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Article ; Online: CSF Dynamics for Shunt Prognostication and Revision in Normal Pressure Hydrocephalus

Afroditi Despina Lalou / Marek Czosnyka / Michal M. Placek / Peter Smielewski / Eva Nabbanja / Zofia Czosnyka

Journal of Clinical Medicine, Vol 10, Iss 1711, p

2021 Volume 1711

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 ... ...

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.
Keywords	hydrocephalus ; normal pressure hydrocephalus ; CSF infusion tests ; CSF dynamics ; intracranial pressure ; cerebral blood flow ; Medicine ; R
Subject code	610
Language	English
Publishing date	2021-04-01T00:00:00Z
Publisher	MDPI AG
Document type	Article ; Online
Database	BASE - Bielefeld Academic Search Engine (life sciences selection)

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Article ; Online: Cerebral hemodynamic monitoring combined with infusion test in hydrocephalus.

Czosnyka, Zofia / Lalou, Afroditi / Pelah, Adam I / Joanides, Alexis J / Smielewski, Peter / Placek, Michal M / Marek, Czosnyka

Brain & spine

2023 Volume 3, Page(s) 102705

Abstract: Introduction: Disturbance in cerebrospinal fluid (CSF) circulation may overlap with abnormality of cerebral blood flow (CBF) in hydrocephalus. Transcranial Doppler (TCD) ultrasonography is a non-invasive technique able to assess CBF velocity (CBFv) ... ...

Abstract	Introduction: Disturbance in cerebrospinal fluid (CSF) circulation may overlap with abnormality of cerebral blood flow (CBF) in hydrocephalus. Transcranial Doppler (TCD) ultrasonography is a non-invasive technique able to assess CBF velocity (CBFv) dynamics in response to a controlled rise in ICP during CSF infusion tests. Research question: Which TCD-derived cerebral hemodynamic parameters change during controlled rise of ICP, and in which direction? Material and methods: Infusion tests combined with TCD monitoring and non-invasive monitoring of arterial blood pressure (ABP) were conducted in 65 hydrocephalic patients. TCD-based hemodynamic variables: spectral pulsatility index (sPI), compliance of CSF space (Ci), cerebral autoregulation index (Mx), critical closing pressure (CrCP), cerebrovascular wall tension (WT) and diastolic closing margin (DCM-distance between diastolic ABP and CrCP) were calculated retrospectively. Results: During the test ICP increased on average to 25 mm Hg (p < 0.0001), with a parallel decrease in cerebral perfusion pressure (CPP, p < 0.0003). The CBFv waveform changed, showing a rise in sPI (p < 0.0001). Ci decreased inversely proportional to a rise in ICP, and correlated well with changes of compliance calculated from the Marmarou model. CrCP increased in response to rising ICP (p < 0.001) while WT decreased (p < 0.002). DCM correlated with cerebrospinal elasticity (R = -0.31; p < 0.04). Cerebral autoregulation was worse in patients with normal CSF circulation, measured as resistance to CSF outflow (Rout): Pearson correlation between Mx and Rout was R = -0.41; p < 0.02. Conclusion: A controlled rise in ICP affects cerebral hemodynamics in a moderate manner. Parameters like cerebral autoregulation index or DCM correlate with CSF dynamics and may be considered as supplementary variables for the diagnosis of hydrocephalus.
Language	English
Publishing date	2023-11-17
Publishing country	Netherlands
Document type	Journal Article
ISSN	2772-5294
ISSN (online)	2772-5294
DOI	10.1016/j.bas.2023.102705
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Article ; Online: Studying Trends of Auto-Regulation in Severe Head Injury in Paediatrics (STARSHIP)

Adam Young / Marek Czosnyka / Peter Smielewski / Anna Maw / Shruti Agrawal / Manuel Cabeleira / Peter John Hutchinson / Deborah White / Esther Daubney / Michal M Placek / Suzanna Watson

BMJ Open, Vol 13, Iss

protocol to study cerebral autoregulation in a prospective multicentre observational research database study

2023 Volume 3

Abstract: Introduction Studying cerebral autoregulation, particularly PRx (Pressure Reactivity Index), is commonly employed in adult traumatic brain injury (TBI) and gives real-time information about intracranial pathophysiology, which can help in patient ... ...

Abstract	Introduction Studying cerebral autoregulation, particularly PRx (Pressure Reactivity Index), is commonly employed in adult traumatic brain injury (TBI) and gives real-time information about intracranial pathophysiology, which can help in patient management. Experience in paediatric TBI (PTBI) is limited to single-centre studies despite disproportionately higher incidence of morbidity and mortality in PTBI than in adult TBI.Project We describe the protocol to study cerebral autoregulation using PRx in PTBI. The project called Studying Trends of Auto-Regulation in Severe Head Injury in Paediatrics is a multicentre prospective ethics approved research database study from 10 centres across the UK. Recruitment started in July 2018 with financial support from local/national charities (Action Medical Research for Children, UK).Methods and analysis The first phase of the project is powered to detect optimal thresholds of PRx associated with favourable outcome in PTBI by recruiting 135 patients (initial target of 3 years which has changed to 5 years due to delays related to COVID-19 pandemic) from 10 centres in the UK with outcome follow-up to 1-year postictus. The secondary objectives are to characterise patterns of optimal cerebral perfusion pressure in PTBI and compare the fluctuations in these measured parameters with outcome. The goal is to create a comprehensive research database of a basic set of high-resolution (full waveforms resolution) neuromonitoring data in PTBI for scientific use.Ethics and dissemination Favourable ethical approval has been provided by Health Research Authority, Southwest-Central Bristol Research Ethics Committee (Ref: 18/SW/0053). Results will be disseminated via publications in peer-reviewed medical journals and presentations at national and international conferences.Trial registration number NCT05688462.
Keywords	Medicine ; R
Subject code	170
Language	English
Publishing date	2023-03-01T00:00:00Z
Publisher	BMJ Publishing Group
Document type	Article ; Online
Database	BASE - Bielefeld Academic Search Engine (life sciences selection)

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Article ; Online: Author Correction

Xiuyun Liu / Xiao Hu / Ken M. Brady / Raymond Koehler / Peter Smielewski / Marek Czosnyka / Joseph Donnelly / Jennifer K. Lee

Scientific Reports, Vol 11, Iss 1, Pp 1-

Comparison of wavelet and correlation indices of cerebral autoregulation in a pediatric swine model of cardiac arrest

2021 Volume 2

Keywords	Medicine ; R ; Science ; Q
Language	English
Publishing date	2021-11-01T00:00:00Z
Publisher	Nature Portfolio
Document type	Article ; Online
Database	BASE - Bielefeld Academic Search Engine (life sciences selection)

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Article ; Online: Anti-decubitus bed mattress may interfere with cerebrovascular pressure reactivity measures due to induced ICP and ABP cyclic peaks.

Jeanette, Tas / Melisa, Borg / Peter, Smielewski / Marek, Czosnyka / Erta, Beqiri / Ari, Ercole / Marcel, Aries

Journal of clinical monitoring and computing

2020 Volume 35, Issue 2, Page(s) 423–425

Abstract: Severe traumatic brain injury (TBI) patients are monitored with continuous arterial blood pressure (ABP) and intracranial pressure (ICP). The pressure reactivity index (PRx) is a frequently used correlation coefficient between ABP and ICP to inform ... ...

Abstract	Severe traumatic brain injury (TBI) patients are monitored with continuous arterial blood pressure (ABP) and intracranial pressure (ICP). The pressure reactivity index (PRx) is a frequently used correlation coefficient between ABP and ICP to inform clinicians at the bedside about trends in global cerebrovascular pressure regulation status. We present an unexpected influence of cyclic anti-decubitus mattress inflations and deflations on invasive ICP, ABP and PRx calculations in our TBI patients. This might affect autoregulation guided management. In our database, 23% (9/39) of the patients show recurrent peaks in the monitoring signals. We hypothesize that these peaks are caused by (a combination) of hydrostatic change, local (cervical) compression and/or incorrect sensor zeroing due to positional changes induced by the anti-decubitus mattress. This warrants further investigation by the manufacturer and exploration of data filters.
MeSH term(s)	Arterial Pressure ; Brain Injuries, Traumatic ; Cerebrovascular Circulation ; Humans ; Intracranial Pressure ; Monitoring, Physiologic
Language	English
Publishing date	2020-02-08
Publishing country	Netherlands
Document type	Letter
ZDB-ID	1418733-4
ISSN	1573-2614 ; 1387-1307 ; 0748-1977
ISSN (online)	1573-2614
ISSN	1387-1307 ; 0748-1977
DOI	10.1007/s10877-020-00471-5
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Article ; Online: Comparison of wavelet and correlation indices of cerebral autoregulation in a pediatric swine model of cardiac arrest

Xiuyun Liu / Xiao Hu / Ken M. Brady / Raymond Koehler / Peter Smielewski / Marek Czosnyka / Joseph Donnelly / Jennifer K. Lee

Scientific Reports, Vol 10, Iss 1, Pp 1-

2020 Volume 9

Abstract: Abstract Existing cerebrovascular blood pressure autoregulation metrics have not been translated to clinical care for pediatric cardiac arrest, in part because signal noise causes high index time-variability. We tested whether a wavelet method that uses ... ...

Abstract	Abstract Existing cerebrovascular blood pressure autoregulation metrics have not been translated to clinical care for pediatric cardiac arrest, in part because signal noise causes high index time-variability. We tested whether a wavelet method that uses near-infrared spectroscopy (NIRS) or intracranial pressure (ICP) decreases index variability compared to that of commonly used correlation indices. We also compared whether the methods identify the optimal arterial blood pressure (ABPopt) and lower limit of autoregulation (LLA). 68 piglets were randomized to cardiac arrest or sham procedure with continuous monitoring of cerebral blood flow using laser Doppler, NIRS and ICP. The arterial blood pressure (ABP) was gradually reduced until it dropped to below the LLA. Several autoregulation indices were calculated using correlation and wavelet methods, including the pressure reactivity index (PRx and wPRx), cerebral oximetry index (COx and wCOx), and hemoglobin volume index (HVx and wHVx). Wavelet methodology had less index variability with smaller standard deviations. Both wavelet and correlation methods distinguished functional autoregulation (ABP above LLA) from dysfunctional autoregulation (ABP below the LLA). Both wavelet and correlation methods also identified ABPopt with high agreement. Thus, wavelet methodology using NIRS may offer an accurate vasoreactivity monitoring method with reduced signal noise after pediatric cardiac arrest.
Keywords	Medicine ; R ; Science ; Q
Subject code	610
Language	English
Publishing date	2020-04-01T00:00:00Z
Publisher	Nature Publishing Group
Document type	Article ; Online
Database	BASE - Bielefeld Academic Search Engine (life sciences selection)

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Article ; Online: Ventricular Volume Load Reveals the Mechanoelastic Impact of Communicating Hydrocephalus on Dynamic Cerebral Autoregulation.

Christina Haubrich / Marek Czosnyka / Rolf Diehl / Peter Smielewski / Zofia Czosnyka

PLoS ONE, Vol 11, Iss 7, p e

2016 Volume 0158506

Abstract: Several studies have shown that the progression of communicating hydrocephalus is associated with diminished cerebral perfusion and microangiopathy. If communicating hydrocephalus similarly alters the cerebrospinal fluid circulation and cerebral blood ... ...

Abstract	Several studies have shown that the progression of communicating hydrocephalus is associated with diminished cerebral perfusion and microangiopathy. If communicating hydrocephalus similarly alters the cerebrospinal fluid circulation and cerebral blood flow, both may be related to intracranial mechanoelastic properties as, for instance, the volume pressure compliance. Twenty-three shunted patients with communicating hydrocephalus underwent intraventricular constant-flow infusion with Hartmann's solution. The monitoring included transcranial Doppler (TCD) flow velocities (FV) in the middle (MCA) and posterior cerebral arteries (PCA), intracranial pressure (ICP), and systemic arterial blood pressure (ABP). The analysis covered cerebral perfusion pressure (CPP), the index of pressure-volume compensatory reserve (RAP), and phase shift angles between Mayer waves (3 to 9 cpm) in ABP and MCA-FV or PCA-FV. Due to intraventricular infusion, the pressure-volume reserve was exhausted (RAP) 0.84+/-0.1 and ICP was increased from baseline 11.5+/-5.6 to plateau levels of 20.7+/-6.4 mmHg. The ratio dRAP/dICP distinguished patients with large 0.1+/-0.01, medium 0.05+/-0.02, and small 0.02+/-0.01 intracranial volume compliances. Both M wave phase shift angles (r = 0.64; p<0.01) and CPP (r = 0.36; p<0.05) displayed a gradual decline with decreasing dRAP/dICP gradients. This study showed that in communicating hydrocephalus, CPP and dynamic cerebral autoregulation in particular, depend on the volume-pressure compliance. The results suggested that the alteration of mechanoelastic characteristics contributes to a reduced cerebral perfusion and a loss of autonomy of cerebral blood flow regulation. Results warrant a prospective TCD follow-up to verify whether the alteration of dynamic cerebral autoregulation may indicate a progression of communicating hydrocephalus.
Keywords	Medicine ; R ; Science ; Q
Subject code	610
Language	English
Publishing date	2016-01-01T00:00:00Z
Publisher	Public Library of Science (PLoS)
Document type	Article ; Online
Database	BASE - Bielefeld Academic Search Engine (life sciences selection)

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Article ; Online: Characterising the dynamics of cerebral metabolic dysfunction following traumatic brain injury

Mathew R Guilfoyle / Adel Helmy / Joseph Donnelly / Matthew G Stovell / Ivan Timofeev / John D Pickard / Marek Czosnyka / Peter Smielewski / David K Menon / Keri L H Carpenter / Peter J Hutchinson

PLoS ONE, Vol 16, Iss 12, p e

A microdialysis study in 619 patients.

2021 Volume 0260291

Abstract: Traumatic brain injury (TBI) is a major cause of death and disability, particularly amongst young people. Current intensive care management of TBI patients is targeted at maintaining normal brain physiology and preventing secondary injury. Microdialysis ... ...

Abstract	Traumatic brain injury (TBI) is a major cause of death and disability, particularly amongst young people. Current intensive care management of TBI patients is targeted at maintaining normal brain physiology and preventing secondary injury. Microdialysis is an invasive monitor that permits real-time assessment of derangements in cerebral metabolism and responses to treatment. We examined the prognostic value of microdialysis parameters, and the inter-relationships with other neuromonitoring modalities to identify interventions that improve metabolism. This was an analysis of prospective data in 619 adult TBI patients requiring intensive care treatment and invasive neuromonitoring at a tertiary UK neurosciences unit. Patients had continuous measurement of intracranial pressure (ICP), arterial blood pressure (ABP), brain tissue oxygenation (PbtO2), and cerebral metabolism and were managed according to a standardized therapeutic protocol. Microdialysate was assayed hourly for metabolites including glucose, pyruvate, and lactate. Cerebral perfusion pressure (CPP) and cerebral autoregulation (PRx) were derived from the ICP and ABP. Outcome was assessed with the Glasgow Outcome Score (GOS) at 6 months. Relationships between monitoring variables was examined with generalized additive mixed models (GAMM). Lactate/Pyruvate Ratio (LPR) over the first 3 to 7 days following injury was elevated amongst patients with poor outcome and was an independent predictor of ordinal GOS (p<0.05). Significant non-linear associations were observed between LPR and cerebral glucose, CPP, and PRx (p<0.001 to p<0.05). GAMM models suggested improved cerebral metabolism (i.e. reduced LPR with CPP >70mmHg, PRx <0.1, PbtO2 >18mmHg, and brain glucose >1mM. Deranged cerebral metabolism is an important determinant of patient outcome following TBI. Variations in cerebral perfusion, oxygenation and glucose supply are associated with changes in cerebral LPR and suggest therapeutic interventions to improve cerebral metabolism. ...
Keywords	Medicine ; R ; Science ; Q
Subject code	610
Language	English
Publishing date	2021-01-01T00:00:00Z
Publisher	Public Library of Science (PLoS)
Document type	Article ; Online
Database	BASE - Bielefeld Academic Search Engine (life sciences selection)

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Article ; Online: The Human Systemic and Cerebral Circulations

Michael O’Rourke / Jonathan Stone / Audrey Adji / Mi Ok Kim / Yan Li / Ji Guang Wang / Alberto Avolio / Per Kristian Eide / Marek Czosnyka

Artery Research, Vol 26, Iss

Contrasts in Structure and Function

2020 Volume 4

Abstract: Apart from peculiarities of the cerebral circulation, required to perfuse the brain with the subject erect, the principles established for function of the human systemic circulation (pulsatile flow at input and steady flow at output in capillaries) are ... ...

Abstract	Apart from peculiarities of the cerebral circulation, required to perfuse the brain with the subject erect, the principles established for function of the human systemic circulation (pulsatile flow at input and steady flow at output in capillaries) are identical to those established for other mammals. Assumption of the erect posture first as Homo erectus, then as Homo sapiens, conferred huge advantage to humans and led to command of the mammalian kingdom. But this required a circulation which could perfuse the brain securely against gravity in all positions of the body. This review covers what presently is known about the human cerebral circulation, and how such knowledge can be applied in some clinical conditions including development of dementia in older subjects, and in management of patients with elevation of intra-cranial pressure in younger subjects.
Keywords	Wave reflection ; reflection coefficient ; pressure waves ; flow waves ; intracranial pressure ; pulse wave analysis ; Specialties of internal medicine ; RC581-951 ; Diseases of the circulatory (Cardiovascular) system ; RC666-701
Subject code	610
Language	English
Publishing date	2020-07-01T00:00:00Z
Publisher	BMC
Document type	Article ; Online
Database	BASE - Bielefeld Academic Search Engine (life sciences selection)

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Article ; Online: Temporal profile of intracranial pressure and cerebrovascular reactivity in severe traumatic brain injury and association with fatal outcome

Hadie Adams / Joseph Donnelly / Marek Czosnyka / Angelos G Kolias / Adel Helmy / David K Menon / Peter Smielewski / Peter J Hutchinson

PLoS Medicine, Vol 14, Iss 7, p e

An observational study.

2017 Volume 1002353

Abstract: Background Both intracranial pressure (ICP) and the cerebrovascular pressure reactivity represent the dysregulation of pathways directly involved in traumatic brain injury (TBI) pathogenesis and have been used to inform clinical management. However, how ... ...

Abstract	Background Both intracranial pressure (ICP) and the cerebrovascular pressure reactivity represent the dysregulation of pathways directly involved in traumatic brain injury (TBI) pathogenesis and have been used to inform clinical management. However, how these parameters evolve over time following injury and whether this evolution has any prognostic importance have not been studied. Methods and findings We analysed the temporal profile of ICP and pressure reactivity index (PRx), examined their relation to TBI-specific mortality, and determined if the prognostic relevance of these parameters was affected by their temporal profile using mixed models for repeated measures of ICP and PRx for the first 240 hours from the time of injury. A total of 601 adults with TBI, admitted between September 2002 to January 2016, and with high-resolution continuous monitoring from a single centre, were studied. At 6 months postinjury, 133 (19%) patients had a fatal outcome; of those, 88 (78%) died from nonsurvivable TBI or brain death. The difference in mean ICP between those with a fatal outcome and functional survivors was only significant for the first 168 hours after injury (all p < 0.05). For PRx, those patients with a fatal outcome also had a higher (more impaired) PRx throughout the first 120 hours after injury (all p < 0.05). The separation of ICP and PRx was greatest in the first 72 hours after injury. Mixed models demonstrated that the explanatory power of the PRx decreases over time; therefore, the prognostic weight assigned to PRx should similarly decrease. However, the ability of ICP to predict a fatal outcome remained relatively stable over time. As control of ICP is the central purpose of TBI management, it is likely that some of the information that is reflected in the natural history of ICP changes is no longer apparent because of therapeutic intervention. Conclusions We demonstrated the temporal evolution of ICP and PRx and their relationship with fatal outcome, indicating a potential early prognostic and ...
Keywords	Medicine ; R
Language	English
Publishing date	2017-07-01T00:00:00Z
Publisher	Public Library of Science (PLoS)
Document type	Article ; Online
Database	BASE - Bielefeld Academic Search Engine (life sciences selection)

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