficient between systolic arterial blood pressure (ABP) and systolic FV (Sx); mean ABP and mean FV (Mx); diastolic ABP and diastolic FV (Dx). Autoregulation was compared across GAs for each aspect of the cardiac cycle. Systolic FV was pressure-passive in infants with the lowest GA, and Sx decreased with increased GA (r = -0.3; p < 0.001). By contrast, Dx was elevated in all subjects, and showed minimal change with increased GA (r = -0.06; p = 0.05). Multivariate analysis confirmed that GA (p < 0.001) and the "closing margin" (p < 0.01) were associated with Sx. Premature infants have low and almost always pressure-passive diastolic cerebral blood FV. Conversely, the regulation of systolic cerebral blood FV by autoregulation was manifested in this cohort at a GA of between 23 and 33 weeks.
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Donnelly J, Czosnyka M, Harland S, Varsos GV, Cardim D, Robba C, Liu X, Ainslie PN, Smielewski P. Cerebral haemodynamics during experimental intracranial hypertension. J Cereb Blood Flow Metab 2017; 37:694-705. [PMID: 26994043 PMCID: PMC5381462 DOI: 10.1177/0271678x16639060] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Intracranial hypertension is a common final pathway in many acute neurological conditions. However, the cerebral haemodynamic response to acute intracranial hypertension is poorly understood. We assessed cerebral haemodynamics (arterial blood pressure, intracranial pressure, laser Doppler flowmetry, basilar artery Doppler flow velocity, and vascular wall tension) in 27 basilar artery-dependent rabbits during experimental (artificial CSF infusion) intracranial hypertension. From baseline (∼9 mmHg; SE 1.5) to moderate intracranial pressure (∼41 mmHg; SE 2.2), mean flow velocity remained unchanged (47 to 45 cm/s; p = 0.38), arterial blood pressure increased (88.8 to 94.2 mmHg; p < 0.01), whereas laser Doppler flowmetry and wall tension decreased (laser Doppler flowmetry 100 to 39.1% p < 0.001; wall tension 19.3 to 9.8 mmHg, p < 0.001). From moderate to high intracranial pressure (∼75 mmHg; SE 3.7), both mean flow velocity and laser Doppler flowmetry decreased (45 to 31.3 cm/s p < 0.001, laser Doppler flowmetry 39.1 to 13.3%, p < 0.001), arterial blood pressure increased still further (94.2 to 114.5 mmHg; p < 0.001), while wall tension was unchanged (9.7 to 9.6 mmHg; p = 0.35).This animal model of acute intracranial hypertension demonstrated two intracranial pressure-dependent cerebroprotective mechanisms: with moderate increases in intracranial pressure, wall tension decreased, and arterial blood pressure increased, while with severe increases in intracranial pressure, an arterial blood pressure increase predominated. Clinical monitoring of such phenomena could help individualise the management of neurocritical patients.
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Affiliation(s)
- Joseph Donnelly
- 1 Brain Physics Laboratory, Division of Neurosurgery, Department of Clinical Neurosciences, Cambridge Biomedical Campus, University of Cambridge, Cambridge, UK
| | - Marek Czosnyka
- 1 Brain Physics Laboratory, Division of Neurosurgery, Department of Clinical Neurosciences, Cambridge Biomedical Campus, University of Cambridge, Cambridge, UK.,2 Institute of Electronic Systems, Warsaw University of Technology, Warsaw, Poland
| | | | - Georgios V Varsos
- 1 Brain Physics Laboratory, Division of Neurosurgery, Department of Clinical Neurosciences, Cambridge Biomedical Campus, University of Cambridge, Cambridge, UK
| | - Danilo Cardim
- 1 Brain Physics Laboratory, Division of Neurosurgery, Department of Clinical Neurosciences, Cambridge Biomedical Campus, University of Cambridge, Cambridge, UK
| | - Chiara Robba
- 1 Brain Physics Laboratory, Division of Neurosurgery, Department of Clinical Neurosciences, Cambridge Biomedical Campus, University of Cambridge, Cambridge, UK
| | - Xiuyun Liu
- 1 Brain Physics Laboratory, Division of Neurosurgery, Department of Clinical Neurosciences, Cambridge Biomedical Campus, University of Cambridge, Cambridge, UK
| | - Philip N Ainslie
- 4 Centre for Heart, Lung and Vascular Health, School of Health and Exercise Sciences, University of British Columbia, Okanagan, Kelowna, British Columbia, Canada
| | - Peter Smielewski
- 1 Brain Physics Laboratory, Division of Neurosurgery, Department of Clinical Neurosciences, Cambridge Biomedical Campus, University of Cambridge, Cambridge, UK
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van den Brule JMD, Vinke E, van Loon LM, van der Hoeven JG, Hoedemaekers CWE. Middle cerebral artery flow, the critical closing pressure, and the optimal mean arterial pressure in comatose cardiac arrest survivors-An observational study. Resuscitation 2016; 110:85-89. [PMID: 27840005 DOI: 10.1016/j.resuscitation.2016.10.022] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2016] [Revised: 10/17/2016] [Accepted: 10/21/2016] [Indexed: 10/20/2022]
Abstract
AIM This study estimated the critical closing pressure (CrCP) of the cerebrovascular circulation during the post-cardiac arrest syndrome and determined if CrCP differs between survivors and non-survivors. We also compared patients after cardiac arrest to normal controls. METHODS A prospective observational study was performed at the ICU of a tertiary university hospital in Nijmegen, the Netherlands. We studied 11 comatose patients successfully resuscitated from a cardiac arrest and treated with mild therapeutic hypothermia and 10 normal control subjects. Mean flow velocity (MFV) in the middle cerebral artery was measured by transcranial Doppler at several time points after admission to the ICU. CrCP was determined by a cerebrovascular impedance model. RESULTS MFV was similar in survivors and non-survivors upon admission to the ICU, but increased stronger in non-survivors compared to survivors throughout the observation period (P<0.001). MFV was significantly lower in survivors immediately after cardiac arrest compared to normal controls (P<0.001), with a gradual restoration toward normal values. CrCP decreased significantly from 61.4[51.0-77.1]mmHg to 41.7[39.9-51.0]mmHg in the first 48h, after which it remained stable (P<0.001). CrCP was significantly higher in survivors compared to non-survivors (P=0.002). CrCP immediately after cardiac arrest was significantly higher compared to the control group (P=0.02). CONCLUSIONS CrCP is high after cardiac arrest with high cerebrovascular resistance and low MFV. This suggests that cerebral perfusion pressure should be maintained at a sufficient high level to avoid secondary brain injury. Failure to normalize the cerebrovascular profile may be a parameter of poor outcome.
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Affiliation(s)
- Judith M D van den Brule
- Department of Intensive Care Medicine, Radboud University Medical Center, Nijmegen, The Netherlands.
| | - Eline Vinke
- Department of Intensive Care Medicine, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Lex M van Loon
- Department of Intensive Care Medicine, Radboud University Medical Center, Nijmegen, The Netherlands
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Cerebral oxidative metabolism failure in traumatic brain injury: "Brain shock". J Crit Care 2016; 37:230-233. [PMID: 27773372 DOI: 10.1016/j.jcrc.2016.09.027] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2016] [Revised: 09/26/2016] [Accepted: 09/29/2016] [Indexed: 12/19/2022]
Abstract
Shock is a systemic form of acute circulatory failure leading to cellular dysoxia and death. Such a state of aerobic metabolism failure also underlies neuronal cell death in severe traumatic brain injury. It is becoming increasingly recognized that ischemic hypoxia is not the sole mechanism and that multiple alternate cooperating mechanisms may be responsible for compromising neuronal oxidative metabolism. These different mechanisms can be usefully understood via analysis of the classic subdivisions of tissue hypoxia. This approach could lead to an alternative treatment paradigm toward cerebral oxygen metabolic rate targeting instead of the traditional targets of intracranial and perfusion pressures.
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Lang EW, Kasprowicz M, Smielewski P, Pickard J, Czosnyka M. Changes in Cerebral Partial Oxygen Pressure and Cerebrovascular Reactivity During Intracranial Pressure Plateau Waves. Neurocrit Care 2016; 23:85-91. [PMID: 25501688 DOI: 10.1007/s12028-014-0074-9] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
BACKGROUND Plateau waves in intracranial pressure (ICP) are frequently recorded in neuro intensive care and are not yet fully understood. To further investigate this phenomenon, we analyzed partial pressure of cerebral oxygen (pbtO2) and a moving correlation coefficient between ICP and mean arterial blood pressure (ABP), called PRx, along with the cerebral oxygen reactivity index (ORx), which is a moving correlation coefficient between cerebral perfusion pressure (CPP) and pbtO2 in an observational study. METHODS We analyzed 55 plateau waves in 20 patients after severe traumatic brain injury. We calculated ABP, ABP pulse amplitude (ampABP), ICP, CPP, pbtO2, heart rate (HR), ICP pulse amplitude (ampICP), PRx, and ORx, before, during, and after each plateau wave. The analysis of variance with Bonferroni post hoc test was used to compare the differences in the variables before, during, and after the plateau wave. We considered all plateau waves, even in the same patient, independent because they are separated by long intervals. RESULTS We found increases for ICP and ampICP according to our operational definitions for plateau waves. PRx increased significantly (p = 0.00026), CPP (p < 0.00001) and pbtO2 (p = 0.00007) decreased significantly during the plateau waves. ABP, ampABP, and HR remained unchanged. PRx during the plateau was higher than before the onset of wave in 40 cases (73 %) with no differences in baseline parameters for those with negative and positive ΔPRx (difference during and after). ORx showed an increase during and a decrease after the plateau waves, however, not statistically significant. PbtO2 overshoot after the wave occurred in 35 times (64 %), the mean difference was 4.9 ± 4.6 Hg (mean ± SD), and we found no difference in baseline parameters between those who overshoot and those who did not overshoot. CONCLUSIONS Arterial blood pressure remains stable in ICP plateau waves, while cerebral autoregulatory indices show distinct changes, which indicate cerebrovascular reactivity impairment at the top of the wave. PbtO2 decreases during the waves and may show a slight overshoot after normalization. We assume that this might be due to different latencies of the cerebral blood flow and oxygen level control mechanisms. Other factors may include baseline conditions, such as pre-plateau wave cerebrovascular reactivity or pbtO2 levels, which differ between studies.
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Affiliation(s)
- Erhard W Lang
- Neurosurgical Associates, Red Cross Hospital, Bergmannstrasse 30, 34121, Kassel, Germany,
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Luís A, Santos AS, Dias C, Almeida R, Rocha AP. Heart rate variability during plateau waves of intracranial pressure: A pilot descriptive study. ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL INTERNATIONAL CONFERENCE 2016; 2015:6142-5. [PMID: 26737694 DOI: 10.1109/embc.2015.7319794] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
This study aims to describe heart rate variability during the first episode of plateau waves of intracranial pressure (ICP) in Traumatic Brain Injury (TBI) in order to characterize and identify at bedside this cerebrovascular phenomenon. The general behavior of the heart rate variability (HRV) spectral measures expressed in the medians across patients is concordant with an increased HRV in the latter part of the baseline and plateau wave, followed by a decrease after the event and a new increase during the recovery. In low and high frequency bands the same increase is more marked in the parametric analysis. Interpretation of HRV may help clinicians to better identify the plateau waves and allow earlier management.
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Varsos GV, Czosnyka M, Smielewski P, Garnett MR, Liu X, Adams H, Pickard JD, Czosnyka Z. Cerebral Critical Closing Pressure During Infusion Tests. ACTA NEUROCHIRURGICA. SUPPLEMENT 2016; 122:215-220. [PMID: 27165909 DOI: 10.1007/978-3-319-22533-3_43] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
We studied possible correlations between cerebral hemodynamic indices based on critical closing pressure (CrCP) and cerebrospinal fluid (CSF) compensatory dynamics, as assessed during lumbar infusion tests. Our data consisted of 34 patients with normal-pressure hydrocephalus who undertook an infusion test, in conjunction with simultaneous transcranial Doppler ultrasonography (TCD) monitoring of blood flow velocity (FV). CrCP was calculated from the monitored signals of ICP, arterial blood pressure (ABP), and FV, whereas vascular wall tension (WT) was estimated as CrCP - ICP. The closing margin (CM) expresses the difference between ABP and CrCP. ICP increased during infusion from 6.67 ± 4.61 to 24.98 ± 10.49 mmHg (mean ± SD; p < 0.001), resulting in CrCP rising by 22.93 % (p < 0.001), with WT decreasing by 11.33 % (p = 0.005) owing to vasodilatation. CM showed a tendency to decrease, albeit not significantly (p = 0.070), because of rising ABP (9.12 %; p = 0.005), and was significantly different from zero for the whole duration of the tests (52.78 ± 22.82 mmHg; p < 0.001). CM at baseline correlated inversely with brain elasticity (R = -0.358; p = 0.038). Neither CrCP nor WT correlated with CSF compensatory parameters. Overall, CrCP increases and WT decreases during infusion tests, whereas CM at baseline pressure may act as a characterizing indicator of the cerebrospinal compensatory reserve.
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Affiliation(s)
- Georgios V Varsos
- Division of Neurosurgery, Department of Clinical Neurosciences, Addenbrooke's Hospital, University of Cambridge, Cambridge, UK.
| | - Marek Czosnyka
- Division of Neurosurgery, Department of Clinical Neurosciences, Addenbrooke's Hospital, University of Cambridge, Cambridge, UK
| | - Peter Smielewski
- Division of Neurosurgery, Department of Clinical Neurosciences, University of Cambridge, Cambridge, UK
| | - Matthew R Garnett
- Division of Neurosurgery, Department of Clinical Neurosciences, Addenbrooke's Hospital, University of Cambridge, Cambridge, UK
| | - Xiuyun Liu
- Division of Neurosurgery, Department of Clinical Neurosciences, Addenbrooke's Hospital, University of Cambridge, Cambridge, UK
| | - Hadie Adams
- Division of Neurosurgery, Department of Clinical Neurosciences, Addenbrooke's Hospital, University of Cambridge, Cambridge, UK
- Department of Neurosurgery, St Radboud University Medical Center, Nijmegen, The Netherlands
| | - John D Pickard
- Division of Neurosurgery, Department of Clinical Neurosciences, Addenbrooke's Hospital, University of Cambridge, Cambridge, UK
| | - Zofia Czosnyka
- Division of Neurosurgery, Department of Clinical Neurosciences, Addenbrooke's Hospital, University of Cambridge, Cambridge, UK
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Varsos GV, Budohoski KP, Kolias AG, Liu X, Smielewski P, Varsos VG, Hutchinson PJ, Pickard JD, Czosnyka M. Relationship of vascular wall tension and autoregulation following traumatic brain injury. Neurocrit Care 2015; 21:266-74. [PMID: 24682849 DOI: 10.1007/s12028-014-9971-1] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
BACKGROUND The vascular wall tension (WT) of small cerebral vessels can be quantitatively estimated through the concept of critical closing pressure (CrCP), which denotes the lower limit of arterial blood pressure (ABP), below which small cerebral arterial vessels collapse and blood flow ceases. WT can be expressed as the difference between CrCP and intracranial pressure (ICP) and represent active vasomotor tone. In this study, we investigated the association of WT and CrCP with autoregulation and outcome of a large group of patients after traumatic brain injury (TBI). METHODS We retrospectively analysed recordings of ABP, ICP and transcranial Doppler (TCD) blood flow velocity from 280 TBI patients (median age: 29 years; interquartile range: 20-43). CrCP and WT were calculated using the cerebrovascular impedance methodology. Autoregulation was assessed based on TCD-based indices, Mx and ARI. RESULTS Low values of WT were found to be associated with an impaired autoregulatory capacity, signified by its correlation to FV-based indices Mx (R = -0.138; p = 0.021) and ARI (R = 0.118; p = 0.048). No relationship could be established between CrCP and any of the autoregulatory indices. Neither CrCP nor WT was found to correlate with outcome. CONCLUSIONS Impaired autoregulation was found to be associated with a lower WT supporting the role of vasoparalysis in the loss of autoregulatory capacity. In contrast, no links between CrCP and autoregulation could be identified.
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Affiliation(s)
- Georgios V Varsos
- Division of Neurosurgery, Department of Clinical Neurosciences, Addenbrooke's Hospital, University of Cambridge, Hills Road, Cambridge, CB2 0QQ, UK,
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Varsos GV, Czosnyka M, Smielewski P, Garnett MR, Liu X, Kim DJ, Donnelly J, Adams H, Pickard JD, Czosnyka Z. Cerebral critical closing pressure in hydrocephalus patients undertaking infusion tests. Neurol Res 2015; 37:674-82. [DOI: 10.1179/1743132815y.0000000044] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
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Rhee CJ, Fraser CD, Kibler K, Easley RB, Andropoulos DB, Czosnyka M, Varsos GV, Smielewski P, Rusin CG, Brady KM, Kaiser JR. The ontogeny of cerebrovascular pressure autoregulation in premature infants. J Perinatol 2014; 34:926-31. [PMID: 25010225 PMCID: PMC4383263 DOI: 10.1038/jp.2014.122] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/04/2013] [Revised: 04/01/2014] [Accepted: 05/16/2014] [Indexed: 11/10/2022]
Abstract
OBJECTIVE To quantify cerebrovascular autoregulation as a function of gestational age (GA) and across the phases of the cardiac cycle. STUDY DESIGN The present study is a hypothesis-generating re-analysis of previously published data. Premature infants (n=179) with a GA range of 23 to 33 weeks were monitored with umbilical artery catheters and transcranial Doppler insonation of the middle cerebral artery for 1-h sessions over the first week of life. Autoregulation was quantified by three methods, as a moving correlation coefficient between: (1) systolic arterial blood pressure (ABP) and systolic cerebral blood flow (CBF) velocity (Sx); (2) mean ABP and mean CBF velocity (Mx); and (3) diastolic ABP and diastolic CBF velocity (Dx). Comparisons of individual and cohort cerebrovascular pressure autoregulation were made across GA for each aspect of the cardiac cycle. RESULTS Systolic, mean and diastolic ABP increased with GA (r=0.3, 0.4 and 0.4; P<0.0001). Systolic CBF velocity was pressure-passive in infants with the lowest GA, and Sx decreased with advancing GA (r=-0.3; P<0.001), indicating increased capacity for cerebral autoregulation during systole during development. By contrast, Dx was elevated, indicating dysautoregulation, in all subjects and showed minimal change with advancing GA (r=-0.06; P=0.05). Multivariate analysis confirmed that both GA (P<0.001) and 'effective cerebral perfusion pressure' (ABP minus critical closing pressure (CrCP); P<0.01) were associated with Sx. CONCLUSION Premature infants have low and usually pressure-passive diastolic CBF velocity. By contrast, the regulation of systolic CBF velocity by pressure autoregulation developed in this cohort between 23 and 33 weeks GA. Elevated effective cerebral perfusion pressure derived from the CrCP was associated with dysautoregulation.
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Affiliation(s)
- Christopher J. Rhee
- Department of Pediatrics, Section of Neonatology, Texas Children’s Hospital, Baylor College of Medicine, Houston, TX, USA
| | | | - Kathleen Kibler
- Departments of Pediatrics and Anesthesiology, Texas Children’s Hospital, Baylor College of Medicine, Houston, TX, USA
| | - Ronald B. Easley
- Departments of Pediatrics and Anesthesiology, Texas Children’s Hospital, Baylor College of Medicine, Houston, TX, USA
| | - Dean B. Andropoulos
- Departments of Pediatrics and Anesthesiology, Texas Children’s Hospital, Baylor College of Medicine, Houston, TX, USA
| | - Marek Czosnyka
- Division of Neurosurgery, Addenbrooke’s Hospital, Cambridge University, Cambridge, England
| | - Georgios V. Varsos
- Division of Neurosurgery, Addenbrooke’s Hospital, Cambridge University, Cambridge, England
| | - Peter Smielewski
- Division of Neurosurgery, Addenbrooke’s Hospital, Cambridge University, Cambridge, England
| | - Craig G. Rusin
- Department of Cardiology, Texas Children’s Hospital, Baylor College of Medicine, Houston, TX, USA
| | - Ken M. Brady
- Departments of Pediatrics and Anesthesiology, Texas Children’s Hospital, Baylor College of Medicine, Houston, TX, USA
| | - Jeffrey R. Kaiser
- Departments of Pediatrics and Obstetrics and Gynecology, Section of Neonatology, Texas Children’s Hospital, Baylor College of Medicine, Houston, TX, USA
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Dias C, Silva MJ, Pereira E, Silva S, Cerejo A, Smielewski P, Rocha AP, Gaio AR, Paiva JA, Czosnyka M. Post-traumatic multimodal brain monitoring: response to hypertonic saline. J Neurotrauma 2014; 31:1872-80. [PMID: 24915462 DOI: 10.1089/neu.2014.3376] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Emerging evidence suggests that hypertonic saline (HTS) is efficient in decreasing intracranial pressure (ICP). However there is no consensus about its interaction with brain hemodynamics and oxygenation. In this study, we investigated brain response to HTS bolus with multimodal monitoring after severe traumatic brain injury (TBI). We included 18 consecutive TBI patients during 10 days after neurocritical care unit admission. Continuous brain monitoring applied included ICP, tissue oxygenation (PtO2) and cerebral blood flow (CBF). Cerebral perfusion pressure (CPP), cerebrovascular resistance (CVR), and reactivity indices related to pressure (PRx) and flow (CBFx) were calculated. ICM+software was used to collect and analyze monitoring data. Eleven of 18 (61%) patients developed 99 episodes of intracranial hypertension (IHT) greater than 20 mm Hg that were managed with 20% HTS bolus. Analysis over time was performed with linear mixed-effects regression modelling. After HTS bolus, ICP and CPP improved over time (p<0.001) following a quadratic model. From baseline to 120 min, ICP had a mean decrease of 6.2 mm Hg and CPP a mean increase of 3.1 mmHg. Mean increase in CBF was 7.8 mL/min/100 g (p<0.001) and mean decrease in CVR reached 0.4 mm Hg*min*100 g/mL (p=0.01). Both changes preceded pressures improvement. PtO2 exhibited a marginal increase and no significant models for time behaviour could be fitted. PRx and CBFx were best described by a linear decreasing model showing autoregulation recover after HTS (p=0.01 and p=0.04 respectively). During evaluation, CO2 remained constant and sodium level did not exhibit significant variation. In conclusion, management of IHT with 20% HTS significantly improves cerebral hemodynamics and cerebrovascular reactivity with recovery of CBF appearing before rise in CPP and decrease in ICP. In spite of cerebral hemodynamic improvement, no significant changes in brain oxygenation were identified.
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Affiliation(s)
- Celeste Dias
- 1 Department of Intensive Care, University Hospital Sao Joao , Porto, Portugal
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Lazaridis C. Plateau waves of intracranial pressure and mechanisms of brain hypoxia. J Crit Care 2013; 29:303-4. [PMID: 24411105 DOI: 10.1016/j.jcrc.2013.12.002] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2013] [Accepted: 12/03/2013] [Indexed: 11/28/2022]
Affiliation(s)
- Christos Lazaridis
- Department of Neurology, Divisions of Neurocritical Care and Vascular Neurology, Baylor College of Medicine, Houston, TX.
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