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Eleveld N, Harmsen M, Elting JWJ, Maurits NM. Haemosync: A synchronisation algorithm for multimodal haemodynamic signals. COMPUTER METHODS AND PROGRAMS IN BIOMEDICINE 2024; 254:108298. [PMID: 38936154 DOI: 10.1016/j.cmpb.2024.108298] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/19/2024] [Revised: 05/30/2024] [Accepted: 06/17/2024] [Indexed: 06/29/2024]
Abstract
BACKGROUND Synchronous acquisition of haemodynamic signals is crucial for their multimodal analysis, such as dynamic cerebral autoregulation (DCA) analysis of arterial blood pressure (ABP) and transcranial Doppler (TCD)-derived cerebral blood velocity (CBv). Several technical problems can, however, lead to (varying) time-shifts between the different signals. These can be difficult to recognise and can strongly influence the multimodal analysis results. METHODS We have developed a multistep, cross-correlation-based time-shift detection and synchronisation algorithm for multimodal pulsatile haemodynamic signals. We have developed the algorithm using ABP and CBv measurements from a dataset that contained combinations of several time-shifts. We validated the algorithm on an external dataset with time-shifts. We additionally quantitatively validated the algorithm's performance on a dataset with artificially added time-shifts, consisting of sample clock differences ranging from -0.2 to 0.2 s/min and sudden time-shifts between -4 and 4 s. The influence of superimposed noise and variation in waveform morphology on the time-shift estimation was quantified, and their influence on DCA-indices was determined. RESULTS The instantaneous median absolute error (MedAE) between the artificially added time-shifts and the estimated time-shifts was 12 ms (median, IQR 12-12, range 11-14 ms) for drifts between -0.1 and 0.1 s/min and sudden time-shifts between -4 and 4 s. For drifts above 0.1 s/min, MedAE was higher (median 753, IQR 19 - 766, range 13 - 772 ms). When a certainty threshold was included (peak cross-correlation > 0.9), MedAE for all drifts-shift combinations decreased to 12 ms, with smaller variability (IQR 12 - 13, range 8 - 22 ms, p < 0.001). The time-shift estimation is robust to noise, as the MedAE was similar for superimposed white noise with variance equal to the signal variance. After time-shift correction, DCA-indices were similar to the original, non-time-shifted signals. Phase shift differed by 0.17° (median, IQR 0.13-0.2°, range 0.0038-1.1°) and 0.54° (median, IQR 0.23-1.7°, range 0.0088-5.6°) for the very low frequency and low frequency ranges, respectively. DISCUSSION This algorithm allows visually interpretable detection and accurate correction of time-shifts between pulsatile haemodynamic signals (ABP and CBv).
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Affiliation(s)
- Nick Eleveld
- University of Groningen, University Medical Center Groningen, Department of Neurology, 9713 GZ Groningen, the Netherlands.
| | - Marije Harmsen
- University of Groningen, University Medical Center Groningen, Department of Neurology, 9713 GZ Groningen, the Netherlands
| | - Jan Willem J Elting
- University of Groningen, University Medical Center Groningen, Department of Neurology, 9713 GZ Groningen, the Netherlands
| | - Natasha M Maurits
- University of Groningen, University Medical Center Groningen, Department of Neurology, 9713 GZ Groningen, the Netherlands
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2
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Merkel CA, Brady KM, Votava-Smith JK, Tran NN. A pilot study: Comparing a novel noninvasive measure of cerebrovascular stability index with an invasive measure of cerebral autoregulation in neonates with congenital heart disease. J Clin Transl Sci 2023; 7:e165. [PMID: 37588677 PMCID: PMC10425865 DOI: 10.1017/cts.2023.581] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2023] [Revised: 06/20/2023] [Accepted: 06/24/2023] [Indexed: 08/18/2023] Open
Abstract
Infants with congenital heart disease (CHD) may have impaired cerebral autoregulation (CA) associated with cerebral fractional tissue oxygen extraction (FTOE). We conducted a pilot study in nine CHD neonates to validate a noninvasive CA measure, cerebrovascular stability index (CSI), by eliciting responses to postural tilts. We compared CSI to an invasive measure of CA and to FTOE collected during tilts (FTOESpot). FTOESpot correlated with CSI, as did the change in FTOE during tilts, but CSI's correlation with impaired CA did not reach significance. Larger trials are indicated to validate CSI, allowing for noninvasive CA measurements and measurements in outpatient settings.
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Affiliation(s)
| | - Kenneth M. Brady
- Division of Cardiac Anesthesia, Northwestern University Feinberg School of Medicine and Ann & Robert H, Lurie Children’s Hospital of Chicago, Chicago, IL, USA
| | - Jodie K. Votava-Smith
- Keck School of Medicine, Los Angeles, CA, USA
- Division of Cardiology, Department of Pediatrics, Children’s Hospital Los Angeles, Los Angeles, CA, USA
| | - Nhu N. Tran
- Keck School of Medicine, Los Angeles, CA, USA
- Division of Neonatology, Department of Pediatrics, Fetal and Neonatal Institute, Children’s Hospital Los Angeles, Los Angeles, CA, USA
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3
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Ferlini L, Gaspard N. What's new on septic encephalopathy? Ten things you need to know. Minerva Anestesiol 2023; 89:217-225. [PMID: 35833857 DOI: 10.23736/s0375-9393.22.16689-7] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Sepsis associated encephalopathy (SAE) is a frequent complication of sepsis and is associated with a higher risk of short-term mortality and long-term cognitive impairment. The EEG is a sensitive complement of the clinical examination that can also detect and quantify encephalopathy and identify features with prognostic value, such as lack of reactivity. Moreover, despite their effect on outcome is still debated, the EEG is the only tool to detect non-convulsive seizures which can occur in a septic setting. Understanding the pathophysiology of SAE is fundamental to define potential therapeutic targets. Neuroinflammation plays an important role in the development of SAE and many blood and imaging biomarkers have recently shown a promising ability to distinguish SAE form non-SAE patient. In recent years, some interesting mediators of inflammation were successfully targeted in animal models, with a significant reduction in the neuroinflammation and in sepsis-induced cognitive decline. However, the complexity of the host response to sepsis currently limits the use of immunomodulation therapies in humans. Alteration in regulatory systems of cerebral blood flow, namely cerebral autoregulation (CA) and neurovascular coupling, contribute to SAE development. Nowadays, clinicians have access to different tools to assess them at the bedside and CA-based blood pressure protocols should be implemented to optimize cerebral perfusion. Its inauspicious consequences, its complex physiopathology and the lack of efficacious treatment make of SAE a highly active research subject.
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Affiliation(s)
- Lorenzo Ferlini
- Department of Neurology, Hôpital Erasme, University of Brussels, Brussels, Belgium
| | - Nicolas Gaspard
- Department of Neurology, Hôpital Erasme, University of Brussels, Brussels, Belgium -
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4
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Favilla CG, Mullen MT, Kahn F, Rasheed IYD, Messe SR, Parthasarathy AB, Yodh AG. Dynamic cerebral autoregulation measured by diffuse correlation spectroscopy. J Cereb Blood Flow Metab 2023:271678X231153728. [PMID: 36703572 PMCID: PMC10369149 DOI: 10.1177/0271678x231153728] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Dynamic cerebral autoregulation (dCA) can be derived from spontaneous oscillations in arterial blood pressure (ABP) and cerebral blood flow (CBF). Transcranial Doppler (TCD) measures CBF-velocity and is commonly used to assess dCA. Diffuse correlation spectroscopy (DCS) is a promising optical technique for non-invasive CBF monitoring, so here we aimed to validate DCS as a tool for quantifying dCA. In 33 healthy adults and 17 acute ischemic stroke patients, resting-state hemodynamic were monitored simultaneously with high-speed (20 Hz) DCS and TCD. dCA parameters were calcaulated by a transfer function analysis using a Fourier decomposition of ABP and CBF (or CBF-velocity). Strong correlation was found between DCS and TCD measured gain (magnitude of regulation) in healthy volunteers (r = 0.73, p < 0.001) and stroke patients (r = 0.76, p = 0.003). DCS-gain retained strong test-retest reliability in both groups (ICC 0.87 and 0.82, respectively). DCS and TCD-derived phase (latency of regulation) did not significantly correlate in healthy volunteers (r = 0.12, p = 0.50) but moderately correlated in stroke patients (r = 0.65, p = 0.006). DCS-derived phase was reproducible in both groups (ICC 0.88 and 0.90, respectively). High-frequency DCS is a promising non-invasive bedside technique that can be leveraged to quantify dCA from resting-state data, but the discrepancy between TCD and DCS-derived phase requires further investigation.
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Affiliation(s)
| | - Michael T Mullen
- Department of Neurology, 6558Temple University, Philadelphia, USA
| | - Farhan Kahn
- Department of Neurology, 6572University of Pennsylvania, Philadelphia, USA
| | | | - Steven R Messe
- Department of Neurology, 6572University of Pennsylvania, Philadelphia, USA
| | | | - Arjun G Yodh
- Department of Physics and Astronomy, University of Pennsylvania, Philadelphia, USA
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5
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Role of Vitamin D Deficiency in the Pathogenesis of Cardiovascular and Cerebrovascular Diseases. Nutrients 2023; 15:nu15020334. [PMID: 36678205 PMCID: PMC9864832 DOI: 10.3390/nu15020334] [Citation(s) in RCA: 30] [Impact Index Per Article: 30.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2022] [Revised: 12/29/2022] [Accepted: 12/30/2022] [Indexed: 01/12/2023] Open
Abstract
Deficiency in vitamin D (VitD), a lipid-soluble vitamin and steroid hormone, affects approximately 24% to 40% of the population of the Western world. In addition to its well-documented effects on the musculoskeletal system, VitD also contributes importantly to the promotion and preservation of cardiovascular health via modulating the immune and inflammatory functions and regulating cell proliferation and migration, endothelial function, renin expression, and extracellular matrix homeostasis. This brief overview focuses on the cardiovascular and cerebrovascular effects of VitD and the cellular, molecular, and functional changes that occur in the circulatory system in VitD deficiency (VDD). It explores the links among VDD and adverse vascular remodeling, endothelial dysfunction, vascular inflammation, and increased risk for cardiovascular and cerebrovascular diseases. Improved understanding of the complex role of VDD in the pathogenesis of atherosclerotic cardiovascular diseases, stroke, and vascular cognitive impairment is crucial for all cardiologists, dietitians, and geriatricians, as VDD presents an easy target for intervention.
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Panerai RB, Brassard P, Burma JS, Castro P, Claassen JA, van Lieshout JJ, Liu J, Lucas SJ, Minhas JS, Mitsis GD, Nogueira RC, Ogoh S, Payne SJ, Rickards CA, Robertson AD, Rodrigues GD, Smirl JD, Simpson DM. Transfer function analysis of dynamic cerebral autoregulation: A CARNet white paper 2022 update. J Cereb Blood Flow Metab 2023; 43:3-25. [PMID: 35962478 PMCID: PMC9875346 DOI: 10.1177/0271678x221119760] [Citation(s) in RCA: 47] [Impact Index Per Article: 47.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Cerebral autoregulation (CA) refers to the control of cerebral tissue blood flow (CBF) in response to changes in perfusion pressure. Due to the challenges of measuring intracranial pressure, CA is often described as the relationship between mean arterial pressure (MAP) and CBF. Dynamic CA (dCA) can be assessed using multiple techniques, with transfer function analysis (TFA) being the most common. A 2016 white paper by members of an international Cerebrovascular Research Network (CARNet) that is focused on CA strove to improve TFA standardization by way of introducing data acquisition, analysis, and reporting guidelines. Since then, additional evidence has allowed for the improvement and refinement of the original recommendations, as well as for the inclusion of new guidelines to reflect recent advances in the field. This second edition of the white paper contains more robust, evidence-based recommendations, which have been expanded to address current streams of inquiry, including optimizing MAP variability, acquiring CBF estimates from alternative methods, estimating alternative dCA metrics, and incorporating dCA quantification into clinical trials. Implementation of these new and revised recommendations is important to improve the reliability and reproducibility of dCA studies, and to facilitate inter-institutional collaboration and the comparison of results between studies.
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Affiliation(s)
- Ronney B Panerai
- Department of Cardiovascular Sciences, University of Leicester and NIHR Biomedical Research Centre, Leicester, UK
| | - Patrice Brassard
- Department of Kinesiology, Faculty of Medicine, and Research Center of the Institut universitaire de cardiologie et de pneumologie de Québec, Université Laval, Québec, QC, Canada
| | - Joel S Burma
- Faculty of Kinesiology, University of Calgary, Calgary, AB, Canada
| | - Pedro Castro
- Department of Neurology, Centro Hospitalar Universitário de São João, Faculty of Medicine, University of Porto, Porto, Portugal
| | - Jurgen Ahr Claassen
- Department of Geriatric Medicine and Donders Institute for Brain, Cognition and Behaviour, Radboud University, Nijmegen, The Netherlands
| | - Johannes J van Lieshout
- Department of Internal Medicine, Amsterdam, UMC, The Netherlands and Division of Physiology, Pharmacology and Neuroscience, School of Life Sciences, University of Nottingham Medical School, Queen's Medical Centre, UK
| | - Jia Liu
- Institute of Advanced Computing and Digital Engineering, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen University Town, Shenzhen, China
| | - Samuel Je Lucas
- School of Sport, Exercise and Rehabilitation Sciences and Centre for Human Brain Health, University of Birmingham, Birmingham, UK
| | - Jatinder S Minhas
- Department of Cardiovascular Sciences, University of Leicester and NIHR Biomedical Research Centre, Leicester, UK
| | - Georgios D Mitsis
- Department of Bioengineering, McGill University, Montreal, Québec, QC, Canada
| | - Ricardo C Nogueira
- Neurology Department, School of Medicine, Hospital das Clinicas, University of São Paulo, São Paulo, Brazil
| | - Shigehiko Ogoh
- Department of Biomedical Engineering, Toyo University, Kawagoe-Shi, Saitama, Japan
| | - Stephen J Payne
- Institute of Applied Mechanics, National Taiwan University, Taipei
| | - Caroline A Rickards
- Department of Physiology & Anatomy, University of North Texas Health Science Center, Fort Worth, Texas, USA
| | - Andrew D Robertson
- Department of Kinesiology and Health Sciences, University of Waterloo, Waterloo, ON, Canada
| | - Gabriel D Rodrigues
- Department of Clinical Sciences and Community Health, University of Milan, Milan, Italy
| | - Jonathan D Smirl
- Faculty of Kinesiology, University of Calgary, Calgary, AB, Canada
| | - David M Simpson
- Institute of Sound and Vibration Research, University of Southampton, Southampton, UK
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Sandru S, Buzescu D, Zahiu CDM, Spataru A, Panaitescu AM, Isac S, Balan CI, Zagrean AM, Pavel B. Near-Infrared Spectroscopy Usefulness in Validation of Hyperventilation Test. MEDICINA (KAUNAS, LITHUANIA) 2022; 58:medicina58101396. [PMID: 36295560 PMCID: PMC9607377 DOI: 10.3390/medicina58101396] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/31/2022] [Revised: 09/23/2022] [Accepted: 09/28/2022] [Indexed: 11/16/2022]
Abstract
Background: The hyperventilation test is used in clinical practice for diagnosis and therapeutic purposes; however, in the absence of a standardized protocol, the procedure varies significantly, predisposing tested subjects to risks such as cerebral hypoxia and ischemia. Near-infrared spectroscopy (NIRS), a noninvasive technique performed for cerebral oximetry monitoring, was used in the present study to identify the minimum decrease in the end-tidal CO2 (ETCO2) during hyperventilation necessary to induce changes on NIRS. Materials and Methods: We recruited 46 volunteers with no preexisting medical conditions. Each subject was asked to breathe at a baseline rate (8−14 breaths/min) for 2 min and then to hyperventilate at a double respiratory rate for the next 4 min. The parameters recorded during the procedure were the regional cerebral oxyhemoglobin and deoxyhemoglobin concentrations via NIRS, ETCO2, and the respiratory rate. Results: During hyperventilation, ETCO2 values dropped (31.4 ± 12.2%) vs. baseline in all subjects. Changes in cerebral oximetry were observed only in those subjects (n = 30) who registered a decrease (%) in ETCO2 of 37.58 ± 10.34%, but not in the subjects (n = 16) for which the decrease in ETCO2 was 20.31 ± 5.6%. According to AUC-ROC analysis, a cutoff value of ETCO2 decrease >26% was found to predict changes in oximetry (AUC-ROC = 0.93, p < 0.0001). Seven subjects reported symptoms, such as dizziness, vertigo, and numbness, throughout the procedure. Conclusions: The rise in the respiratory rate alone cannot effectively predict the occurrence of a cerebral vasoconstrictor response induced by hyperventilation, and synchronous ETCO2 and cerebral oximetry monitoring could be used to validate this clinical test. NIRS seems to be a useful tool in predicting vasoconstriction following hyperventilation.
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Affiliation(s)
- Stefan Sandru
- Department of Functional Sciences, Carol Davila University of Medicine and Pharmacy, 050474 Bucharest, Romania
| | - Dan Buzescu
- Department of Functional Sciences, Carol Davila University of Medicine and Pharmacy, 050474 Bucharest, Romania
| | - Carmen Denise Mihaela Zahiu
- Department of Functional Sciences, Carol Davila University of Medicine and Pharmacy, 050474 Bucharest, Romania
- Correspondence: (C.D.M.Z.); (B.P.)
| | - Ana Spataru
- Department of Critical Care, King’s College Hospital Denmark Hill, London SE5 9RS, UK
| | - Anca Maria Panaitescu
- Department of Obstetrics and Gynecology, Filantropia Clinical Hospital Bucharest, 011171 Bucharest, Romania
- Department of Obstetrics and Gynecology, Carol Davila University of Medicine and Pharmacy, 050474 Bucharest, Romania
| | - Sebastian Isac
- Department of Functional Sciences, Carol Davila University of Medicine and Pharmacy, 050474 Bucharest, Romania
| | - Cosmin Ion Balan
- Department I of Cardiovascular Anesthesiology and Intensive Care, “Prof. C. C Iliescu” Emergency Institute for Cardiovascular Diseases, 050474 Bucharest, Romania
| | - Ana-Maria Zagrean
- Department of Functional Sciences, Carol Davila University of Medicine and Pharmacy, 050474 Bucharest, Romania
| | - Bogdan Pavel
- Department of Functional Sciences, Carol Davila University of Medicine and Pharmacy, 050474 Bucharest, Romania
- Correspondence: (C.D.M.Z.); (B.P.)
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8
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Tas J, Bos KDJ, Le Feber J, Beqiri E, Czosnyka M, Haeren R, van der Horst ICC, van Kuijk SMJ, Strauch U, Brady KM, Smielewski P, Aries MJH. Inducing oscillations in positive end-expiratory pressure improves assessment of cerebrovascular pressure reactivity in patients with traumatic brain injury. J Appl Physiol (1985) 2022; 133:585-592. [PMID: 35796613 PMCID: PMC9448337 DOI: 10.1152/japplphysiol.00199.2022] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2022] [Revised: 07/05/2022] [Accepted: 07/05/2022] [Indexed: 11/22/2022] Open
Abstract
The cerebral pressure reactivity index (PRx), through intracranial pressure (ICP) measurements, informs clinicians about the cerebral autoregulation (CA) status in adult-sedated patients with traumatic brain injury (TBI). Using PRx in clinical practice is currently limited by variability over shorter monitoring periods. We applied an innovative method to reduce the PRx variability by ventilator-induced slow (1/min) positive end-expiratory pressure (PEEP) oscillations. We hypothesized that, as seen in a previous animal model, the PRx variability would be reduced by inducing slow arterial blood pressure (ABP) and ICP oscillations without other clinically relevant physiological changes. Patients with TBI were ventilated with a static PEEP for 30 min (PRx period) followed by a 30-min period of slow [1/min (0.0167 Hz)] +5 cmH2O PEEP oscillations (induced (iPRx period). Ten patients with TBI were included. No clinical monitoring was discontinued and no additional interventions were required during the iPRx period. The PRx variability [measured as the standard deviation (SD) of PRx] decreased significantly during the iPRx period from 0.25 (0.22-0.30) to 0.14 (0.09-0.17) (P = 0.006). There was a power increase around the induced frequency (1/min) for both ABP and ICP (P = 0.002). In conclusion, 1/min PEEP-induced oscillations reduced the PRx variability in patients with TBI with ICP levels <22 mmHg. No other clinically relevant physiological changes were observed. Reduced PRx variability might improve CA-guided perfusion management by reducing the time to find "optimal" perfusion pressure targets. Larger studies with prolonged periods of PEEP-induced oscillations are required to take it to routine use.NEW & NOTEWORTHY Cerebral autoregulation assessment requires sufficient slow arterial blood pressure (ABP) waves. However, spontaneous ABP waves may be insufficient for reliable cerebral autoregulation estimations. Therefore, we applied a ventilator "sigh-function" to generate positive end-expiratory pressure oscillations that induce slow ABP waves. This method demonstrated a reduced variability of the pressure reactivity index, commonly used as continuous cerebral autoregulation measure in a traumatic brain injury population.
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Affiliation(s)
- Jeanette Tas
- Department of Intensive Care Medicine, University Maastricht, Maastricht University Medical Center+, Maastricht, The Netherlands
- School for Mental Health and Neuroscience (MHeNS), University Maastricht, Maastricht, The Netherlands
| | - Kirsten D J Bos
- Department of Intensive Care Medicine, University Maastricht, Maastricht University Medical Center+, Maastricht, The Netherlands
- Department of Clinical Neurophysiology, University of Twente, Enschede, The Netherlands
| | - Joost Le Feber
- Department of Clinical Neurophysiology, University of Twente, Enschede, The Netherlands
| | - Erta Beqiri
- Brain Physics Laboratory, Division of Neurosurgery, Department of Clinical Neurosciences, University of Cambridge, Cambridge, United Kingdom
| | - Marek Czosnyka
- Brain Physics Laboratory, Division of Neurosurgery, Department of Clinical Neurosciences, University of Cambridge, Cambridge, United Kingdom
| | - Roel Haeren
- School for Mental Health and Neuroscience (MHeNS), University Maastricht, Maastricht, The Netherlands
- Department of Neurosurgery, University Maastricht, Maastricht University Medical Center+ Maastricht, Maastricht, The Netherlands
| | - Iwan C C van der Horst
- Department of Intensive Care Medicine, University Maastricht, Maastricht University Medical Center+, Maastricht, The Netherlands
- Cardiovascular Research Institute Maastricht (CARIM), Maastricht, The Netherlands
| | - Sander M J van Kuijk
- Department of Clinical Epidemiology and Medical Technology Assessment, (KEMTA), Maastricht University Medical Center+, Maastricht, The Netherlands
| | - Ulrich Strauch
- Department of Intensive Care Medicine, University Maastricht, Maastricht University Medical Center+, Maastricht, The Netherlands
| | - Ken M Brady
- Division of Cardiovascular Anesthesia, Department of Anesthesiology, Northwestern University Feinberg School of Medicine, Chicago, Illinois
- Department of Pediatrics, Northwestern University Feinberg School of Medicine, Chicago, Illinois
| | - Peter Smielewski
- Brain Physics Laboratory, Division of Neurosurgery, Department of Clinical Neurosciences, University of Cambridge, Cambridge, United Kingdom
| | - Marcel J H Aries
- Department of Intensive Care Medicine, University Maastricht, Maastricht University Medical Center+, Maastricht, The Netherlands
- School for Mental Health and Neuroscience (MHeNS), University Maastricht, Maastricht, The Netherlands
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9
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Tas J, Eleveld N, Borg M, Bos KDJ, Langermans AP, van Kuijk SMJ, van der Horst ICC, Elting JWJ, Aries MJH. Cerebral Autoregulation Assessment Using the Near Infrared Spectroscopy ‘NIRS-Only’ High Frequency Methodology in Critically Ill Patients: A Prospective Cross-Sectional Study. Cells 2022; 11:cells11142254. [PMID: 35883697 PMCID: PMC9317651 DOI: 10.3390/cells11142254] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2022] [Revised: 07/13/2022] [Accepted: 07/17/2022] [Indexed: 01/10/2023] Open
Abstract
Impairments in cerebral autoregulation (CA) are related to poor clinical outcome. Near infrared spectroscopy (NIRS) is a non-invasive technique applied to estimate CA. Our general purpose was to study the clinical feasibility of a previously published ‘NIRS-only’ CA methodology in a critically ill intensive care unit (ICU) population and determine its relationship with clinical outcome. Bilateral NIRS measurements were performed for 1–2 h. Data segments of ten-minutes were used to calculate transfer function analyses (TFA) CA estimates between high frequency oxyhemoglobin (oxyHb) and deoxyhemoglobin (deoxyHb) signals. The phase shift was corrected for serial time shifts. Criteria were defined to select TFA phase plot segments (segments) with ‘high-pass filter’ characteristics. In 54 patients, 490 out of 729 segments were automatically selected (67%). In 34 primary neurology patients the median (q1–q3) low frequency (LF) phase shift was higher in 19 survivors compared to 15 non-survivors (13° (6.3–35) versus 0.83° (−2.8–13), p = 0.0167). CA estimation using the NIRS-only methodology seems feasible in an ICU population using segment selection for more robust and consistent CA estimations. The ‘NIRS-only’ methodology needs further validation, but has the advantage of being non-invasive without the need for arterial blood pressure monitoring.
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Affiliation(s)
- Jeanette Tas
- Department of Intensive Care Medicine, Maastricht University Medical Center+, University Maastricht, 6229 HX Maastricht, The Netherlands; (M.B.); (K.D.J.B.); (A.P.L.); (I.C.C.v.d.H.); (M.J.H.A.)
- School for Mental Health and Neuroscience (MHeNS), University Maastricht, 6229 HX Maastricht, The Netherlands
- Correspondence:
| | - Nick Eleveld
- Department of Neurology and Clinical Neurophysiology, University Medical Center Groningen, 9713 GZ Groningen, The Netherlands; (N.E.); (J.W.J.E.)
| | - Melisa Borg
- Department of Intensive Care Medicine, Maastricht University Medical Center+, University Maastricht, 6229 HX Maastricht, The Netherlands; (M.B.); (K.D.J.B.); (A.P.L.); (I.C.C.v.d.H.); (M.J.H.A.)
| | - Kirsten D. J. Bos
- Department of Intensive Care Medicine, Maastricht University Medical Center+, University Maastricht, 6229 HX Maastricht, The Netherlands; (M.B.); (K.D.J.B.); (A.P.L.); (I.C.C.v.d.H.); (M.J.H.A.)
| | - Anne P. Langermans
- Department of Intensive Care Medicine, Maastricht University Medical Center+, University Maastricht, 6229 HX Maastricht, The Netherlands; (M.B.); (K.D.J.B.); (A.P.L.); (I.C.C.v.d.H.); (M.J.H.A.)
| | - Sander M. J. van Kuijk
- Department of Clinical Epidemiology and Medical Technology Assessment, (KEMTA), Maastricht University Medical Center+, 6229 HX Maastricht, The Netherlands;
| | - Iwan C. C. van der Horst
- Department of Intensive Care Medicine, Maastricht University Medical Center+, University Maastricht, 6229 HX Maastricht, The Netherlands; (M.B.); (K.D.J.B.); (A.P.L.); (I.C.C.v.d.H.); (M.J.H.A.)
- Cardiovascular Research Institute Maastricht (CARIM), 6229 HX Maastricht, The Netherlands
| | - Jan Willem J. Elting
- Department of Neurology and Clinical Neurophysiology, University Medical Center Groningen, 9713 GZ Groningen, The Netherlands; (N.E.); (J.W.J.E.)
| | - Marcel J. H. Aries
- Department of Intensive Care Medicine, Maastricht University Medical Center+, University Maastricht, 6229 HX Maastricht, The Netherlands; (M.B.); (K.D.J.B.); (A.P.L.); (I.C.C.v.d.H.); (M.J.H.A.)
- School for Mental Health and Neuroscience (MHeNS), University Maastricht, 6229 HX Maastricht, The Netherlands
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Li S, Zhao W, Liu G, Ren C, Meng R, Wang Y, Song H, Ma Q, Ding Y, Ji X. Chronic remote ischemic conditioning for symptomatic internal carotid or middle cerebral artery occlusion: A prospective cohort study. CNS Neurosci Ther 2022; 28:1365-1371. [PMID: 35702956 PMCID: PMC9344079 DOI: 10.1111/cns.13874] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2021] [Revised: 05/12/2022] [Accepted: 05/13/2022] [Indexed: 01/05/2023] Open
Abstract
AIMS Remote ischemic conditioning (RIC) has been demonstrated to reduce recurrent stroke in patients with intracranial artery stenosis. This study aimed to evaluate the effects of RIC in patients with the symptomatic internal carotid artery (ICA) or middle cerebral artery (MCA) occlusion. METHODS This study is based on a high-volume single-center prospective cohort study in China, which included patients with symptomatic ICA or MCA occlusion with impaired hemodynamics and receiving chronic RIC. Clinical follow-up visits were performed regularly, and cardio-cerebrovascular events were assessed. RESULTS In total, 131 patients (68 with ICA occlusion and 63 with MCA occlusion; mean age, 52.6 ± 13.7 years; stroke, 73.5%; transient ischemic attack TIA, 26.5%) qualified for the analysis; the mean follow-up period was 8.8 years (range, 3-14 years). The compliance of RIC was 95.6 ± 3.7%, and no associated severe adverse events happened. The annual risk of ischemic stroke and ischemic cerebrovascular events was 2.4% and 3.3%, respectively. The cumulative probabilities of ischemic cerebrovascular events and major adverse cardiovascular and cerebrovascular events were 32.8% and 44.8% at 14 years, respectively. CONCLUSION In patients with symptomatic ICA or MCA occlusion with impaired hemodynamics, chronic RIC is well-tolerated, and it appears to be associated with a low annual risk of ischemic stroke and cardio-cerebrovascular events.
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Affiliation(s)
- Sijie Li
- Department of Emergency, Xuanwu Hospital, Beijing Institute for Brain Disorders, Capital Medical University, Beijing, China.,Beijing Key Laboratory of Hypoxic Conditioning Translational Medicine, Xuanwu Hospital, Capital Medical University, Beijing, China
| | - Wenbo Zhao
- Beijing Key Laboratory of Hypoxic Conditioning Translational Medicine, Xuanwu Hospital, Capital Medical University, Beijing, China.,Department of Neurology, Xuanwu Hospital, Capital Medical University, Beijing, China
| | - Guiyou Liu
- Department of Emergency, Xuanwu Hospital, Beijing Institute for Brain Disorders, Capital Medical University, Beijing, China
| | - Changhong Ren
- Beijing Key Laboratory of Hypoxic Conditioning Translational Medicine, Xuanwu Hospital, Capital Medical University, Beijing, China
| | - Ran Meng
- Department of Neurology, Xuanwu Hospital, Capital Medical University, Beijing, China
| | - Yuan Wang
- Department of Neurology, Xuanwu Hospital, Capital Medical University, Beijing, China
| | - Haiqing Song
- Department of Neurology, Xuanwu Hospital, Capital Medical University, Beijing, China
| | - Qingfeng Ma
- Department of Neurology, Xuanwu Hospital, Capital Medical University, Beijing, China
| | - Yuchuan Ding
- Department of Neurosurgery, Wayne State University School of Medicine, Detroit, MI, USA
| | - Xunming Ji
- Department of Neurosurgery, Xuanwu Hospital, Capital Medical University, Beijing, China
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11
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Molina-Rodríguez S, Mirete-Fructuoso M, Martínez LM, Ibañez-Ballesteros J. Frequency-domain analysis of fNIRS fluctuations induced by rhythmic mental arithmetic. Psychophysiology 2022; 59:e14063. [PMID: 35394075 PMCID: PMC9540762 DOI: 10.1111/psyp.14063] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2021] [Revised: 01/19/2022] [Accepted: 03/08/2022] [Indexed: 12/25/2022]
Abstract
Functional near‐infrared spectroscopy (fNIRS) is an increasingly used technology for imaging neural correlates of cognitive processes. However, fNIRS signals are commonly impaired by task‐evoked and spontaneous hemodynamic oscillations of non‐cerebral origin, a major challenge in fNIRS research. In an attempt to isolate the task‐evoked cortical response, we investigated the coupling between hemodynamic changes arising from superficial and deep layers during mental effort. For this aim, we applied a rhythmic mental arithmetic task to induce cyclic hemodynamic fluctuations suitable for effective frequency‐resolved measurements. Twenty university students aged 18–25 years (eight males) underwent the task while hemodynamic changes were monitored in the forehead using a newly developed NIRS device, capable of multi‐channel and multi‐distance recordings. We found significant task‐related fluctuations for oxy‐ and deoxy‐hemoglobin, highly coherent across shallow and deep tissue layers, corroborating the strong influence of surface hemodynamics on deep fNIRS signals. Importantly, after removing such surface contamination by linear regression, we show that the frontopolar cortex response to a mental math task follows an unusual inverse oxygenation pattern. We confirm this finding by applying for the first time an alternative method to estimate the neural signal, based on transfer function analysis and phasor algebra. Altogether, our results demonstrate the feasibility of using a rhythmic mental task to impose an oscillatory state useful to separate true brain functional responses from those of non‐cerebral origin. This separation appears to be essential for a better understanding of fNIRS data and to assess more precisely the dynamics of the neuro‐visceral link. We proposed the use of rhythmic mental arithmetic tasks to induce cyclic oscillations in multi‐distance fNIRS signals measured on the forehead, suitable for effective frequency‐domain analysis to better identify the actual neural functional response. We confirm the impairment of deep signals by task‐evoked non‐cerebral confounds, while providing evidence for an inverse oxygenation response in the frontopolar cortex.
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Affiliation(s)
- Sergio Molina-Rodríguez
- Cellular and Systems Neurobiology, Institute of Neurosciences, Spanish National Research Council-Miguel Hernandez University, Alicante, Spain
| | - Marcos Mirete-Fructuoso
- Cellular and Systems Neurobiology, Institute of Neurosciences, Spanish National Research Council-Miguel Hernandez University, Alicante, Spain
| | - Luis M Martínez
- Cellular and Systems Neurobiology, Institute of Neurosciences, Spanish National Research Council-Miguel Hernandez University, Alicante, Spain
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12
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Zeng L, Li G, Zhang M, Zhu R, Chen J, Li M, Yin S, Bai Z, Zhuang W, Sun J. A noninvasive and comprehensive method for continuous assessment of cerebral blood flow pulsation based on magnetic induction phase shift. PeerJ 2022; 10:e13002. [PMID: 35228911 PMCID: PMC8881914 DOI: 10.7717/peerj.13002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2021] [Accepted: 02/03/2022] [Indexed: 01/11/2023] Open
Abstract
Cerebral blood flow (CBF) monitoring is of great significance for treating and preventing strokes. However, there has not been a fully accepted method targeting continuous assessment in clinical practice. In this work, we built a noninvasive continuous assessment system for cerebral blood flow pulsation (CBFP) that is based on magnetic induction phase shift (MIPS) technology and designed a physical model of the middle cerebral artery (MCA). Physical experiments were carried out through different simulations of CBF states. Four healthy volunteers were enrolled to perform the MIPS and ECG synchronously monitoring trials. Then, the components of MIPS related to the blood supply level and CBFP were investigated by signal analysis in time and frequency domain, wavelet decomposition and band-pass filtering. The results show that the time-domain baseline of MIPS increases with blood supply level. A pulse signal was identified in the spectrum (0.2-2 Hz in 200-2,000 ml/h groups, respectively) of MIPS when the simulated blood flow rate was not zero. The pulsation frequency with different simulated blood flow rates is the same as the squeezing frequency of the feeding pump. Similar to pulse waves, the MIPS signals on four healthy volunteers all had periodic change trends with obvious peaks and valleys. Its frequency is close to that of the ECG signal and there is a certain time delay between them. These results indicate that the CBFP component can effectively be extracted from MIPS, through which different blood supply levels can be distinguished. This method has the potential to become a new solution for non-invasive and comprehensive monitoring of CBFP.
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Affiliation(s)
- Lingxi Zeng
- School of Pharmacy and Bioengineering, Chongqing University of Technology, Chongqing, China
| | - Gen Li
- School of Pharmacy and Bioengineering, Chongqing University of Technology, Chongqing, China
| | - Maoting Zhang
- College of Biomedical Engineering, Army Medical University, Chongqing, China
| | - Rui Zhu
- School of Pharmacy and Bioengineering, Chongqing University of Technology, Chongqing, China
| | - Jingbo Chen
- College of Biomedical Engineering, Army Medical University, Chongqing, China
| | - Mingyan Li
- College of Artificial Intelligence, Chongqing University of Technology, Chongqing, China
| | - Shengtong Yin
- School of Pharmacy and Bioengineering, Chongqing University of Technology, Chongqing, China
| | - Zelin Bai
- College of Biomedical Engineering, Army Medical University, Chongqing, China
| | - Wei Zhuang
- College of Biomedical Engineering, Army Medical University, Chongqing, China
| | - Jian Sun
- College of Biomedical Engineering, Army Medical University, Chongqing, China
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13
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Naraoka M, Matsuda N, Shimamura N, Ohkuma H. Role of microcirculatory impairment in delayed cerebral ischemia and outcome after aneurysmal subarachnoid hemorrhage. J Cereb Blood Flow Metab 2022; 42:186-196. [PMID: 34496662 PMCID: PMC8721782 DOI: 10.1177/0271678x211045446] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Early brain injury (EBI) is considered an important cause of morbidity and mortality after aneurysmal subarachnoid hemorrhage (aSAH). As a factor in EBI, microcirculatory dysfunction has become a focus of interest, but whether microcirculatory dysfunction is more important than angiographic vasospasm (aVS) remains unclear. Using data from 128 cases, we measured the time to peak (TTP) in several regions of interest on digital subtraction angiography. The intracerebral circulation time (iCCT) was obtained between the TTP in the ultra-early phase (the baseline iCCT) and in the subacute phase and/or at delayed cerebral ischemia (DCI) onset (the follow-up iCCT). In addition, the difference in the iCCT was calculated by subtracting the baseline iCCT from the follow-up iCCT. Univariate analysis showed that DCI was significantly increased in those patients with a prolonged baseline iCCT, prolonged follow-up iCCT, increased differences in the iCCT, and with severe aVS. Poor outcome was significantly increased in patients with prolonged follow-up iCCT and increased differences in the iCCT. Multivariate analysis revealed that increased differences in the iCCT were a significant risk factor that increased DCI and poor outcome. The results suggest that the increasing microcirculatory dysfunction over time, not aVS, causes DCI and poor outcome after aneurysmal aSAH.
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Affiliation(s)
- Masato Naraoka
- Department of Neurosurgery, Hirosaki University School of Medicine & Hospital, Hirosaki, Japan
| | - Naoya Matsuda
- Department of Neurosurgery, Hirosaki University School of Medicine & Hospital, Hirosaki, Japan
| | - Norihito Shimamura
- Department of Neurosurgery, Hirosaki University School of Medicine & Hospital, Hirosaki, Japan
| | - Hiroki Ohkuma
- Department of Neurosurgery, Hirosaki University School of Medicine & Hospital, Hirosaki, Japan
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14
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Li W, Liu H, Huo C, Xu G, Zhang T, Li Z. Effects of acupuncture on the relationship between cerebral hemodynamics and arterial blood pressure in patients with hypertension. MEDICINE IN NOVEL TECHNOLOGY AND DEVICES 2021. [DOI: 10.1016/j.medntd.2021.100093] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022] Open
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15
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Eleveld N, Hoedemaekers CWE, van Kaam CR, Leijte GP, van den Brule JMD, Pickkers P, Aries MJH, Maurits NM, Elting JWJ. Near-Infrared Spectroscopy-Derived Dynamic Cerebral Autoregulation in Experimental Human Endotoxemia-An Exploratory Study. Front Neurol 2021; 12:695705. [PMID: 34566840 PMCID: PMC8461327 DOI: 10.3389/fneur.2021.695705] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2021] [Accepted: 08/11/2021] [Indexed: 11/13/2022] Open
Abstract
Cerebral perfusion may be altered in sepsis patients. However, there are conflicting findings on cerebral autoregulation (CA) in healthy participants undergoing the experimental endotoxemia protocol, a proxy for systemic inflammation in sepsis. In the current study, a newly developed near-infrared spectroscopy (NIRS)-based CA index is investigated in an endotoxemia study population, together with an index of focal cerebral oxygenation. Methods: Continuous-wave NIRS data were obtained from 11 healthy participants receiving a continuous infusion of bacterial endotoxin for 3 h (ClinicalTrials.gov NCT02922673) under extensive physiological monitoring. Oxygenated–deoxygenated hemoglobin phase differences in the (very)low frequency (VLF/LF) bands and the Tissue Saturation Index (TSI) were calculated at baseline, during systemic inflammation, and at the end of the experiment 7 h after the initiation of endotoxin administration. Results: The median (inter-quartile range) LF phase difference was 16.2° (3.0–52.6°) at baseline and decreased to 3.9° (2.0–8.8°) at systemic inflammation (p = 0.03). The LF phase difference increased from systemic inflammation to 27.6° (12.7–67.5°) at the end of the experiment (p = 0.005). No significant changes in VLF phase difference were observed. The TSI (mean ± SD) increased from 63.7 ± 3.4% at baseline to 66.5 ± 2.8% during systemic inflammation (p = 0.03) and remained higher at the end of the experiment (67.1 ± 4.2%, p = 0.04). Further analysis did not reveal a major influence of changes in several covariates such as blood pressure, heart rate, PaCO2, and temperature, although some degree of interaction could not be excluded. Discussion: A reversible decrease in NIRS-derived cerebral autoregulation phase difference was seen after endotoxin infusion, with a small, sustained increase in TSI. These findings suggest that endotoxin administration in healthy participants reversibly impairs CA, accompanied by sustained microvascular vasodilation.
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Affiliation(s)
- Nick Eleveld
- Department of Neurology, University Medical Center Groningen, University of Groningen, Groningen, Netherlands
| | - Cornelia W E Hoedemaekers
- Department of Intensive Care Medicine, Radboud University Medical Center, Radboud University, Nijmegen, Netherlands
| | - C Ruud van Kaam
- Department of Intensive Care Medicine, Radboud University Medical Center, Radboud University, Nijmegen, Netherlands
| | - Guus P Leijte
- Department of Intensive Care Medicine, Radboud University Medical Center, Radboud University, Nijmegen, Netherlands.,Radboud Center for Infectious Diseases (RCI), Radboud University Medical Center, Radboud University, Nijmegen, Netherlands
| | - Judith M D van den Brule
- Department of Intensive Care Medicine, Radboud University Medical Center, Radboud University, Nijmegen, Netherlands
| | - Peter Pickkers
- Department of Intensive Care Medicine, Radboud University Medical Center, Radboud University, Nijmegen, Netherlands.,Radboud Center for Infectious Diseases (RCI), Radboud University Medical Center, Radboud University, Nijmegen, Netherlands
| | - Marcel J H Aries
- Department of Intensive Care Medicine, School of Mental Health and NeuroSciences (MHeNS), University Medical Center Maastricht (MUMC+), Maastricht University, Maastricht, Netherlands
| | - Natasha M Maurits
- Department of Neurology, University Medical Center Groningen, University of Groningen, Groningen, Netherlands
| | - Jan Willem J Elting
- Department of Neurology, University Medical Center Groningen, University of Groningen, Groningen, Netherlands
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16
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Intermittent Sequential Pneumatic Compression Improves Coupling between Cerebral Oxyhaemoglobin and Arterial Blood Pressure in Patients with Cerebral Infarction. BIOLOGY 2021; 10:biology10090869. [PMID: 34571746 PMCID: PMC8470335 DOI: 10.3390/biology10090869] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/20/2021] [Revised: 08/31/2021] [Accepted: 09/01/2021] [Indexed: 11/16/2022]
Abstract
This study aims to explore the effect of intermittent sequential pneumatic compression (ISPC) intervention on the coupling relationship between arterial blood pressure (ABP) and changes in oxyhaemoglobin (Δ [O2Hb]). The coupling strength between the two physiological systems was estimated using a coupling function based on dynamic Bayesian inference. The participants were 22 cerebral infarction patients and 20 age- and sex-matched healthy controls. Compared with resting state, the coupling strength from ABP to Δ [O2Hb] oscillations was significantly lower in the bilateral prefrontal cortex (PFC), sensorimotor cortex (SMC), and temporal lobe cortex (TLC) during the ISPC intervention in cerebral infarction patients in interval II. Additionally, the coupling strength was significantly lower in the bilateral SMC in both groups in interval III. These findings indicate that ISPC intervention may facilitate cerebral circulation in the bilateral PFC, SMC, and TLC in cerebral infarction patients. ISPC may promote motor function recovery through its positive influences on motor-related networks. Furthermore, the coupling between Δ [O2Hb] and ABP allows non-invasive assessments of autoregulatory function to quantitatively assess the effect of rehabilitation tasks and to guide therapy in clinical situations.
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17
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Cerebral autoregulation assessed by near-infrared spectroscopy: validation using transcranial Doppler in patients with controlled hypertension, cognitive impairment and controls. Eur J Appl Physiol 2021; 121:2165-2176. [PMID: 33860383 PMCID: PMC8260523 DOI: 10.1007/s00421-021-04681-w] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2020] [Accepted: 04/02/2021] [Indexed: 01/05/2023]
Abstract
PURPOSE Cerebral autoregulation (CA) aims to attenuate the effects of blood pressure variation on cerebral blood flow. This study assessed the criterion validity of CA derived from near-infrared spectroscopy (NIRS) as an alternative for Transcranial Doppler (TCD). METHODS Measurements of continuous blood pressure (BP), oxygenated hemoglobin (O2Hb) using NIRS and cerebral blood flow velocity (CBFV) using TCD (gold standard) were performed in 82 controls, 27 patients with hypertension and 94 cognitively impaired patients during supine rest (all individuals) and repeated sit to stand transitions (cognitively impaired patients). The BP-CBFV and BP-O2Hb transfer function phase shifts (TFφ) were computed as CA measures. Spearman correlations (ρ) and Bland Altman limits of agreement (BAloa) between NIRS- and TCD-derived CA measures were computed. BAloa separation < 50° was considered a high absolute agreement. RESULTS NIRS- and TCD-derived CA estimates were significantly correlated during supine rest (ρ = 0.22-0.30, N = 111-120) and repeated sit-to-stand transitions (ρ = 0.46-0.61, N = 19-32). BAloa separation ranged between 87° and 112° (supine rest) and 65°-77° (repeated sit to stand transitions). CONCLUSION Criterion validity of NIRS-derived CA measures allows for comparison between groups but was insufficient for clinical application in individuals.
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18
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Optimal Hemodynamic Parameters for Brain-injured Patients in the Clinical Setting: A Narrative Review of the Evidence. J Neurosurg Anesthesiol 2021; 34:288-299. [PMID: 33443353 DOI: 10.1097/ana.0000000000000752] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2020] [Accepted: 12/07/2020] [Indexed: 11/25/2022]
Abstract
Defining optimal hemodynamic targets for brain-injured patients is a challenging undertaking. The physiological interference observed in various intracranial pathologies can have varying effects on cerebral physiology at different time points. This narrative review provides an overview of cerebral autoregulatory physiology and common misconceptions, and examines the physiological considerations and clinical evidence for determining optimal hemodynamic parameters in acutely brain-injured patients with relevance to modern neuroanesthesia and neurocritical care practice.
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19
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Cerebral macro- and microcirculatory blood flow dynamics in successfully treated chronic hypertensive patients with and without white mater lesions. Sci Rep 2020; 10:9213. [PMID: 32514031 PMCID: PMC7280202 DOI: 10.1038/s41598-020-66317-x] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2019] [Accepted: 05/18/2020] [Indexed: 01/14/2023] Open
Abstract
The mechanisms of high blood pressure (HBP) -related brain pathology progression remain relatively unclear. We investigated whether lowering BP in chronic HBP patients normalizes cerebral perfusion dynamics at resistance vessel and capillary levels. Sixty-seven patients with HBP and 49 age- and sex-matched healthy controls underwent simultaneous recordings of middle cerebral artery blood flow velocity (CBFV), BP, and end-tidal CO2 concentration. Thirty-four controls and 28 patients underwent additional near-infrared spectroscopy recordings (oxygenated [O2Hb] and deoxygenated [HHb] hemoglobin). Degree of microcirculatory white matter lesions was graded by Fazekas scale. Dynamic cerebral autoregulation (dCA) was assessed by transfer function analysis. BP was successfully lowered (patients = 89 ± 15 mm Hg, controls = 87 ± 17), but cerebrovascular resistance was higher in BP patients (p < 0.05). BP-CBFV phase was lower in very low frequency (VLF) (left/right: 48 ± 20°/44 ± 17; controls: 61 ± 20/60 ± 21; p < 0.001) and low frequency (LF) (34 ± 14/35 ± 14; controls: 48 ± 20/44 ± 17; p < 0.05) ranges. Gain was higher in VLF range (in %/ mm Hg 0.56 ± 0.44/0.59 ± 0.49; controls: 0.32 ± 0.29/0.34 ± 0.32; p ≤ 0.005). BP-CBFV phase and gain did not differ across Fazekas groups. Across all patients, the capillary phases and gains (CBFV-[O2Hb], CBFV-[HHb]) were comparable to controls. Successfully treated chronic HBP results in normal brain capillary hemodynamics while the resistance vessel state is disturbed (phase decrease, gain increase).
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20
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Müller M, Österreich M. Cerebral Microcirculatory Blood Flow Dynamics During Rest and a Continuous Motor Task. Front Physiol 2019; 10:1355. [PMID: 31708802 PMCID: PMC6821676 DOI: 10.3389/fphys.2019.01355] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2019] [Accepted: 10/11/2019] [Indexed: 12/13/2022] Open
Abstract
Objectives: To examine the brain’s microcirculatory response over the course of a continuous 5-min elbow movement task in order to estimate its potential role in grading vaso-neural coupling compared to the macrocirculatory response. Methods: We simultaneously recorded cerebral blood flow velocity (CBFV), changes in oxygenated/deoxygenated hemoglobin concentrations ([oxHb], [deoxHb]), blood pressure (BP), and end-tidal CO2 over 5-min periods of rest and left elbow movements in 24 healthy persons (13 women and 11 men of mean age ± SD, 38 ± 11 years). A low frequency range (0.07–0.15 Hz) was used for analysis by transfer function estimates of phase and gain. Results: Elbow movement led to a small BP increase (mean BP at rest 83 mm Hg, at movement 87; p < 0.01) and a small ETCO2 decrease (at rest 44.6 mm Hg, at movement 41.7 mm Hg; p < 0.01). Further, it increased BP-[oxHb] phase from 55° (both sides) to 74° (right; p < 0.05)/69° (left; p < 0.05), and BP-[deoxHb] phase from 264° (right)/270° (left) to 288° (right; p < 0.05)/297° (left; p = 0.09). The cerebral mean transit time at 0.1 Hz of 5.6 s of rest remained unchanged by movement. Elbow movement significantly decreased BP-CBFV gain on both sides, and BP-CBFV phase only on the right side (p = 0.05). Conclusion: Elbow movement leads to an increased time delay between BP and [oxHb]/[deoxHb] while leaving the cerebral mean transit time unchanged. Phase shifting is usually the more robust parameter when using a transfer function to estimate dynamic cerebral autoregulation; phase shifting at the microcirculatory level seems to be a better marker of VNC-induced changes than phase shifting between BP and CBFV.
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Affiliation(s)
- Martin Müller
- Neurovascular Laboratory, Neurocenter, Lucerne Kantonsspital, Lucerne, Switzerland
| | - Mareike Österreich
- Neurovascular Laboratory, Neurocenter, Lucerne Kantonsspital, Lucerne, Switzerland
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