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Kazimierska A, Uryga A, Mataczyński C, Czosnyka M, Lang EW, Kasprowicz M. Relationship between the shape of intracranial pressure pulse waveform and computed tomography characteristics in patients after traumatic brain injury. Crit Care 2023; 27:447. [PMID: 37978548 PMCID: PMC10656987 DOI: 10.1186/s13054-023-04731-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2023] [Accepted: 11/09/2023] [Indexed: 11/19/2023] Open
Abstract
BACKGROUND Midline shift and mass lesions may occur with traumatic brain injury (TBI) and are associated with higher mortality and morbidity. The shape of intracranial pressure (ICP) pulse waveform reflects the state of cerebrospinal pressure-volume compensation which may be disturbed by brain injury. We aimed to investigate the link between ICP pulse shape and pathological computed tomography (CT) features. METHODS ICP recordings and CT scans from 130 TBI patients from the CENTER-TBI high-resolution sub-study were analyzed retrospectively. Midline shift, lesion volume, Marshall and Rotterdam scores were assessed in the first CT scan after admission and compared with indices derived from the first 24 h of ICP recording: mean ICP, pulse amplitude of ICP (AmpICP) and pulse shape index (PSI). A neural network model was applied to automatically group ICP pulses into four classes ranging from 1 (normal) to 4 (pathological), with PSI calculated as the weighted sum of class numbers. The relationship between each metric and CT measures was assessed using Mann-Whitney U test (groups with midline shift > 5 mm or lesions > 25 cm3 present/absent) and the Spearman correlation coefficient. Performance of ICP-derived metrics in identifying patients with pathological CT findings was assessed using the area under the receiver operating characteristic curve (AUC). RESULTS PSI was significantly higher in patients with mass lesions (with lesions: 2.4 [1.9-3.1] vs. 1.8 [1.1-2.3] in those without; p << 0.001) and those with midline shift (2.5 [1.9-3.4] vs. 1.8 [1.2-2.4]; p < 0.001), whereas mean ICP and AmpICP were comparable. PSI was significantly correlated with the extent of midline shift, total lesion volume and the Marshall and Rotterdam scores. PSI showed AUCs > 0.7 in classification of patients as presenting pathological CT features compared to AUCs ≤ 0.6 for mean ICP and AmpICP. CONCLUSIONS ICP pulse shape reflects the reduction in cerebrospinal compensatory reserve related to space-occupying lesions despite comparable mean ICP and AmpICP levels. Future validation of PSI is necessary to explore its association with volume imbalance in the intracranial space and a potential complementary role to the existing monitoring strategies.
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Affiliation(s)
- Agnieszka Kazimierska
- Department of Biomedical Engineering, Faculty of Fundamental Problems of Technology, Wroclaw University of Science and Technology, 27 Wybrzeze Wyspianskiego Street, 50-370, Wroclaw, Poland.
| | - Agnieszka Uryga
- Department of Biomedical Engineering, Faculty of Fundamental Problems of Technology, Wroclaw University of Science and Technology, 27 Wybrzeze Wyspianskiego Street, 50-370, Wroclaw, Poland
| | - Cyprian Mataczyński
- Department of Computer Engineering, Faculty of Electronics, Wroclaw University of Science and Technology, Wroclaw, Poland
| | - Marek Czosnyka
- Brain Physics Laboratory, Division of Neurosurgery, Department of Clinical Neurosciences, University of Cambridge, Cambridge, UK
- Institute of Electronic Systems, Faculty of Electronics and Information Technology, Warsaw University of Technology, Warsaw, Poland
| | - Erhard W Lang
- Neurosurgical Associates, Red Cross Hospital, Kassel, Germany
- Department of Neurosurgery, Faculty of Medicine, Georg-August-Universität, Göttingen, Germany
| | - Magdalena Kasprowicz
- Department of Biomedical Engineering, Faculty of Fundamental Problems of Technology, Wroclaw University of Science and Technology, 27 Wybrzeze Wyspianskiego Street, 50-370, Wroclaw, Poland.
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Kazimierska A, Manet R, Vallet A, Schmidt E, Czosnyka Z, Czosnyka M, Kasprowicz M. Analysis of intracranial pressure pulse waveform in studies on cerebrospinal compliance: a narrative review. Physiol Meas 2023; 44:10TR01. [PMID: 37793420 DOI: 10.1088/1361-6579/ad0020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2023] [Accepted: 10/04/2023] [Indexed: 10/06/2023]
Abstract
Continuous monitoring of mean intracranial pressure (ICP) has been an essential part of neurocritical care for more than half a century. Cerebrospinal pressure-volume compensation, i.e. the ability of the cerebrospinal system to buffer changes in volume without substantial increases in ICP, is considered an important factor in preventing adverse effects on the patient's condition that are associated with ICP elevation. However, existing assessment methods are poorly suited to the management of brain injured patients as they require external manipulation of intracranial volume. In the 1980s, studies suggested that spontaneous short-term variations in the ICP signal over a single cardiac cycle, called the ICP pulse waveform, may provide information on cerebrospinal compensatory reserve. In this review we discuss the approaches that have been proposed so far to derive this information, from pulse amplitude estimation and spectral techniques to most recent advances in morphological analysis based on artificial intelligence solutions. Each method is presented with focus on its clinical significance and the potential for application in standard clinical practice. Finally, we highlight the missing links that need to be addressed in future studies in order for ICP pulse waveform analysis to achieve widespread use in the neurocritical care setting.
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Affiliation(s)
- Agnieszka Kazimierska
- Department of Biomedical Engineering, Wroclaw University of Science and Technology, Wroclaw, Poland
| | - Romain Manet
- Department of Neurosurgery B, Neurological Hospital Pierre Wertheimer, University Hospital of Lyon, Lyon, France
| | - Alexandra Vallet
- Department of Mathematics, University of Oslo, Oslo, Norway
- INSERM U1059 Sainbiose, Ecole des Mines Saint-Étienne, Saint-Étienne, France
| | - Eric Schmidt
- Department of Neurosurgery, University Hospital of Toulouse, Toulouse, France
| | - Zofia Czosnyka
- Brain Physics Laboratory, Department of Clinical Neurosciences, Division of Neurosurgery, Addenbrooke's Hospital, University of Cambridge, Cambridge, United Kingdom
| | - Marek Czosnyka
- Brain Physics Laboratory, Department of Clinical Neurosciences, Division of Neurosurgery, Addenbrooke's Hospital, University of Cambridge, Cambridge, United Kingdom
- Institute of Electronic Systems, Warsaw University of Technology, Warsaw, Poland
| | - Magdalena Kasprowicz
- Department of Biomedical Engineering, Wroclaw University of Science and Technology, Wroclaw, Poland
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Lower Breakpoint of Intracranial Amplitude-Pressure Relationship in Normal Pressure Hydrocephalus. ACTA NEUROCHIRURGICA. SUPPLEMENT 2021. [PMID: 33839863 DOI: 10.1007/978-3-030-59436-7_57] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register]
Abstract
The relationship between intracranial pulse amplitude (AMP) and mean intracranial pressure (ICP) has been previously described. Generally, AMP increases proportionally to rises in ICP. However, at low ICP a lower breakpoint (LB) of amplitude-pressure relationship can be observed, below which pulse amplitude stays constant when ICP varies. Theoretically, below this breakpoint, the pressure-volume relationship is linear (good compensatory reserve, brain compliance stays constant); above the breakpoint, it is exponential (brain compliance decreases with rising ICP).Infusion tests performed in 169 patients diagnosed for idiopathic normal pressure hydrocephalus (iNPH) during the period 2004-2013 were available for analysis. A lower breakpoint was observed in 62 patients diagnosed for iNPH. Improvement after shunt surgery in patients in whom LB was recorded was 77% versus 90% in patients where LB was absent (p < 0.02). There was no correlation between improvement and slope of amplitude-pressure line above LB.The detection of a lower breakpoint is associated with less frequent improvement after shunting in NPH. It may be interpreted that cerebrospinal fluid dynamics of patients working on the flat part of the pressure-volume curve and having a 'luxurious' compensatory reserve, are more frequently caused by brain atrophy, which is obviously not responding to shunting.
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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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Caton MT, Laguna B, Soderlund KA, Dillon WP, Shah VN. Spinal Compliance Curves: Preliminary Experience with a New Tool for Evaluating Suspected CSF Venous Fistulas on CT Myelography in Patients with Spontaneous Intracranial Hypotension. AJNR Am J Neuroradiol 2021; 42:986-992. [PMID: 33602750 DOI: 10.3174/ajnr.a7018] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2020] [Accepted: 11/19/2020] [Indexed: 11/07/2022]
Abstract
BACKGROUND AND PURPOSE Craniospinal space compliance reflects the distensibility of the spinal and intracranial CSF spaces as a system. Craniospinal space compliance has been studied in intracranial pathologies, but data are limited in assessing it in spinal CSF leak. This study describes a method to estimate craniospinal space compliance using saline infusion during CT myelography and explores the use of craniospinal space compliance and pressure-volume curves in patients with suspected cerebrospinal-venous fistula. MATERIALS AND METHODS Patients with suspected cerebrospinal-venous fistula underwent dynamic CT myelography. During the procedure, 1- to 5-mL boluses of saline were infused, and incremental changes in CSF pressure were recorded. These data were used to plot craniospinal space compliance curves. We calculated 3 quantitative craniospinal space compliance parameters: overall compliance, compliance at opening pressure, and the pressure volume index. These variables were compared between patients with confirmed cerebrospinal-venous fistula and those with no confirmed source of CSF leak. RESULTS Thirty-four CT myelograms in 22 patients were analyzed. Eight of 22 (36.4%) patients had confirmed cerebrospinal-venous fistulas. Bolus infusion was well-tolerated with no complications and transient headache in 2/34 (5.8%). Patients with confirmed cerebrospinal-venous fistulas had higher compliance at opening pressure and overall compliance (2.6 versus 1.8 mL/cm H20, P < .01). There was no difference in the pressure volume index (77.5 versus 54.3 mL, P = .13) between groups. CONCLUSIONS A method of deriving craniospinal space compliance curves using saline intrathecal infusion is described. Preliminary analysis of craniospinal space compliance curves provides qualitative and quantitative information about pressure-volume dynamics and may serve as a diagnostic tool in patients with known or suspected cerebrospinal-venous fistulas.
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Affiliation(s)
- M T Caton
- From the Department of Radiology and Biomedical Imaging, Neuroradiology Section, University of California San Francisco. San Francisco, California
| | - B Laguna
- From the Department of Radiology and Biomedical Imaging, Neuroradiology Section, University of California San Francisco. San Francisco, California
| | - K A Soderlund
- From the Department of Radiology and Biomedical Imaging, Neuroradiology Section, University of California San Francisco. San Francisco, California
| | - W P Dillon
- From the Department of Radiology and Biomedical Imaging, Neuroradiology Section, University of California San Francisco. San Francisco, California
| | - V N Shah
- From the Department of Radiology and Biomedical Imaging, Neuroradiology Section, University of California San Francisco. San Francisco, California
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Norager NH, Olsen MH, Riedel CS, Juhler M. Changes in intracranial pressure and pulse wave amplitude during postural shifts. Acta Neurochir (Wien) 2020; 162:2983-2989. [PMID: 32886224 DOI: 10.1007/s00701-020-04550-z] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2020] [Accepted: 08/24/2020] [Indexed: 11/27/2022]
Abstract
BACKGROUND Monitoring of intracranial pressure (ICP) and ICP pulse wave amplitude (PWA) is an integrated part of neurosurgery. An increase in ICP usually leads to an increase in PWA. These findings have yet to be replicated during the positional shift from supine to upright, where we only know that ICP decreases. Our main aim is to clarify whether the positional shift also results in a change in pulse wave amplitude. METHOD Our database was retrospectively reviewed for subjects having had a standardized investigation of positional ICP. In all subjects, mean ICP and PWA were determined with both an automatic and a manual method and compared using Student's t test. Finally, ICP and PWA were tested for correlation in both in supine and upright position. RESULTS The study included 29 subjects. A significant change in ICP (Δ14.1 mmHg, p < 0.01) and no significant change in PWA (Δ0.4 mmHg, p = 0.06) were found. Furthermore, a linear correlation between ICP and PWA was found in both supine and upright positions (p < 0.01). CONCLUSIONS We found that during the positional shift from supine to upright, ICP is reduced while PWA remains unaffected. This indicates that the pressure-volume curve is shifted downward according to a hydrostatic pressure offset, while the slope of the curve does not change. In addition, the correlation between ICP and PWA in both supine and upright position validates the previous research on the matter.
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Affiliation(s)
| | | | - Casper Schwartz Riedel
- Department of Neurosurgery, Rigshospitalet, Copenhagen, Denmark
- Department of Neurophysiology, Rigshospitalet, Glostrup, Denmark
| | - Marianne Juhler
- Department of Neurosurgery, Rigshospitalet, Copenhagen, Denmark
- Department of Neurosurgery, Aarhus University Hospital, Aarhus, Denmark
- Institute of Clinical Medicine, University of Copenhagen, Copenhagen, Denmark
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7
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Does the brain have mechanical compliance? MAGMA (NEW YORK, N.Y.) 2020; 33:753-756. [PMID: 32770369 DOI: 10.1007/s10334-020-00880-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/26/2020] [Revised: 07/29/2020] [Accepted: 07/31/2020] [Indexed: 10/23/2022]
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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: 59] [Impact Index Per Article: 14.8] [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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Lalou AD, Czosnyka M, Garnett MR, Nabbanja E, Petrella G, Hutchinson PJ, Pickard JD, Czosnyka Z. Shunt infusion studies: impact on patient outcome, including health economics. Acta Neurochir (Wien) 2020; 162:1019-1031. [PMID: 32078047 PMCID: PMC7156359 DOI: 10.1007/s00701-020-04212-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2019] [Accepted: 01/06/2020] [Indexed: 12/03/2022]
Abstract
Objectives The diagnosis of shunt malfunction is often not straightforward. We have explored, in symptomatic shunted patients with hydrocephalus or pseudotumour cerebri syndrome (PTCS), the accuracy of CSF infusion tests in differentiating a functioning shunt from one with possible problems, and the health economic consequences. Methods Participants: hydrocephalus/PTCS patients with infusion tests performed from January 2013 until December 2015. We followed patients up after 6 and 12 months from the test to determine whether they had improved, had persisting symptoms or had required urgent revision. We calculated the total cost savings of revision versus infusion tests and standard protocol of revision and ICP monitoring versus infusion tests. Results Three hundred sixty-five shunt infusion tests had been performed where a shunt prechamber/reservoir was present. For hydrocephalus patients, more than half of the tests (~ 55%, 155 out of 280) showed no shunt malfunction versus 125 with possible malfunction (ages 4 months to 90 years old). For PTCS patients aged 10 to 77 years old, 47 had possible problems and 38 no indication for shunt malfunction. Overall, > 290 unnecessary revisions were avoided over 3 years’ time. Two hundred fifty-eight (> 85%) of those non-surgically managed, remained well, did not deteriorate and did not require surgery. No infections were associated with infusion studies. For Cambridge, the overall savings from avoiding revisions was £945,415 annually. Conclusions Our results provide evidence of the importance of shunt testing in vivo to confirm shunt malfunction. Avoiding unnecessary shunt revisions carries a strong health benefit for patients that also translates to a significant financial benefit for the National Health Service and potentially for other healthcare systems worldwide. Electronic supplementary material The online version of this article (10.1007/s00701-020-04212-0) contains supplementary material, which is available to authorized users.
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Donnelly J, Smielewski P, Adams H, Zeiler FA, Cardim D, Liu X, Fedriga M, Hutchinson P, Menon DK, Czosnyka M. Observations on the Cerebral Effects of Refractory Intracranial Hypertension After Severe Traumatic Brain Injury. Neurocrit Care 2020; 32:437-447. [PMID: 31240622 PMCID: PMC7082389 DOI: 10.1007/s12028-019-00748-x] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
BACKGROUND Raised intracranial pressure (ICP) is a prominent cause of morbidity and mortality after severe traumatic brain injury (TBI). However, in the clinical setting, little is known about the cerebral physiological response to severe and prolonged increases in ICP. METHODS Thirty-three severe TBI patients from a single center who developed severe refractory intracranial hypertension (ICP > 40 mm Hg for longer than 1 h) with ICP, arterial blood pressure, and brain tissue oxygenation (PBTO2) monitoring (subcohort, n = 9) were selected for retrospective review. Secondary parameters reflecting autoregulation (including pressure reactivity index-PRx, which was available in 24 cases), cerebrospinal compensatory reserve (RAP), and ICP pulse amplitude were calculated. RESULTS PRx deteriorated from 0.06 ± 0.26 a.u. at baseline levels of ICP to 0.57 ± 0.24 a.u. (p < 0.0001) at high levels of ICP (> 50 mm Hg). In 4 cases, PRx was impaired (> 0.25 a.u.) before ICP was raised above 25 mm Hg. Concurrently, PBTO2 decreased from 27.3 ± 7.32 mm Hg at baseline ICP to 12.68 ± 7.09 mm Hg at high levels of ICP (p < 0.001). The pulse amplitude of the ICP waveform increased with increasing ICP but showed an 'upper breakpoint'-whereby further increases in ICP lead to decreases in pulse amplitude-in 6 out of the 33 patients. DISCUSSION Severe intracranial hypertension after TBI leads to decreased brain oxygenation, impaired pressure reactivity, and changes in the pulse amplitude of ICP. Impaired pressure reactivity may denote increased risk of developing refractory intracranial hypertension in some patients.
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Affiliation(s)
- Joseph Donnelly
- Brain Physics Laboratory, Division of Neurosurgery, Department of Clinical Neurosciences, Cambridge Biomedical Campus, University of Cambridge, Cambridge, UK.
- Department of Anaesthesiology, Level 12 Auckland Support Building, Auckland City Hospital, University of Auckland, 2 Park Road, Grafton, Auckland, New Zealand.
| | - Peter Smielewski
- Brain Physics Laboratory, Division of Neurosurgery, Department of Clinical Neurosciences, Cambridge Biomedical Campus, University of Cambridge, Cambridge, UK
| | - Hadie Adams
- Division of Neurosurgery, Department of Clinical Neurosciences, Cambridge Biomedical Campus, University of Cambridge, Cambridge, UK
| | - Frederick A Zeiler
- Division of Anaesthesia, Department of Medicine, Addenbrooke's Hospital, University of Cambridge, Cambridge, UK
- Department of Surgery, Rady Faculty of Health Sciences, University of Manitoba, Winnipeg, Canada
- Biomedical Engineering, Faculty of Engineering, University of Manitoba, Winnipeg, Canada
- Department of Human Anatomy and Cell Sciences, Rady Faculty of Health Sciences, University of Manitoba, Winnipeg, Canada
| | - Danilo Cardim
- Department of Anesthesiology, Pharmacology and Therapeutics, Vancouver General Hospital, University of British Columbia, Vancouver, Canada
| | - Xiuyun Liu
- Brain Physics Laboratory, Division of Neurosurgery, Department of Clinical Neurosciences, Cambridge Biomedical Campus, University of Cambridge, Cambridge, UK
| | - Marta Fedriga
- Brain Physics Laboratory, Division of Neurosurgery, Department of Clinical Neurosciences, Cambridge Biomedical Campus, University of Cambridge, Cambridge, UK
| | - Peter Hutchinson
- Division of Neurosurgery, Department of Clinical Neurosciences, Cambridge Biomedical Campus, University of Cambridge, Cambridge, UK
- NIHR Global Health Research Group on Neurotrauma, University of Cambridge, Cambridge, UK
| | - David K Menon
- Division of Anaesthesia, Department of Medicine, Addenbrooke's Hospital, University of Cambridge, Cambridge, UK
- NIHR Global Health Research Group on Neurotrauma, University of Cambridge, Cambridge, UK
| | - Marek Czosnyka
- Brain Physics Laboratory, Division of Neurosurgery, Department of Clinical Neurosciences, Cambridge Biomedical Campus, University of Cambridge, Cambridge, UK
- Institute of Electronic Systems, Warsaw University of Technology, Warsaw, Poland
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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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Baghbani R. An Electrical Model of Hydrocephalus Shunt Incorporating the CSF Dynamics. Sci Rep 2019; 9:9751. [PMID: 31278327 PMCID: PMC6611941 DOI: 10.1038/s41598-019-46328-z] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2019] [Accepted: 06/26/2019] [Indexed: 01/18/2023] Open
Abstract
The accumulation of cerebrospinal fluid (CSF) in brain ventricles and subarachnoid space is known as hydrocephalus. Hydrocephalus is a result of disturbances in the secretion or absorption process of CSF. A hydrocephalus shunt is an effective method for the treatment of hydrocephalus. In this paper, at first, the procedures of secretion, circulation, and absorption of CSF are studied and subsequently, the mathematical relations governing the pressures in different interacting compartments of the brain are considered. A mechanical-electrical model is suggested based on the brain physiology and blood circulation. In the proposed model, hydrocephalus is modeled with an incremental resistance (Ro) and hydrocephalus shunt, which is a low resistance path to drain the accumulated CSF in the brain ventricles, is modeled with a resistance in series with a diode. At the end, the simulation results are shown. The simulation results can be used to predict the shunt efficiency in reducing CSF pressure and before a real shunt implementation surgery is carried out in a patient's body.
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Affiliation(s)
- R Baghbani
- Biomedical Engineering Department, Hamedan University of Technology, Hamedan, Iran.
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Doron O, Or T, Battino L, Rosenthal G, Barnea O. Cerebral blood flow augmentation using a cardiac-gated intracranial pulsating balloon pump in a swine model of elevated ICP. J Neurosurg 2019; 132:1606-1615. [PMID: 30978692 DOI: 10.3171/2019.1.jns182864] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2018] [Accepted: 01/03/2019] [Indexed: 11/06/2022]
Abstract
OBJECTIVE Augmenting brain perfusion or reducing intracranial pressure (ICP) dose is the end target of many therapies in the neuro-critical care unit. Many present therapies rely on aggressive systemic interventions that may lead to untoward effects. Previous studies have used a cardiac-gated intracranial balloon pump (ICBP) to model hydrocephalus or to flatten the ICP waveform. The authors sought to sought to optimize ICBP activation parameters to improve cerebral physiological parameters in a swine model of raised ICP. METHODS The authors developed a cardiac-gated ICBP in which the volume, timing, and duty cycle (time relative to a single cardiac cycle) of balloon inflation could be altered. They studied the ICBP in a swine model of elevated ICP attained by continuous intracranial fluid infusion with continuous monitoring of systemic and cerebral physiological parameters, and defined two specific protocols of ICBP activation. RESULTS Eleven swine were studied, 3 of which were studied to define the optimal timing, volume, and duty cycle of balloon inflation. Eight swine were studied with two defined protocols at baseline and with ICP gradually raised to a mean of 30.5 mm Hg. ICBP activation caused a consistent modification of the ICP waveform. Two ICBP activation protocols were used. Balloon activation protocol A led to a consistent elevation in cerebral blood flow (8%-25% above baseline, p < 0.00001). Protocol B resulted in a modest reduction of ICP over time (8%-11%, p < 0.0001) at all ICP levels. Neither protocol significantly affected systemic physiological parameters. CONCLUSIONS The preliminary results indicate that optimized protocols of ICBP activation may have beneficial effects on cerebral physiological parameters, with minimal effect on systemic parameters. Further studies are warranted to explore whether ICBP protocols may be of clinical benefit in patients with brain injuries with increased ICP.
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Affiliation(s)
- Omer Doron
- 1Department of Neurosurgery, Hadassah-Hebrew University Medical Center, Jerusalem; and.,2Department of Biomedical Engineering, Tel Aviv University, Tel Aviv, Israel
| | - Tal Or
- 2Department of Biomedical Engineering, Tel Aviv University, Tel Aviv, Israel
| | - Limor Battino
- 2Department of Biomedical Engineering, Tel Aviv University, Tel Aviv, Israel
| | - Guy Rosenthal
- 1Department of Neurosurgery, Hadassah-Hebrew University Medical Center, Jerusalem; and
| | - Ofer Barnea
- 2Department of Biomedical Engineering, Tel Aviv University, Tel Aviv, Israel
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14
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Burman R, Alperin N, Lee SH, Ertl-Wagner B. Patient-specific cranio-spinal compliance distribution using lumped-parameter model: its relation with ICP over a wide age range. Fluids Barriers CNS 2018; 15:29. [PMID: 30428887 PMCID: PMC6236958 DOI: 10.1186/s12987-018-0115-4] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2018] [Accepted: 10/01/2018] [Indexed: 12/23/2022] Open
Abstract
Background The distribution of cranio-spinal compliance (CSC) in the brain and spinal cord is a fundamental question, as it would determine the overall role of the compartments in modulating ICP in healthy and diseased states. Invasive methods for measurement of CSC using infusion-based techniques provide overall CSC estimate, but not the individual sub-compartmental contribution. Additionally, the outcome of the infusion-based method depends on the infusion site and dynamics. This article presents a method to determine compliance distribution between the cranium and spinal canal non-invasively using data obtained from patients. We hypothesize that this CSC distribution is indicative of the ICP. Methods We propose a lumped-parameter model representing the hydro and hemodynamics of the cranio-spinal system. The input and output to the model are phase-contrast MRI derived volumetric transcranial blood flow measured in vivo, and CSF flow at the spinal cervical level, respectively. The novelty of the method lies in the model mathematics that predicts CSC distribution (that obeys the physical laws) from the system dc gain of the discrete-domain transfer function. 104 healthy individuals (48 males, 56 females, age 25.4 ± 14.9 years, range 3–60 years) without any history of neurological diseases, were used in the study. Non-invasive MR assisted estimate of ICP was calculated and compared with the cranial compliance to prove our hypothesis. Results A significant negative correlation was found between model-predicted cranial contribution to CSC and MR-ICP. The spinal canal provided majority of the compliance in all the age groups up to 40 years. However, no single sub-compartment provided majority of the compliance in 41–60 years age group. The cranial contribution to CSC and MR-ICP were significantly correlated with age, with gender not affecting the compliance distribution. Spinal contribution to CSC significantly positively correlated with CSF stroke volume. Conclusions This paper describes MRI-based non-invasive way to determine the cranio-spinal compliance distribution in the brain and spinal canal sub-compartments. The proposed mathematics makes the model always stable and within the physiological range. The model-derived cranial compliance was strongly negatively correlated to non-invasive MR-ICP data from 104 patients, indicating that compliance distribution plays a major role in modulating ICP.
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Affiliation(s)
- Ritambhar Burman
- Biomedical Engineering Department, University of Miami, Coral Gables, FL, 33146, USA
| | - Noam Alperin
- Radiology Department, University of Miami, Miami, FL, 33136, USA.
| | - Sang H Lee
- Radiology Department, University of Miami, Miami, FL, 33136, USA
| | - Brigit Ertl-Wagner
- Department of Radiology, Ludwig-Maximilians University, 80539, Munich, Germany
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15
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Evensen KB, Paulat K, Prieur F, Holm S, Eide PK. Utility of the Tympanic Membrane Pressure Waveform for Non-invasive Estimation of The Intracranial Pressure Waveform. Sci Rep 2018; 8:15776. [PMID: 30361489 PMCID: PMC6202360 DOI: 10.1038/s41598-018-34083-6] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2018] [Accepted: 10/11/2018] [Indexed: 11/09/2022] Open
Abstract
Time domain analysis of the intracranial pressure (ICP) waveform provides important information about the intracranial pressure-volume reserve capacity. The aim here was to explore whether the tympanic membrane pressure (TMP) waveform can be used to non-invasively estimate the ICP waveform. Simultaneous invasive ICP and non-invasive TMP signals were measured in a total of 28 individuals who underwent invasive ICP measurements as a part of their clinical work up (surveillance after subarachnoid hemorrhage in 9 individuals and diagnostic for CSF circulation disorders in 19 individuals). For each individual, a transfer function estimate between the invasive ICP and non-invasive TMP signals was established in order to explore the potential of the method. To validate the results, ICP waveform parameters including the mean wave amplitude (MWA) were computed in the time domain for both the ICP estimates and the invasively measured ICP. The patient-specific non-invasive ICP signals predicted MWA rather satisfactorily in 4/28 individuals (14%). In these four patients the differences between original and estimated MWA were <1.0 mmHg in more than 50% of observations, and <0.5 mmHg in more than 20% of observations. The study further disclosed that the cochlear aqueduct worked as a physical lowpass filter.
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Affiliation(s)
- Karen Brastad Evensen
- Department of Informatics, University of Oslo, Oslo, Norway.,Department of Neurosurgery, Oslo University Hospital - Rikshospitalet, Oslo, Norway
| | - Klaus Paulat
- Institute of Medical Engineering and Mechatronics, Hochschule Ulm, Ulm, Germany
| | - Fabrice Prieur
- Department of Informatics, University of Oslo, Oslo, Norway
| | - Sverre Holm
- Department of Informatics, University of Oslo, Oslo, Norway
| | - Per Kristian Eide
- Department of Neurosurgery, Oslo University Hospital - Rikshospitalet, Oslo, Norway. .,Institute of Clinical Medicine, Faculty of Medicine, University of Oslo, Oslo, Norway.
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16
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Okon MD, Roberts CJ, Mahmoud AM, Springer AN, Small RH, McGregor JM, Katz SE. Characteristics of the cerebrospinal fluid pressure waveform and craniospinal compliance in idiopathic intracranial hypertension subjects. Fluids Barriers CNS 2018; 15:21. [PMID: 30064442 PMCID: PMC6069551 DOI: 10.1186/s12987-018-0106-5] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2018] [Accepted: 07/14/2018] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Idiopathic intracranial hypertension (IIH) is a condition of abnormally high intracranial pressure with an unknown etiology. The objective of this study is to characterize craniospinal compliance and measure the cerebrospinal fluid (CSF) pressure waveform as CSF is passively drained during a diagnostic and therapeutic lumbar puncture (LP) in IIH. METHODS Eighteen subjects who met the Modified Dandy Criteria, including papilledema and visual field loss, received an ultrasound guided LP where CSF pressure (CSFP) was recorded at each increment of CSF removal. Joinpoint regression models were used to calculate compliance from CSF pressure and the corresponding volume removed at each increment for each subject. Twelve subjects had their CSFP waveform recorded with an electronic transducer. Body mass index, mean CSFP, and cerebral perfusion pressure (CPP) were also calculated. T-tests were used to compare measurements, and correlations were performed between parameters. RESULTS Cerebrospinal fluid pressure, CSFP pulse amplitude (CPA), and CPP were found to be significantly different (p < 0.05) before and after the LP. CSFP and CPA decreased after the LP, while CPP increased. The craniospinal compliance significantly increased (p < 0.05) post-LP. CPA and CSFP were significantly positively correlated. CONCLUSIONS Both low craniospinal compliance (at high CSFP) and high craniospinal compliance (at low CSFP) regions were determined. The CSFP waveform morphology in IIH was characterized and CPA was found to be positively correlated to the magnitude of CSFP. Future studies will investigate how craniospinal compliance may correlate to symptoms and/or response to therapy in IIH subjects.
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Affiliation(s)
- Monica D Okon
- Department of Biomedical Engineering, The Ohio State University, 1080 Carmack Rd, Columbus, OH, 43210, USA
| | - Cynthia J Roberts
- Department of Biomedical Engineering, The Ohio State University, 1080 Carmack Rd, Columbus, OH, 43210, USA. .,Department of Ophthalmology & Visual Science, The Ohio State University, 915 Olentangy River Rd, Columbus, OH, 43212, USA.
| | - Ashraf M Mahmoud
- Department of Biomedical Engineering, The Ohio State University, 1080 Carmack Rd, Columbus, OH, 43210, USA.,Department of Ophthalmology & Visual Science, The Ohio State University, 915 Olentangy River Rd, Columbus, OH, 43212, USA
| | - Andrew N Springer
- Department of Anesthesiology, The Ohio State University, 410W. 10th Avenue, Columbus, OH, 43210, USA
| | - Robert H Small
- Department of Biomedical Engineering, The Ohio State University, 1080 Carmack Rd, Columbus, OH, 43210, USA.,Department of Anesthesiology, The Ohio State University, 410W. 10th Avenue, Columbus, OH, 43210, USA
| | - John M McGregor
- Department of Neurosurgery, The Ohio State University, 1581 Dodd Drive, Columbus, OH, 43210, USA
| | - Steven E Katz
- Ohio Neuro-Ophthalmology, Orbital Disease & Oculoplastics, 3545 Olentangy River Rd, Suite 200, Columbus, OH, 43214, USA
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17
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Yao HD, Svensson MY, Nilsson H. Deformation of dorsal root ganglion due to pressure transients of venous blood and cerebrospinal fluid in the cervical vertebral canal. J Biomech 2018; 76:16-26. [PMID: 29801662 DOI: 10.1016/j.jbiomech.2018.05.012] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2017] [Revised: 04/26/2018] [Accepted: 05/07/2018] [Indexed: 11/17/2022]
Abstract
The dorsal root ganglion (DRG) that is embedded in the foramen of the cervical vertebra can be injured during a whiplash motion. A potential cause is that whilst the neck bends in the whiplash motion, the changes of spinal canal volume induce impulsive pressure transients in the venous blood outside the dura mater (DM) and in the cerebrospinal fluid (CSF) inside the DM. The fluids can dynamically interact with the DRG and DM, which are deformable. In this work, the interaction is investigated numerically using a strong-coupling partitioned method that synchronize the computations of the fluid and structure. It is found that the interaction includes two basic processes, i.e., the pulling and pressing processes. In the pulling process, the DRG is stretched towards the spinal canal, and the venous blood is driven into the canal via the foramen. This process results from negative pressure in the fluids. In contrast, the pressing process is caused by positive pressure that leads to compression of the DRG and the outflow of the venous blood from the canal. The largest pressure gradient is observed at the foramen, where the DRG is located at. The DRG is subject to prominent von Mises stress near its end, which is fixed without motions. The negative internal pressure is more efficient to deform the DRG than the positive internal pressure. This indicates that the most hazardous condition for the DRG is the pulling process.
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Affiliation(s)
- Hua-Dong Yao
- Chalmers University of Technology, SE-412 96 Gothenburg, Sweden.
| | - Mats Y Svensson
- Chalmers University of Technology, SE-412 96 Gothenburg, Sweden; SAFER Vehicle and Traffic Safety Centre, Chalmers University of Technology, Sweden
| | - Håkan Nilsson
- Chalmers University of Technology, SE-412 96 Gothenburg, Sweden
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18
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Unnerbäck M, Bloomfield EL, Söderström S, Reinstrup P. The intracranial pressure curve correlates to the pulsatile component of cerebral blood flow. J Clin Monit Comput 2018; 33:77-83. [PMID: 29549499 PMCID: PMC6315053 DOI: 10.1007/s10877-018-0129-0] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2017] [Accepted: 03/13/2018] [Indexed: 12/02/2022]
Abstract
Current methods to measure cerebral blood flow (CBF) in the neuro critical care setting cannot monitor the CBF continuously. In contrast, continuous measurement of intracranial pressure (ICP) is readily accomplished, and there is a component of ICP that correlates with arterial inflow of blood into the cranial cavity. This property may have utility in using continuous ICP curve analysis to continuously estimate CBF. We examined the data from 13 patients, monitored with an intraventricular ICP device determining the pulsatile amplitude ICPamp as well as the area under the ICP curve (AUCICP). Using an elastance measurement, the ICP curve was converted to craniospinal volume (AUCΔV). The patients were examined with Phase Contrast Magnetic Resonance Imaging (MRI), measuring flow in the carotid and vertebral arteries. This made it possible to calculate CBF for one cardiac cycle (ccCBFMRtot) and divide it into the pulsatile (ccCBFMRpuls) and non-pulsatile (ccCBFMRconst) flow. ICP derived data and MRI measurements were compared. Linear regression was used to establish wellness of fit and ANOVA was used to calculate the P value. No correlation was found between ICPamp and the ccICPMRpuls (P = 0.067). In contrast there was a correlation between the AUCICP and ccCBFMRpuls (R2 = 0.440 P = 0.013). The AUCΔV correlated more appropriately with the ccCBFMRpuls. (R2 = 0.688 P < 0.001). Our findings suggests that the pulsatile part of the intracranial pressure curve, especially when transformed into a volume curve, correlates to the pulsatile part of the CBF.
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Affiliation(s)
- Mårten Unnerbäck
- Department of Clinical Sciences Lund, Intensive Care and Perioperative Medicine, Lund University, Skane University Hospital, Malmö, Sweden. .,IPV SUS Malmö, Inga Marie Nilssons gata 47, 205 02, Malmö, Sweden.
| | | | - Sven Söderström
- Department of Clinical Sciences Lund, Neurosurgery, Lund University, Skane University Hospital, Lund, Sweden
| | - Peter Reinstrup
- Department of Clinical Sciences Lund, Neurosurgery, Lund University, Skane University Hospital, Lund, Sweden
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19
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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: 80] [Impact Index Per Article: 13.3] [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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20
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Calviello L, Donnelly J, Cardim D, Robba C, Zeiler FA, Smielewski P, Czosnyka M. Compensatory-Reserve-Weighted Intracranial Pressure and Its Association with Outcome After Traumatic Brain Injury. Neurocrit Care 2017; 28:212-220. [DOI: 10.1007/s12028-017-0475-7] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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21
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Thompson SD, Coutts A, Craven CL, Toma AK, Thorne LW, Watkins LD. Elective ICP monitoring: how long is long enough? Acta Neurochir (Wien) 2017; 159:485-490. [PMID: 28108854 DOI: 10.1007/s00701-016-3074-z] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2016] [Accepted: 12/29/2016] [Indexed: 10/20/2022]
Abstract
BACKGROUND Intracranial pressure monitoring is commonly undertaken to assess and manage acute patients following head injury. However, ICP monitoring can also be a useful diagnostic tool in the management of CSF dynamics in elective patients. To date, there is little published research to suggest how long these elective patients require ICP monitoring in order to gain an accurate picture of a patient's ICP dynamics. At the author's institution, a minimum of 48-h data collection is currently undertaken in patients with a suspected ICP abnormality. METHODS A retrospective audit was undertaken comparing overall median ICP and overall median pulse amplitude data at three time points, 24 h, 48 h and total time analysed (if longer than 48 h). Paired T-test was used to assess if there were statistically significant differences between 24-h versus 48-h monitoring and total duration of monitoring. All patients admitted over a 6-month period for ICPM who met the inclusion/exclusion criteria were included. RESULTS Eighteen patients met the criteria. Median age was 45.8 years, range 22-83 years, 12 female and 6 male. No complications were experienced as a result of ICPM. Diagnosis included NPH, IIH, suspected shunt malfunction and Chiari malformation. The results demonstrated that there is no statistical difference between 24 h and 48 h or longer for both overall median ICP and pulse amplitude. CONCLUSION The results of this study demonstrate that ICP monitoring of elective adult patients using a Spiegelberg intraparenchymal bolt for 24 h gives an accurate picture of a patient's ICP dynamics compared with longer periods of monitoring.
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22
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Czosnyka M, Pickard J, Steiner L. Principles of intracranial pressure monitoring and treatment. HANDBOOK OF CLINICAL NEUROLOGY 2017; 140:67-89. [DOI: 10.1016/b978-0-444-63600-3.00005-2] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
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23
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Eide PK. The correlation between pulsatile intracranial pressure and indices of intracranial pressure-volume reserve capacity: results from ventricular infusion testing. J Neurosurg 2016; 125:1493-1503. [PMID: 26918478 DOI: 10.3171/2015.11.jns151529] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
OBJECTIVE The objective of this study was to examine how pulsatile and static intracranial pressure (ICP) scores correlate with indices of intracranial pressure-volume reserve capacity, i.e., intracranial elastance (ICE) and intracranial compliance (ICC), as determined during ventricular infusion testing. METHODS All patients undergoing ventricular infusion testing and overnight ICP monitoring during the 6-year period from 2007 to 2012 were included in the study. Clinical data were retrieved from a quality registry, and the ventricular infusion pressure data and ICP scores were retrieved from a pressure database. The ICE and ICC (= 1/ICE) were computed during the infusion phase of the infusion test. RESULTS During the period from 2007 to 2012, 82 patients with possible treatment-dependent hydrocephalus underwent ventricular infusion testing within the department of neurosurgery. The infusion tests revealed a highly significant positive correlation between ICE and the pulsatile ICP scores mean wave amplitude (MWA) and rise-time coefficient (RTC), and the static ICP score mean ICP. The ICE was negatively associated with linear measures of ventricular size. The overnight ICP recordings revealed significantly increased MWA (> 4 mm Hg) and RTC (> 20 mm Hg/sec) values in patients with impaired ICC (< 0.5 ml/mm Hg). CONCLUSIONS In this study cohort, there was a significant positive correlation between pulsatile ICP and ICE measured during ventricular infusion testing. In patients with impaired ICC during infusion testing (ICC < 0.5 ml/mm Hg), overnight ICP recordings showed increased pulsatile ICP (MWA > 4 mm Hg, RTC > 20 mm Hg/sec), but not increased mean ICP (< 10-15 mm Hg). The present data support the assumption that pulsatile ICP (MWA and RTC) may serve as substitute markers of pressure-volume reserve capacity, i.e., ICE and ICC.
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Affiliation(s)
- Per Kristian Eide
- Department of Neurosurgery, Oslo University Hospital-Rikshospitalet, and Faculty of Medicine, University of Oslo, Norway
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24
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Gehlen M, Kurtcuoglu V, Daners MS. Patient Specific Hardware-in-the-Loop Testing of Cerebrospinal Fluid Shunt Systems. IEEE Trans Biomed Eng 2016. [DOI: 10.1109/tbme.2015.2457681] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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25
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Yao HD, Svensson MY, Nilsson H. Transient pressure changes in the vertebral canal during whiplash motion--A hydrodynamic modeling approach. J Biomech 2016; 49:416-22. [PMID: 26827171 DOI: 10.1016/j.jbiomech.2016.01.005] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2015] [Revised: 12/30/2015] [Accepted: 01/04/2016] [Indexed: 11/17/2022]
Abstract
In vehicle collisions, the occupant's torso is accelerated in a given direction while the unsupported head tends to lag behind. This mechanism results in whiplash motion to the neck. In whiplash experiments conducted for animals, pressure transients have been recorded in the spinal canal. It was hypothesized that the transients caused dorsal root ganglion dysfunction. Neck motion introduces volume changes inside the vertebral canal. The changes require an adaptation which is likely achieved by redistribution of blood volume in the internal vertebral venous plexus (IVVP). Pressure transients then arise from the rapid redistribution. The present study aimed to explore the hypothesis theoretically and analytically. Further, the objectives were to quantify the effect of the neck motion on the pressure generation and to identify the physical factors involved. We developed a hydrodynamic system of tubes that represent the IVVP and its lateral intervertebral vein connections. An analytical model was developed for an anatomical geometrical relation that the venous blood volume changes with respect to the vertebral angular displacement. This model was adopted in the hydrodynamic tube system so that the system can predict the pressure transients on the basis of the neck vertebral motion data from a whiplash experiment. The predicted pressure transients were in good agreement with the earlier experimental data. A parametric study was conducted and showed that the system can be used to assess the influences of anatomical geometrical properties and vehicle collision severity on the pressure generation.
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Affiliation(s)
- Hua-Dong Yao
- Chalmers University of Technology, SE-412 96 Gothenburg, Sweden.
| | - Mats Y Svensson
- Chalmers University of Technology, SE-412 96 Gothenburg, Sweden
| | - Håkan Nilsson
- Chalmers University of Technology, SE-412 96 Gothenburg, Sweden
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26
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Varsos GV, Werndle MC, Czosnyka ZH, Smielewski P, Kolias AG, Phang I, Saadoun S, Bell BA, Zoumprouli A, Papadopoulos MC, Czosnyka M. Intraspinal pressure and spinal cord perfusion pressure after spinal cord injury: an observational study. J Neurosurg Spine 2015; 23:763-71. [DOI: 10.3171/2015.3.spine14870] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
OBJECT
In contrast to intracranial pressure (ICP) in traumatic brain injury (TBI), intraspinal pressure (ISP) after traumatic spinal cord injury (TSCI) has not received the same attention in terms of waveform analysis. Based on a recently introduced technique for continuous monitoring of ISP, here the morphological characteristics of ISP are observationally described. It was hypothesized that the waveform analysis method used to assess ICP could be similarly applied to ISP.
METHODS
Data included continuous recordings of ISP and arterial blood pressure (ABP) in 18 patients with severe TSCI.
RESULTS
The morphology of the ISP pulse waveform resembled the ICP waveform shape and was composed of 3 peaks representing percussion, tidal, and dicrotic waves. Spectral analysis demonstrated the presence of slow, respiratory, and pulse waves at different frequencies. The pulse amplitude of ISP was proportional to the mean ISP, suggesting a similar exponential pressure-volume relationship as in the intracerebral space. The interaction between the slow waves of ISP and ABP is capable of characterizing the spinal autoregulatory capacity.
CONCLUSIONS
This preliminary observational study confirms morphological and spectral similarities between ISP in TSCI and ICP. Therefore, the known methods used for ICP waveform analysis could be transferred to ISP analysis and, upon verification, potentially used for monitoring TSCI patients.
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Affiliation(s)
- Georgios V. Varsos
- 1Division of Neurosurgery, Department of Clinical Neurosciences, Addenbrooke’s Hospital, University of Cambridge, Cambridge
| | | | - Zofia H. Czosnyka
- 1Division of Neurosurgery, Department of Clinical Neurosciences, Addenbrooke’s Hospital, University of Cambridge, Cambridge
| | - Peter Smielewski
- 1Division of Neurosurgery, Department of Clinical Neurosciences, Addenbrooke’s Hospital, University of Cambridge, Cambridge
| | - Angelos G. Kolias
- 1Division of Neurosurgery, Department of Clinical Neurosciences, Addenbrooke’s Hospital, University of Cambridge, Cambridge
| | - Isaac Phang
- 2Academic Neurosurgery Unit, St. George’s University of London
| | - Samira Saadoun
- 2Academic Neurosurgery Unit, St. George’s University of London
| | - B. Anthony Bell
- 2Academic Neurosurgery Unit, St. George’s University of London
| | - Argyro Zoumprouli
- 3Department of Anaesthesia, St. George’s Hospital, London, United Kingdom; and
| | | | - Marek Czosnyka
- 1Division of Neurosurgery, Department of Clinical Neurosciences, Addenbrooke’s Hospital, University of Cambridge, Cambridge
- 4Institute of Electronic Systems, Warsaw University of Technology, Warsaw, Poland
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27
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Reinitz LZ, Bajzik G, Garamvölgyi R, Petneházy Ö, Lassó A, Abonyi-Tóth Z, Lőrincz B, Sótonyi P. COMPARISON BETWEEN MAGNETIC RESONANCE IMAGING ESTIMATES OF EXTRACRANIAL CEREBROSPINAL FLUID VOLUME AND PHYSICAL MEASUREMENTS IN HEALTHY DOGS. Vet Radiol Ultrasound 2015; 56:658-65. [PMID: 26311617 DOI: 10.1111/vru.12283] [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: 08/02/2014] [Accepted: 05/13/2015] [Indexed: 11/29/2022] Open
Abstract
Dosages for myelography procedures in dogs are based on a hypothetical proportional relationship between bodyweight and cerebrospinal fluid (CSF) volume. Anecdotal radiographic evidence and recent studies have challenged the existence of such a defined relationship in dogs. The objectives of this prospective cross-sectional study were to describe CSF volumes using magnetic resonance imaging (MRI) in a group of clinically healthy dogs, measure the accuracy of MRI CSF volumes, and compare MRI CSF volumes with dog physical measurements. A sampling perfection with application optimized contrast using different flip-angle evolution MRI examination of the central nervous system was carried out on 12 healthy, male mongrel dogs, aged between 3 and 5 years with a bodyweight range of 7.5-35.0 kg. The images were processed with image analysis freeware (3D Slicer) in order to calculate the volume of extracranial CSF. Cylindrical phantoms of known volume were included in scans and used to calculate accuracy of MRI volume estimates. The accuracy of MRI volume estimates was 99.8%. Extracranial compartment CSF volumes ranged from 20.21 to 44.06 ml. Overall volume of the extracranial CSF increased linearly with bodyweight, but the proportional volume (ml/bodyweight kilograms) of the extracranial CSF was inversely proportional to bodyweight. Relative ratios of volumes in the cervical, thoracic, and lumbosacral regions were constant. Findings indicated that the current standard method of using body weight to calculate dosages of myelographic contrast agents in dogs may need to be revised.
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Affiliation(s)
- László Z Reinitz
- Department of Anatomy and Histology, Faculty of Veterinary Science, Szent István University, Hungary
| | - Gábor Bajzik
- Institute of Diagnostic Imaging and Radiation Oncology, Kaposvár University, Hungary
| | - Rita Garamvölgyi
- Institute of Diagnostic Imaging and Radiation Oncology, Kaposvár University, Hungary
| | - Örs Petneházy
- Institute of Diagnostic Imaging and Radiation Oncology, Kaposvár University, Hungary
| | - András Lassó
- School of Computing, Queen's University, Kingston, Canada
| | - Zsolt Abonyi-Tóth
- Department of Biomathematics and Informatics, Faculty of Veterinary Science, Szent István University, Hungary
| | - Borbála Lőrincz
- Institute of Diagnostic Imaging and Radiation Oncology, Kaposvár University, Hungary
| | - Péter Sótonyi
- Department of Anatomy and Histology, Faculty of Veterinary Science, Szent István University, Hungary
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Sæhle T, Eide PK. Characteristics of intracranial pressure (ICP) waves and ICP in children with treatment-responsive hydrocephalus. Acta Neurochir (Wien) 2015; 157:1003-14. [PMID: 25870129 DOI: 10.1007/s00701-015-2410-z] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2014] [Accepted: 03/23/2015] [Indexed: 10/23/2022]
Abstract
BACKGROUND One important goal of modern treatment of pediatric hydrocephalus is to normalize the intracranial pressure (ICP) and ICP volume reserve capacity to optimize normal brain development. Better knowledge of the characteristics of ICP waves/ICP in pediatric hydrocephalus may provide new insight into the mechanisms behind modern hydrocephalus treatment. The aim of the present work was to characterize the ICP waves/ICP in children with either communicating or non-communicating hydrocephalus who improved clinically after surgery. The hydrocephalic children not treated surgically following ICP monitoring served as reference patients. METHODS The patient material includes all children with hydrocephalus and no previous surgical treatment who underwent diagnostic ICP wave/ICP monitoring during the period 2002-2011. We retrieved the information about the patients from the patient records and the digitally stored ICP waveforms. The ICP wave characteristics amplitude, rise time and rise time coefficient and the mean ICP were determined in the patients treated surgically for their hydrocephalus. The findings were compared with findings in children not treated surgically after ICP monitoring who served as reference patients. RESULTS The patient material includes 58 patients. Thirty-one (53%) were treated surgically after ICP monitoring, of whom all improved clinically. As compared to the reference patients, patients treated surgically presented with increased ICP wave amplitudes (MWA) and mean ICP. Alterations were comparable in communicating and non-communicating hydrocephalus. We found no apparent association between the ICP wave/ICP scores and presence of symptoms, indices of ventricular size or age. CONCLUSIONS Children with either communicating or non-communicating hydrocephalus improving clinically after surgery presented with elevated MWA and mean ICP. In particular, the levels of MWA were raised to a magnitude seen when intracranial compliance is impaired. Hence, the present observations may support the idea that improvement of intracranial compliance can be an important mechanism by which shunts work in pediatric hydrocephalus.
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Sæhle T, Eide PK. Intracranial pressure monitoring in pediatric and adult patients with hydrocephalus and tentative shunt failure: a single-center experience over 10 years in 146 patients. J Neurosurg 2015; 122:1076-86. [PMID: 25679270 DOI: 10.3171/2014.12.jns141029] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
OBJECT In patients with hydrocephalus and shunts, lasting symptoms such as headache and dizziness may be indicative of shunt failure, which may necessitate shunt revision. In cases of doubt, the authors monitor intracranial pressure (ICP) to determine the presence of over- or underdrainage of CSF to tailor management. In this study, the authors reviewed their experience of ICP monitoring in shunt failure. The aims of the study were to identify the complications and impact of ICP monitoring, as well as to determine the mean ICP and characteristics of the cardiac-induced ICP waves in pediatric versus adult over- and underdrainage. METHODS The study population included all pediatric and adult patients with hydrocephalus and shunts undergoing diagnostic ICP monitoring for tentative shunt failure during the 10-year period from 2002 to 2011. The patients were allocated into 3 groups depending on how they were managed following ICP monitoring: no drainage failure, overdrainage, or underdrainage. While patients with no drainage failure were managed conservatively without further actions, over- or underdrainage cases were managed with shunt revision or shunt valve adjustment. The ICP and ICP wave scores were determined from the continuous ICP waveforms. RESULTS The study population included 71 pediatric and 75 adult patients. There were no major complications related to ICP monitoring, but 1 patient was treated for a postoperative superficial wound infection and another experienced a minor bleed at the tip of the ICP sensor. Following ICP monitoring, shunt revision was performed in 74 (51%) of 146 patients, while valve adjustment was conducted in 17 (12%) and conservative measures without any actions in 55 (38%). Overdrainage was characterized by a higher percentage of episodes with negative mean ICP less than -5 to -10 mm Hg. The ICP wave scores, in particular the mean ICP wave amplitude (MWA), best differentiated underdrainage. Neither mean ICP nor MWA levels showed any significant association with age. CONCLUSIONS In this cohort of pediatric and adult patients with hydrocephalus and tentative shunt failure, the risk of ICP monitoring was very low, and helped the authors avoid shunt revision in 49% of the patients. Mean ICP best differentiated overdrainage, which was characterized by a higher percentage of episodes with negative mean ICP less than -5 to -10 mm Hg. Underdrainage was best characterized by elevated MWA values, indicative of impaired intracranial compliance.
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Affiliation(s)
- Terje Sæhle
- Department of Neurosurgery, Oslo University Hospital-Rikshospitalet; and
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Hawthorne C, Piper I. Monitoring of intracranial pressure in patients with traumatic brain injury. Front Neurol 2014; 5:121. [PMID: 25076934 PMCID: PMC4100218 DOI: 10.3389/fneur.2014.00121] [Citation(s) in RCA: 74] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2014] [Accepted: 06/25/2014] [Indexed: 02/01/2023] Open
Abstract
Since Monro published his observations on the nature of the contents of the intracranial space in 1783, there has been investigation of the unique relationship between the contents of the skull and the intracranial pressure (ICP). This is particularly true following traumatic brain injury (TBI), where it is clear that elevated ICP due to the underlying pathological processes is associated with a poorer clinical outcome. Consequently, there is considerable interest in monitoring and manipulating ICP in patients with TBI. The two techniques most commonly used in clinical practice to monitor ICP are via an intraventricular or intraparenchymal catheter with a microtransducer system. Both of these techniques are invasive and are thus associated with complications such as hemorrhage and infection. For this reason, significant research effort has been directed toward development of a non-invasive method to measure ICP. The principle aims of ICP monitoring in TBI are to allow early detection of secondary hemorrhage and to guide therapies that limit intracranial hypertension (ICH) and optimize cerebral perfusion. However, information from the ICP value and the ICP waveform can also be used to assess the intracranial volume-pressure relationship, estimate cerebrovascular pressure reactivity, and attempt to forecast future episodes of ICH.
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Affiliation(s)
- Christopher Hawthorne
- Clinical Lecturer, Academic Unit of Anaesthesia, Pain and Critical Care Medicine, University of Glasgow, Glasgow, UK
| | - Ian Piper
- Clinical Physics, Southern General Hospital, Greater Glasgow Health Board, Glasgow, UK
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Prediction of methotrexate CNS distribution in different species - influence of disease conditions. Eur J Pharm Sci 2014; 57:11-24. [PMID: 24462766 DOI: 10.1016/j.ejps.2013.12.020] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2013] [Revised: 12/30/2013] [Accepted: 12/31/2013] [Indexed: 01/05/2023]
Abstract
Children and adults with malignant diseases have a high risk of prevalence of the tumor in the central nervous system (CNS). As prophylaxis treatment methotrexate is often given. In order to monitor methotrexate exposure in the CNS, cerebrospinal fluid (CSF) concentrations are often measured. However, the question is in how far we can rely on CSF concentrations of methotrexate as appropriate surrogate for brain target site concentrations, especially under disease conditions. In this study, we have investigated the spatial distribution of unbound methotrexate in healthy rat brain by parallel microdialysis, with or without inhibition of Mrp/Oat/Oatp-mediated active transport processes by a co-administration of probenecid. Specifically, we have focused on the relationship between brain extracellular fluid (brainECF) and CSF concentrations. The data were used to develop a systems-based pharmacokinetic (SBPK) brain distribution model for methotrexate. This model was subsequently applied on literature data on methotrexate brain distribution in other healthy and diseased rats (brainECF), healthy dogs (CSF) and diseased children (CSF) and adults (brainECF and CSF). Important differences between brainECF and CSF kinetics were found, but we have found that inhibition of Mrp/Oat/Oatp-mediated active transport processes does not significantly influence the relationship between brainECF and CSF fluid methotrexate concentrations. It is concluded that in parallel obtained data on unbound brainECF, CSF and plasma concentrations, under dynamic conditions, combined with advanced mathematical modeling is a most valid approach to develop SBPK models that allow for revealing the mechanisms underlying the relationship between brainECF and CSF concentrations in health and disease.
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Kasprowicz M, Czosnyka Z, Czosnyka M, Momjian S, Juniewicz H, Pickard JD. Slight elevation of baseline intracranial pressure after fluid infusion into CSF space in patients with hydrocephalus. Neurol Res 2013; 26:628-31. [PMID: 15327752 DOI: 10.1179/016164104225017596] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022]
Abstract
OBJECTIVE To investigate the elevation of resting cerebrospinal fluid (CSF) pressure recorded after a CSF infusion test in patients with hydrocephalus. MATERIAL AND METHODS Fifty patients (30 men and 20 women, mean age 68 +/- 13 years) with ventriculomegaly and clinical symptoms of normal pressure hydrocephalus have been studied. Lumbar (56%) or intraventricular (44%) computerized infusion studies were performed to investigate the hydrodynamics of CSF. After infusion, the fall in ICP was recorded until a steady-state level was achieved and the difference between pre- and post-infusion resting ICP was calculated (DeltaICP). RESULTS A positive difference (>2 mm Hg) between post- and pre-infusion resting ICP was identified in 31 infusion tests (62%). The mean value of the difference was 6.7 with an SD of 3.5 mm Hg. The patients who demonstrated this phenomenon had a greater elastance coefficient (p>0.05); DeltaICP was positively correlated with age (R=0.27; p=0.03), with the size of the brain's ventricles (R=0.63, p=0.03) and inversely with the severity of clinical impairment (Stein-Langfitt score R=-0.61, p=0.02; normal pressure hydrocephalus score: R=0.54; p<0.05). DeltaICP was independent of the site of infusion (lumbar or ventricular). CONCLUSION In patients with a 'stiffer' brain, ICP returns to the resting level after the infusion test at a slightly higher level than before the test. The magnitude of this increase is greater when ventricles are more dilated and clinical symptoms are less severe.
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Eide PK, Sorteberg W. Association among intracranial compliance, intracranial pulse pressure amplitude and intracranial pressure in patients with intracranial bleeds. Neurol Res 2013; 29:798-802. [PMID: 17601366 DOI: 10.1179/016164107x224132] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
OBJECTIVE To investigate the association among intracranial compliance (ICC), intracranial pulse pressure amplitude and intracranial pressure (ICP) in patients with intracranial bleeds. METHODS Five patients with intracranial bleeds had their ICC and ICP monitored during days 1-8 after ictus. The recordings were stored as raw data files and analysed retrospectively. The parameters mean ICC, mean ICP wave amplitude and mean ICP were determined and average values were calculated in 1 hour time periods. RESULTS A total of 262 1 hour recordings were analysed. There was a significant correlation between mean ICC and mean ICP wave amplitude and between mean ICC and mean ICP. The mean ICP wave amplitude was significantly higher during the 1 hour periods with mean ICC<0.5 ml/mmHg and significantly lower during 1 hour periods with mean ICC 1.5-3.0 ml/mmHg. Correspondingly, in the 159 1 hour recordings with mean ICP wave amplitude> or =5.0 mmHg, mean ICC was significantly lower than in the 103 recordings with mean ICP wave amplitude<5.0 mmHg. Mean ICP was normal (i.e. <20 mmHg) in 260 of 262 (99.2%) of the 1 hour recordings; in the 49 1 hour recordings with mean ICP>15 mmHg, mean ICC was significantly lower than in the 213 recordings with mean ICP<15.0 mmHg. CONCLUSION In this cohort of pressure recordings, there was a strong association between ICC and intracranial pulse pressure amplitude. There also was a strong association between ICC and mean ICP, but mean ICP was normal in 260 of 262 1 hour recordings (99.2%).
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Affiliation(s)
- P K Eide
- Department of Neurosurgery, The National Hospital, Rikshospitalet, 0027 Oslo, Norway.
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Park EH, Eide PK, Zurakowski D, Madsen JR. Impaired pulsation absorber mechanism in idiopathic normal pressure hydrocephalus. J Neurosurg 2012; 117:1189-96. [DOI: 10.3171/2012.9.jns121227] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Object
The pathophysiology of normal pressure hydrocephalus (NPH), and the related problem of patient selection for treatment of this condition, have been of great interest since the description of this seemingly paradoxical condition nearly 50 years ago. Recently, Eide has reported that measurements of the amplitude of the intracranial pressure (ICP) can both positively and negatively predict response to CSF shunting. Specifically, the fraction of time spent in a “high amplitude” (> 4 mm Hg) state predicted response to shunting, which may represent a marker for hydrocephalic pathophysiology. Increased ICP amplitude might suggest decreased brain compliance, meaning a static measure of a pressure-volume ratio. Recent studies of canine data have shown that the brain compliance can be described as a frequency-dependent function. The normal canine brain seems to show enhanced ability to absorb the pulsations around the heart rate, quantified as a cardiac pulsation absorbance (CPA), with properties like a notch filter in engineering. This frequency dependence of the function is diminished with development of hydrocephalus in dogs. In this pilot study, the authors sought to determine whether frequency dependence could be observed in humans, and whether the frequency dependence would be any different in epochs with high ICP amplitude compared with epochs of low ICP amplitude.
Methods
Systems analysis was applied to arterial blood pressure (ABP) and ICP waveforms recorded from 10 patients undergoing evaluations of idiopathic NPH to calculate a time-varying transfer function that reveals frequency dependence and CPA, the measure of frequency-dependent compliance previously used in animal experiments. The ICP amplitude was also calculated in the same samples, so that epochs with high (> 4 mm Hg) versus low (≤ 4 mm Hg) amplitude could be compared in CPA and transfer functions.
Results
Transfer function analysis for the more “normal” epochs with low amplitude exhibits a dip or notch in the physiological frequency range of the heart rate, confirming in humans the pulsation absorber phenomenon previously observed in canine studies. Under high amplitude, however, the dip in the transfer function is absent. An inverse relationship between CPA index and ICP amplitude is evident and statistically significant. Thus, elevated ICP amplitude indicates decreased performance of the human pulsation absorber.
Conclusions
The results suggest that the human intracranial system shows frequency dependence as seen in animal experiments. There is an inverse relationship between CPA index and ICP amplitude, indicating that higher amplitudes may occur with a reduced performance of the pulsation absorber. Our findings show that frequency dependence can be observed in humans and imply that reduced frequency-dependent compliance may be responsible for elevated ICP amplitude observed in patients who respond to CSF shunting.
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Affiliation(s)
| | - Per Kristian Eide
- 2Department of Neurosurgery, Oslo University Hospital–Rikshospitalet, Oslo; and
- 4Faculty of Medicine, University of Oslo, Norway
| | - David Zurakowski
- 3Anesthesiology, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts
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The intracranial volume pressure response in increased intracranial pressure patients: Part 1. Calculation of the volume pressure indicator. Acta Neurochir (Wien) 2012; 154:2271-5; discussion 2275. [PMID: 20714759 DOI: 10.1007/s00701-010-0765-8] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2010] [Accepted: 08/04/2010] [Indexed: 10/19/2022]
Abstract
BACKGROUND The intracranial pressure (ICP) is usually continuously monitored in the management of patients with increased ICP. The aim of this study was to discover a mathematic equation to express the intracranial pressure-volume (P-V) curve and a single indicator to reflect the status of the curve. METHODS Patients with severe brain damage who had bilateral external ventricular drainage (EVD) from December 2008 to February 2010 were included in this study. The EVD was used as drainage of CSF and ICP monitor. The successive volume pressure response [6] values were obtained by successive drainage of CSF from ICP 20-25 to 10 mmHg. Parabolic, exponential, and linear regression models were designed to have a single parameter as the indicator to determine the P-V curves. RESULTS The mean of parameter "a" in the exponential equation is 1.473 ± 0.054; in the parabolic equation, it is 0.332 ± 0.061; and in the linear equation, it is 1.717 ± 0.209. All regression equations of P-V curves had statistical significance (p < 0.005). Parabolic and exponential equations are closer to the original ICP curve than linear equation (p < 0.005). There is no statistically significant difference between parabolic and exponential regressions. CONCLUSIONS The P-V curve can be expressed with linear, parabolic, and exponential regression models in increased ICP patients. The parabolic and exponential equations are more accurate methods to represent the P-V curve. The single parameter in the three regression equations can be compared in different conditions of one patient in clinical practice.
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Radolovich DK, Aries MJH, Castellani G, Corona A, Lavinio A, Smielewski P, Pickard JD, Czosnyka M. Pulsatile intracranial pressure and cerebral autoregulation after traumatic brain injury. Neurocrit Care 2012; 15:379-86. [PMID: 21805216 DOI: 10.1007/s12028-011-9553-4] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
BACKGROUND Strong correlation between mean intracranial pressure (ICP) and its pulse wave amplitude (AMP) has been demonstrated in different clinical scenarios. We investigated the relationship between invasive mean arterial blood pressure (ABP) and AMP to explore its potential role as a descriptor of cerebrovascular pressure reactivity after traumatic brain injury (TBI). METHODS We retrospectively analyzed data of patients suffering from TBI with brain monitoring. Transcranial Doppler blood flow velocity, ABP, ICP were recorded digitally. Cerebral perfusion pressure (CPP) and AMP were derived. A new index-pressure-amplitude index (PAx)-was calculated as the Pearson correlation between (averaged over 10 s intervals) ABP and AMP with a 5 min long moving average window. The previously introduced transcranial Doppler-based autoregulation index Mx was evaluated in a similar way, as the moving correlation between blood flow velocity and CPP. The clinical outcome was assessed after 6 months using the Glasgow outcome score. RESULTS 293 patients were studied. The mean PAx was -0.09 (standard deviation 0.21). This negative value indicates that, on average, an increase in ABP causes a decrease in AMP and vice versa. PAx correlated strong with Mx (R (2) = 0.46, P < 0.0002). PAx also correlated with age (R (2) = 0.18, P < 0.05). PAx was found to have as good predictive outcome value (area under curve 0.71, P < 0.001) as Mx (area under curve 0.69, P < 0.001). CONCLUSIONS We demonstrated significant correlation between the known cerebral autoregulation index Mx and PAx. This new index of cerebrovascular pressure reactivity using ICP pulse wave information showed to have a strong association with outcome in TBI patients.
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Affiliation(s)
- D K Radolovich
- Neurosurgical Unit, Department of Clinical Neurosciences, University of Cambridge, Cambridge, UK.
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Arany-Tóth A, Csébi P, Reiczigel J, Németh T. Pressure-volume index-based volume calculation of contrast medium for atlanto-occipital myelography in dogs. Vet Radiol Ultrasound 2012; 53:430-6. [PMID: 22548310 DOI: 10.1111/j.1740-8261.2012.01935.x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2011] [Accepted: 02/09/2012] [Indexed: 11/30/2022] Open
Abstract
Subarachnoid pressure recordings were made during atlanto-occipital myelography in 45 dogs with clinical signs of spinal disease. Iohexol was injected at a dosage of 0.3 ml/kg body weight and simultaneous pressure values were recorded in the cerebellomedullary cistern. The mean subarachnoid pressure was 9 ± 3 mmHg before and 70 ± 32 mmHg at the end of administration. From the pressure change induced by the volume load, the pressure-volume index (PVI) of the subarachnoid space was calculated and found to be in close correlation with body weight and the crown-rump length (r = 0.94 and 0.87). Using the estimated PVI values, the appropriate volume of contrast medium can be calculated for an animal according to body weight. Dogs of a large body size require relatively less contrast medium than small-sized dogs (range 0.17-0.35 ml/kg). This calculated volume is unlikely to increase the subarachnoid pressure above 40 mmHg as a specific pressure limit. Using these data, simplified recommendations for the choice of contrast medium volumes have been generated.
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Affiliation(s)
- Attila Arany-Tóth
- Department of Surgery and Ophthalmology, Szent Istvan University, Budapest, Hungary.
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Czosnyka M, Citerio G. Brain compliance: the old story with a new 'et cetera'. Intensive Care Med 2012; 38:925-7. [PMID: 22527086 DOI: 10.1007/s00134-012-2572-6] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2012] [Accepted: 03/27/2012] [Indexed: 11/28/2022]
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Modeling of CSF Dynamics: Legacy of Professor Anthony Marmarou. ACTA NEUROCHIRURGICA SUPPLEMENTUM 2012; 113:9-14. [DOI: 10.1007/978-3-7091-0923-6_2] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/03/2022]
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Tain RW, Bagci AM, Lam BL, Sklar EM, Ertl-Wagner B, Alperin N. Determination of cranio-spinal canal compliance distribution by MRI: Methodology and early application in idiopathic intracranial hypertension. J Magn Reson Imaging 2011; 34:1397-404. [PMID: 21972076 DOI: 10.1002/jmri.22799] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2011] [Accepted: 08/11/2011] [Indexed: 11/09/2022] Open
Abstract
PURPOSE To develop a method for derivation of the cranial-spinal compliance distribution, assess its reliability, and apply to obese female patients with a diagnosis of idiopathic intracranial hypertension (IIH). MATERIALS AND METHODS Phase contrast-based measurements of blood and cerebrospinal fluid (CSF) flows to, from, and between the cranial and spinal canal compartments were used with lumped-parameter modeling to estimate systolic volume and pressure changes from which cranial and spinal compliance indices are obtained. The proposed MRI indices are analogous to pressure volume indices (PVI) currently being measured invasively with infusion-based techniques. The consistency of the proposed method was assessed using MRI data from seven aged healthy subjects. Measurement reproducibility was assessed using five repeated MR scans from one subject. The method was then applied to compare spinal canal compliance contribution in seven IIH patients and six matched healthy controls. RESULTS In the healthy subjects, as expected, spinal canal contribution was consistently larger than the cranial contribution (average value of 69%). Measurement variability was 8%. In IIH, the spinal canal contribution is significantly smaller than normal controls (60 versus 78%, P < 0.03). CONCLUSION An MRI-based method for derivation of compliance indices analogous to PVI has been implemented and applied to healthy subjects. The application of the method to obese IIH patients suggests a spinal canal involvement in the pathophysiology of IIH.
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Affiliation(s)
- Rong-Wen Tain
- Department of Radiology, University of Miami, Miami, Florida, USA
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Laing RJ, Smielewski P, Czosnyka M, Quaranta N, Moffat DA. A study of perioperative lumbar cerebrospinal fluid pressure in patients undergoing acoustic neuroma surgery. Skull Base Surg 2011; 10:179-85. [PMID: 17171145 PMCID: PMC1656864 DOI: 10.1055/s-2000-9330] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/16/2022]
Abstract
The objective of this study was to measure changes in cerebrospinal fluid (CSF) pressure and cerebrovascular hemodynamics following acoustic neuroma surgery. The subjects were 32 patients undergoing translabyrinthine or retrosigmoid excision of acoustic neuroma. CSF pressure and the amplitude of the CSF pressure pulse wave were measured using lumbar catheters, and all variables were recorded minute by minute on a microcomputer. Transcranial doppler (TCD) was used to measure flow velocity in the middle cerebral artery in 10 patients to monitor changes in cerebral hemodynamics. In the 24 hours after surgery, all patients showed a statistically significant rise in CSF pressure from 11.4 mm Hg (standard deviation [SD] 6.1) to 19.6 mm Hg (SD 5.2) and a corresponding fall in the compliance of the CSF compartment. These changes were reversed within 48 hours, and the CSF pressure fell below the preoperative level over the next 4 days without any drainage of CSF. The results of this study demonstrate a transient increase in CSF pressure and decrease in craniospinal compliance that is provoked by surgery. The most plausible explanation for this disturbance is impaired CSF absorption, which resolves rapidly in most patients without therapeutic CSF drainage.
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Eide PK, Park EH, Madsen JR. Arterial blood pressure vs intracranial pressure in normal pressure hydrocephalus. Acta Neurol Scand 2010; 122:262-9. [PMID: 20070274 DOI: 10.1111/j.1600-0404.2009.01304.x] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
OBJECTIVE To characterize the association between arterial blood pressure (ABP) and intracranial pressure (ICP) in idiopathic normal pressure hydrocephalus (iNPH) patients, and its impact on outcome of shunt surgery. MATERIALS AND METHODS We analyzed all 35 iNPH patients whose ABP and ICP were recorded simultaneously during 6 years (2002-2007). The static and pulsatile pressures were averaged over consecutive 6-s intervals; the moving correlations between ICP and ABP (static and pulsatile) were determined during consecutive 4-min periods to explore time-related variations. RESULTS Neither static nor pulsatile ABP were altered in iNPH shunt responders. Elevated pulsatile ICP, but normal static ICP, was seen in responders. The time-varying correlations of static and of pulsatile pressures were generally low, and did not differ between shunt responders/non-responders. CONCLUSIONS In iNPH shunt responders, static or pulsatile ABP were not altered and only pulsatile ICP was elevated.
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Affiliation(s)
- P K Eide
- Department of Neurosurgery, Division of Clinical Neuroscience, Rikshospitalet University Hospital, Oslo, Norway.
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Colgan NC, Cronin MM, Gobbo OL, O'Mara SM, O'Connor WT, Gilchrist MD. Quantitative MRI Analysis of Brain Volume Changes due to Controlled Cortical Impact. J Neurotrauma 2010; 27:1265-74. [DOI: 10.1089/neu.2009.1267] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Affiliation(s)
- Niall C. Colgan
- School of Electrical, Electronic & Mechanical Engineering, University College Dublin, Belfield, Dublin, Ireland
| | | | | | | | - William T. O'Connor
- Conway Institute, University College Dublin, Belfield, Dublin, Ireland
- Graduate Entry Medical School, University of Limerick, Castletroy, County Limerick, Ireland
| | - Michael D. Gilchrist
- School of Electrical, Electronic & Mechanical Engineering, University College Dublin, Belfield, Dublin, Ireland
- School of Human Kinetics, University of Ottawa, Ontario, Canada
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Eide PK, Rapoport BI, Gormley WB, Madsen JR. A dynamic nonlinear relationship between the static and pulsatile components of intracranial pressure in patients with subarachnoid hemorrhage. J Neurosurg 2010; 112:616-25. [PMID: 19731984 DOI: 10.3171/2009.7.jns081593] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
OBJECT In the search for optimal monitoring and predictive tools in neurocritical care, the relationship of the pulsatile component of intracranial pressure (ICP) and the pressure itself has long been of great interest. Higher pressure often correlates with a higher pulsatile response to the heartbeat, interpreted as a type of compliance curve. Various mathematical approaches have been used, but regardless of the formula used, it is implicitly assumed that a reproducible curve exists. The authors investigated the stability of the correlation between static and pulsatile ICPs in patients with subarachnoid hemorrhage (SAH) who were observed for several hours by using data sets large enough to allow such calculations to be made. METHODS The ICP recordings were obtained in 39 patients with SAH and were parsed into 6-second time windows (1,998,944 windows in 197 recordings). The ICP parameters were computed for each window as follows: static ICP was defined as the mean ICP, and pulsatile ICP was characterized by mean ICP wave amplitude, rise time, and rise time coefficient. RESULTS The mean ICP and ICP wave amplitudes were simultaneously high or low (the expected correlation) in only approximately 60% of observations. Furthermore, static and pulsatile ICP correlated well only over short intervals; the degree of correlation weakened over periods of hours and was inconsistent across patients and within individual patients over time. Decorrelation originated with abrupt shifting and gradual drifting of mean ICP and ICP wave amplitude over several hours. CONCLUSIONS The relationship between the static and pulsatile components of ICPs changes over time. It evolves, even in individual patients, over a number of hours. This can be one reason the observation of high pulsatile ICP (indicative of reduced intracranial compliance) despite normal mean ICP that is seen in some patients with SAH. The meaning and potential clinical usefulness of such changes in the curves is uncertain, but it implies that clinical events result not only from moving further out on a compliance curve; in practice, the curve, and the biological system that underlies the curve, may itself change.
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Affiliation(s)
- Per K Eide
- Department of Neurosurgery, Rikshospitalet University Hospital, Oslo, Norway.
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Carrera E, Kim DJ, Castellani G, Zweifel C, Czosnyka Z, Kasprowicz M, Smielewski P, Pickard JD, Czosnyka M. What Shapes Pulse Amplitude of Intracranial Pressure? J Neurotrauma 2010; 27:317-24. [DOI: 10.1089/neu.2009.0951] [Citation(s) in RCA: 69] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Affiliation(s)
- Emmanuel Carrera
- Academic Neurosurgical Unit, Department of Clinical Neurosciences, Addenbrooke's Hospital, University of Cambridge, Cambridge, United Kingdom
| | - Dong-Joo Kim
- Academic Neurosurgical Unit, Department of Clinical Neurosciences, Addenbrooke's Hospital, University of Cambridge, Cambridge, United Kingdom
| | - Gianluca Castellani
- Academic Neurosurgical Unit, Department of Clinical Neurosciences, Addenbrooke's Hospital, University of Cambridge, Cambridge, United Kingdom
| | - Christian Zweifel
- Academic Neurosurgical Unit, Department of Clinical Neurosciences, Addenbrooke's Hospital, University of Cambridge, Cambridge, United Kingdom
| | - Zofia Czosnyka
- Academic Neurosurgical Unit, Department of Clinical Neurosciences, Addenbrooke's Hospital, University of Cambridge, Cambridge, United Kingdom
| | - Magdalena Kasprowicz
- Academic Neurosurgical Unit, Department of Clinical Neurosciences, Addenbrooke's Hospital, University of Cambridge, Cambridge, United Kingdom
| | - Peter Smielewski
- Academic Neurosurgical Unit, Department of Clinical Neurosciences, Addenbrooke's Hospital, University of Cambridge, Cambridge, United Kingdom
| | - John D. Pickard
- Academic Neurosurgical Unit, Department of Clinical Neurosciences, Addenbrooke's Hospital, University of Cambridge, Cambridge, United Kingdom
| | - Marek Czosnyka
- Academic Neurosurgical Unit, Department of Clinical Neurosciences, Addenbrooke's Hospital, University of Cambridge, Cambridge, United Kingdom
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Kim DJ, Czosnyka Z, Keong N, Radolovich DK, Smielewski P, Sutcliffe MP, Pickard JD, Czosnyka M. INDEX OF CEREBROSPINAL COMPENSATORY RESERVE IN HYDROCEPHALUS. Neurosurgery 2009; 64:494-501; discussion 501-2. [DOI: 10.1227/01.neu.0000338434.59141.89] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Abstract
OBJECTIVE
An index of cerebrospinal compensatory reserve (RAP) has been introduced as a potential descriptor of neurological deterioration after head trauma. It is numerically computed as a linear correlation coefficient between the mean intracranial pressure and the pulse amplitude of the pressure waveform. We explore how RAP varies with different forms of physiological or nonphysiological intracranial volume loads in adult hydrocephalus, with and without a functioning cerebrospinal fluid (CSF) shunt.
METHODS
A database of intracranial pressure recordings during CSF infusion studies and overnight monitoring in hydrocephalic patients was reviewed for clinical comparison of homogeneous subgroups of patients with hypothetical differences of pressure-volume compensatory reserve. The database includes 980 patients of mixed etiology: idiopathic normal pressure hydrocephalus (NPH), 47%; postsubarachnoid hemorrhage NPH, 12%; noncommunicating hydrocephalus, 22%; others, 19%. All CSF compensatory parameters were calculated by using intracranial pressure waveforms.
RESULTS
In NPH, RAP correlated strongly with the resistance to CSF outflow (rs = 0.35; P = 0.045), but weakly correlated with ventriculomegaly (rs = 0.13; P = 0.41). In idiopathic nonshunted NPH patients, RAP did not correlate significantly with elasticity calculated from the CSF infusion test (rs = 0.11; P = 0.21). During infusion studies, RAP increased in comparison to values recorded at baseline (from a median of 0.45–0.86, P = 0.14 * 10−8), indicating a narrowing of the volume-pressure compensatory reserve. During B-waves associated with the REM (rapid eye movement) phase of sleep, RAP increased from a median of 0.53 to 0.89; P = 1.2 * 10−5. After shunting, RAP decreased (median before shunting, 0.59; median after shunting, 0.34; P = 0.0001). RAP also showed the ability to reflect the functional state of the shunt (patent shunt median, 0.36; blocked shunt median, 0.84; P = 0.0002).
CONCLUSION
RAP appears to characterize pressure-volume compensatory reserve in patients with hydrocephalus.
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Affiliation(s)
- Dong-Joo Kim
- Academic Neurosurgical Unit, Addenbrooke's Hospital, University of Cambridge, Cambridge, England
- Micromechanics Laboratory, Department of Engineering, University of Cambridge, Cambridge, England
| | - Zofia Czosnyka
- Academic Neurosurgical Unit, Addenbrooke's Hospital, University of Cambridge, Cambridge, England
| | - Nicole Keong
- Academic Neurosurgical Unit, Addenbrooke's Hospital, University of Cambridge, Cambridge, England
| | - Danila K. Radolovich
- Academic Neurosurgical Unit, Addenbrooke's Hospital, University of Cambridge, Cambridge, England
- Department of Anaesthesiology, University of Pavia, Pavia, Italy
| | - Peter Smielewski
- Academic Neurosurgical Unit, Addenbrooke's Hospital, University of Cambridge, Cambridge, England
| | | | - John D. Pickard
- Academic Neurosurgical Unit, Addenbrooke's Hospital, University of Cambridge, Cambridge, England
| | - Marek Czosnyka
- Academic Neurosurgical Unit, Addenbrooke's Hospital, University of Cambridge, Cambridge, England
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Abstract
OBJECTIVE Hydrocephalus is much more complex than a simple disorder of cerebrospinal fluid (CSF) circulation. Shunting primarily corrects disturbed fluid flow which may have an impact on cerebral blood flow and metabolism. We studied hydrocephalic patients before and after shunting to characterize changes in their CSF compensatory parameters. MATERIAL AND METHODS We selected 25 patients and studied them retrospectively. All patients had ventriculomegaly and clinical symptoms of normal pressure hydrocephalus. After shunting, they were still presenting with some adverse symptoms, mainly headaches, slow improvement or no improvement of ventriculomegaly. Therefore, they underwent further infusion studies to assess shunt function. In all cases, the shunts were confirmed to be draining CSF adequately. Parameters of CSF dynamics: baseline intracranial pressure (ICP), resistance to CSF outflow, cerebrospinal elasticity, content of vasogenic pressure waves (pulse, respiratory and B waves) and compensatory reserve assessed as moving correlation coefficient between mean CSF pressure and pulse amplitude (RAP), were compared before and after shunting. RESULTS Mean ICP and resistance to CSF outflow decreased (P < 0.003) after shunting. All vasogenic pressure waves decreased (P < 0.005). Compensatory reserve (RAP) significantly improved (P < 0.005). CONCLUSION A functioning shunt has an important impact on CSF circulation and pressure-volume compensation. Infusion studies can demonstrate the return of disturbed CSF dynamics to normal values even if clinical or radiological changes are not dramatic.
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Affiliation(s)
- G Petrella
- Academic Neurosurgical Unit, Addenbrookes Hospital, Cambridge, UK
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Lewis PM, Rosenfeld JV, Diehl RR, Mehdorn HM, Lang EW. Phase shift and correlation coefficient measurement of cerebral autoregulation during deep breathing in traumatic brain injury (TBI). Acta Neurochir (Wien) 2008; 150:139-46; discussion 146-7. [PMID: 18213440 DOI: 10.1007/s00701-007-1447-z] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2007] [Accepted: 10/22/2007] [Indexed: 01/09/2023]
Abstract
BACKGROUND Impairment of cerebral autoregulation is known to adversely affect outcome following traumatic brain injury (TBI). The phase shift (PS) method of cerebral autoregulation (CA) assessment describes the time lag between fluctuations in arterial blood pressure (ABP) and cerebral blood flow velocity (CBFV) in the middle cerebral artery. An alternative method (Mx-ABP) is based on the statistical correlation between ABP and CBFV waveforms over time. We compared these two indices in a cohort of severely head injured patients undergoing controlled, 6-breaths-per-minute ventilation. METHODS PS and Mx-ABP were calculated from 33 recordings of CBFV and MAP in 22 patients with TBI. Spearman's correlation coefficient was used to assess the agreement between PS and Mx-ABP. The relationship between ICP slow wave amplitude, MAP slow wave amplitude and mean ICP was also examined. FINDINGS Mean values for Mx-ABP and PS were 0.44 +/- 0.27, and 49 +/- 26 (degrees), respectively. PS correlated significantly with Mx-ABP (r = -0.648, p < 0.001). A Bland-Altman plot of normalised Mx-ABP and Phase Shift values showed no significant bias or relationship (mean difference = 0.0004, r = -0.037, p = 0.852). During the test procedure, ICP fluctuated in an approximately sinusoidal fashion, with a mean amplitude of 4.96 +/- 2.72 mmHg (peak to peak). The magnitude of ICP fluctuation during deep breathing correlated weakly but significantly with mean ICP (r = 0.391, p < 0.05) and with the amplitude of ABP fluctuations (r = 0.625, p < 0.0005). CONCLUSIONS Phase shift and Mx-ABP in TBI are well correlated. Deep breathing presents as an effective tool with which to assess autoregulation using the phase shift method.
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Affiliation(s)
- P M Lewis
- Department of Neurosurgery, The Alfred Hospital, Melbourne, Australia.
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Shahsavari S, McKelvey T, Skoglund T, Ritzèn CE. A comparison between the transfer function of ABP to ICP and compensatory reserve index in TBI. ACTA NEUROCHIRURGICA. SUPPLEMENT 2008; 102:9-13. [PMID: 19388279 DOI: 10.1007/978-3-211-85578-2_2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
BACKGROUND The transfer functions which map the arterial blood pressure to the intracranial pressure and the compensatory reserve index have been investigated by various groups to evaluate the brain compliance of patients with traumatic brain injury. The focus of this study has been to assess the capability of both the above mentioned methods to monitor the intracranial compliance in patients suffering from brain swelling. MATERIALS AND METHODS Clinical data was collected from sixteen traumatic brain injury patients and split into 4 min segments. For each segment, both the magnitude of the empirical transfer function at the fundamental cardiac frequency and the compensatory reserve index were extracted. FINDINGS The mean values of the compensatory reserve index and the magnitude of the transfer function which scored higher than 0.7 and 0.1 respectively were recorded for all patients suffering from brain swelling. By comparing the histogram of the magnitude of the transfer function at the fundamental cardiac frequency with the histogram of the compensatory reserve index for all patients, a positive correlation between the mean values and a negative correlation among their variances were observed. The linear correlation between the mean values was estimated at r = 0.82 (p < 0.0001). CONCLUSIONS These observations suggest that to evaluate the intracranial compensatory reserve, the magnitude of 0.1 could be a useful threshold for the transfer function at the fundamental cardiac frequency.
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Affiliation(s)
- Sima Shahsavari
- Department of Signals and Systems, Chalmers University of Technology, SE-412 96 Gothenburg, Sweden.
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