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Canova D, Roatta S, Saglietto A, Scarsoglio S, Gianotto NR, Piccotti A, De Ferrari GM, Ridolfi L, Anselmino M. A Quantitative Assessment of Cerebral Hemodynamic Perturbations Associated with Long R-R Intervals in Atrial Fibrillation: A Pilot-Case-Based Experience. MEDICINA (KAUNAS, LITHUANIA) 2024; 60:531. [PMID: 38674177 PMCID: PMC11052310 DOI: 10.3390/medicina60040531] [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: 01/23/2024] [Revised: 02/08/2024] [Accepted: 03/18/2024] [Indexed: 04/28/2024]
Abstract
Background and Objectives: Atrial fibrillation (AF) results in systemic hemodynamic perturbations which impact cerebral circulation, possibly contributing to the development of dementia. However, evidence documenting effects in cerebral perfusion is scarce. The aim of this study is to provide a quantitative characterization of the magnitude and time course of the cerebral hemodynamic response to the short hypotensive events associated with long R-R intervals, as detected by near-infrared spectroscopy (NIRS). Materials and Methods: Cerebral NIRS signals and arterial blood pressure were continuously recorded along with an electrocardiogram in twelve patients with AF undergoing elective electrical cardioversion (ECV). The top 0.5-2.5% longest R-R intervals during AF were identified in each patient and used as triggers to carry out the triggered averaging of hemodynamic signals. The average curves were then characterized in terms of the latency, magnitude, and duration of the observed effects, and the possible occurrence of an overshoot was also investigated. Results: The triggered averages revealed that long R-R intervals produced a significant drop in diastolic blood pressure (-13.7 ± 6.1 mmHg) associated with an immediate drop in cerebral blood volume (THI: -0.92 ± 0.46%, lasting 1.9 ± 0.8 s), followed by a longer-lasting decrease in cerebral oxygenation (TOI: -0.79 ± 0.37%, lasting 5.2 ± 0.9 s, p < 0.01). The recovery of the TOI was generally followed by an overshoot (+1.06 ± 0.12%). These effects were progressively attenuated in response to R-R intervals of a shorter duration. Conclusions: Long R-R intervals cause a detectable and consistent cerebral hemodynamic response which concerns both cerebral blood volume and oxygenation and outlasts the duration of the systemic perturbation. These effects are compatible with the activation of dynamic autoregulatory mechanisms in response to the hypotensive stimulus.
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Affiliation(s)
- Daniela Canova
- Department of Neuroscience, University of Torino, 10125 Torino, Italy; (D.C.); (S.R.)
| | - Silvestro Roatta
- Department of Neuroscience, University of Torino, 10125 Torino, Italy; (D.C.); (S.R.)
| | - Andrea Saglietto
- Division of Cardiology, Cardiovascular and Thoracic Department, “Città della Salute e della Scienza” Hospital, 10126 Torino, Italy;
| | - Stefania Scarsoglio
- Department of Water Engineering, Politecnico di Torino, 10129 Torino, Italy;
| | - Nefer Roberta Gianotto
- Department of Medical Sciences, University of Torino, 10124 Torino, Italy; (N.R.G.); (A.P.); (G.M.D.F.)
| | - Alessandro Piccotti
- Department of Medical Sciences, University of Torino, 10124 Torino, Italy; (N.R.G.); (A.P.); (G.M.D.F.)
| | - Gaetano Maria De Ferrari
- Department of Medical Sciences, University of Torino, 10124 Torino, Italy; (N.R.G.); (A.P.); (G.M.D.F.)
| | - Luca Ridolfi
- Department of Environment, Land and Infrastructure Engineering, Politecnico di Torino DIATI, 10129 Torino, Italy;
| | - Matteo Anselmino
- Division of Cardiology, Cardiovascular and Thoracic Department, “Città della Salute e della Scienza” Hospital, 10126 Torino, Italy;
- Department of Medical Sciences, University of Torino, 10124 Torino, Italy; (N.R.G.); (A.P.); (G.M.D.F.)
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Khan MN, Shallwani H, Khan MU, Shamim MS. Noninvasive monitoring intracranial pressure - A review of available modalities. Surg Neurol Int 2017; 8:51. [PMID: 28480113 PMCID: PMC5402331 DOI: 10.4103/sni.sni_403_16] [Citation(s) in RCA: 45] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2016] [Accepted: 01/26/2017] [Indexed: 12/28/2022] Open
Abstract
Background: Intracranial pressure (ICP) monitoring is important in many neurosurgical and neurological patients. The gold standard for monitoring ICP, however, is via an invasive procedure resulting in the placement of an intraventricular catheter, which is associated with many risks. Several noninvasive ICP monitoring techniques have been examined with the hope to replace the invasive techniques. The goal of this paper is to provide an overview of all modalities that have been used for noninvasive ICP monitoring to date. Methods: A thorough literature search was conducted on PubMed, selected articles were reviewed in completion, and pertinent data was included in the review. Results: A total of 94 publications were reviewed, and we found that over the past few decades clinicians have attempted to use a number of modalities to monitor ICP noninvasively. Conclusion: Although the intraventricular catheter remains the gold standard for monitoring ICP, several noninvasive modalities that can be used in settings when invasive monitoring is not possible are also available. In our opinion, measurement of optic nerve sheath diameter and pupillometry are the two modalities which may prove to be valid options for centers not performing invasive ICP monitoring.
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Affiliation(s)
| | - Hussain Shallwani
- Endovascular Research Fellow, University of Buffalo Neurosurgery, Buffalo, New York, USA
| | - Muhammad Ulusyar Khan
- Division of Biological and Biomedical Sciences, Aga Khan University Hospital, Karachi, Pakistan
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Weigl W, Milej D, Janusek D, Wojtkiewicz S, Sawosz P, Kacprzak M, Gerega A, Maniewski R, Liebert A. Application of optical methods in the monitoring of traumatic brain injury: A review. J Cereb Blood Flow Metab 2016; 36:1825-1843. [PMID: 27604312 PMCID: PMC5094301 DOI: 10.1177/0271678x16667953] [Citation(s) in RCA: 49] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/07/2016] [Revised: 06/28/2016] [Accepted: 07/18/2016] [Indexed: 01/19/2023]
Abstract
We present an overview of the wide range of potential applications of optical methods for monitoring traumatic brain injury. The MEDLINE database was electronically searched with the following search terms: "traumatic brain injury," "head injury," or "head trauma," and "optical methods," "NIRS," "near-infrared spectroscopy," "cerebral oxygenation," or "cerebral oximetry." Original reports concerning human subjects published from January 1980 to June 2015 in English were analyzed. Fifty-four studies met our inclusion criteria. Optical methods have been tested for detection of intracranial lesions, monitoring brain oxygenation, assessment of brain perfusion, and evaluation of cerebral autoregulation or intracellular metabolic processes in the brain. Some studies have also examined the applicability of optical methods during the recovery phase of traumatic brain injury . The limitations of currently available optical methods and promising directions of future development are described in this review. Considering the outstanding technical challenges, the limited number of patients studied, and the mixed results and opinions gathered from other reviews on this subject, we believe that optical methods must remain primarily research tools for the present. More studies are needed to gain confidence in the use of these techniques for neuromonitoring of traumatic brain injury patients.
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Affiliation(s)
- Wojciech Weigl
- Department of Surgical Sciences/Anaesthesiology and Intensive Care, Uppsala University, Akademiska Hospital, Uppsala, Sweden
| | - Daniel Milej
- Nalecz Institute of Biocybernetics and Biomedical Engineering, Polish Academy of Sciences, Warsaw, Poland
| | - Dariusz Janusek
- Nalecz Institute of Biocybernetics and Biomedical Engineering, Polish Academy of Sciences, Warsaw, Poland
| | - Stanisław Wojtkiewicz
- Nalecz Institute of Biocybernetics and Biomedical Engineering, Polish Academy of Sciences, Warsaw, Poland
| | - Piotr Sawosz
- Nalecz Institute of Biocybernetics and Biomedical Engineering, Polish Academy of Sciences, Warsaw, Poland
| | - Michał Kacprzak
- Nalecz Institute of Biocybernetics and Biomedical Engineering, Polish Academy of Sciences, Warsaw, Poland
| | - Anna Gerega
- Nalecz Institute of Biocybernetics and Biomedical Engineering, Polish Academy of Sciences, Warsaw, Poland
| | - Roman Maniewski
- Nalecz Institute of Biocybernetics and Biomedical Engineering, Polish Academy of Sciences, Warsaw, Poland
| | - Adam Liebert
- Nalecz Institute of Biocybernetics and Biomedical Engineering, Polish Academy of Sciences, Warsaw, Poland
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Hu G, Zhang Q, Ivkovic V, Strangman GE. Ambulatory diffuse optical tomography and multimodality physiological monitoring system for muscle and exercise applications. JOURNAL OF BIOMEDICAL OPTICS 2016; 21:091314. [PMID: 27467190 DOI: 10.1117/1.jbo.21.9.091314] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/19/2016] [Accepted: 07/08/2016] [Indexed: 05/09/2023]
Abstract
Ambulatory diffuse optical tomography (aDOT) is based on near-infrared spectroscopy (NIRS) and enables three-dimensional imaging of regional hemodynamics and oxygen consumption during a person’s normal activities. Although NIRS has been previously used for muscle assessment, it has been notably limited in terms of the number of channels measured, the extent to which subjects can be ambulatory, and/or the ability to simultaneously acquire synchronized auxiliary data such as electromyography (EMG) or electrocardiography (ECG). We describe the development of a prototype aDOT system, called NINscan-M, capable of ambulatory tomographic imaging as well as simultaneous auxiliary multimodal physiological monitoring. Powered by four AA size batteries and weighing 577 g, the NINscan-M prototype can synchronously record 64-channel NIRS imaging data, eight channels of EMG, ECG, or other analog signals, plus force, acceleration, rotation, and temperature for 24+ h at up to 250 Hz. We describe the system’s design, characterization, and performance characteristics. We also describe examples of isometric, cycle ergometer, and free-running ambulatory exercise to demonstrate tomographic imaging at 25 Hz. NINscan-M represents a multiuse tool for muscle physiology studies as well as clinical muscle assessment.
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Affiliation(s)
- Gang Hu
- Harvard Medical School, Massachusetts General Hospital, Neural Systems Group, Building 149, 13th Street, Charlestown, Massachusetts 02129, United States
| | - Quan Zhang
- Harvard Medical School, Massachusetts General Hospital, Neural Systems Group, Building 149, 13th Street, Charlestown, Massachusetts 02129, United StatesbBaylor College of Medicine, Center for Space Medicine, 6500 Main Street, Houston, Texas 77030, United
| | - Vladimir Ivkovic
- Harvard Medical School, Massachusetts General Hospital, Neural Systems Group, Building 149, 13th Street, Charlestown, Massachusetts 02129, United States
| | - Gary E Strangman
- Harvard Medical School, Massachusetts General Hospital, Neural Systems Group, Building 149, 13th Street, Charlestown, Massachusetts 02129, United StatesbBaylor College of Medicine, Center for Space Medicine, 6500 Main Street, Houston, Texas 77030, United
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Noninvasive methods of detecting increased intracranial pressure. Childs Nerv Syst 2016; 32:1371-86. [PMID: 27351182 DOI: 10.1007/s00381-016-3143-x] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/07/2016] [Accepted: 06/05/2016] [Indexed: 12/26/2022]
Abstract
The detection of elevated intracranial pressure (ICP) is of paramount importance in the diagnosis and management of a number of neurologic pathologies. The current gold standard is the use of intraventricular or intraparenchymal catheters; however, this is invasive, expensive, and requires anesthesia. On the other hand, diagnosing intracranial hypertension based on clinical symptoms such as headaches, vomiting, and visual changes lacks sensitivity. As such, there exists a need for a noninvasive yet accurate and reliable method for detecting elevated ICP. In this review, we aim to cover both structural modalities such as computed tomography (CT), magnetic resonance imaging (MRI), ocular ultrasound, fundoscopy, and optical coherence tomography (OCT) as well as functional modalities such as transcranial Doppler ultrasound (TCD), visual evoked potentials (VEPs), and near-infrared spectroscopy (NIRS).
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Fantini S, Sassaroli A, Tgavalekos KT, Kornbluth J. Cerebral blood flow and autoregulation: current measurement techniques and prospects for noninvasive optical methods. NEUROPHOTONICS 2016; 3:031411. [PMID: 27403447 PMCID: PMC4914489 DOI: 10.1117/1.nph.3.3.031411] [Citation(s) in RCA: 216] [Impact Index Per Article: 27.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/04/2016] [Accepted: 05/10/2016] [Indexed: 05/23/2023]
Abstract
Cerebral blood flow (CBF) and cerebral autoregulation (CA) are critically important to maintain proper brain perfusion and supply the brain with the necessary oxygen and energy substrates. Adequate brain perfusion is required to support normal brain function, to achieve successful aging, and to navigate acute and chronic medical conditions. We review the general principles of CBF measurements and the current techniques to measure CBF based on direct intravascular measurements, nuclear medicine, X-ray imaging, magnetic resonance imaging, ultrasound techniques, thermal diffusion, and optical methods. We also review techniques for arterial blood pressure measurements as well as theoretical and experimental methods for the assessment of CA, including recent approaches based on optical techniques. The assessment of cerebral perfusion in the clinical practice is also presented. The comprehensive description of principles, methods, and clinical requirements of CBF and CA measurements highlights the potentially important role that noninvasive optical methods can play in the assessment of neurovascular health. In fact, optical techniques have the ability to provide a noninvasive, quantitative, and continuous monitor of CBF and autoregulation.
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Affiliation(s)
- Sergio Fantini
- Tufts University, Department of Biomedical Engineering, 4 Colby Street, Medford, Massachusetts 02155, United States
| | - Angelo Sassaroli
- Tufts University, Department of Biomedical Engineering, 4 Colby Street, Medford, Massachusetts 02155, United States
| | - Kristen T. Tgavalekos
- Tufts University, Department of Biomedical Engineering, 4 Colby Street, Medford, Massachusetts 02155, United States
| | - Joshua Kornbluth
- Tufts University School of Medicine, Department of Neurology, Division of Neurocritical Care, 800 Washington Street, Box #314, Boston, Massachusetts 02111, United States
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Assessment of Cerebral Autoregulation Patterns with Near-infrared Spectroscopy during Pharmacological-induced Pressure Changes. Anesthesiology 2015; 123:327-35. [DOI: 10.1097/aln.0000000000000715] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Abstract
Background:
Previous work has demonstrated paradoxical increases in cerebral oxygen saturation (ScO2) as blood pressure decreases and paradoxical decreases in ScO2 as blood pressure increases. It has been suggested that these paradoxical responses indicate a functional cerebral autoregulation mechanism. Accordingly, the authors hypothesized that if this suggestion is correct, paradoxical responses will occur exclusively in patients with intact cerebral autoregulation.
Methods:
Thirty-four patients undergoing elective cardiac surgery were included. Cerebral autoregulation was assessed with the near-infrared spectroscopy–derived cerebral oximetry index (COx), computed by calculating the Spearman correlation coefficient between mean arterial pressure and ScO2. COx less than 0.30 was previously defined as functional autoregulation. During cardiopulmonary bypass, 20% change in blood pressure was accomplished with the use of nitroprusside for decreasing pressure and phenylephrine for increasing pressure. Effects on COx were assessed. Data were analyzed using two-way ANOVA, Kruskal–Wallis test, and Wilcoxon and Mann–Whitney U test.
Results:
Sixty-five percent of patients had a baseline COx less than 0.30, indicating functional baseline autoregulation. In 50% of these patients (n = 10), COx became highly negative after vasoactive drug administration (from −0.04 [−0.25 to 0.16] to −0.63 [−0.83 to −0.26] after administration of phenylephrine, and from −0.05 [−0.19 to 0.17] to −0.55 [−0.94 to −0.35] after administration of nitroprusside). A negative COx implies a decrease in ScO2 with increase in pressure and, conversely, an increase in ScO2 with decrease in pressure.
Conclusions:
In this study, paradoxical changes in ScO2 after pharmacological-induced pressure changes occurred exclusively in patients with intact cerebral autoregulation, corroborating the hypothesis that these paradoxical responses might be attributable to a functional cerebral autoregulation.
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Innovative Application of Cerebral rSO2 Monitoring During Shunt Tap in Pediatric Ventricular Malfunctioning Shunts. Pediatr Emerg Care 2015; 31:479-86. [PMID: 24901951 DOI: 10.1097/pec.0000000000000141] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
OBJECTIVE This study aimed to determine the reliability and potential application of cerebral regional tissue oxygenation (rSO2) monitoring in malfunctioning ventricular shunts during tap. METHODS This is a prospective case series using convenience sample in subjects with confirmed malfunctioning shunt who had left and right cerebral rSO2 monitoring every 5 seconds before, during, and 1 hour after shunt tap. RESULTS Ninety-four subjects had cerebral rSO2 monitoring. Sixty-three subjects had proximal malfunctions, and 31 subjects had distal shunt malfunctions. The intrasubject's cerebral rSO2 trend and variability at pretap, during, and posttap times were highly correlated. Overall, the average rSO2 is lower in pretap as compared with posttap. Left cerebral rSO2 had lower means and larger SD as compared with right cerebral rSO2. Left pretap and posttap cerebral rSO2 variability was significantly associated with the location of shunt malfunction regardless of pretap, during, or posttap periods (P < 0.001), whereas right rSO2 variability was not predictive for malfunction location. Left cerebral rSO2 variability showed utility for identifying the location of malfunction with area under the receiver operating characteristic curve equal to 0.8. CONCLUSIONS Reliable cerebral rSO2 readings before, during, and after shunt tap were demonstrated. Left cerebral rSO2 changes from before to after shunt tap were more predictive for shunt malfunction location than right cerebral rSO2 changes. Observing cerebral rSO2 changes in relationship to shunt tap represents a potential surrogate in measuring cerebral pressures and blood flow changes after cerebral spinal fluid drainage. Significantly greater cerebral rSO2 changes occur for distal malfunction versus proximal malfunction after shunt tap, indicating its potential as an adjunct tool for detecting shunt malfunction type.
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Cerebral oximetry with blood volume index in asystolic pediatric cerebrospinal fluid malfunctioning shunt patients. Am J Emerg Med 2014; 32:1439.e1-7. [PMID: 24856750 DOI: 10.1016/j.ajem.2014.04.007] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2014] [Revised: 04/04/2014] [Accepted: 04/05/2014] [Indexed: 11/22/2022] Open
Abstract
Pediatric cerebrospinal fluid shunt malfunctions can present with varying complaints. The primary cause is elevated intracranial pressure (ICP). Malfunctioning sites are the proximal or distal sites[1-4]. A rare presenting complaint is cardiac arrest. Immediate ICP reduction is the only reversible option for this type of cardiac arrest.
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Abramo TJ, Zhou C, Estrada C, Drayna PC, Locklair MR, Miller R, Pearson M, Tulipan N, Arnold DH. Cerebral regional oxygen saturation monitoring in pediatric malfunctioning shunt patients. Am J Emerg Med 2012; 31:365-74. [PMID: 23154102 DOI: 10.1016/j.ajem.2012.09.006] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2012] [Revised: 09/05/2012] [Accepted: 09/05/2012] [Indexed: 11/26/2022] Open
Abstract
BACKGROUND Shunt malfunction produces increased intracranial pressure causing decreased cerebral regional perfusion and tissue O(2)sat. Cerebral regional oxygen saturation (rSO(2)) by near-infrared spectroscopy represents tissue perfusion and oxygen saturation. Cerebral rSO(2) is used to detect cerebral ischemia in pediatric clinical settings. OBJECTIVE The objective of the study was to determine the reliability of cerebral rSO(2) in pediatric malfunctioning shunt. METHODS A prospective observational study of pediatric patients presented to the pediatric emergency department was conducted. Confirmed malfunctioning shunt subjects had cerebral rSO(2) monitoring. RESULTS A total of 131 malfunctioning shunt subjects had cerebral rSO(2) monitoring. Patient's central trend and intrasubject variability of cerebral rSO(2) readings for left and right probe and malfunction sites (n = 131) are as follows: Intrasubject left and right rSO(2) Pearson correlation was -0.46 to 0.98 (mean ± SD, 0.35 ± 0.34; median, 0.34; interquartile range, 0.06-0.61). The correlation coefficients of 99 subjects between left and right rSO(2) was significantly different (P < .001), suggesting that intrasubjects' left and right rSO(2) are highly correlated. Sample mean difference between left and right rSO(2) were -1.7% (95% confidence interval [CI], -1.8 to -1.6; P < .001) supporting overall left lower than right. Intraclass correlation for left rSO(2) was 87.4% (95% CI, 87.2%-87.6%), and that for right rSO(2) was 83.8% (95% CI, 83.8%-84%), showing intersubject differences accounting for the variation, and relative to intersubject variation, intrasubjects readings are consistent. Intrasubjects, left and right rSO(2) highly correlate and are asymmetrical. Left and right rSO(2) are consistent in intrasubject with large rSO(2) variations in trend and variability across subjects. CONCLUSION This study demonstrates reliable cerebral rSO(2) readings in subjects with malfunctioning shunts, with asymmetrical cerebral rSO(2) hemispheric dynamics within subjects.
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Affiliation(s)
- Thomas J Abramo
- Department of Pediatrics, Division of Pediatric Emergency Medicine, Vanderbilt University School of Medicine, Nashville, TN 37232-9001, USA.
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Saeed NP, Panerai RB, Robinson TG. Are hand-held TCD measurements acceptable for estimates of CBFv? ULTRASOUND IN MEDICINE & BIOLOGY 2012; 38:1839-1844. [PMID: 22766118 DOI: 10.1016/j.ultrasmedbio.2012.05.008] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/05/2012] [Revised: 04/18/2012] [Accepted: 05/11/2012] [Indexed: 06/01/2023]
Abstract
Cerebral blood flow velocity (CBFv) and the autoregulation index (ARI) can be reproducibly assessed by noninvasive transcranial Doppler (TCD) methodology using frame-held (FH) ultrasound probes. However, FH techniques may be impractical in severe head injury patients and neonates, where CBFv and ARI estimates are an important component of clinical assessment and management. Therefore, the aim of this study was to investigate the feasibility of an alternative hand-held (HH) approach to CBFv and ARI measurement. In a healthy volunteer population of 11 subjects, mean age 37 years, CBFv and ARI estimates were not significantly different between HH and FH acquisition techniques. In addition, in the hands of a single observer, good reproducibility over two visits, a mean of 6 days apart, was observed: intra-visit coefficient of variation (CV) 5.3% and 15.8%; and intraclass correlation coefficient (ICC) 0.8 and 0.4 for CBFv and ARI, respectively. Further work is required to assess the use of alternative sites to the middle cerebral artery (MCA) for the assessment of CBFv and ARI using HH rather than FH techniques and the applicability of this methodology in patient populations.
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Affiliation(s)
- Nazia P Saeed
- Ageing and Stroke Medicine, University of Leicester, Leicester, United Kingdom.
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Diedler J, Zweifel C, Budohoski KP, Kasprowicz M, Sorrentino E, Haubrich C, Brady KM, Czosnyka M, Pickard JD, Smielewski P. The limitations of near-infrared spectroscopy to assess cerebrovascular reactivity: the role of slow frequency oscillations. Anesth Analg 2011; 113:849-57. [PMID: 21821514 DOI: 10.1213/ane.0b013e3182285dc0] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
BACKGROUND A total hemoglobin reactivity index (THx) derived from near-infrared spectroscopy (NIRS) has recently been introduced to assess cerebrovascular reactivity noninvasively. Analogously to the pressure reactivity index (PRx), THx is calculated as correlation coefficient with arterial blood pressure (ABP). However, the reliability of THx in the injured brain is uncertain. Although slow oscillations have been described in NIRS signals, their significance for assessment of autoregulation remains unclear. In the current study, we investigated the role of slow oscillations of total hemoglobin for NIRS-based cerebrovascular reactivity monitoring. METHODS This study was based on a retrospective analysis of data that were consecutively recorded for a different project published previously. Thirty-seven patients with traumatic brain injury and admitted to Addenbrooke's Neurosciences Critical Care Unit between June 2008 and June 2009 were included. After artifact removal, we performed spectral analysis of the tissue hemoglobin index (THI, a measure of oxy- and deoxygenated hemoglobin) and intracranial pressure (ICP) signal. PRx and THx were calculated as moving correlations between ICP and ABP, and THI and ABP, respectively. The agreement between PRx and THx as a function of normalized power of slow oscillations (0.015-0.055 Hz) contained in the input signals was assessed performing between-subject and within-subject correlation analyses. Furthermore, the correlation between the THx values derived from the right and left sides was analyzed. RESULTS The agreement between PRx and THx depended on the power of slow oscillations in the input signals. Between-subject comparisons revealed a significant correlation between THx and PRx (r = 0.80, 95% confidence interval 0.53-0.92, P < 0.01) for patients with normalized slow wave activity >0.4 in the THI signal, compared with r = 0.07 (95% confidence interval -0.40 to 0.51, P = 0.79) in the remaining files. Furthermore, within-subject comparisons suggested that THx may be used as a substitute for PRx only when there is an at least moderate agreement (r = 0.36) between the THx values derived from the right and left sides. CONCLUSIONS Our results suggest that the NIRS-based cerebrovascular reactivity index THx can be used as a noninvasive substitute for PRx, but only during phases with sufficient slow wave power in the input signal. Furthermore, a good agreement between the THx measures on both sides seems to be a prerequisite for comparison of a global (PRx) versus the more local (THx) index. Nevertheless, noninvasive assessment of cerebrovascular reactivity may be desirable in patients without ICP monitoring and help to guide ABP management in these patients.
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Affiliation(s)
- Jennifer Diedler
- Academic Neurosurgical Unit, University of Cambridge Clinical School, Cambridge, United Kingdom.
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Abstract
Near-infrared spectroscopy is a noninvasive means of determining real-time changes in regional oxygen saturation of cerebral and somatic tissues. Hypoxic neurologic injuries not only involve devastating effects on patients and their families but also increase health care costs to the society. At present, monitors of cerebral function such as electroencephalograms, transcranial Doppler, jugular bulb mixed venous oximetry, and brain tissue oxygenation monitoring involve an invasive procedure, are operator-dependent, and/or lack the sensitivity required to identify patients at risk for cerebral hypoxia. Although 20th century advances in the understanding and management of resuscitation of critically ill and injured children have focused on global parameters (ie, pulse oximetry, capnography, base deficit, lactate, etc), a growing body of evidence now points to regional disturbances in microcirculation that will lead us in a new direction of adjunctive tissue monitoring and response to resuscitation. In the coming years, near-infrared spectroscopy will be accepted as a way for clinicians to more quickly and noninvasively identify patients with altered levels of cerebral and/or somatic tissue oxygenation and, in conjunction with global physiologic parameters, guide efficient and effective resuscitation to improve outcomes for critically ill and injured pediatric patients.
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Wagner BP, Ammann RA, Bachmann DCG, Born S, Schibler A. Rapid assessment of cerebral autoregulation by near-infrared spectroscopy and a single dose of phenylephrine. Pediatr Res 2011; 69:436-41. [PMID: 21258266 DOI: 10.1203/pdr.0b013e3182110177] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Rapid bedside determination of cerebral blood pressure autoregulation (AR) may improve clinical utility. We tested the hypothesis that cerebral Hb oxygenation (HbDiff) and cerebral Hb volume (HbTotal) measured by near-infrared spectroscopy (NIRS) would correlate with cerebral blood flow (CBF) after single dose phenylephrine (PE). Critically ill patients requiring artificial ventilation and arterial lines were eligible. During rapid blood pressure rise induced by i.v. PE bolus, ΔHbDiff and ΔHbTotal were calculated by subtracting values at baseline (normotension) from values at peak blood pressure elevation (hypertension). With the aid of NIRS and bolus injection of indocyanine green, relative measures of CBF, called blood flow index (BFI), were determined during normotension and during hypertension. BFI during hypertension was expressed as percentage from BFI during normotension (BFI%). Autoregulation indices (ARIs) were calculated by dividing BFI%, ΔHbDiff, and ΔHbTotal by the concomitant change in blood pressure. In 24 patients (11 newborns and 13 children), significant correlations between BFI% and ΔHbDiff (or ΔHbTotal) were found. In addition, the associations between Hb-based ARI and BFI%-based ARI were significant with correlation coefficients of 0.73 (or 0.72). Rapid determination of dynamic AR with the aid of cerebral Hb signals and PE bolus seems to be reliable.
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Affiliation(s)
- Bendicht P Wagner
- Department of Pediatrics, University of Berne, Inselspital, 3010 Berne, Switzerland.
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15
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Zweifel C, Castellani G, Czosnyka M, Carrera E, Brady KM, Kirkpatrick PJ, Pickard JD, Smielewski P. Continuous assessment of cerebral autoregulation with near-infrared spectroscopy in adults after subarachnoid hemorrhage. Stroke 2010; 41:1963-8. [PMID: 20651272 DOI: 10.1161/strokeaha.109.577320] [Citation(s) in RCA: 115] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BACKGROUND AND PURPOSE In patients with subarachnoid hemorrhage, the assessment of cerebral autoregulation aids in prognosis as well as detection of vasospasm. Mx is a validated index of cerebral autoregulation based on measures of cerebral perfusion pressure and mean flow velocity on transcranial Doppler but is impractical for longer-term monitoring. Near-infrared spectroscopy is noninvasive and suitable for continuous monitoring of cerebral tissue oxygenation using the Tissue Oxygenation Index. In this study, we compared near-infrared spectroscopy-based indices of cerebral autoregulation (TOx) with Mx in patients with subarachnoid hemorrhage. METHODS Arterial blood pressure, intracranial pressure, mean flow velocity, and Tissue Oxygenation Index were recorded. Mx and TOx were calculated as moving correlation coefficients between 10-second averaged values of cerebral perfusion pressure and mean flow velocity and between cerebral perfusion pressure and Tissue Oxygenation Index. We also calculated TOxA, the moving correlation coefficient between arterial blood pressure and Tissue Oxygenation Index. RESULTS Fifty-one recording sessions were performed in 27 patients with subarachnoid hemorrhage with a total duration of 62.5 hours. Correlations of Mx and TOx over time varied markedly among individual recordings. However, time-averaging over the entire recording interval in each of the 51 recordings, we found correlations between Mx and TOx and between Mx and TOxA were highly significant. This correlation was even stronger after correction for multiple sampling for each patient, reaching r=0.81 for Mx and TOx and r=0.72 for Mx and TOxA. CONCLUSIONS Near-infrared spectroscopy can be used to continuously assess cerebral autoregulation in adults after subarachnoid hemorrhage.
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Affiliation(s)
- Christian Zweifel
- Academic Neurosurgical Unit, University of Cambridge Clinical School, Cambridge, UK.
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Gatto R, Hoffman WE, Mueller M, Paisansathan C, Charbel F. Age effects on brain oxygenation during hypercapnia. JOURNAL OF BIOMEDICAL OPTICS 2007; 12:062113. [PMID: 18163816 DOI: 10.1117/1.2804705] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
Previous studies showed that the cerebrovasodilation response to hypercapnia is attenuated with aging. The purpose of this study was to determine if normal aging attenuates increases in brain oxygenation during hypercapnia. Prefrontal cortex oxyhemoglobin (OHb) and deoxyhemoglobin (HHb) concentrations were measured in 13 healthy subjects ages 26 to 59 years using a frequency domain tissue oximeter. Measurements were obtained under the following conditions: (1) subject awake breathing spontaneously, (2) during mask ventilation with 21% oxygen, (3) mask ventilation with 100% oxygen, (4) 100% oxygen in a rebreathing circuit to increase end-tidal CO(2). Under baseline conditions breathing room air, there was a negative correlation between baseline OHb and age (r=-0.60, P<0.05). Ventilation with 100% oxygen increased OHb without a change in total hemoglobin and no affect of age. During mask rebreathing, end-tidal CO(2) increased from 39.5+/-5.0 mm Hg (millimeters of mercury) to 56.5+/-5.7 mm Hg, which produced significant increases in OHb and total blood volume that were negatively correlated with age (r=-0.67, P<0.05) and positively correlated to baseline OHb (r=0.60, P<0.05). These results indicate that OHb concentrations decreased with age, consistent with attenuated cerebral vasodilation during hypercapnia.
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Affiliation(s)
- Rodolfo Gatto
- University of Illinois at Chicago, Department of Neurosurgery, Chicago, Illinois 60612, USA
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18
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Català-Temprano A, Claret Teruel G, Cambra Lasaosa FJ, Pons Odena M, Noguera Julián A, Palomeque Rico A. Intracranial pressure and cerebral perfusion pressure as risk factors in children with traumatic brain injuries. J Neurosurg 2007; 106:463-6. [PMID: 17566403 DOI: 10.3171/ped.2007.106.6.463] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
OBJECT The authors evaluated the initial intracranial pressure (ICP) and cerebral perfusion pressure (CPP) as prognostic factors in severe head injury in children and tried to determine the optimal CPP range. METHODS The authors performed a 9-year retrospective review of all patients with severe traumatic brain injuries (TBIs) who required invasive ICP monitoring and were admitted to the pediatric intensive care unit at their institution between January 1995 and December 2003. These patients had Glasgow Coma Scale scores lower than 8 and/or required ICP monitoring due to worsening neurological status or neuroimaging results suggestive of cerebral hypertension. Clinical summaries and imaging studies were reviewed. Data for 156 pediatric patients who ranged in age from 1 to 18 years were obtained. Half of these patients presented with normal initial ICPs (< 20 mm Hg), and a good outcome was achieved in 80% of these children. An unfavorable outcome was observed in more than 60% of patients with an initial CPP lower than 40 mm Hg. The proportion of patients with an unfavorable outcome decreased to 10% with initial CPPs higher than 60 mm Hg, but patients with initial CPPs higher than 70 mm Hg did not improve. CONCLUSIONS Initial ICP and CPP measurements were useful as prognostic factors in pediatric patients with severe TBIs: patients with initial CPPs between 40 and 70 mm Hg were found to have a better neurological prognosis than those with CPPs either higher or lower than that range.
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Affiliation(s)
- Albert Català-Temprano
- Pediatric Intensive Care Unit, Pediatrics Department, Integrated Unit Sant Joan de Déu-Clínic, Hospital Universitari Sant Joan de Déu, Universitat de Barcelona, Esplugues, Barcelona, Spain.
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19
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Bein B, Cavus E, Stadlbauer KH, Tonner PH, Steinfath M, Scholz J, Dörges V. Monitoring of cerebral oxygenation with near infrared spectroscopy and tissue oxygen partial pressure during cardiopulmonary resuscitation in pigs. Eur J Anaesthesiol 2006; 23:501-9. [PMID: 16507191 DOI: 10.1017/s0265021506000366] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/15/2006] [Indexed: 11/07/2022]
Abstract
BACKGROUND AND OBJECTIVE The present study was designed to compare cerebral oxygenation measured with near infrared spectroscopy and local brain tissue oxygen partial pressure, respectively, in pigs during cardiopulmonary resuscitation. Since tissue overlying the brain may have an impact on near infrared spectroscopy readings, we tested whether optode placement on intact skin or on the skull yielded comparable results. METHODS Twelve healthy pigs were anaesthetized and subjected to continuous haemodynamic, near infrared spectroscopy and brain tissue oxygen partial pressure monitoring. After 4 min of untreated ventricular fibrillation, cardiopulmonary resuscitation was started and arginine vasopressin was administered repeatedly three times. Near infrared spectroscopy values recorded were both the tissue oxygenation index and the tissue haemoglobin index as well as relative changes of chromophores (haemoglobin and cytochrome oxidase). Four animals served as control and were measured with both near infrared spectroscopy optodes mounted on the intact skin of the forehead, while in the remaining eight animals, one near infrared spectroscopy optode was implanted directly on the skull. RESULTS Near infrared spectroscopy readings at the skin or at the skull differed consistently throughout the study period. After arginine vasopressin administration, near infrared spectroscopy values at the different locations showed a transient dissociation. In contrast to near infrared spectroscopy measured on intact skin, near infrared spectroscopy readings obtained from skull showed a significant correlation to brain tissue oxygen partial pressure values (r = 0.67, P < 0.001). CONCLUSION Near infrared spectroscopy readings obtained from skin and skull differed largely after vasopressor administration. Near infrared spectroscopy optode placement therefore may have an important influence on the tissue region investigated.
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Affiliation(s)
- B Bein
- Department of Anaesthesiology and Intensive Care Medicine, University Hospital Schleswig-Holstein, Kiel, Germany.
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Panerai RB, Kerins V, Fan L, Yeoman PM, Hope T, Evans DH. Association between dynamic cerebral autoregulation and mortality in severe head injury. Br J Neurosurg 2005; 18:471-9. [PMID: 15799148 DOI: 10.1080/02688690400012343] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
The objective of the study was to test the hypothesis that dynamic cerebral pressure-autoregulation is associated with the outcome of patients with severe head injury and to derive optimal criteria for future studies on the predictive value of autoregulation indices. Repeated measurements were performed on 32 patients with severe head injury. Arterial blood pressure (ABP) was measured continuously with an intravascular catheter, intracranial pressure (ICP) was recorded with a subdural semiconductor transducer and cerebral blood flow velocity (CBFV) was measured with Doppler ultrasound in the middle cerebral artery. Transfer function analysis was performed on mean beat-to-beat values, using ABP or CBFV as input variables and CBFV or ICP as the output variables. A dynamic index of autoregulation (ARI) ranging between 0 and 9 was extracted from the CBFV step response for a change in ABP. No significant differences between survivors and non-survivors were found due to mean values of ICP, ABP, CPP, CBFV, pCO2, GCS, age or heart rate. The transfer functions between ABP-ICP and CBFV-ICP did not show any significant differences either. The median [lower, upper quartiles] ARI was significantly lower for non-survivors compared with survivors [4.8 (0.0, 5.9) v. 6.9 (5.9, 7.4), p= 0.004]. The correlation between ARI and GOS was also significant (r=0.464, p=0.011). Cohen's coefficient was optimal for a threshold of ARI= 5.86 (kappa 0.51, p=0.0036), leading to a sensitivity for death of 75%, specificity=76.5%, odds ratio =9.75 and overall precision = 75.8%. The difference in ARI values between survivors and non-survivors persisted when results were adjusted for GCS (p = 0.028). A similar analysis for the Marshall CT scale did not reach significance (p = 0.072). A logistic regression analysis confirmed that apart from the ARI, no other variables had a significant contribution to predict outcome. In this group of patients, death following severe head injury could not be explained by traditional indices of risk, but was strongly correlated to indices of dynamic cerebral pressure-autoregulation extracted by means of transfer function analysis. Future studies using a prospective design are needed to validate the predictive value of the ARI index, as estimated by transfer function analysis, in relation to death and other unfavourable outcomes.
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Affiliation(s)
- R B Panerai
- Department of Cardiovascular Sciences, Faculty of Medicine, University of Leicester, Leicester Royal Infirmary, Leicester, UK.
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Bein B, Cavus E, Dörges V, Stadlbauer KH, Tonner PH, Steinfath M, Scholz J. Arginine vasopressin reduces cerebral oxygenation and cerebral blood volume during intact circulation in swine---a near infrared spectroscopy study. Eur J Anaesthesiol 2005; 22:62-6. [PMID: 15816576 DOI: 10.1017/s026502150500013x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
BACKGROUND AND OBJECTIVE The aim of the present study was to investigate the impact of arginine vasopressin (AVP), a drug currently under investigation for use during cardiopulmonary resuscitation, on cerebral oxygenation and cerebral blood volume (CBV) in pigs with intact systemic circulation using near infrared spectroscopy. METHODS Nine healthy pigs were anaesthetized and subjected to invasive haemodynamic monitoring as well as to non-invasive determination (with near infrared spectroscopy) of changes in the Tissue Oxygenation Index (TOI is the ratio of oxygenated to total tissue haemoglobin), Tissue Haemoglobin Index (THI, representing CBV) and cytochrome oxidase (deltaCytOx, representing the balance of intracellular oxygen supply). RESULTS At both 3 and 5 min after AVP administration, TOI, THI and deltaCytOx were significantly (P < 0.001) reduced compared to baseline, while cerebral perfusion pressure increased significantly (P < 0.001). The effects of AVP on TOI and THI lasted longer than on deltaCytOx. There were no significant changes with respect to the intracranial pressure throughout the study period. CONCLUSIONS No improvement of cerebral oxygenation was detected after AVP administration in swine with an intact systemic circulation. In contrast to recently published investigations, AVP provoked a sustained drop in indices of cerebral oxygenation and CBV.
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Affiliation(s)
- B Bein
- University Hospital Schleswig-Holstein, Department of Anaesthesiology and Intensive Care Medicine, Campus Kiel, Germany.
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Arginine vasopressin reduces cerebral oxygenation and cerebral blood volume during intact circulation in swine - a near infrared spectroscopy study. Eur J Anaesthesiol 2005. [DOI: 10.1097/00003643-200501000-00013] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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