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Froese L, Gomez A, Sainbhi AS, Vakitbilir N, Marquez I, Amenta F, Park K, Stein KY, Berrington N, Dhaliwal P, Zeiler FA. Optimal bispectral index exists in healthy patients undergoing general anesthesia: A validation study. J Clin Monit Comput 2024:10.1007/s10877-024-01136-3. [PMID: 38436898 DOI: 10.1007/s10877-024-01136-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2023] [Accepted: 02/05/2024] [Indexed: 03/05/2024]
Abstract
PURPOSE Continuous cerebrovascular reactivity monitoring in both neurocritical and intra-operative care has gained extensive interest in recent years, as it has documented associations with long-term outcomes (in neurocritical care populations) and cognitive outcomes (in operative cohorts). This has sparked further interest into the exploration and evaluation of methods to achieve an optimal cerebrovascular reactivity measure, where the individual patient is exposed to the lowest insult burden of impaired cerebrovascular reactivity. Recent literature has documented, in neural injury populations, the presence of a potential optimal sedation level in neurocritical care, based on the relationship between cerebrovascular reactivity and quantitative depth of sedation (using bispectral index (BIS)) - termed BISopt. The presence of this measure outside of neural injury patients has yet to be proven. METHODS We explore the relationship between BIS and continuous cerebrovascular reactivity in two cohorts: (A) healthy population undergoing elective spinal surgery under general anesthesia, and (B) healthy volunteer cohort of awake controls. RESULTS We demonstrate the presence of BISopt in the general anesthesia population (96% of patients), and its absence in awake controls, providing preliminary validation of its existence outside of neural injury populations. Furthermore, we found BIS to be sufficiently separate from overall systemic blood pressure, this indicates that they impact different pathophysiological phenomena to mediate cerebrovascular reactivity. CONCLUSIONS Findings here carry implications for the adaptation of the individualized physiologic BISopt concept to non-neural injury populations, both within critical care and the operative theater. However, this work is currently exploratory, and future work is required.
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Affiliation(s)
- Logan Froese
- Biomedical Engineering, Price Faculty of Engineering, University of Manitoba, Winnipeg, MB, Canada.
| | - Alwyn Gomez
- Section of Neurosurgery, Department of Surgery, Rady Faculty of Health Sciences, University of Manitoba, Winnipeg, MB, Canada
- Department of Human Anatomy and Cell Science, Rady Faculty of Health Sciences, University of Manitoba, Winnipeg, MB, Canada
| | - Amanjyot Singh Sainbhi
- Biomedical Engineering, Price Faculty of Engineering, University of Manitoba, Winnipeg, MB, Canada
| | - Nuray Vakitbilir
- Biomedical Engineering, Price Faculty of Engineering, University of Manitoba, Winnipeg, MB, Canada
| | - Izabella Marquez
- Undergraduate Engineering, Price Faculty of Engineering, University of Manitoba, Winnipeg, MB, Canada
| | - Fiorella Amenta
- Undergraduate Engineering, Price Faculty of Engineering, University of Manitoba, Winnipeg, MB, Canada
| | - Kangyun Park
- Undergraduate Medical Education, Rady Faculty of Health Sciences, University of Manitoba, Winnipeg, MB, Canada
| | - Kevin Y Stein
- Biomedical Engineering, Price Faculty of Engineering, University of Manitoba, Winnipeg, MB, Canada
- Undergraduate Medical Education, Rady Faculty of Health Sciences, University of Manitoba, Winnipeg, MB, Canada
| | - Neil Berrington
- Section of Neurosurgery, Department of Surgery, Rady Faculty of Health Sciences, University of Manitoba, Winnipeg, MB, Canada
| | - Perry Dhaliwal
- Section of Neurosurgery, Department of Surgery, Rady Faculty of Health Sciences, University of Manitoba, Winnipeg, MB, Canada
| | - Frederick A Zeiler
- Biomedical Engineering, Price Faculty of Engineering, University of Manitoba, Winnipeg, MB, Canada
- Section of Neurosurgery, Department of Surgery, Rady Faculty of Health Sciences, University of Manitoba, Winnipeg, MB, Canada
- Department of Human Anatomy and Cell Science, Rady Faculty of Health Sciences, University of Manitoba, Winnipeg, MB, Canada
- Division of Clinical Neuroscience, Karolinska Institutet, Stockholm, Sweden
- Division of Anaesthesia, Department of Medicine, Addenbrooke's Hospital, University of Cambridge, Cambridge, UK
- Centre on Aging, University of Manitoba, Winnipeg, MB, Canada
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2
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Bergmann T, Froese L, Gomez A, Sainbhi AS, Vakitbilir N, Islam A, Stein K, Marquez I, Amenta F, Park K, Ibrahim Y, Zeiler FA. Evaluation of Morlet Wavelet Analysis for Artifact Detection in Low-Frequency Commercial Near-Infrared Spectroscopy Systems. Bioengineering (Basel) 2023; 11:33. [PMID: 38247909 PMCID: PMC11154537 DOI: 10.3390/bioengineering11010033] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2023] [Revised: 12/23/2023] [Accepted: 12/25/2023] [Indexed: 01/23/2024] Open
Abstract
Regional cerebral oxygen saturation (rSO2), a method of cerebral tissue oxygenation measurement, is recorded using non-invasive near-infrared Spectroscopy (NIRS) devices. A major limitation is that recorded signals often contain artifacts. Manually removing these artifacts is both resource and time consuming. The objective was to evaluate the applicability of using wavelet analysis as an automated method for simple signal loss artifact clearance of rSO2 signals obtained from commercially available devices. A retrospective observational study using existing populations (healthy control (HC), elective spinal surgery patients (SP), and traumatic brain injury patients (TBI)) was conducted. Arterial blood pressure (ABP) and rSO2 data were collected in all patients. Wavelet analysis was determined to be successful in removing simple signal loss artifacts using wavelet coefficients and coherence to detect signal loss artifacts in rSO2 signals. The removal success rates in HC, SP, and TBI populations were 100%, 99.8%, and 99.7%, respectively (though it had limited precision in determining the exact point in time). Thus, wavelet analysis may prove to be useful in a layered approach NIRS signal artifact tool utilizing higher-frequency data; however, future work is needed.
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Affiliation(s)
- Tobias Bergmann
- Biosystems Engineering, Faculty of Engineering, University of Manitoba, Winnipeg, MB R3T 5V6, Canada; (I.M.); (F.A.)
| | - Logan Froese
- Biomedical Engineering, Faculty of Engineering, University of Manitoba, Winnipeg, MB R3T 5V6, Canada; (L.F.); (A.S.S.); (N.V.); (A.I.); (K.S.); (Y.I.)
| | - Alwyn Gomez
- Section of Neurosurgery, Department of Surgery, Rady Faculty of Health Sciences, University of Manitoba, Winnipeg, MB R3A 1R9, Canada;
- Department of Human Anatomy and Cell Science, Rady Faculty of Health Sciences, University of Manitoba, Winnipeg, MB R3E 0J9, Canada
| | - Amanjyot Singh Sainbhi
- Biomedical Engineering, Faculty of Engineering, University of Manitoba, Winnipeg, MB R3T 5V6, Canada; (L.F.); (A.S.S.); (N.V.); (A.I.); (K.S.); (Y.I.)
| | - Nuray Vakitbilir
- Biomedical Engineering, Faculty of Engineering, University of Manitoba, Winnipeg, MB R3T 5V6, Canada; (L.F.); (A.S.S.); (N.V.); (A.I.); (K.S.); (Y.I.)
| | - Abrar Islam
- Biomedical Engineering, Faculty of Engineering, University of Manitoba, Winnipeg, MB R3T 5V6, Canada; (L.F.); (A.S.S.); (N.V.); (A.I.); (K.S.); (Y.I.)
| | - Kevin Stein
- Biomedical Engineering, Faculty of Engineering, University of Manitoba, Winnipeg, MB R3T 5V6, Canada; (L.F.); (A.S.S.); (N.V.); (A.I.); (K.S.); (Y.I.)
- Undergraduate Medicine, Rady Faculty of Health Sciences, University of Manitoba, Winnipeg, MB R3E 3P5, Canada;
| | - Izzy Marquez
- Biosystems Engineering, Faculty of Engineering, University of Manitoba, Winnipeg, MB R3T 5V6, Canada; (I.M.); (F.A.)
| | - Fiorella Amenta
- Biosystems Engineering, Faculty of Engineering, University of Manitoba, Winnipeg, MB R3T 5V6, Canada; (I.M.); (F.A.)
| | - Kevin Park
- Undergraduate Medicine, Rady Faculty of Health Sciences, University of Manitoba, Winnipeg, MB R3E 3P5, Canada;
| | - Younis Ibrahim
- Biomedical Engineering, Faculty of Engineering, University of Manitoba, Winnipeg, MB R3T 5V6, Canada; (L.F.); (A.S.S.); (N.V.); (A.I.); (K.S.); (Y.I.)
| | - Frederick A. Zeiler
- Biomedical Engineering, Faculty of Engineering, University of Manitoba, Winnipeg, MB R3T 5V6, Canada; (L.F.); (A.S.S.); (N.V.); (A.I.); (K.S.); (Y.I.)
- Section of Neurosurgery, Department of Surgery, Rady Faculty of Health Sciences, University of Manitoba, Winnipeg, MB R3A 1R9, Canada;
- Department of Human Anatomy and Cell Science, Rady Faculty of Health Sciences, University of Manitoba, Winnipeg, MB R3E 0J9, Canada
- Centre on Aging, University of Manitoba, Winnipeg, MB R3T 2N2, Canada
- Division of Anaesthesia, Department of Medicine, Addenbrooke’s Hospital, University of Cambridge, Cambridge CB2 0QQ, UK
- Department of Clinical Neuroscience, Karolinska Institutet, 171 77 Stockholm, Sweden
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3
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Vitt JR, Loper NE, Mainali S. Multimodal and autoregulation monitoring in the neurointensive care unit. Front Neurol 2023; 14:1155986. [PMID: 37153655 PMCID: PMC10157267 DOI: 10.3389/fneur.2023.1155986] [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] [Accepted: 04/04/2023] [Indexed: 05/10/2023] Open
Abstract
Given the complexity of cerebral pathology in patients with acute brain injury, various neuromonitoring strategies have been developed to better appreciate physiologic relationships and potentially harmful derangements. There is ample evidence that bundling several neuromonitoring devices, termed "multimodal monitoring," is more beneficial compared to monitoring individual parameters as each may capture different and complementary aspects of cerebral physiology to provide a comprehensive picture that can help guide management. Furthermore, each modality has specific strengths and limitations that depend largely on spatiotemporal characteristics and complexity of the signal acquired. In this review we focus on the common clinical neuromonitoring techniques including intracranial pressure, brain tissue oxygenation, transcranial doppler and near-infrared spectroscopy with a focus on how each modality can also provide useful information about cerebral autoregulation capacity. Finally, we discuss the current evidence in using these modalities to support clinical decision making as well as potential insights into the future of advanced cerebral homeostatic assessments including neurovascular coupling.
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Affiliation(s)
- Jeffrey R. Vitt
- Department of Neurological Surgery, UC Davis Medical Center, Sacramento, CA, United States
- Department of Neurology, UC Davis Medical Center, Sacramento, CA, United States
| | - Nicholas E. Loper
- Department of Neurological Surgery, UC Davis Medical Center, Sacramento, CA, United States
| | - Shraddha Mainali
- Department of Neurology, Virginia Commonwealth University, Richmond, VA, United States
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Assessment of Optimal Arterial Pressure with Near-Infrared Spectroscopy in Traumatic Brain Injury Patients. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2022; 1395:133-137. [PMID: 36527627 PMCID: PMC10066817 DOI: 10.1007/978-3-031-14190-4_23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
In patients with severe traumatic brain injury (TBI), simultaneous measurement of intracranial and arterial blood pressure (ICP and ABP, respectively) allows monitoring of cerebral perfusion pressure (CPP) and the assessment of cerebral autoregulation (CA). CPP, a difference between ICP and ABP, is the pressure gradient that drives oxygen delivery to cerebral tissue. CA is the ability of cerebral vasculature to maintain stable blood flow despite changes in CPP and thus, is an important homeostatic mechanism. Pressure reactivity index (PRx), a moving Pearson's correlation between slow waves in ICP and ABP, has been most frequently cited in literature over the past two decades as a tool for CA evaluation. However, in some clinical situations, ICP monitoring may be unavailable or contraindicated. In such cases, simultaneous mean arterial pressure (MAP) monitoring and near-infrared spectroscopy (NIRS) can be used for CA assessment by cerebral oximetry index (COx), allowing calculation of the optimal blood pressure (MAPOPT). The purpose of this study was to compare regional oxygen saturation (rSO2)-based CA (COx) with ICP/ABP-based CA (PRx) in TBI patients and to compare MAPOPT derived from both technologies. Three TBI patients were monitored at the bedside to measure CA using both PRx and COx. Patients were monitored daily for up to 3 days from TBI. Averaged PRx and COx-, and PRx and COx-based MAPOPT were compared using Pearson's correlation. Bias analysis was performed between these same CA metrics. Correlation between averaged values of COx and PRx was R = 0.35, p = 0.15. Correlation between optimal MAP calculated for COx and PRx was R = 0.49, p < 0.038. Bland-Altman analysis showed moderate agreement with a bias of 0.16 ± 0.23 for COx versus PRx and good agreement with a bias of 0.39 ± 7.89 for optimal MAP determined by COx versus PRx. Non-invasive measurement of CA by NIRS (COx) is not correlated with invasive ICP/ABP-based CA (PRx). However, the determination of MAPOPT using COx is correlated with MAPOPT derived from PRx. Obtained results demonstrate that COx is not an acceptable substitute for PRx in TBI patients. However, in some TBI cases, NIRS may be useful in determining MAP determination.
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Semenyutin V, Antonov V, Malykhina G, Salnikov V. Investigation of Cerebral Autoregulation Using Time-Frequency Transformations. Biomedicines 2022; 10:biomedicines10123057. [PMID: 36551813 PMCID: PMC9775421 DOI: 10.3390/biomedicines10123057] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2022] [Revised: 10/24/2022] [Accepted: 11/20/2022] [Indexed: 11/29/2022] Open
Abstract
The authors carried out the study of the state of systemic and cerebral hemodynamics in normal conditions and in various neurosurgical pathologies using modern signal processing methods. The results characterize the condition for the mechanisms of cerebral circulation Institute of Computer Science and Control, Higher School of Cyber-Physical Systems and Control regulation, which allows for finding a solution to fundamental and specific clinical problems for the effective treatment of patients with various pathologies. The proposed method is based on the continuous wavelet transform of systemic arterial pressure and blood flow velocity signals in the middle cerebral artery recorded by non-invasive methods of photoplethysmography and transcranial doppler ultrasonography. The study of these signals in real-time in the frequency range of Mayer waves makes it possible to determine the cerebral autoregulation state in certain diseases before and after surgical interventions. The proposed method uses a cross-wavelet spectrum, which helps obtain wavelet coherence and a phase shift between the wavelet coefficients of systemic arterial pressure signals and blood flow velocity in the Mayer wave range. The obtained results enable comparing the proposed method with that based on the short-time Fourier transform. The comparison showed that the proposed method has higher sensitivity to changes in cerebral autoregulation and better localization of changes in time and frequency.
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Affiliation(s)
- Vladimir Semenyutin
- Almazov National Medical Research Center, Ministry of Health of Russia, Polenov Neurosurgical Research Institute, 12 Mayakovsky Street, Saint-Petersburg 191014, Russia
| | - Valery Antonov
- Department of Higher Mathematics, Peter the Great St. Petersburg Polytechnic University, Saint-Petersburg 195251, Russia
| | - Galina Malykhina
- Higher School of Cyber-Physical Systems and Control, Institute of Computer Science and Control, Peter the Great St. Petersburg Polytechnic University, Saint-Petersburg 195251, Russia
- Correspondence: ; Tel.: +8-921-43-15-114
| | - Vyacheslav Salnikov
- Higher School of Cyber-Physical Systems and Control, Institute of Computer Science and Control, Peter the Great St. Petersburg Polytechnic University, Saint-Petersburg 195251, Russia
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Sainbhi AS, Froese L, Gomez A, Batson C, Stein KY, Alizadeh A, Zeiler FA. Continuous Time-Domain Cerebrovascular Reactivity Metrics and Discriminate Capacity for the Upper and Lower Limits of Autoregulation: A Scoping Review of the Animal Literature. Neurotrauma Rep 2022; 2:639-659. [PMID: 35018365 PMCID: PMC8742280 DOI: 10.1089/neur.2021.0043] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Over a wide range of systemic arterial pressures, cerebral blood flow (CBF) is regulated fairly constantly by the cerebral vessels in a process termed cerebral autoregulation (CA), which is depicted by the Lassen autoregulatory curve. After traumatic brain injury (TBI), CA can get impaired and these impairments manifest in changes of the Lassen autoregulatory curve. Continuous surrogate metrics of pressure-based CA, termed cerebrovascular reactivity (CVR) metrics, evaluate the relationship between slow vasogenic fluctuations in a driving pressure for cerebral blood flow, and the most commonly studied and utilized measures are based in the time domain and have been increasingly applied in bedside TBI care and have sparked the investigation of individualized cerebral perfusion pressure targets. However, not all CVR metrics have been validated as true measures of autoregulation in the pre-clinical setting. We reviewed all available pre-clinical animal literature that assessed the association between continuous time-domain metrics of CVR and some aspect of the Lassen autoregulatory curve. All 15 articles found associated the evaluated continuous metrics to the lower limit of autoregulation curve whereas none looked at the upper limit. Most of the evaluated metrics showed the ability to discriminate the lower limit of autoregulation with various methods of perturbation. Further work is required to evaluate the utility of such surrogate measures against the upper limit of autoregulation, while also providing validation to the existing literature supporting specific indices and their ability to discriminate the lower limit.
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Affiliation(s)
- Amanjyot Singh Sainbhi
- Biomedical Engineering, Faculty of Engineering, University of Manitoba, Winnipeg, Manitoba, Canada
| | - Logan Froese
- Biomedical Engineering, Faculty of Engineering, University of Manitoba, Winnipeg, Manitoba, Canada
| | - Alwyn Gomez
- Section of Neurosurgery, Department of Surgery, Rady Faculty of Health Sciences, University of Manitoba, Winnipeg, Manitoba, Canada.,Department of Human Anatomy and Cell Science, Rady Faculty of Health Sciences, University of Manitoba, Winnipeg, Manitoba, Canada
| | - Carleen Batson
- Department of Human Anatomy and Cell Science, Rady Faculty of Health Sciences, University of Manitoba, Winnipeg, Manitoba, Canada
| | - Kevin Y Stein
- Section of Neurosurgery, Department of Surgery, Rady Faculty of Health Sciences, University of Manitoba, Winnipeg, Manitoba, Canada
| | - Arsalan Alizadeh
- Section of Neurosurgery, Department of Surgery, Rady Faculty of Health Sciences, University of Manitoba, Winnipeg, Manitoba, Canada
| | - Frederick A Zeiler
- Biomedical Engineering, Faculty of Engineering, University of Manitoba, Winnipeg, Manitoba, Canada.,Section of Neurosurgery, Department of Surgery, Rady Faculty of Health Sciences, University of Manitoba, Winnipeg, Manitoba, Canada.,Department of Human Anatomy and Cell Science, Rady Faculty of Health Sciences, University of Manitoba, Winnipeg, Manitoba, Canada.,Centre on Aging, University of Manitoba, Winnipeg, Manitoba, Canada.,Division of Anaesthesia, Department of Medicine, Addenbrooke's Hospital, University of Cambridge, Cambridge, United Kingdom
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7
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Precision neuroresuscitation after hypoxic-ischemic brain injury. Resuscitation 2021; 167:414-416. [PMID: 34438001 DOI: 10.1016/j.resuscitation.2021.08.020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2021] [Accepted: 08/10/2021] [Indexed: 11/20/2022]
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8
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Liu X, Tekes A, Perin J, Chen MW, Soares BP, Massaro AN, Govindan RB, Parkinson C, Chavez-Valdez R, Northington FJ, Brady KM, Lee JK. Wavelet Autoregulation Monitoring Identifies Blood Pressures Associated With Brain Injury in Neonatal Hypoxic-Ischemic Encephalopathy. Front Neurol 2021; 12:662839. [PMID: 33995258 PMCID: PMC8113412 DOI: 10.3389/fneur.2021.662839] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2021] [Accepted: 03/22/2021] [Indexed: 11/15/2022] Open
Abstract
Dysfunctional cerebrovascular autoregulation may contribute to neurologic injury in neonatal hypoxic-ischemic encephalopathy (HIE). Identifying the optimal mean arterial blood pressure (MAPopt) that best supports autoregulation could help identify hemodynamic goals that support neurologic recovery. In neonates who received therapeutic hypothermia for HIE, we hypothesized that the wavelet hemoglobin volume index (wHVx) would identify MAPopt and that blood pressures closer to MAPopt would be associated with less brain injury on MRI. We also tested a correlation-derived hemoglobin volume index (HVx) and single- and multi-window data processing methodology. Autoregulation was monitored in consecutive 3-h periods using near infrared spectroscopy in an observational study. The neonates had a mean MAP of 54 mmHg (standard deviation: 9) during hypothermia. Greater blood pressure above the MAPopt from single-window wHVx was associated with less injury in the paracentral gyri (p = 0.044; n = 63), basal ganglia (p = 0.015), thalamus (p = 0.013), and brainstem (p = 0.041) after adjustments for sex, vasopressor use, seizures, arterial carbon dioxide level, and a perinatal insult score. Blood pressure exceeding MAPopt from the multi-window, correlation HVx was associated with less injury in the brainstem (p = 0.021) but not in other brain regions. We conclude that applying wavelet methodology to short autoregulation monitoring periods may improve the identification of MAPopt values that are associated with brain injury. Having blood pressure above MAPopt with an upper MAP of ~50–60 mmHg may reduce the risk of brain injury during therapeutic hypothermia. Though a cause-and-effect relationship cannot be inferred, the data support the need for randomized studies of autoregulation and brain injury in neonates with HIE.
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Affiliation(s)
- Xiuyun Liu
- Department of Anesthesiology and Critical Care Medicine, Johns Hopkins University, Baltimore, MD, United States
| | - Aylin Tekes
- Department of Radiology, Johns Hopkins University, Baltimore, MD, United States
| | - Jamie Perin
- Department of Pediatrics, Center for Child and Community Health Research, Johns Hopkins University, Baltimore, MD, United States
| | - May W Chen
- Division of Neonatology, Johns Hopkins University, Baltimore, MD, United States
| | - Bruno P Soares
- Department of Radiology, University of Vermont, Burlington, VT, United States
| | - An N Massaro
- Fetal Medicine Institute, Children's National Health System, Washington, DC, United States.,The George Washington University School of Medicine, Washington, DC, United States.,Division of Neonatology, Children's National Health System, Washington, DC, United States
| | - Rathinaswamy B Govindan
- Fetal Medicine Institute, Children's National Health System, Washington, DC, United States.,The George Washington University School of Medicine, Washington, DC, United States
| | | | - Raul Chavez-Valdez
- Division of Neonatology, Johns Hopkins University, Baltimore, MD, United States
| | | | - Ken M Brady
- Department of Anesthesiology, Lurie Children's Hospital, Chicago, IL, United States
| | - Jennifer K Lee
- Department of Anesthesiology and Critical Care Medicine, Johns Hopkins University, Baltimore, MD, United States
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9
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Liu X, Akiyoshi K, Nakano M, Brady K, Bush B, Nadkarni R, Venkataraman A, Koehler RC, Lee JK, Hogue CW, Czosnyka M, Smielewski P, Brown CH. Determining Thresholds for Three Indices of Autoregulation to Identify the Lower Limit of Autoregulation During Cardiac Surgery. Crit Care Med 2021; 49:650-660. [PMID: 33278074 PMCID: PMC7979429 DOI: 10.1097/ccm.0000000000004737] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
OBJECTIVES Monitoring cerebral autoregulation may help identify the lower limit of autoregulation in individual patients. Mean arterial blood pressure below lower limit of autoregulation appears to be a risk factor for postoperative acute kidney injury. Cerebral autoregulation can be monitored in real time using correlation approaches. However, the precise thresholds for different cerebral autoregulation indexes that identify the lower limit of autoregulation are unknown. We identified thresholds for intact autoregulation in patients during cardiopulmonary bypass surgery and examined the relevance of these thresholds to postoperative acute kidney injury. DESIGN A single-center retrospective analysis. SETTING Tertiary academic medical center. PATIENTS Data from 59 patients was used to determine precise cerebral autoregulation thresholds for identification of the lower limit of autoregulation. These thresholds were validated in a larger cohort of 226 patients. METHODS AND MAIN RESULTS Invasive mean arterial blood pressure, cerebral blood flow velocities, regional cortical oxygen saturation, and total hemoglobin were recorded simultaneously. Three cerebral autoregulation indices were calculated, including mean flow index, cerebral oximetry index, and hemoglobin volume index. Cerebral autoregulation curves for the three indices were plotted, and thresholds for each index were used to generate threshold- and index-specific lower limit of autoregulations. A reference lower limit of autoregulation could be identified in 59 patients by plotting cerebral blood flow velocity against mean arterial blood pressure to generate gold-standard Lassen curves. The lower limit of autoregulations defined at each threshold were compared with the gold-standard lower limit of autoregulation determined from Lassen curves. The results identified the following thresholds: mean flow index (0.45), cerebral oximetry index (0.35), and hemoglobin volume index (0.3). We then calculated the product of magnitude and duration of mean arterial blood pressure less than lower limit of autoregulation in a larger cohort of 226 patients. When using the lower limit of autoregulations identified by the optimal thresholds above, mean arterial blood pressure less than lower limit of autoregulation was greater in patients with acute kidney injury than in those without acute kidney injury. CONCLUSIONS This study identified thresholds of intact and impaired cerebral autoregulation for three indices and showed that mean arterial blood pressure below lower limit of autoregulation is a risk factor for acute kidney injury after cardiac surgery.
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Affiliation(s)
- Xiuyun Liu
- Department of Anesthesiology and Critical Care Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Kei Akiyoshi
- Department of Anesthesiology and Critical Care Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Mitsunori Nakano
- Department of Anesthesiology and Critical Care Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
- Saitama Medical Center, Jichi Medical University, Saitama, Japan 330-8503
| | - Ken Brady
- Northwestern University, Ann & Robert H. Lurie Children’s Hospital of Chicago, Department of Anesthesiology, Chicago, Illinois, USA
| | - Brian Bush
- Department of Anesthesiology and Critical Care Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Rohan Nadkarni
- Department of Biomedical Engineering, Johns Hopkins University, Baltimore, Maryland, USA
| | - Archana Venkataraman
- Department of Electrical and Computer Engineering, Whiting School of Engineering, Johns Hopkins University, Baltimore, Maryland, USA
| | - Raymond C. Koehler
- Department of Anesthesiology and Critical Care Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Jennifer K. Lee
- Department of Anesthesiology and Critical Care Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Charles W. Hogue
- Department of Anesthesiology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, USA
| | - Marek Czosnyka
- Brain Physics Laboratory, Division of Neurosurgey, Cambridge University Hospitals, University of Cambridge, Cambridge, UK
- Institute of Electronic Systems, Warsaw University of Technology, Warsaw, Poland
| | - Peter Smielewski
- Brain Physics Laboratory, Division of Neurosurgey, Cambridge University Hospitals, University of Cambridge, Cambridge, UK
| | - Charles H. Brown
- Department of Anesthesiology and Critical Care Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
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