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Teo EJ, Petautschnig S, Hellerstedt J, Grace SA, Savage JS, Fafiani B, Smith PD, Jhamb A, Haydon T, Dixon B. Cerebrovascular Responses in a Patient with Lundberg B Waves Following Subarachnoid Haemorrhage Assessed with a Novel Non-Invasive Brain Pulse Monitor: A Case Report. MEDICAL DEVICES-EVIDENCE AND RESEARCH 2024; 17:73-87. [PMID: 38404631 PMCID: PMC10886819 DOI: 10.2147/mder.s452938] [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: 12/19/2023] [Accepted: 02/09/2024] [Indexed: 02/27/2024] Open
Abstract
Subarachnoid haemorrhage (SAH) can trigger a range of poorly understood cerebrovascular responses that may play a role in delayed cerebral ischemia. The brain pulse monitor is a novel non-invasive device that detects a brain photoplethysmography signal that provides information on intracranial pressure (ICP), compliance, blood flow and tissue oxygen saturation. We monitored the cerebrovascular responses in a patient with Lundberg B waves following a SAH. The patient presented with a Fischer grade 4 SAH that required urgent left posterior communicating artery aneurysm coiling and ventricular drain insertion. On hospital day 4 oscillations or spikes on the invasive ICP were noted, consistent with Lundberg B waves. Brain pulse monitoring demonstrated concurrent pulse waveform features consistent with reduced brain compliance and raised ICP over both brain hemispheres. Oxygen levels also demonstrated slow oscillations correlated with the ICP spikes. Brief infrequent episodes of reduced and absent brain pulses were also noted over the right hemisphere. Our findings suggest that the brain pulse monitor holds promise for early detection of delayed cerebral ischemia and could offer insights into the vascular mechanisms at play.
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Affiliation(s)
- Elliot John Teo
- Cyban Pty Ltd, Melbourne, Victoria, Australia
- Department of Critical Care Medicine, St Vincent’s Hospital, Melbourne, Victoria, Australia
| | - Sigrid Petautschnig
- Cyban Pty Ltd, Melbourne, Victoria, Australia
- Department of Critical Care Medicine, St Vincent’s Hospital, Melbourne, Victoria, Australia
| | | | | | | | | | - Paul Daniel Smith
- Department of Neurosurgery, St Vincent’s Hospital, Melbourne, Victoria, Australia
- University of Melbourne Medical School, Melbourne, VIC, Australia
| | - Ashu Jhamb
- Department of Medical Imaging, St Vincent’s Hospital, Melbourne, Victoria, Australia
| | - Timothy Haydon
- Department of Critical Care Medicine, St Vincent’s Hospital, Melbourne, Victoria, Australia
- Department of Critical Care, the University of Melbourne, Melbourne, VIC, Australia
| | - Barry Dixon
- Cyban Pty Ltd, Melbourne, Victoria, Australia
- Department of Medical Imaging, St Vincent’s Hospital, Melbourne, Victoria, Australia
- Department of Critical Care, the University of Melbourne, Melbourne, VIC, Australia
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Zhu J, Shan Y, Li Y, Liu J, Wu X, Gao G. Spindle wave in intracranial pressure signal analysis for patients with traumatic brain injury: A single-center prospective observational cohort study. Front Physiol 2023; 13:1043328. [PMID: 36699681 PMCID: PMC9868554 DOI: 10.3389/fphys.2022.1043328] [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: 09/13/2022] [Accepted: 12/28/2022] [Indexed: 01/11/2023] Open
Abstract
Objective: Intracranial pressure (ICP) monitoring is an integral part of the multimodality monitoring system in the neural intensive care unit. The present study aimed to describe the morphology of the spindle wave (a shuttle shape with wide middle and narrow ends) during ICP signal monitoring in TBI patients and to investigate its clinical significance. Methods: Sixty patients who received ICP sensor placement and admitted to the neurosurgical intensive care unit between January 2021 and September 2021 were prospectively enrolled. The patient's Glasgow Coma Scale (GCS) score on admission and at discharge and length of stay in hospital were recorded. ICP monitoring data were monitored continuously. The primary endpoint was 6-month Glasgow Outcome Scale-Extended (GOSE) score. Patients with ICP spindle waves were assigned to the spindle wave group and those without were assigned to the control group. The correlation between the spindle wave and 6-month GOSE was analyzed. Meanwhile, the mean ICP and two ICP waveform-derived indices, ICP pulse amplitude (AMP) and correlation coefficient between AMP and ICP (RAP) were comparatively analyzed. Results: There were no statistically significant differences between groups in terms of age (p = 0.89), gender composition (p = 0.62), and GCS score on admission (p = 0.73). Patients with spindle waves tended to have a higher GCS score at discharge (12.75 vs. 10.90, p = 0.01), a higher increment in GCS score during hospitalization (ΔGCS, the difference between discharge GCS score and admission GCS score) (4.95 vs. 2.80, p = 0.01), and a better 6-month GOSE score (4.90 vs. 3.68, p = 0.04) compared with the control group. And the total duration of the spindle wave was positively correlated with 6-month GOSE (r = 0.62, p = 0.004). Furthermore, the parameters evaluated during spindle waves, including mean ICP, AMP, and RAP, demonstrated significant decreases compared with the parameters before the occurrence of the spindle wave (all p < 0.025). Conclusion: The ICP spindle wave was associated with a better prognosis in TBI patients. Physiological parameters such as ICP, AMP, and RAP were significantly improved when spindle waves occurred, which may explain the enhancement of clinical outcomes. Further studies are needed to investigate the pathophysiological mechanisms behind this wave.
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Affiliation(s)
- Jun Zhu
- Department of Neurosurgery, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Yingchi Shan
- Department of Neurosurgery, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Yihua Li
- Department of Neurosurgery, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Jiaqi Liu
- Department of Neurosurgery, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Xiang Wu
- Department of Neurosurgery, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China,*Correspondence: Xiang Wu, ; Guoyi Gao,
| | - Guoyi Gao
- Department of Neurosurgery, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China,Shanghai Head Trauma Institute, Shanghai, China,*Correspondence: Xiang Wu, ; Guoyi Gao,
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Black RD, Chaparro E. Time-varying caloric vestibular stimulation for the treatment of neurodegenerative disease. Front Aging Neurosci 2022; 14:1049637. [DOI: 10.3389/fnagi.2022.1049637] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2022] [Accepted: 10/26/2022] [Indexed: 11/11/2022] Open
Abstract
Time-varying caloric vestibular stimulation (tvCVS) is a new form of non-invasive neuromodulation similar to, but different from, diagnostic caloric vestibular stimulation (CVS). Using a non-invasive, solid-state delivery device, tvCVS has been successfully used in a human clinical trial with Parkinson’s disease (PD) subjects. Additionally, the effects of tvCVS on brain activation have been studied in healthy human subjects using transcranial Doppler sonography (TCD) and functional magnetic resonance imaging (BOLD fMRI). A novel finding in the TCD and fMRI studies was the induction of cerebral blood flow velocity (CBFv) oscillations. How such oscillations might lead to the observed clinical effects seen in PD subjects will be discussed. Enabling studies of tvCVS with rodents is an attractive goal in support of explorations of the mechanism of action. Male Wistar rats were used in a proof-of-concept study described herein. Rats were anesthetized (isoflurane) and ventilated for the duration of the tvCVS runs. Time-varying thermal stimuli were administered using a digital temperature controller to modulate Peltier-type heater/cooler devices. Blunt ear bars conveyed the thermal stimulus to the external ear canals of the rats. Different thermal waveform combinations were evaluated for evidence of successful induction of the CVS effect. It was found that bilateral triangular thermal waveforms could induce oscillations in CBFv both during and after the application of tvCVS. These oscillations were similar to, but different from those observed in awake human subjects. The establishment of a viable animal model for the study of tvCVS will augment ongoing clinical investigations of this new form of neuromodulation in patients with neurodegenerative disease.
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Black RD, Bell RP, Riska KM, Spankovich C, Peters RW, Lascola CD, Whitlow CT. The Acute Effects of Time-Varying Caloric Vestibular Stimulation as Assessed With fMRI. Front Syst Neurosci 2021; 15:648928. [PMID: 34434093 PMCID: PMC8381736 DOI: 10.3389/fnsys.2021.648928] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2021] [Accepted: 07/14/2021] [Indexed: 11/13/2022] Open
Abstract
We describe preliminary results from the application of time-varying caloric vestibular stimulation (tvCVS) to volunteers during a continuous blood oxygen level dependent (BOLD) functional MRI (fMRI) acquisition, recording baseline, during-tvCVS and post-tvCVS epochs. The modifications necessary to enable the use of this novel device in a 3-Tesla magnetic field are discussed. Independent component analysis (ICA) was used as a model-free method to highlight spatially and temporally coherent brain networks. The ICA results are consistent with tvCVS induction being mediated principally by thermoconvection in the vestibular labyrinth and not by direct thermal effects. The activation of hub networks identified by ICA is consistent with the concept of sensory neuromodulation, which posits that a modulatory signal introduced to a sensory organ is able to traverse the regions innervated (directly and indirectly) by that organ, while being transformed so as to be “matched” to regional neuronal dynamics. The data suggest that regional neurovascular coupling and a systemic cerebral blood flow component account for the BOLD contrast observed. The ability to modulate cerebral hemodynamics is of significant interest. The implications of these initial findings for the use of tvCVS therapeutically are discussed.
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Affiliation(s)
| | - Ryan P Bell
- Department of Psychiatry & Behavioral Sciences, Duke University School of Medicine, Durham, NC, United States
| | - Kristal M Riska
- Department of Head and Neck Surgery & Communication Sciences, Duke University School of Medicine, Durham, NC, United States
| | - Christopher Spankovich
- Department of Otolaryngology & Head and Neck Surgery, University of Mississippi Medical Center, Jackson, MS, United States
| | | | - Christopher D Lascola
- Department of Radiology and Neurobiology, Duke University School of Medicine, Durham, NC, United States
| | - Christopher T Whitlow
- Department of Radiology, Wake Forest School of Medicine, Winston-Salem, NC, United States
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Fedriga M, Czigler A, Nasr N, Zeiler FA, Park S, Donnelly J, Papaioannou V, Frisvold SK, Wolf S, Rasulo F, Sykora M, Smielewski P, Czosnyka M. Autonomic Nervous System Activity during Refractory Rise in Intracranial Pressure. J Neurotrauma 2021; 38:1662-1669. [PMID: 33280491 PMCID: PMC8336253 DOI: 10.1089/neu.2020.7091] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Refractory intracranial hypertension (RIH) is a dramatic increase in intracranial pressure (ICP) that cannot be controlled by treatment. Recent reports suggest that the autonomic nervous system (ANS) activity may be altered during changes in ICP. Our study aimed to assess ANS activity during RIH and the causal relationship between rising in ICP and autonomic activity. We reviewed retrospectively 24 multicenter (Cambridge, Tromso, Berlin) patients in whom RIH developed as a pre-terminal event after acute brain injury (ABI). They were monitored with ICP, arterial blood pressure (ABP), and electrocardiography (ECG) using ICM+ software. Parameters reflecting autonomic activity were computed in time and frequency domain through the measurement of heart rate variability (HRV) and baroreflex sensitivity (BRS). Our results demonstrated that a rise in ICP was associated to a significant rise in HRV and BRS with a higher significance level in the high-frequency HRV (p < 0.001). This increase was followed by a significant decrease in HRV and BRS above the upper-breakpoint of ICP where ICP pulse-amplitude starts to decrease whereas the mean ICP continues to rise. Temporality measured with a Granger test suggests a causal relationship from ICP to ANS. The above results suggest that a rise in ICP interacts with ANS activity, mainly interfacing with the parasympathetic-system. The ANS seems to react to the rise in ICP with a response possibly focused on maintaining the cerebrovascular homeostasis. This happens until the critical threshold of ICP is reached above which the ANS variables collapse, probably because of low perfusion of the brain and the central autonomic network.
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Affiliation(s)
- Marta Fedriga
- Brain Division of Neurosurgery, Department of Clinical Neurosciences, Physics Laboratory, University of Cambridge, Cambridge, United Kingdom
- Department of Anaesthesia, Critical Care and Emergency, Spedali Civili University Hospital, Brescia, Italy
| | - Andras Czigler
- Brain Division of Neurosurgery, Department of Clinical Neurosciences, Physics Laboratory, University of Cambridge, Cambridge, United Kingdom
- Department of Neurosurgery and Szentagothai Research Center, University of Pecs, Pecs, Hungary
| | - Nathalie Nasr
- Unitè de Neurologie Vasculaire, CHU de Toulouse, Universitè de Toulouse, Toulouse, France
| | - Frederick. A. Zeiler
- Department of Surgery, Faculty of Engineering, University of Manitoba, University of Manitoba, Winnipeg, Manitoba, Canada
- Department of Human Anatomy and Cell Science, Rady Faculty of Health Sciences, Faculty of Engineering, University of Manitoba, University of Manitoba, Winnipeg, Manitoba, Canada
- Biomedical Engineering, Faculty of Engineering, University of Manitoba, University of Manitoba, Winnipeg, Manitoba, Canada
- Division of Anaesthesia, Department of Medicine, University of Cambridge, Cambridge, United Kingdom
| | - Soojin Park
- Department of Neurology, Division of Hospitalist and Critical Care Neurology, Columbia University, New York, New York, USA
| | - Joseph Donnelly
- Department of Anaesthesiology, University of Auckland, Aukland, New Zealand
| | - Vasilios Papaioannou
- University Hospital of Alexandroupolis, Intensive Care Unit, Democritus University of Thrace, Alexandroupolis, Greece
| | - Shirin K Frisvold
- Department of Intensive Care, University Hospital of North Norway, UiT The Arctic University of Norway, Tromso, Norway
| | - Stephan Wolf
- Department of Neurosurgery, Charite Hospital, Berlin, Germany
| | - Frank Rasulo
- Department of Anaesthesia, Critical Care and Emergency, Spedali Civili University Hospital, Brescia, Italy
| | - Marek Sykora
- Department of Neurology, St. John's Hospital Vienna, Medical Faculty, Sigmund Freud University, Vienna, Austria
| | - Peter Smielewski
- Brain Division of Neurosurgery, Department of Clinical Neurosciences, Physics Laboratory, University of Cambridge, Cambridge, United Kingdom
| | - Marek Czosnyka
- Brain Division of Neurosurgery, Department of Clinical Neurosciences, Physics Laboratory, University of Cambridge, Cambridge, United Kingdom
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Lalou AD, Czosnyka M, Placek MM, Smielewski P, Nabbanja E, Czosnyka Z. CSF Dynamics for Shunt Prognostication and Revision in Normal Pressure Hydrocephalus. J Clin Med 2021; 10:jcm10081711. [PMID: 33921142 PMCID: PMC8071572 DOI: 10.3390/jcm10081711] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2020] [Revised: 04/09/2021] [Accepted: 04/12/2021] [Indexed: 11/16/2022] Open
Abstract
BACKGROUND Despite the quantitative information derived from testing of the CSF circulation, there is still no consensus on what the best approach could be in defining criteria for shunting and predicting response to CSF diversion in normal pressure hydrocephalus (NPH). OBJECTIVE We aimed to review the lessons learned from assessment of CSF dynamics in our center and summarize our findings to date. We have focused on reporting the objective perspective of CSF dynamics testing, without further inferences to individual patient management. DISCUSSION No single parameter from the CSF infusion study has so far been able to serve as an unquestionable outcome predictor. Resistance to CSF outflow (Rout) is an important biological marker of CSF circulation. It should not, however, be used as a single predictor for improvement after shunting. Testing of CSF dynamics provides information on hydrodynamic properties of the cerebrospinal compartment: the system which is being modified by a shunt. Our experience of nearly 30 years of studying CSF dynamics in patients requiring shunting and/or shunt revision, combined with all the recent progress made in producing evidence on the clinical utility of CSF dynamics, has led to reconsidering the relationship between CSF circulation testing and clinical improvement. CONCLUSIONS Despite many open questions and limitations, testing of CSF dynamics provides unique perspectives for the clinician. We have found value in understanding shunt function and potentially shunt response through shunt testing in vivo. In the absence of infusion tests, further methods that provide a clear description of the pre and post-shunting CSF circulation, and potentially cerebral blood flow, should be developed and adapted to the bed-space.
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Affiliation(s)
- Afroditi Despina Lalou
- Brain Physics Laboratory, Division of Neurosurgery, Department of Clinical Neurosciences, University of Cambridge, Cambridge CB2 0QQ, UK; (M.C.); (M.M.P.); (P.S.); (E.N.); (Z.C.)
- Correspondence: ; Tel.: +44-774-3567-585
| | - Marek Czosnyka
- Brain Physics Laboratory, Division of Neurosurgery, Department of Clinical Neurosciences, University of Cambridge, Cambridge CB2 0QQ, UK; (M.C.); (M.M.P.); (P.S.); (E.N.); (Z.C.)
- Institute of Electronic Systems, Faculty of Electronics and Information Sciences, Warsaw University of Technology, 00-661 Warsaw, Poland
| | - Michal M. Placek
- Brain Physics Laboratory, Division of Neurosurgery, Department of Clinical Neurosciences, University of Cambridge, Cambridge CB2 0QQ, UK; (M.C.); (M.M.P.); (P.S.); (E.N.); (Z.C.)
| | - Peter Smielewski
- Brain Physics Laboratory, Division of Neurosurgery, Department of Clinical Neurosciences, University of Cambridge, Cambridge CB2 0QQ, UK; (M.C.); (M.M.P.); (P.S.); (E.N.); (Z.C.)
| | - Eva Nabbanja
- Brain Physics Laboratory, Division of Neurosurgery, Department of Clinical Neurosciences, University of Cambridge, Cambridge CB2 0QQ, UK; (M.C.); (M.M.P.); (P.S.); (E.N.); (Z.C.)
| | - Zofia Czosnyka
- Brain Physics Laboratory, Division of Neurosurgery, Department of Clinical Neurosciences, University of Cambridge, Cambridge CB2 0QQ, UK; (M.C.); (M.M.P.); (P.S.); (E.N.); (Z.C.)
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Stroh JN, Bennett TD, Kheyfets V, Albers D. Clinical Decision Support for Traumatic Brain Injury: Identifying a Framework for Practical Model-Based Intracranial Pressure Estimation at Multihour Timescales. JMIR Med Inform 2021; 9:e23215. [PMID: 33749613 PMCID: PMC8077603 DOI: 10.2196/23215] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2020] [Revised: 01/21/2021] [Accepted: 01/22/2021] [Indexed: 01/27/2023] Open
Abstract
BACKGROUND The clinical mitigation of intracranial hypertension due to traumatic brain injury requires timely knowledge of intracranial pressure to avoid secondary injury or death. Noninvasive intracranial pressure (nICP) estimation that operates sufficiently fast at multihour timescales and requires only common patient measurements is a desirable tool for clinical decision support and improving traumatic brain injury patient outcomes. However, existing model-based nICP estimation methods may be too slow or require data that are not easily obtained. OBJECTIVE This work considers short- and real-time nICP estimation at multihour timescales based on arterial blood pressure (ABP) to better inform the ongoing development of practical models with commonly available data. METHODS We assess and analyze the effects of two distinct pathways of model development, either by increasing physiological integration using a simple pressure estimation model, or by increasing physiological fidelity using a more complex model. Comparison of the model approaches is performed using a set of quantitative model validation criteria over hour-scale times applied to model nICP estimates in relation to observed ICP. RESULTS The simple fully coupled estimation scheme based on windowed regression outperforms a more complex nICP model with prescribed intracranial inflow when pulsatile ABP inflow conditions are provided. We also show that the simple estimation data requirements can be reduced to 1-minute averaged ABP summary data under generic waveform representation. CONCLUSIONS Stronger performance of the simple bidirectional model indicates that feedback between the systemic vascular network and nICP estimation scheme is crucial for modeling over long intervals. However, simple model reduction to ABP-only dependence limits its utility in cases involving other brain injuries such as ischemic stroke and subarachnoid hemorrhage. Additional methodologies and considerations needed to overcome these limitations are illustrated and discussed.
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Affiliation(s)
- J N Stroh
- Department of Bioengineering, University of Colorado Denver
- Anschutz Medical Campus, Aurora, CO, United States
| | - Tellen D Bennett
- Department of Pediatrics, University of Colorado School of Medicine, Aurora, CO, United States
| | - Vitaly Kheyfets
- Department of Bioengineering, University of Colorado Denver
- Anschutz Medical Campus, Aurora, CO, United States
| | - David Albers
- Department of Bioengineering, University of Colorado Denver
- Anschutz Medical Campus, Aurora, CO, United States.,Department of Pediatrics, University of Colorado School of Medicine, Aurora, CO, United States
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Svedung Wettervik T, Howells T, Hånell A, Ronne-Engström E, Lewén A, Enblad P. Low intracranial pressure variability is associated with delayed cerebral ischemia and unfavorable outcome in aneurysmal subarachnoid hemorrhage. J Clin Monit Comput 2021; 36:569-578. [PMID: 33728586 PMCID: PMC9123038 DOI: 10.1007/s10877-021-00688-y] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2020] [Accepted: 03/04/2021] [Indexed: 11/30/2022]
Abstract
Purpose High intracranial pressure variability (ICPV) is associated with favorable outcome in traumatic brain injury, by mechanisms likely involving better cerebral blood flow regulation. However, less is known about ICPV in aneurysmal subarachnoid hemorrhage (aSAH). In this study, we investigated the explanatory variables for ICPV in aSAH and its association with delayed cerebral ischemia (DCI) and clinical outcome. Methods
In this retrospective study, 242 aSAH patients, treated at the neurointensive care, Uppsala, Sweden, 2008–2018, with ICP monitoring the first ten days post-ictus were included. ICPV was evaluated on three time scales: (1) ICPV-1 m—ICP slow wave amplitude of wavelengths between 55 and 15 s, (2) ICPV-30 m—the deviation from the mean ICP averaged over 30 min, and (3) ICPV-4 h—the deviation from the mean ICP averaged over 4 h. The ICPV measures were analyzed in the early phase (day 1–3), in the early vasospasm phase (day 4–6.5), and the late vasospasm phase (day 6.5–10). Results High ICPV was associated with younger age, reduced intracranial pressure/volume reserve (high RAP), and high blood pressure variability in multiple linear regression analyses for all ICPV measures. DCI was associated with reduced ICPV in both vasospasm phases. High ICPV-1 m in the post-ictal early phase and the early vasospasm phase predicted favorable outcome in multiple logistic regressions, whereas ICPV-30 m and ICPV-4 h in the late vasospasm phase had a similar association. Conclusions Higher ICPV may reflect more optimal cerebral vessel activity, as reduced values are associated with an increased risk of DCI and unfavorable outcome after aSAH.
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Affiliation(s)
- Teodor Svedung Wettervik
- Department of Neuroscience, Section of Neurosurgery, Uppsala University, SE-751 85, Uppsala, Sweden.
| | - Timothy Howells
- Department of Neuroscience, Section of Neurosurgery, Uppsala University, SE-751 85, Uppsala, Sweden
| | - Anders Hånell
- Department of Neuroscience, Section of Neurosurgery, Uppsala University, SE-751 85, Uppsala, Sweden
| | - Elisabeth Ronne-Engström
- Department of Neuroscience, Section of Neurosurgery, Uppsala University, SE-751 85, Uppsala, Sweden
| | - Anders Lewén
- Department of Neuroscience, Section of Neurosurgery, Uppsala University, SE-751 85, Uppsala, Sweden
| | - Per Enblad
- Department of Neuroscience, Section of Neurosurgery, Uppsala University, SE-751 85, Uppsala, Sweden
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Ipertensione intracranica. Neurologia 2021. [DOI: 10.1016/s1634-7072(21)44503-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
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10
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Evensen KB, Eide PK. Measuring intracranial pressure by invasive, less invasive or non-invasive means: limitations and avenues for improvement. Fluids Barriers CNS 2020; 17:34. [PMID: 32375853 PMCID: PMC7201553 DOI: 10.1186/s12987-020-00195-3] [Citation(s) in RCA: 62] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2020] [Accepted: 04/19/2020] [Indexed: 12/20/2022] Open
Abstract
Sixty years have passed since neurosurgeon Nils Lundberg presented his thesis about intracranial pressure (ICP) monitoring, which represents a milestone for its clinical introduction. Monitoring of ICP has since become a clinical routine worldwide, and today represents a cornerstone in surveillance of patients with acute brain injury or disease, and a diagnostic of individuals with chronic neurological disease. There is, however, controversy regarding indications, clinical usefulness and the clinical role of the various ICP scores. In this paper, we critically review limitations and weaknesses with the current ICP measurement approaches for invasive, less invasive and non-invasive ICP monitoring. While risk related to the invasiveness of ICP monitoring is extensively covered in the literature, we highlight other limitations in current ICP measurement technologies, including limited ICP source signal quality control, shifts and drifts in zero pressure reference level, affecting mean ICP scores and mean ICP-derived indices. Control of the quality of the ICP source signal is particularly important for non-invasive and less invasive ICP measurements. We conclude that we need more focus on mitigation of the current limitations of today's ICP modalities if we are to improve the clinical utility of ICP monitoring.
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Affiliation(s)
- Karen Brastad Evensen
- Department of Neurosurgery, Oslo University Hospital-Rikshospitalet, P.O. Box 4950, Nydalen, 0424, Oslo, Norway
- Department of Informatics, Faculty of Mathematics and Natural Sciences, University of Oslo, Oslo, Norway
| | - Per Kristian Eide
- Department of Neurosurgery, Oslo University Hospital-Rikshospitalet, P.O. Box 4950, Nydalen, 0424, Oslo, Norway.
- Institute of Clinical Medicine, Faculty of Medicine, University of Oslo, Oslo, Norway.
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Hüser M, Kündig A, Karlen W, De Luca V, Jaggi M. Forecasting intracranial hypertension using multi-scale waveform metrics. Physiol Meas 2020; 41:014001. [PMID: 31851948 DOI: 10.1088/1361-6579/ab6360] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
OBJECTIVE Acute intracranial hypertension is an important risk factor of secondary brain damage after traumatic brain injury. Hypertensive episodes are often diagnosed reactively, leading to late detection and lost time for intervention planning. A pro-active approach that predicts critical events several hours ahead of time could assist in directing attention to patients at risk. APPROACH We developed a prediction framework that forecasts onsets of acute intracranial hypertension in the next 8 h. It jointly uses cerebral auto-regulation indices, spectral energies and morphological pulse metrics to describe the neurological state of the patient. One-minute base windows were compressed by computing signal metrics, and then stored in a multi-scale history, from which physiological features were derived. MAIN RESULTS Our model predicted events up to 8 h in advance with an alarm recall rate of 90% at a precision of 30% in the MIMIC-III waveform database, improving upon two baselines from the literature. We found that features derived from high-frequency waveforms substantially improved the prediction performance over simple statistical summaries of low-frequency time series, and each of the three feature classes contributed to the performance gain. The inclusion of long-term history up to 8 h was especially important. SIGNIFICANCE Our results highlight the importance of information contained in high-frequency waveforms in the neurological intensive care unit. They could motivate future studies on pre-hypertensive patterns and the design of new alarm algorithms for critical events in the injured brain.
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Affiliation(s)
- Matthias Hüser
- Biomedical Informatics Group, Institute of Machine Learning, Department of Computer Science, ETH Zürich, 8092 Zürich, Switzerland
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Abstract
OBJECTIVE This study applied a new external ventricular catheter, which allows intracranial pressure (ICP) monitoring and cerebral spinal fluid (CSF) drainage simultaneously, to study cerebral vascular responses during acute CSF drainage. METHODS Six patients with 34 external ventricular drain (EVD) opening sessions were retrospectively analyzed. A published algorithm was used to extract morphological features of ICP recordings, and a template-matching algorithm was applied to calculate the likelihood of cerebral vasodilation index (VDI) and cerebral vasoconstriction index (VCI) based on the changes of ICP waveforms during CSF drainage. Power change (∆P) of ICP B-waves after EVD opening was also calculated. Cerebral autoregulation (CA) was assessed through phase difference between arterial blood pressure (ABP) and ICP using a previously published wavelet-based algorithm. RESULTS The result showed that acute CSF drainage reduced mean ICP (P = 0.016) increased VCI (P = 0.02) and reduced ICP B-wave power (P = 0.016) significantly. VCI reacted to ICP changes negatively when ICP was between 10 and 25 mmHg, and VCI remained unchanged when ICP was outside the 10-25 mmHg range. VCI negatively (r = - 0.44) and VDI positively (r = 0.82) correlated with ∆P of ICP B-waves, indicating that stronger vasoconstriction resulted in bigger power drop in ICP B-waves. Better CA prior to EVD opening triggered bigger drop in the power of ICP B-waves (r = - 0.612). CONCLUSIONS This study demonstrates that acute CSF drainage reduces mean ICP, and results in vasoconstriction which can be detected through an index, VCI. Cerebral vessels actively respond to ICP changes or cerebral perfusion pressure (CPP) changes in a certain range; beyond which, the vessels are insensitive to the changes in ICP and CPP.
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Cerebrospinal fluid dynamics in pediatric pseudotumor cerebri syndrome. Childs Nerv Syst 2020; 36:73-86. [PMID: 31325030 DOI: 10.1007/s00381-019-04263-4] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/22/2019] [Accepted: 06/17/2019] [Indexed: 12/18/2022]
Abstract
PURPOSE There is a growing body of evidence highlighting the importance of comprehensive intracranial pressure (ICP) values in pseudotumor cerebri syndrome (PTCS). Due to the highly dynamic nature of ICP, several methods of ICP monitoring have been established, including the CSF infusion study. We have performed a retrospective review of the CSF dynamics measurements for all pediatric patients investigated for PTCS in our center and examined their diagnostic value compared with clinical classification. METHODS We retrospectively recruited 31 patients under 16 years of age investigated for PTCS by CSF infusion test. We used the clinically provided Friedman classification 13/31 patients with definite PTCS (group A), 13/31 with probable PTCS (group B), and 5/31 not PTCS (group C), to compare CSF dynamics in the 3 groups. RESULTS CSF pressure (CSFp) was significantly increased in group A (29.18 ± 7.72 mmHg) compared with B (15.31 ± 3.47 mmHg; p = 1.644e-05) and C (17.51 ± 5.87; p = 0.01368). The amplitude (AMP) was higher in the definite (2.18 ± 2.06 mmHg) than in group B (0.68 ± 0.37; p = 0.01382). There was no in either CSFp or AMP between groups B and C. No lower breakpoint of the AMP-P line was observed in group A but was present in 2/13 and 2/5 patients in groups B and C. In group A, sagittal sinus pressure (SSp) and elasticity were the only parameters above threshold (p = 4.2e-06 and p = 0.001953, respectively), In group B, only the elasticity was significantly higher than the threshold (p = 004257). Group C did not have any of the parameters raised. The AUC of CSFp, elasticity, and SSp for the 3 groups was 93.8% (84.8-100% CI). CONCLUSIONS Monitoring of CSFp and its dynamics, besides providing a more precise methodology for measuring CSFp, could yield information on the dynamic parameters of CSFp that cannot be derived from CSFp as a number, accurately differentiating between the clinically and radiologically derived entities of PTCS.
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Martinez-Tejada I, Arum A, Wilhjelm JE, Juhler M, Andresen M. B waves: a systematic review of terminology, characteristics, and analysis methods. Fluids Barriers CNS 2019; 16:33. [PMID: 31610775 PMCID: PMC6792201 DOI: 10.1186/s12987-019-0153-6] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2019] [Accepted: 09/15/2019] [Indexed: 11/18/2022] Open
Abstract
Background Although B waves were introduced as a concept in the analysis of intracranial pressure (ICP) recordings nearly 60 years ago, there is still a lack consensus on precise definitions, terminology, amplitude, frequency or origin. Several competing terms exist, addressing either their probable physiological origin or their physical characteristics. To better understand B wave characteristics and ease their detection, a literature review was carried out. Methods A systematic review protocol including search strategy and eligibility criteria was prepared in advance. A literature search was carried out using PubMed/MEDLINE, with the following search terms: B waves + review filter, slow waves + review filter, ICP B waves, slow ICP waves, slow vasogenic waves, Lundberg B waves, MOCAIP. Results In total, 19 different terms were found, B waves being the most common. These terminologies appear to be interchangeable and seem to be used indiscriminately, with some papers using more than five different terms. Definitions and etiologies are still unclear, which makes systematic and standardized detection difficult. Conclusions Two future lines of action are available for automating macro-pattern identification in ICP signals: achieving strict agreement on morphological characteristics of “traditional” B waveforms, or starting a new with a fresh computerized approach for recognition of new clinically relevant patterns.
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Affiliation(s)
- Isabel Martinez-Tejada
- Clinic of Neurosurgery, Copenhagen University Hospital, Rigshospitalet, Copenhagen, Denmark. .,Department of Health Technology, Technical University of Denmark, Kongens Lyngby, Denmark.
| | - Alexander Arum
- Clinic of Neurosurgery, Copenhagen University Hospital, Rigshospitalet, Copenhagen, Denmark
| | - Jens E Wilhjelm
- Department of Health Technology, Technical University of Denmark, Kongens Lyngby, Denmark
| | - Marianne Juhler
- Clinic of Neurosurgery, Copenhagen University Hospital, Rigshospitalet, Copenhagen, Denmark
| | - Morten Andresen
- Clinic of Neurosurgery, Copenhagen University Hospital, Rigshospitalet, Copenhagen, Denmark
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15
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Svedung Wettervik T, Howells T, Enblad P, Lewén A. Intracranial pressure variability: relation to clinical outcome, intracranial pressure-volume index, cerebrovascular reactivity and blood pressure variability. J Clin Monit Comput 2019; 34:733-741. [PMID: 31538266 PMCID: PMC7367899 DOI: 10.1007/s10877-019-00387-9] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2019] [Accepted: 09/10/2019] [Indexed: 02/03/2023]
Abstract
It was recently found in traumatic brain injury (TBI) that ICP variability (ICPV) predicted favorable outcome. We hypothesized that ICPV may depend on intracranial compliance, unstable blood pressure and cerebral vasomotion. In this study, we aimed to further investigate the explanatory variables for ICPV and its relation to outcome. Data from 362 TBI patients were retrospectively analyzed day 2 to 5 post-injury. ICPV was evaluated in three ways. First, variability in the sub-minute time interval (similar to B waves) was calculated as the amplitude of the ICP slow waves using a bandpass filter, limiting the analysis to oscillations of 55 to 15 s (ICP AMP 55-15). The second and third ICPV measures were calculated as the deviation from the mean ICP averaged over 30 min (ICPV-30m) and 4 h (ICPV-4h), respectively. All ICPV measures were associated with a reduced intracranial pressure/volume state (high ICP and RAP) and high blood pressure variability in multiple linear regression analyses. Higher ICPV was associated with better pressure reactivity in the univariate, but not the multiple analyses. All ICPV measures were associated with favorable outcome in univariate analysis, but only ICP AMP 55-15 and ICPV-30m did so in the multiple logistic regression analysis. Higher ICPV can be explained by a reduced intracranial compliance and variations in cerebral blood volume due to the vessel response to unstable blood pressure. As ICP AMP 55-15 and ICPV-30m independently predicted favorable outcome, it may represent general cerebral vessel activity, associated with better cerebral blood flow regulation and less secondary insults.
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Affiliation(s)
| | - Timothy Howells
- Section of Neurosurgery, Department of Neuroscience, Uppsala University, 751 85 Uppsala, Sweden
| | - Per Enblad
- Section of Neurosurgery, Department of Neuroscience, Uppsala University, 751 85 Uppsala, Sweden
| | - Anders Lewén
- Section of Neurosurgery, Department of Neuroscience, Uppsala University, 751 85 Uppsala, Sweden
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16
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Abstract
OBJECTIVES Slow waves of intracranial pressure (ICP) are spontaneous oscillations with a frequency of 0.3-4 cycles/min. They are often associated with pathological conditions, following vasomotor activity in the cranial enclosure. This study quantifies the effects of general anaesthesia (GA) on the magnitude of B-waves compared with natural sleep and the conscious state. MATERIALS AND METHODS Four groups of 30 patients each were formed to assess the magnitude of slow waves. Group A and group B consisted of normal pressure hydrocephalus (NPH) patients, each undergoing cerebrospinal fluid (CSF) infusion studies, conscious and under GA respectively. Group C comprised conscious, naturally asleep hydrocephalic patients undergoing overnight ICP monitoring; group D, which included deeply sedated head injury patients monitored in the intensive care unit (ICU), was compared with group C. RESULTS The average amplitude for group A patients was higher (0.23 ± 0.10 mmHg) than that of group B (0.15 ± 0.10 mmHg; p = 0.01). Overnight magnitude of slow waves was higher in group C (0.20 ± 0.13 mmHg) than in group D (0.11 ± 0.09 mmHg; p = 0.002). CONCLUSION Slow waves of ICP are suppressed by GA and deep sedation. When using slow waves in clinical decision-making, it is important to consider the patients' level of consciousness to avoid incorrect therapeutic and management decisions.
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Harary M, Dolmans RGF, Gormley WB. Intracranial Pressure Monitoring-Review and Avenues for Development. SENSORS (BASEL, SWITZERLAND) 2018; 18:E465. [PMID: 29401746 PMCID: PMC5855101 DOI: 10.3390/s18020465] [Citation(s) in RCA: 81] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/02/2018] [Revised: 01/25/2018] [Accepted: 02/01/2018] [Indexed: 12/27/2022]
Abstract
Intracranial pressure (ICP) monitoring is a staple of neurocritical care. The most commonly used current methods of monitoring in the acute setting include fluid-based systems, implantable transducers and Doppler ultrasonography. It is well established that management of elevated ICP is critical for clinical outcomes. However, numerous studies show that current methods of ICP monitoring cannot reliably define the limit of the brain's intrinsic compensatory capacity to manage increases in pressure, which would allow for proactive ICP management. Current work in the field hopes to address this gap by harnessing live-streaming ICP pressure-wave data and a multimodal integration with other physiologic measures. Additionally, there is continued development of non-invasive ICP monitoring methods for use in specific clinical scenarios.
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Affiliation(s)
- Maya Harary
- Computational Neuroscience Outcomes Center, Department of Neurosurgery, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, USA.
| | - Rianne G F Dolmans
- Computational Neuroscience Outcomes Center, Department of Neurosurgery, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, USA.
- Department of Neurosurgery, University Medical Center, 3584 CS Utrecht, The Netherlands.
| | - William B Gormley
- Computational Neuroscience Outcomes Center, Department of Neurosurgery, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, USA.
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18
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Venkataraman P, Browd SR, Lutz BR. A physical framework for implementing virtual models of intracranial pressure and cerebrospinal fluid dynamics in hydrocephalus shunt testing. J Neurosurg Pediatr 2016; 18:296-305. [PMID: 27203135 DOI: 10.3171/2016.2.peds15478] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
OBJECTIVE The surgical placement of a shunt designed to resolve the brain's impaired ability to drain excess CSF is one of the most common treatments for hydrocephalus. The use of a dynamic testing platform is an important part of shunt testing that can faithfully reproduce the physiological environment of the implanted shunts. METHODS A simulation-based framework that serves as a proof of concept for enabling the application of virtual intracranial pressure (ICP) and CSF models to a physical shunt-testing system was engineered. This was achieved by designing hardware and software that enabled the application of dynamic model-driven inlet and outlet pressures to a shunt and the subsequent measurement of the resulting drainage rate. RESULTS A set of common physiological scenarios was simulated, including oscillations in ICP due to respiratory and cardiac cycles, changes in baseline ICP due to changes in patient posture, and transient ICP spikes caused by activities such as exercise, coughing, sneezing, and the Valsalva maneuver. The behavior of the Strata valve under a few of these physiological conditions is also demonstrated. CONCLUSIONS Testing shunts with dynamic ICP and CSF simulations can facilitate the optimization of shunts to be more failure resistant and better suited to patient physiology.
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Affiliation(s)
| | - Samuel R Browd
- Division of Pediatric Neurosurgery, Seattle Children's Hospital, Seattle, Washington
| | - Barry R Lutz
- Department of Bioengineering, University of Washington, Seattle; and
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19
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Lalou DA, Czosnyka M, Donnelly J, Lavinio A, Pickard JD, Garnett M, Czosnyka Z. Influence of general anaesthesia on slow waves of intracranial pressure. Neurol Res 2016; 38:587-92. [PMID: 27278507 DOI: 10.1080/01616412.2016.1189200] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
OBJECTIVE Slow vasogenic intracranial pressure (ICP) waves are spontaneous ICP oscillations with a low frequency bandwidth of 0.3-4 cycles/min (B-waves). B-waves reflect dynamic oscillations in cerebral blood volume associated with autoregulatory cerebral vasodilation and vasoconstriction. This study quantifies the effects of general anaesthesia (GA) on the magnitude of B-waves compared to natural sleep and conscious state. MATERIALS AND METHODS The magnitude of B-waves was assessed in 4 groups of 30 patients each with clinical indications for ICP monitoring. Normal pressure hydrocephalus patients undergoing Cerebrospinal Fluid (CSF) infusion studies in the conscious state (GROUP A) and under GA (GROUP B), and hydrocephalus patients undergoing overnight ICP monitoring during physiological sleep (GROUP C) were compared to deeply sedated traumatic brain injury (TBI) patients with well-controlled ICP during the first night of Intensive Care Unit (ICU) stay (GROUP D). RESULTS A total of 120 patients were included. During CSF infusion studies, the magnitude of slow waves was higher in conscious patients ( GROUP A 0.23+/-0.10 mm Hg) when compared to anaesthetised patients ( GROUP B 0.15+/-0.10 mm Hg; p = 0.011). Overnight magnitude of slow waves was higher in patients during natural sleep (GROUP C: 0.20+/-0.13 mm Hg) when compared to TBI patients under deep sedation (GROUP D: 0.11+/- 0.09 mm Hg; p = 0.002). CONCLUSION GA and deep sedation are associated with a reduced magnitude of B-waves. ICP monitoring carried out under GA is affected by iatrogenic suppression of slow vasogenic waves of ICP. Accounting for the effects of anaesthesia on vasogenic waves may prevent the misidentification of potential shunt-responders as non-responders.
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Affiliation(s)
- Despina A Lalou
- a Division of Neurosurgery, Department of Clinical Neuroscience , University of Cambridge , Cambridge , UK.,b Division of Neurosurgery , Addenbrooke's Hospital , Cambridge , UK.,c National and Kapodistrian University of Athens Medical School , Athens , Greece
| | - Marek Czosnyka
- a Division of Neurosurgery, Department of Clinical Neuroscience , University of Cambridge , Cambridge , UK.,b Division of Neurosurgery , Addenbrooke's Hospital , Cambridge , UK
| | - Joseph Donnelly
- a Division of Neurosurgery, Department of Clinical Neuroscience , University of Cambridge , Cambridge , UK.,b Division of Neurosurgery , Addenbrooke's Hospital , Cambridge , UK
| | - Andrea Lavinio
- d Neurosciences Critical Care Unit, Department of Anesthesia , Cambridge University Hospitals NHS Foundation Trust , Cambridge , UK
| | - John D Pickard
- a Division of Neurosurgery, Department of Clinical Neuroscience , University of Cambridge , Cambridge , UK.,b Division of Neurosurgery , Addenbrooke's Hospital , Cambridge , UK
| | - Matthew Garnett
- a Division of Neurosurgery, Department of Clinical Neuroscience , University of Cambridge , Cambridge , UK.,b Division of Neurosurgery , Addenbrooke's Hospital , Cambridge , UK
| | - Zofia Czosnyka
- a Division of Neurosurgery, Department of Clinical Neuroscience , University of Cambridge , Cambridge , UK.,b Division of Neurosurgery , Addenbrooke's Hospital , Cambridge , UK
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20
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Martín-Láez R, Vázquez-Barquero A. [Long-term prognosis of idiopathic chronic adult hydrocephalus: I. The University Hospital Marqués de Valdecilla diagnostic and therapeutic protocol]. Neurocirugia (Astur) 2016; 28:141-156. [PMID: 27255166 DOI: 10.1016/j.neucir.2016.04.004] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2016] [Accepted: 04/19/2016] [Indexed: 11/17/2022]
Abstract
INTRODUCTION Despite the existence of published guidelines for more than a decade, there is still a substantial variation in the management of idiopathic normal pressure hydrocephalus due to its diagnostic and therapeutic complexity. DEVELOPMENT The diagnostic and therapeutic protocol for the management of idiopathic normal pressure hydrocephalus in use at the Department of Neurosurgery of the University Hospital Marqués de Valdecilla is presented. The diagnostic process includes neuropsychological testing, phase contrast cine MRI, urodynamic evaluation, continuous intracranial pressure monitoring, cerebrospinal fluid hydrodynamics by means of lumbar infusion testing, and intra-abdominal pressure measurement. A patient is considered a surgical candidate if any of the following criteria is met: mean intracranial pressure >15mmHg, or B-waves present in >10% of overnight recording; pressure-volume index <15ml, or resistance to cerebrospinal fluid outflow (ROUT) >4.5mmHg/ml/min in bolus infusion test; ROUT >12mmHg/ml/min, intracranial pressure >22mmHg, or high amplitude B-waves in the steady-state of the continuous rate infusion test; or a clinical response to high-volume cerebrospinal fluid withdrawal. CONCLUSIONS The implementation of a diagnostic and therapeutic protocol for idiopathic normal pressure hydrocephalus management could improve various aspects of patient care. It could reduce variability in clinical practice, optimise the use of health resources, and help in identifying scientific uncertainty areas, in order to direct research efforts in a more appropriate way.
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Affiliation(s)
- Rubén Martín-Láez
- Servicio de Neurocirugía-Unidad de Raquis Quirúrgico, Servicio de Neurocirugía, Hospital Universitario Marqués de Valdecilla, Universidad de Cantabria, Santander, Cantabria; Instituto de Investigación Sanitaria Marqués de Valdecilla (IDIVAL), Santander, Cantabria; Observatorio de Salud Pública de Cantabria, Fundación Marqués de Valdecilla, Santander, Cantabria.
| | - Alfonso Vázquez-Barquero
- Servicio de Neurocirugía-Unidad de Raquis Quirúrgico, Servicio de Neurocirugía, Hospital Universitario Marqués de Valdecilla, Universidad de Cantabria, Santander, Cantabria; Instituto de Investigación Sanitaria Marqués de Valdecilla (IDIVAL), Santander, Cantabria; Observatorio de Salud Pública de Cantabria, Fundación Marqués de Valdecilla, Santander, Cantabria
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21
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Liu X, Czosnyka M, Donnelly J, Budohoski KP, Varsos GV, Nasr N, Brady KM, Reinhard M, Hutchinson PJ, Smielewski P. Comparison of frequency and time domain methods of assessment of cerebral autoregulation in traumatic brain injury. J Cereb Blood Flow Metab 2015; 35:248-56. [PMID: 25407266 PMCID: PMC4426741 DOI: 10.1038/jcbfm.2014.192] [Citation(s) in RCA: 62] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/11/2014] [Revised: 09/29/2014] [Accepted: 10/14/2014] [Indexed: 01/31/2023]
Abstract
The impulse response (IR)-based autoregulation index (ARI) allows for continuous monitoring of cerebral autoregulation using spontaneous fluctuations of arterial blood pressure (ABP) and cerebral flow velocity (FV). We compared three methods of autoregulation assessment in 288 traumatic brain injury (TBI) patients managed in the Neurocritical Care Unit: (1) IR-based ARI; (2) transfer function (TF) phase, gain, and coherence; and (3) mean flow index (Mx). Autoregulation index was calculated using the TF estimation (Welch method) and classified according to the original Tiecks' model. Mx was calculated as a correlation coefficient between 10-second averages of ABP and FV using a moving 300-second data window. Transfer function phase, gain, and coherence were extracted in the very low frequency (VLF, 0 to 0.05 Hz) and low frequency (LF, 0.05 to 0.15 Hz) bandwidths. We studied the relationship between these parameters and also compared them with patients' Glasgow outcome score. The calculations were performed using both cerebral perfusion pressure (CPP; suffix 'c') as input and ABP (suffix 'a'). The result showed a significant relationship between ARI and Mx when using either ABP (r=-0.38, P<0.001) or CPP (r=-0.404, P<0.001) as input. Transfer function phase and coherence_a were significantly correlated with ARI_a and ARI_c (P<0.05). Only ARI_a, ARI_c, Mx_a, Mx_c, and phase_c were significantly correlated with patients' outcome, with Mx_c showing the strongest association.
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Affiliation(s)
- Xiuyun Liu
- Division of Neurosurgery, Department of Clinical Neurosciences, Addenbrooke's Hospital, University of Cambridge, Cambridge, UK
| | - Marek Czosnyka
- 1] Division of Neurosurgery, Department of Clinical Neurosciences, Addenbrooke's Hospital, University of Cambridge, Cambridge, UK [2] Institute of Electronic Systems, Warsaw University of Technology, Warsaw, Poland
| | - Joseph Donnelly
- Division of Neurosurgery, Department of Clinical Neurosciences, Addenbrooke's Hospital, University of Cambridge, Cambridge, UK
| | - Karol P Budohoski
- Division of Neurosurgery, Department of Clinical Neurosciences, Addenbrooke's Hospital, University of Cambridge, Cambridge, UK
| | - Georgios V Varsos
- Division of Neurosurgery, Department of Clinical Neurosciences, Addenbrooke's Hospital, University of Cambridge, Cambridge, UK
| | - Nathalie Nasr
- 1] Division of Neurosurgery, Department of Clinical Neurosciences, Addenbrooke's Hospital, University of Cambridge, Cambridge, UK [2] Service de Neurologie Vasculaire, Hôpital Rangueil, INSERM U1048 - Team 11 (I2MC-Toulouse), Université de Toulouse III, Toulouse, France
| | - Ken M Brady
- Baylor College of Medicine, Texas Children's Hospital, Houston, Texas, USA
| | - Matthias Reinhard
- Department of Neurology, University Hospital, University of Freiburg, Freiburg, Germany
| | - Peter J Hutchinson
- 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
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Kvandal P, Sheppard L, Landsverk SA, Stefanovska A, Kirkeboen KA. Impaired cerebrovascular reactivity after acute traumatic brain injury can be detected by wavelet phase coherence analysis of the intracranial and arterial blood pressure signals. J Clin Monit Comput 2013; 27:375-83. [PMID: 23748602 PMCID: PMC3689920 DOI: 10.1007/s10877-013-9484-z] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2012] [Accepted: 05/14/2013] [Indexed: 11/25/2022]
Abstract
The objective of the study was to evaluate the wavelet spectral energy of oscillations in the intracranial pressure (ICP) signal in patients with acute traumatic brain injury (TBI). The wavelet phase coherence and phase shift in the 0.006-2 Hz interval between the ICP and the arterial blood pressure (ABP) signals were also investigated. Patients were separated into normal or impaired cerebrovascular reactivity, based on the pressure reactivity index (PRx). Spectral energy, phase coherence and phase shift in the low frequency and cardiorespiratory intervals were compared for the two groups. Data were prospectively collected and analyzed retrospectively in 22 patients, within the first week after acute TBI. The ICP and ABP signals were continuously recorded for [Formula: see text]40 min and the wavelet transform was used to calculate the spectral energy and phase of the signals. The average ICP wavelet energy spectrum showed distinct peaks around 1.0 (cardiac), 0.25 (respiratory) and 0.03 Hz. Patients with normal cerebrovascular reactivity (negative PRx) had 38.6 % (±SD 16.7 %) of the mean wavelet energy below the lower limit of the respiratory frequency band (0.14 Hz) compared to only 18.1 % (±SD 17.8 %) in patients with altered cerebrovascular reactivity (positive PRx) (difference: p = 0.0057). Wavelet phase coherence between the ABP and ICP signals was statistically significant (p < 0.05) in the 0.006-2 Hz interval. The phase shift between the ABP and ICP signals was around zero in the 0.14-1.0 Hz interval. Seven patients with PRx between -0.4943 and -0.1653 had a phase shift in the interval 0.07-0.14 Hz, whereas 15 patients with PRx between -0.1019 and 0.3881 had a phase shift in the interval 0.006-0.07 Hz. We conclude that the wavelet transform of the ICP signal shows spectral peaks at the cardiac, respiratory and 0.03 Hz frequencies. Normal cerebrovascular reactivity seems to be manifested as increased spectral energy in the frequency interval <0.14 Hz. A phase shift between the ICP and ABP signals in the interval 0.07-0.14 Hz indicates normal cerebrovascular reactivity, while a phase shift in the interval 0.006-0.07 Hz indicates altered cerebrovascular reactivity.
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Affiliation(s)
- Per Kvandal
- Intensive Care Unit, Oslo University Hospital, 0407 Ullevål, Oslo, Norway
| | - Lawrence Sheppard
- Physics Department, Nonlinear Biomedical Physics Group, Lancaster University, Lancaster, UK
- Present Address: Division of Ecology and Evolution, Faculty of Natural Sciences, Imperial College London, London, UK
| | - Svein A. Landsverk
- Department of Anesthesiology, Ullevål and Faculty of Medicine, Oslo University Hospital, University of Oslo, Oslo, Norway
| | - Aneta Stefanovska
- Physics Department, Nonlinear Biomedical Physics Group, Lancaster University, Lancaster, UK
| | - Knut A. Kirkeboen
- Department of Anesthesiology, Ullevål and Faculty of Medicine, Oslo University Hospital, University of Oslo, Oslo, Norway
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García M, Poza J, Santamarta D, Abásolo D, Barrio P, Hornero R. Spectral analysis of intracranial pressure signals recorded during infusion studies in patients with hydrocephalus. Med Eng Phys 2013; 35:1490-8. [PMID: 23664413 DOI: 10.1016/j.medengphy.2013.04.002] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2012] [Revised: 02/26/2013] [Accepted: 04/11/2013] [Indexed: 10/26/2022]
Abstract
Hydrocephalus includes a number of disorders characterised by clinical symptoms, enlarged ventricles (observable using neuroimaging techniques) and altered cerebrospinal fluid (CSF) dynamics. Infusion tests are one of the available procedures to study CSF circulation in patients with clinical and radiological features of hydrocephalus. In them, intracranial pressure (ICP) is deliberately raised and CSF circulation disorders evaluated through measurements of the resulting ICP. In this study, we analysed seventy-seven ICP signals recorded during infusion tests using four spectral-based parameters: median frequency (MF) and relative power (RP) in three frequency bands. These measures provide a novel perspective for the analysis of ICP signals in the frequency domain. Each signal was divided into four artefact-free epochs (corresponding to the basal, early infusion, plateau and recovery phases of the infusion study). The four spectral parameters were calculated for each epoch. We analysed differences between epochs of the infusion test and correlations between these epochs and patient data. Statistically significant differences (p < 1.7 × 10(-3), Bonferroni-corrected Wilcoxon signed-rank tests) were found between epochs of the infusion test using MF and RP. Furthermore, some spectral parameters (MF in the basal phase, RP for the first frequency band and in the early infusion phase, RP for the second frequency band and in all phases of the infusion study and RP in the third frequency band and in the basal phase) revealed significant correlations (p < 0.01) between epochs of the infusion test and signal amplitude in the basal and plateau phases. Our results suggest that spectral analysis of ICP signals could be useful for understanding CSF dynamics in hydrocephalus.
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Affiliation(s)
- María García
- Biomedical Engineering Group, Department T.S.C.I.T., E.T.S. Ingenieros de Telecomunicación, University of Valladolid, Valladolid, Spain.
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24
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Abstract
The monitoring of intracranial pressure (ICP) is an important tool in medicine for its ability to portray the brain’s compliance status. The bedside monitor displays the ICP waveform and intermittent mean values to guide physicians in the management of patients, particularly those having sustained a traumatic brain injury. Researchers in the fields of engineering and physics have investigated various mathematical analysis techniques applicable to the waveform in order to extract additional diagnostic and prognostic information, although they largely remain limited to research applications. The purpose of this review is to present the current techniques used to monitor and interpret ICP and explore the potential of using advanced mathematical techniques to provide information about system perturbations from states of homeostasis. We discuss the limits of each proposed technique and we propose that nonlinear analysis could be a reliable approach to describe ICP signals over time, with the fractal dimension as a potential predictive clinically meaningful biomarker. Our goal is to stimulate translational research that can move modern analysis of ICP using these techniques into widespread practical use, and to investigate to the clinical utility of a tool capable of simplifying multiple variables obtained from various sensors.
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Affiliation(s)
- Antonio Di Ieva
- Department of Surgery, Division of Neurosurgery, St. Michael’s Hospital, University of Toronto, Toronto, ON, Canada
- Injury Prevention Research Office, St. Michael’s Hospital, Toronto, ON, Canada
| | - Erika M. Schmitz
- Injury Prevention Research Office, St. Michael’s Hospital, Toronto, ON, Canada
| | - Michael D. Cusimano
- Department of Surgery, Division of Neurosurgery, St. Michael’s Hospital, University of Toronto, Toronto, ON, Canada
- Injury Prevention Research Office, St. Michael’s Hospital, Toronto, ON, Canada
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25
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Shahsavari S, McKelvey T, Ritzén CE, Rydenhag B. Cerebrovascular mechanical properties and slow waves of intracranial pressure in TBI patients. IEEE Trans Biomed Eng 2011; 58:2072-82. [PMID: 21507769 DOI: 10.1109/tbme.2011.2142415] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Myogenic autoregulation of cerebral blood flow is one of the mechanisms affecting cerebral hemodynamics. Short or long-lasting changes in intracranial pressure (ICP) are believed to reveal the responses of the cerebral system to myogenic stimuli. Through the incorporation of a theoretical model into the experimental measurements of cerebrovascular distensibility and compliance in patients with traumatic brain injury (TBI), the current study is an attempt to explain ICP dynamics in either presence or absence of cerebral autoregulation. The pulse wave velocity and transfer function between arterial blood pressure and ICP were utilized as the major tools to reflect variations in the mechanical properties of distant cerebral artries/arteriols. The results imply that different states of cerebral autoregulation and associated regimes within the cerebrovascular system can lead to different types of interrelationship between the slow variations of ICP, cerebral arterial distensibility, and compliance. Consequently, each of these classes may require different types of treatment on patients with TBI.
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Affiliation(s)
- Sima Shahsavari
- Department of Signals and Systems, Chalmers University of Technology, Gothenburg 41296, Sweden.
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26
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Slow vasogenic fluctuations of intracranial pressure and cerebral near infrared spectroscopy--an observational study. Acta Neurochir (Wien) 2010; 152:1763-9. [PMID: 20700750 DOI: 10.1007/s00701-010-0748-9] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2010] [Accepted: 07/12/2010] [Indexed: 11/27/2022]
Abstract
BACKGROUND/PURPOSE Increased slow-wave activity in intracranial pressure (ICP) signifies an exhausted cerebrospinal compensatory reserve across a range of conditions. In this study, we attempted to describe synchronisation between slow waves of ICP and of near-infrared spectroscopy (NIRS) variables during controlled elevation of ICP. METHOD Nineteen patients presenting with symptomatic hydrocephalus underwent a Computerised Infusion Test. NIRS-derived indices, ICP and arterial blood pressure (ABP) were recorded simultaneously. FINDINGS ICP increased from 9.3 (6.0) mmHg to a 17.1 (8.9) mmHg during infusion. Slow waves in ICP were accompanied by concurrent waves in each NIRS variable (including deoxygenated haemoglobin (Hb) and oxygenated haemoglobin (HbO2)) with a mean coherence of >0.7 and no significant phase shift. In the same bandwidth (0.3-1.8 min(-1)), ABP fluctuations occurred with a coherence of 0.77 and phase lead of 40° with respect to ICP. The power of ICP slow waves increased significantly during infusion plateau with a corresponding increase in power of Hb waves. CONCLUSIONS Slow fluctuations in cerebral oximetry as detected by NIRS coincide with and are implicated in the origin of ICP slow waves and increases during periods of exhausted cerebrospinal compensatory reserve. NIRS may be used as a non-invasive marker of increased ICP slow waves (and therefore reduced CSF compensatory reserve).
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27
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Brady KM, Mytar JO, Lee JK, Cameron DE, Vricella LA, Thompson WR, Hogue CW, Easley RB. Monitoring cerebral blood flow pressure autoregulation in pediatric patients during cardiac surgery. Stroke 2010; 41:1957-62. [PMID: 20651273 DOI: 10.1161/strokeaha.109.575167] [Citation(s) in RCA: 129] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BACKGROUND AND PURPOSE The limits of cerebral blood flow-pressure autoregulation have not been adequately defined for pediatric patients. Mean arterial blood pressure below these limits might contribute to brain injury during cardiac surgery. The purpose of this pilot study was to assess a novel method of determining the lower limits of pressure autoregulation in pediatric patients supported with cardiopulmonary bypass. METHODS A prospective, observational pilot study was conducted in children (n=54) undergoing cardiac surgery with cardiopulmonary bypass for correction of congenital heart defects. Cerebral oximetry index (COx) was calculated as a moving, linear correlation coefficient between slow waves of arterial blood pressure and cerebral oximetry measured with near-infrared spectroscopy. An autoregulation curve was constructed for each patient with averaged COx values sorted by arterial blood pressure. RESULTS Hypotension was associated with increased values of COx (P<0.0001). For 77% of patients, an individual estimate of lower limits of pressure autoregulation could be determined using a threshold COx value of 0.4. The mean lower limits of pressure autoregulation for the cohort using this method was 42+/-7 mm Hg. CONCLUSIONS This pilot study of COx monitoring in pediatric patients demonstrates an association between hypotension during cardiopulmonary bypass and impairment of autoregulation. The COx may be useful to identify arterial blood pressure-dependent limits of cerebral autoregulation during cardiopulmonary bypass. Larger trials with neurological outcomes are indicated.
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Affiliation(s)
- Ken M Brady
- Department of Anesthesiology and Critical Care Medicine, Johns Hopkins Hospital, Baltimore, MD, USA.
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Caire F, Moreau JJ. Méthode et résultats du test de perfusion dans l’hydrocéphalie à pression normale : revue de la littérature. Rev Neurol (Paris) 2010; 166:494-501. [DOI: 10.1016/j.neurol.2009.10.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2009] [Revised: 08/23/2009] [Accepted: 10/27/2009] [Indexed: 11/25/2022]
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Ocon AJ, Kulesa J, Clarke D, Taneja I, Medow MS, Stewart JM. Increased phase synchronization and decreased cerebral autoregulation during fainting in the young. Am J Physiol Heart Circ Physiol 2009; 297:H2084-95. [PMID: 19820196 DOI: 10.1152/ajpheart.00705.2009] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Vasovagal syncope may be due to a transient cerebral hypoperfusion that accompanies frequency entrainment between arterial pressure (AP) and cerebral blood flow velocity (CBFV). We hypothesized that cerebral autoregulation fails during fainting; a phase synchronization index (PhSI) between AP and CBFV was used as a nonlinear, nonstationary, time-dependent measurement of cerebral autoregulation. Twelve healthy control subjects and twelve subjects with a history of vasovagal syncope underwent 10-min tilt table testing with the continuous measurement of AP, CBFV, heart rate (HR), end-tidal CO2 (ETCO2), and respiratory frequency. Time intervals were defined to compare physiologically equivalent periods in fainters and control subjects. A PhSI value of 0 corresponds to an absence of phase synchronization and efficient cerebral autoregulation, whereas a PhSI value of 1 corresponds to complete phase synchronization and inefficient cerebral autoregulation. During supine baseline conditions, both control and syncope groups demonstrated similar oscillatory changes in phase, with mean PhSI values of 0.58+/-0.04 and 0.54+/-0.02, respectively. Throughout tilt, control subjects demonstrated similar PhSI values compared with supine conditions. Approximately 2 min before fainting, syncopal subjects demonstrated a sharp decrease in PhSI (0.23+/-0.06), representing efficient cerebral autoregulation. Immediately after this period, PhSI increased sharply, suggesting inefficient cerebral autoregulation, and remained elevated at the time of faint (0.92+/-0.02) and during the early recovery period (0.79+/-0.04) immediately after the return to the supine position. Our data demonstrate rapid, biphasic changes in cerebral autoregulation, which are temporally related to vasovagal syncope. Thus, a sudden period of highly efficient cerebral autoregulation precedes the virtual loss of autoregulation, which continued during and after the faint.
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Affiliation(s)
- Anthony J Ocon
- Department of Physiology, The Center for Hypotension, New York Medical College, 19 Bradhurst Ave., Suite 1600S, Hawthorne, NY 10532, USA
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Brady KM, Lee JK, Kibler KK, Easley RB, Koehler RC, Shaffner DH. Continuous measurement of autoregulation by spontaneous fluctuations in cerebral perfusion pressure: comparison of 3 methods. Stroke 2008; 39:2531-7. [PMID: 18669896 DOI: 10.1161/strokeaha.108.514877] [Citation(s) in RCA: 154] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BACKGROUND AND PURPOSE Clinical application of continuous autoregulation monitoring would benefit from a comparison of curves generated by online monitoring with standard autoregulation curves in animal models. We characterized the accuracy of 3 continuous monitors of autoregulation in a piglet model of hypotension. METHODS Piglets 5 to10 days old with intracranial pressure (ICP) at naïve or elevated (20 mm Hg) levels had gradual arterial hypotension induced by a balloon catheter in the inferior vena cava. Elevated ICP was maintained by a continuous infusion of artificial cerebrospinal fluid. Three indices of autoregulation were simultaneously and continuously calculated. A moving, linear Pearson's coefficient between spontaneous slow waves of cerebral perfusion pressure and slow waves of laser-Doppler flux or cortical oxygenation rendered the laser-Doppler index and cerebral-oximetry index, respectively. Similar correlation between slow waves of arterial blood pressure and ICP rendered the pressure-reactivity index. The lower limit of autoregulation was determined directly for each animal by plotting laser-Doppler cortical red blood cell flux as a function of cerebral perfusion pressure. Receiver-operator characteristics were determined for the 3 indices. RESULTS The areas under the receiver-operator characteristics curves for discriminating the individual lower limit of autoregulation at low and high ICP were 0.89 and 0.85 for the laser-Doppler index, 0.89 and 0.84 for the cerebral-oximetry index, and 0.79 and 0.79 for the pressure-reactivity index. The pressure-reactivity index performed equally well at low and high ICPs. CONCLUSIONS Continuous monitoring of autoregulation by spontaneous slow waves of cerebral perfusion pressure can accurately detect loss of autoregulation due to hypotension in piglets by all 3 modalities.
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Affiliation(s)
- Ken M Brady
- Department of Anesthesiology, Division of Pediatric Anesthesiology and Critical Care Medicine, Johns Hopkins University School of Medicine, 600 N Wolfe St, Blalock 904, Baltimore MD 21287, USA.
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31
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Hu X, Nenov V, Bergsneider M, Martin N. A Data mining framework of noninvasive intracranial pressure assessment. Biomed Signal Process Control 2006. [DOI: 10.1016/j.bspc.2006.05.003] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Nicolet J, Gillard T, Gindre G, Cervenansky F, Duale C, Bazin JE, De Riberolles C, Schoeffler P, Lemaire JJ. Modifications of spontaneous cerebral blood flow oscillations during cardiopulmonary bypass. ACTA NEUROCHIRURGICA. SUPPLEMENT 2005; 95:337-9. [PMID: 16463877 DOI: 10.1007/3-211-32318-x_69] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
UNLABELLED Spontaneous slow waves are present in the systemic circulation including the intracranial compartment. They are supposed to reflect the cerebral autoregulation. We hypothesised that in the absence of cardio respiratory variability, during cardiopulmonary bypass (CPB), we should reveal extreme physiologic controls. MATERIAL/METHODS Ten patients were included. Arterial blood pressure (ABP, radial invasive), extracorporeal circuitry pressure and cerebral blood flow velocity (CBFV, middle cerebral artery) were recorded. We analysed the slow waves in the B (8 to 50) and the UB (>50 to 200) bands (in milli-Hz). The analysis, before and during CPB, was performed in the tine domain (correlation coefficient, entropy, mean quantity of mutual information, relative entropy) and in the frequency domain (spectrogram, frequency spectrum, coherence). RESULTS CPB dramatically changed monitored signals decreasing their entropy and revealing a dominant CBFV 70 mHz-frequency and a dominant ABP 9 mHz-frequency. There was no association between the signals (p < 0.05). Before CPB we found complex patterns where B and UB waves were present. CONCLUSION We hypothesised that CPB provoked a highly protective mechanism, reducing the fluctuations of CBF, by a deactivation of B waves, revealing monotonous UB waves.
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Affiliation(s)
- J Nicolet
- Cardiovascular Surgery Department, University Hospital and Auvergne University, Clermont-Ferrand, France
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Ragauskas A, Daubaris G, Petkus V, Ragaisis V, Ursino M. Clinical study of continuous non-invasive cerebrovascular autoregulation monitoring in neurosurgical ICU. ACTA NEUROCHIRURGICA. SUPPLEMENT 2005; 95:367-70. [PMID: 16463883 DOI: 10.1007/3-211-32318-x_75] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
Ultrasonic "time-of-flight" monitor (Vittamed) was used for continuous monitoring of intracranial blood volume (IBV) pulse, respiratory, slow waves and cerebrovascular autoregulation (CA). The objectives are to compare of invasively and non-invasively monitored slow intracranial waves and CA of ICU patients and to evaluate the phase shift between ABP and IBV respiratory waves as a possible estimator of CA. CA monitoring has been performed in 13 patients with severe TBI (age mean/range 30.5/(18-64)). Data were collected from 87 one-hour sessions of simultaneous invasive and non-invasive wave monitoring and from 53 one-hour sessions of invasive and non-invasive CA monitoring. High correlation (R > 0.9) has been obtained between invasively and non-invasively recorded intracranial slow waves. Bland Altman difference between invasively and non-invasively recorded intracranial slow waves is clinically not significant (mean =-0.07, SD = 0.089, alpha = 0.05). Agreement has been confirmed between invasive and non-invasive CA monitoring data in a wide range of R = [-0.85; +0.96]. Hypothesis of the coincidence of invasive and non-invasive CA assessment is accepted (p < 0.05). Phase shift monitoring of permanent respiratory ABP waves and IBV waves permit continuous non-invasive CA estimation without unnatural physical or pharmacological stimulations of CA system.
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Affiliation(s)
- A Ragauskas
- Kaunas University of Technology, Kaunas, Lithuania.
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Abstract
Intracranial pressure (ICP) is derived from cerebral blood and cerebrospinal fluid (CSF) circulatory dynamics and can be affected in the course of many diseases of the central nervous system. Monitoring of ICP requires an invasive transducer, although some attempts have been made to measure it non-invasively. Because of its dynamic nature, instant CSF pressure measurement using the height of a fluid column via lumbar puncture may be misleading. An averaging over 30 minutes should be the minimum, with a period of overnight monitoring in conscious patients providing the optimal standard. Computer-aided recording with online waveform analysis of ICP is very helpful. Although there is no "Class I" evidence, ICP monitoring is useful, if not essential, in head injury, poor grade subarachnoid haemorrhage, stroke, intracerebral haematoma, meningitis, acute liver failure, hydrocephalus, benign intracranial hypertension, craniosynostosis etc. Information which can be derived from ICP and its waveforms includes cerebral perfusion pressure (CPP), regulation of cerebral blood flow and volume, CSF absorption capacity, brain compensatory reserve, and content of vasogenic events. Some of these parameters allow prediction of prognosis of survival following head injury and optimisation of "CPP-guided therapy". In hydrocephalus CSF dynamic tests aid diagnosis and subsequent monitoring of shunt function.
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Affiliation(s)
- M Czosnyka
- Academic Neurosurgical Unit, University of Cambridge Clinical School, Cambridge, UK.
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