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Mathis M, Steffner KR, Subramanian H, Gill GP, Girardi NI, Bansal S, Bartels K, Khanna AK, Huang J. Overview and Clinical Applications of Artificial Intelligence and Machine Learning in Cardiac Anesthesiology. J Cardiothorac Vasc Anesth 2024; 38:1211-1220. [PMID: 38453558 PMCID: PMC10999327 DOI: 10.1053/j.jvca.2024.02.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/25/2023] [Revised: 01/30/2024] [Accepted: 02/05/2024] [Indexed: 03/09/2024]
Abstract
Artificial intelligence- (AI) and machine learning (ML)-based applications are becoming increasingly pervasive in the healthcare setting. This has in turn challenged clinicians, hospital administrators, and health policymakers to understand such technologies and develop frameworks for safe and sustained clinical implementation. Within cardiac anesthesiology, challenges and opportunities for AI/ML to support patient care are presented by the vast amounts of electronic health data, which are collected rapidly, interpreted, and acted upon within the periprocedural area. To address such challenges and opportunities, in this article, the authors review 3 recent applications relevant to cardiac anesthesiology, including depth of anesthesia monitoring, operating room resource optimization, and transthoracic/transesophageal echocardiography, as conceptual examples to explore strengths and limitations of AI/ML within healthcare, and characterize this evolving landscape. Through reviewing such applications, the authors introduce basic AI/ML concepts and methodologies, as well as practical considerations and ethical concerns for initiating and maintaining safe clinical implementation of AI/ML-based algorithms for cardiac anesthesia patient care.
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Affiliation(s)
- Michael Mathis
- Department of Anesthesiology, University of Michigan Medicine, Ann Arbor, MI
| | - Kirsten R Steffner
- Department of Anesthesiology, Perioperative and Pain Medicine, Stanford University School of Medicine, Stanford, CA
| | - Harikesh Subramanian
- Department of Anesthesiology and Perioperative Medicine, University of Pittsburgh, Pittsburgh, PA
| | - George P Gill
- Department of Anesthesiology, Cedars Sinai, Los Angeles, CA
| | | | - Sagar Bansal
- Department of Anesthesiology and Perioperative Medicine, University of Missouri School of Medicine, Columbia, MO
| | - Karsten Bartels
- Department of Anesthesiology, University of Nebraska Medical Center, Omaha, NE
| | - Ashish K Khanna
- Department of Anesthesiology, Section on Critical Care Medicine, School of Medicine, Wake Forest University, Atrium Health Wake Forest Baptist Medical Center, Winston-Salem, NC
| | - Jiapeng Huang
- Department of Anesthesiology and Perioperative Medicine, University of Louisville, Louisville, KY.
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Nourmohammadi A, Swift JR, de Pesters A, Guay CS, Adamo MA, Dalfino JC, Ritaccio AL, Schalk G, Brunner P. Passive functional mapping of receptive language cortex during general anesthesia using electrocorticography. Clin Neurophysiol 2023; 147:31-44. [PMID: 36634533 PMCID: PMC10267852 DOI: 10.1016/j.clinph.2022.11.021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2022] [Revised: 09/30/2022] [Accepted: 11/10/2022] [Indexed: 12/24/2022]
Abstract
OBJECTIVE To investigate the feasibility of passive functional mapping in the receptive language cortex during general anesthesia using electrocorticographic (ECoG) signals. METHODS We used subdurally placed ECoG grids to record cortical responses to speech stimuli during awake and anesthesia conditions. We identified the cortical areas with significant responses to the stimuli using the spectro-temporal consistency of the brain signal in the broadband gamma (BBG) frequency band (70-170 Hz). RESULTS We found that ECoG BBG responses during general anesthesia effectively identify cortical regions associated with receptive language function. Our analyses demonstrated that the ability to identify receptive language cortex varies across different states and depths of anesthesia. We confirmed these results by comparing them to receptive language areas identified during the awake condition. Quantification of these results demonstrated an average sensitivity and specificity of passive language mapping during general anesthesia to be 49±7.7% and 100%, respectively. CONCLUSION Our results demonstrate that mapping receptive language cortex in patients during general anesthesia is feasible. SIGNIFICANCE Our proposed protocol could greatly expand the population of patients that can benefit from passive language mapping techniques, and could eliminate the risks associated with electrocortical stimulation during an awake craniotomy.
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Affiliation(s)
- Amin Nourmohammadi
- National Center for Adaptive Neurotechnologies, Washington University School of Medicine, St. Louis, MO, USA; Department of Neurosurgery, Washington University School of Medicine, St. Louis, MO, USA; Department of Biomedical Sciences, State University of New York at Albany, Albany, NY, USA.
| | - James R Swift
- National Center for Adaptive Neurotechnologies, Washington University School of Medicine, St. Louis, MO, USA; Department of Neurosurgery, Washington University School of Medicine, St. Louis, MO, USA; Department of Biomedical Sciences, State University of New York at Albany, Albany, NY, USA.
| | - Adriana de Pesters
- National Center for Adaptive Neurotechnologies, Washington University School of Medicine, St. Louis, MO, USA; Department of Biomedical Sciences, State University of New York at Albany, Albany, NY, USA.
| | - Christian S Guay
- Department of Anesthesiology, Washington University School of Medicine, St. Louis, MO, USA.
| | - Matthew A Adamo
- Department of Neurosurgery, Albany Medical College, Albany, NY, USA.
| | - John C Dalfino
- Department of Neurosurgery, Albany Medical College, Albany, NY, USA.
| | - Anthony L Ritaccio
- Department of Neurology, Albany Medical College, Albany, NY, USA; Department of Neurology, Mayo Clinic, Jacksonville, FL, USA.
| | - Gerwin Schalk
- National Center for Adaptive Neurotechnologies, Washington University School of Medicine, St. Louis, MO, USA; Department of Biomedical Sciences, State University of New York at Albany, Albany, NY, USA; Chen Frontier Lab for Applied Neurotechnology, Tianqiao and Chrissy Chen Institute, Shanghai, P.R. China.
| | - Peter Brunner
- National Center for Adaptive Neurotechnologies, Washington University School of Medicine, St. Louis, MO, USA; Department of Neurosurgery, Washington University School of Medicine, St. Louis, MO, USA; Department of Biomedical Sciences, State University of New York at Albany, Albany, NY, USA; Department of Neurology, Albany Medical College, Albany, NY, USA.
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Garbe J, Eisenmann S, Kantelhardt JW, Duenninghaus F, Michl P, Rosendahl J. Capability of processed EEG parameters to monitor conscious sedation in endoscopy is similar to general anaesthesia. United European Gastroenterol J 2021; 9:354-361. [PMID: 32921270 PMCID: PMC8259428 DOI: 10.1177/2050640620959153] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/30/2020] [Accepted: 08/20/2020] [Indexed: 11/23/2022] Open
Abstract
Background Reliable and safe sedation is a prerequisite for endoscopic interventions. The current standard is rather safe, yet, an objective device to measure sedation depth is missing. To date, anaesthesia monitors based on processed electroencephalogram (EEG) have not been utilised in conscious sedation. Objective To investigate EEG parameters to differentiate consciousness in endoscopic propofol sedation. Methods In total, 171 patients aged 21–83 years (ASA I–III) undergoing gastrointestinal and bronchial endoscopy were enrolled. Standard monitoring and a frontotemporal two‐channel EEG were recorded. The state of consciousness was identified by repeated requests to squeeze the investigator's hand. Results In total, 1132 state‐of‐consciousness (SOC) transitions were recorded in procedures ranging from 5 to 69 min. Thirty‐four EEG parameters from the frequency domain, time‐frequency domain and complexity measures were calculated. Area under the curve ranged from 0.51 to 0.82 with complexity and optimised frequency domain parameters yielding the best results. Conclusion Prediction of the SOC with processed EEG parameters is feasible, and the results for sedation in endoscopic procedures are similar to those reported from general anaesthesia. These results are insufficient for a clinical application, but prediction capability may be increased with optimisation and modelling. Electroencephalogram (EEG)‐based anaesthesia monitors, like the Bispectral Index, have been investigated as an adjunct to monitor propofol sedation in the endoscopy ward. These studies showed very limited benefit. Capability of processed EEG parameters to differentiate the state of consciousness (SOC) in endoscopy is similar to general anaesthesia. However, artefacts arising from the less controlled endoscopy environment as compared to anaesthesia limit their use in sedation monitoring. The Bispectral Index and its underlying parameters are ineffective in the determination of the SOC in sedation during endoscopic procedures.
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Affiliation(s)
- Jakob Garbe
- Department of Internal Medicine I, University Hospital Halle, Halle (Saale), Germany
| | - Stephan Eisenmann
- Department of Internal Medicine I, University Hospital Halle, Halle (Saale), Germany
| | - Jan W Kantelhardt
- Institute of Physics, Martin-Luther-University Halle-Wittenberg, Halle (Saale), Germany
| | - Florian Duenninghaus
- Department of Internal Medicine I, University Hospital Halle, Halle (Saale), Germany
| | - Patrick Michl
- Department of Internal Medicine I, University Hospital Halle, Halle (Saale), Germany
| | - Jonas Rosendahl
- Department of Internal Medicine I, University Hospital Halle, Halle (Saale), Germany
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Gounon LJ, Davies C, Milan Z, Kunst G. Concordance of Depth of Anesthesia Monitors During Cardiopulmonary Bypass? J Cardiothorac Vasc Anesth 2020; 34:308-310. [DOI: 10.1053/j.jvca.2019.05.037] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/21/2019] [Accepted: 05/25/2019] [Indexed: 11/11/2022]
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Permutation entropy in intraoperative ECoG of brain tumour patients in awake tumour surgery- a robust parameter to separate consciousness from unconsciousness. Sci Rep 2019; 9:16482. [PMID: 31712616 PMCID: PMC6848144 DOI: 10.1038/s41598-019-52949-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2019] [Accepted: 10/25/2019] [Indexed: 01/10/2023] Open
Abstract
Awake craniotomies represent an essential opportunity in the case of lesions in eloquent areas. Thus, optimal surveillance of the patient during different stages of sedation, as well as the detection of seizure activity during brain surgery, remains difficult, as skin electrodes for electroencephalographic (EEG) analysis are not applicable in most cases. We assessed the applicability of ECoG to monitor different stages of sedation, as well as the influence of different patient characteristics, such as tumour volume, size, entity, and age or gender on permutation entropy (PeEn). We conducted retrospective analysis of the ECoG data of 16 patients, who underwent awake craniotomies because of left-sided brain tumours at our centre between 2014 and 2016. PeEn could be easily calculated and compared using frontal and parietal cortical electrodes. A comparison of PeEn scores showed significantly higher values in awake patients than in patients under anaesthesia (p ≤ 0.004) and significantly higher ones in the state of transition than under general anaesthesia (p = 0.023). PeEn scores in frontal and parietal leads did not differ significantly, making them both applicable for continuous surveillance during brain surgery. None of the following clinical characteristics showed significant correlation with PeEn scores: tumour volume, WHO grade, first or recurrent tumour, gender, and sex. Being 50 years or older led to significantly lower values in parietal leads but not in frontal leads. ECoG and a consecutive analysis of PeEn are feasible and suitable for the continuous surveillance of patients during awake craniotomies. Hence, the analysis is not influenced by patients' clinical characteristics.
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Yuan J, Yang MC, Wu MJ, Gou YS. Sedative depth on neurological outcomes in a juvenile rat model of cardiopulmonary resuscitation. Med Hypotheses 2019; 132:109233. [PMID: 31606702 DOI: 10.1016/j.mehy.2019.109233] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2019] [Revised: 05/11/2019] [Accepted: 05/18/2019] [Indexed: 01/26/2023]
Abstract
The guidelines for cardiopulmonary resuscitation (CPR) in pediatric advanced life support suggest that midazolam is the preferred agent for sedation in patients with mild hypothermia, whereas children with cardiac arrest (CA) are at a crucial stage regarding their immature nervous system. Studies have shown that midazolam may have a detrimental effect on the developmental of the pediatric nervous system. Our previous study found that midazolam induced neuronal damage after CPR in young rats. It is speculated that: midazolam causes the potential injury of neurons by inhibiting mitochondrial autophagy expression and is an important factor for the poor prognosis in children after successful CPR. This project intends to adopt the modified asphyxiant CPR model in juvenile rats. Survival rate, neurological function and histopathological changes were evaluated to determine the protective effects of appropriate sedation depth on cerebral ischemia-reperfusion injury in juvenile rats after CPR. Combined with cell biology and molecular biology related technologies, the mechanism by which the mitochondrial pinkl-parkin signaling pathway induces autophagy to inhibit neuronal apoptosis may be key factor in the protective effects of sedation depth on the brain. The aim of this study is to provide experimental evidence and elucidate the mechanisms of improvement of cerebral ischemia-reperfusion injury by sedation depth in children after successful CPR and to lay a theoretical and experimental basis for clinical treatment.
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Affiliation(s)
- Jing Yuan
- The Third People(')s Hospital of Chengdu, The Affiliated Hospital of Southwest Jiaotong University, China
| | - Meng-Chang Yang
- Department of Anesthesiology, Sichuan Academy of Medical Sciences and Sichuan Provincial People's Hospital, Chengdu 610072, Sichuan, China
| | - Meng-Jun Wu
- Department of Anesthesiology, Chengdu Women and Children(')s Central Hospital, Chengdu 610041, Sichuan, China.
| | - Yong-Sheng Gou
- Department of Orthopedics, Shuangliu First People's Hospital, Chengdu 610200, Sichuan, China.
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Assessment of pain in critically ill children. Is cutaneous conductance a reliable tool? J Crit Care 2015; 30:481-5. [PMID: 25758636 DOI: 10.1016/j.jcrc.2015.01.008] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2014] [Revised: 11/28/2014] [Accepted: 01/08/2015] [Indexed: 11/21/2022]
Abstract
PURPOSE The purpose of this study is to assess the usefulness and accuracy of skin conductance (SC) as a tool to evaluate the level of sedation and pain in pediatric critical patients during painful procedures and to compare it with hemodynamic variables, clinical scales, and bispectral index (BIS). MATERIALS AND METHODS This is a prospective observational study in 61 critical children undergoing invasive procedures. Hemodynamic data (heart rate and arterial blood pressure), clinical scales punctuation (Ramsay, COMFORT, and numeric rating pain scales), BIS, and the number of fluctuations of SC per second were collected before, during, and at the end of the procedure. RESULTS The mean age of the patients was 42.9 (range, 1 month to 16 years). Seventy-two point six percent were postcardiac surgery patients. Nonmuscle-relaxed patients showed a moderate increase in heart rate (P = .02), numeric rating pain scales (P = .03), and Ramsay scale (P = .002). The number of fluctuations of SC per second increased significantly during the procedure (basal, 0.1; maneuver, 0.2; P = .015), but it never reached the level considered as pain or stress nor did it precede clinical scales or BIS. None of the variables studied showed a significant change during the procedure in muscle-relaxed patients. CONCLUSIONS Skin conductance was not found to be more sensitive or faster than clinical scales for the assessment of pain or stress in critical children undergoing painful procedures. Skin conductance was not useful in muscle-relaxed children.
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Li TN, Li Y. Depth of anaesthesia monitors and the latest algorithms. ASIAN PAC J TROP MED 2014; 7:429-37. [DOI: 10.1016/s1995-7645(14)60070-5] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2014] [Revised: 03/15/2014] [Accepted: 04/15/2014] [Indexed: 10/25/2022] Open
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Chung HS. Awareness and recall during general anesthesia. Korean J Anesthesiol 2014; 66:339-45. [PMID: 24910724 PMCID: PMC4041951 DOI: 10.4097/kjae.2014.66.5.339] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2014] [Revised: 04/07/2014] [Accepted: 04/08/2014] [Indexed: 11/18/2022] Open
Abstract
Anesthesia awareness is defined as both consciousness and recall of surgical events. New research has been conducted out to test this phenomenon. However, testing methods have not proven reliable, including those using devices based on electroencephalographic techniques to detect and prevent intraoperative awareness. The limitations of a standard intraoperative brain monitor reflect our insufficient understanding of consciousness. Moreover, patients who experience an intraoperative awareness can develop serious post-traumatic stress disorders that should not be overlooked. In this review, we introduce the incidence of intraoperative awareness during general anesthesia and discuss the mechanisms of consciousness, as well as risk factors, various monitoring methods, outcome and prevention of intraoperative awareness.
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Affiliation(s)
- Hyun Sik Chung
- Department of Anaesthesiology and Pain Medicine, Seoul St. Mary's Hospital, The Catholic University of Korea, College of Medicine, Seoul, Korea
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Musialowicz T, Lahtinen P. Current Status of EEG-Based Depth-of-Consciousness Monitoring During General Anesthesia. CURRENT ANESTHESIOLOGY REPORTS 2014. [DOI: 10.1007/s40140-014-0061-x] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
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Pandit J, Cook T. National Institute for Clinical Excellence guidance on measuring depth of anaesthesia: limitations of EEG-based technology. Br J Anaesth 2014; 112:385-6. [DOI: 10.1093/bja/aet562] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Dimpel L. National Institute for Clinical Excellence guidance on measuring depth of anaesthesia: limitations of EEG-based technology. Br J Anaesth 2014; 112:383-4. [PMID: 24431356 DOI: 10.1093/bja/aet560] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
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Singh SK, Kumar A, Mahajan R, Katyal S, Mann S. Comparison of recovery profile for propofol and sevoflurane anesthesia in cases of open cholecystectomy. Anesth Essays Res 2013; 7:386-9. [PMID: 25885989 PMCID: PMC4173547 DOI: 10.4103/0259-1162.123259] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
Objective: Sevoflurane and propofol are considered to be the agents of choice in surgeries of short duration due to their better recovery profile and few post-operative complications. This study was designed to compare the early recovery profile of sevoflurane and propofol anesthesia in patients undergoing open cholecystectomy. Materials and Methods: A total of 60 patients of either sex with American Society of Anesthesiologists grade 1 and 2 scheduled for elective cholecystectomy were prospectively randomized into two groups. Group S (30 patients) were maintained with sevoflurane anesthesia (1-2%), while in Group P (30 patients) were maintained with propofol infusion (75-125 μg/kg/min) in both the groups the anesthetic concentration/dose was so adjusted to keep hemodynamic parameter (mean arterial pressure and heart rate) within 15% of their respective baselines values. Results: It was observed that there was no significant difference (P > 0.05) between there early recovery profile that includes spontaneous eye opening (7.5 ± 1.6 min for sevoflurane group and 6.9 ± 1.7 min for propofol group), following simple verbal command (9.2 ± 2.2 min for sevoflurane group and 8.9 ± 1.9 min for propofol group) and extubation time (10.7 ± 2.3 min for sevoflurane group and 10.3 ± 2.0 min for propofol group) but there was a significant difference (P < 0.05) in incidence of post-operative nausea and vomiting (PONV) in both groups. Conclusion: Propofol is as good as sevoflurane for maintenance of anesthesia in surgeries like open cholecystectomy with an added advantage of lower incidence of PONV owing to its intrinsic antiemetic properties.
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Affiliation(s)
- Shiv Kumar Singh
- Department of Anaesthesiology, S.H.K.M., Government Medical College, Nalhar, District Mewat, Haryana, India
| | - Amit Kumar
- Department of Anaesthesiology, S.H.K.M., Government Medical College, Nalhar, District Mewat, Haryana, India
| | - Reena Mahajan
- Department of Anaesthesiology, S.H.K.M., Government Medical College, Nalhar, District Mewat, Haryana, India
| | - Surabhi Katyal
- Department of OBG, S.H.K.M., Government Medical College, Nalhar, District Mewat, Haryana, India
| | - Sfurti Mann
- Department of Medicine, S.H.K.M., Government Medical College, Nalhar, District Mewat, Haryana, India
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Liu C, Zhang Y, She S, Xu L, Ruan X. A randomised controlled trial of dexmedetomidine for suspension laryngoscopy. Anaesthesia 2012; 68:60-6. [DOI: 10.1111/j.1365-2044.2012.07331.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Mellema A, Borner M, Joppich R, Burmester S, Schütte JK, Wappler F. Vergleich inhalativer versus intravenöser Anästhesieverfahren für elektive Bandscheibenoperationen unter vergleichbarer Narkosetiefe mittels BIS-Monitoring. Eine randomisierte, prospektive klinische Untersuchung. ACTA ACUST UNITED AC 2010. [DOI: 10.1016/j.periop.2010.02.004] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
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Isley MR, Edmonds HL, Stecker M. Guidelines for intraoperative neuromonitoring using raw (analog or digital waveforms) and quantitative electroencephalography: a position statement by the American Society of Neurophysiological Monitoring. J Clin Monit Comput 2009; 23:369-90. [DOI: 10.1007/s10877-009-9191-y] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2009] [Accepted: 07/02/2009] [Indexed: 10/20/2022]
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Women need more propofol than men during EEG-monitored total intravenous anaesthesia / Frauen benötigen mehr Propofol als Männer während EEG-überwachter total-intravenöser Anästhesie. ACTA ACUST UNITED AC 2009; 54:76-82. [DOI: 10.1515/bmt.2009.010] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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Olofsen E, Sleigh JW, Dahan A. Permutation entropy of the electroencephalogram: a measure of anaesthetic drug effect. Br J Anaesth 2008; 101:810-21. [PMID: 18852113 DOI: 10.1093/bja/aen290] [Citation(s) in RCA: 196] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
BACKGROUND It would be useful to have an open-source electroencephalographic (EEG) index of gamma-amino-butyric acid (GABA)-ergic anaesthetic drug effect that is resistant to eye-blink artifact, responds rapidly to changes in EEG pattern, and can be linked to underlying neurophysiological and neuropharmacological mechanisms that control the conscious state. METHODS The EEG waveform can be described as a sequence of ordinal patterns. The permutation entropy (PE) describes the relative occurrence of each of these patterns. It is high ( approximately 1.0) when the signal has predominantly high frequencies and low ( approximately 0.4) when the signal consists of only low frequencies. The response of the PE to various computer-generated EEG-like waveforms was assessed. A composite PE index (CPEI) was developed, which was the sum of two simple PEs and included a small measurement-noise threshold (0.5 microV). We also applied the CPEI to two small pilot EEG data sets from patients receiving sevoflurane (n=21) or propofol (n=9) anaesthesia. RESULTS With minimal pre-processing or artifact rejection, the CPEI reliably tracked the anaesthetic-related EEG changes, namely loss of high frequencies, spindle-like waves, and delta waves. Using NONMEM, it was possible to construct adequate pharmacokinetic-pharmacodynamic models from the data. The CPEI was comparable with models derived using the bispectral index [BIS R(2)=0.88 (0.08) vs CPEI R(2)=0.91 (0.06) for the propofol data] and M-entropy indices [M-entropy R(2)=0.91 (0.06) vs CPEI R(2)=0.87 (0.09) for the sevoflurane data]. CONCLUSIONS PE of the EEG shows promise as a simple measure of GABAergic anaesthetic drug effect.
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Affiliation(s)
- E Olofsen
- Department of Anesthesiology, Leiden University Medical Center, Leiden University, Leiden, The Netherlands
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Dissociating the effects of nitrous oxide on brain electrical activity using fixed order time series modeling. Comput Biol Med 2008; 38:1121-30. [DOI: 10.1016/j.compbiomed.2008.08.011] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2007] [Revised: 04/24/2008] [Accepted: 08/22/2008] [Indexed: 11/21/2022]
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Weber F, Hollnberger H, Weber J. Electroencephalographic Narcotrend Index monitoring during procedural sedation and analgesia in children. Paediatr Anaesth 2008; 18:823-30. [PMID: 18768042 DOI: 10.1111/j.1460-9592.2008.02692.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
BACKGROUND The electroencephalographic Narcotrend Index (NI) may potentially help to titrate sedative medication during diagnostic and therapeutic procedures in children. METHODS With local ethics committee approval and informed parental consent, 31 patients, aged 8.9 +/- 4.3 years, scheduled for elective upper gastrointestinal endoscopy were enrolled in this prospective, double-blinded observational study. Initially, patients received a single dose of intravenous piritramide 0.1 mg x kg(-1), followed by propofol 2 mg x kg(-1) and, if necessary, additional propofol doses (0.5 mg x kg(-1)) to achieve and maintain a level of deep sedation throughout the procedure. Sedation was assessed by the University of Michigan Sedation Scale (UMSS). We investigated the relationship between depth of sedation, and the NI, and the classical EEG parameters (cEEG), total EEG power (Power), spectral edge (SEF) and median frequency, and relative power in the beta, alpha, theta and delta bands. The performance of the NI and cEEG parameters was evaluated by prediction probability (P(K)), receiver operating characteristic (ROC) and Spearman rank order correlation analysis. RESULTS Mean P(K) values for NI (0.88) vs UMSS were higher than for the other cEEG parameters, except for Power (0.82) and SEF(0.81). Spearman correlation analysis revealed superiority of the NI over all cEEG parameters. The area under the curve for the NI was 0.93, which was superior to all other EEG parameters beside Power (0.86) and relative power in alpha (0.82). CONCLUSIONS The results of this study suggest that the NI may be an objective nondisruptive tool for assessment of hypnotic depth in children under propofol-induced procedural sedation.
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Affiliation(s)
- Frank Weber
- Department of Anesthesiology, Erasmus University Medical Center Rotterdam, Sophia Children's Hospital, Rotterdam, The Netherlands
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Doenicke AW, Kugler J, Kochs E, Rau J, Mückter H, Hoernecke R, Conzen P, Bromber H, Schneider G. The Narcotrend monitor and the electroencephalogram in propofol-induced sedation. Anesth Analg 2007; 105:982-92, table of contents. [PMID: 17898377 DOI: 10.1213/01.ane.0000281145.46541.de] [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: 11/05/2022]
Abstract
BACKGROUND The Narcotrend (NCT) is a one-channel electroencephalogram (EEG) monitor of the level of sedation. It is based on a visual EEG scoring system, which was developed by Loomis and modified by Kugler, to yield a visual expert classification (VEC) scheme for differentiation of six levels of sedation (A-F), which are subdivided into 16 substages. We designed the present study to test whether results of the automated classification of one-channel NCT input reflect those from VEC of five-channel EEG. METHODS Twelve healthy male volunteers received propofol using two different infusion regimens in a randomized, crossover design with concomitant NCT monitoring and VEC. Scoring results of NCT were compared with those of VEC. RESULTS During the infusion period, score differences of more than three substages were observed in 14 of 24 (= 58%) propofol administrations (4%-7% of total data). Often, the NCT indicated lighter sedation than VEC, which revealed more delta activity from nonfrontal leads. During recovery, NCT reported deeper sedation than VEC in 6 of 24 (= 25%) propofol administrations. Discordant trends (periods of at least five subsequent epochs with monotonic, but opposite trends for both NCT and VEC) were noted in 9 of 24 propofol administrations (37%). Furthermore, NCT had several periods when no staging information was displayed, varying from a few seconds to 10 min. CONCLUSIONS As the algorithm of NCT is proprietary and not accessible to the public, reasons for the observed differences between NCT and VEC cannot be analyzed and explanations must remain speculative.
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Affiliation(s)
- Alfred W Doenicke
- Institute for Anesthesiology, Ludwig Maximilians University, Munich, Germany.
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Wallenborn J, Kluba K, Olthoff D. Comparative evaluation of Bispectral Index and Narcotrend Index in children below 5 years of age. Paediatr Anaesth 2007; 17:140-7. [PMID: 17238885 DOI: 10.1111/j.1460-9592.2006.02036.x] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
BACKGROUND The use of electroencephalogram (EEG) monitoring devices for assessing the depth of hypnosis is most difficult in children under 5 years of age. METHODS Forty five children aged 0-60 months were included in a prospective observational study. A direct comparison of the processed EEG variables Bispectral Index (BIS, version 3.4) and Narcotrend Index (NI, version 2.0AF) was to be achieved by simultaneous recording. The ability of these parameters to differentiate between various clinical states was evaluated by using the prediction probability (P(k)). Age-related effects on the BIS and NI were analyzed by dividing the children into three age groups: 0-6, 7-18 and 19-60 months. RESULTS The preanesthesia, conscious children were differentiated from anesthetized patients by the BIS and NI with no overlap (P(k) = 1.0). In the awake period the BIS was superior to the NI (P(k) to differentiate 'end of anesthesia' from 'awakening' was 0.97 vs 0.73 respectively; P = 0.002). Patients aged 7-18 months showed higher BIS and NI values in the course of anesthesia than the younger and older children (P = 0.001). On awakening, children aged 0-6 months showed the lowest mean BIS (n.s.) and NI (P = 0.006) values. CONCLUSIONS The BIS currently seems to be superior to the NI, but age-related processing algorithms of the raw EEG must be implemented in both BIS and NI in order to be useful in children younger than 5 years of age.
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Affiliation(s)
- Jan Wallenborn
- Department of Anaesthesiology and Intensive Care Medicine, University of Leipzig, Leipzig, Germany.
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Abstract
Depth-of-anesthesia monitoring with EEG or EEG combined with mLAER is becoming widely used in anesthesia practice. Evidence shows that this monitoring improves outcome by reducing the incidence of intra-operative awareness while reducing the average amount of anesthesia that is administered, resulting in faster wake-up and recovery, and perhaps reduced nausea and vomiting. As with any monitoring device, there are limitations in the use of the monitors and the anesthesiologist must be able to interpret the data accordingly. The limitations include the following. The currently available monitoring algorithms do not account for all anesthetic drugs, including ketamine, nitrous oxide and halothane. EMG and other high-frequency electrical artifacts are common and interfere with EEG interpretation. Data processing time produces a lag in the computation of the depth-of-anesthesia monitoring index. Frequently the EEG effects of anesthetic drugs are not good predictors of movement in response to a surgical stimulus because the main site of action for anesthetic drugs to prevent movement is the spinal cord. The use of depth-of-anesthesia monitoring in children is not as well understood as in adults. Several monitoring devices are commercially available. The BIS monitor is the most thoroughly studied and most widely used, but the amount of information about other monitors is growing. In the future, depth-of-anesthesia monitoring will probably help in further refining and better understanding the process of administering anesthesia.
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Affiliation(s)
- T Andrew Bowdle
- Division of Cardiothoracic Anesthesiology, Department of Anesthesiology, Mail Stop 356540, Room AA-117C, University of Washington, Seattle, WA 98195, USA.
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Abstract
The use of processed electroencephalography (EEG) using a simple frontal lead system has been made available for assessing the impact of anesthetic medications during surgery. This review discusses the basic principles behind these devices. The foundations of anesthesia monitoring rest on the observations of Guedel with ether that the depth of anesthesia relates to the cortical, brainstem and spinal effects of the anesthetic agents. Anesthesiologists strive to have a patient who is immobile, is unconscious, is hemodynamically stable and who has no intraoperative awareness or recall. These anesthetic management principles apply today, despite the absence of ether from the available anesthetic medications. The use of the EEG as a supplement to the usual monitoring techniques rests on the observation that anesthetic medications all alter the synaptic function which produces the EEG. Frontal EEG can be viewed as a surrogate for the drug effects on the entire central nervous system (CNS). Using mathematical processing techniques, commercial EEG devices create an index usually between 0 and 100 to characterize this drug effect. Critical aspects of memory formation occur in the frontal lobes making EEG monitoring in this area a possible method to assess risk of recall. Integration of processed EEG monitoring into anesthetic management is evolving and its ability to characterize all of the anesthetic effects on the CNS (in particular awareness and recall) and improve decision making is under study.
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Affiliation(s)
- Leslie C Jameson
- Anesthesiology, University of Colorado at Denver and Health Sciences Center, 4200 East 9th Ave, Campus Box B113, Denver, CO 80262, USA.
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Ledowski T, Bromilow J, Paech MJ, Storm H, Hacking R, Schug SA. Skin conductance monitoring compared with Bispectral Index to assess emergence from total i.v. anaesthesia using propofol and remifentanil. Br J Anaesth 2006; 97:817-21. [PMID: 17060330 DOI: 10.1093/bja/ael278] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND Arousal after sevoflurane anaesthesia has been detectable by monitoring changes in skin conductance (SC) with similar accuracy as monitoring Bispectral Index (BIS). As SC monitoring detects changes in sympathetic tone, the measurements might be confounded by the sympatholytic properties of propofol, a component of total i.v. anaesthesia (TIVA). Therefore in this study, monitoring of SC during emergence from TIVA was compared with the monitoring of BIS. METHODS Twenty-five patients undergoing plastic surgery were investigated. The number of fluctuations of SC per second (NFSC), BIS and haemodynamic variables [systolic blood pressure (SBP) and heart rate (HR)] were recorded simultaneously. The performance of the monitoring devices in distinguishing between the clinical states 'steady-state anaesthesia', 'first clinical reaction' and 'extubation' were compared using the method of prediction probability (Pk) calculation. RESULTS BIS((R)) showed the best performance in distinguishing between 'steady-state anaesthesia' and 'first reaction' (Pk BIS 0.99 vs NFSC 0.80; P<0.01), and 'steady-state anaesthesia' and 'extubation' (Pk BIS) 1.00 vs NFSC 0.91; P<0.05); the time from first change of BIS or NFSC to a first clinical reaction was significantly longer for NFSC (median BIS 135 s vs NFSC 191 s; P<0.05). BIS and NFSC performed better in distinguishing between the investigated clinical states than SBP and HR. CONCLUSIONS In this study, BIS was found to predict arousal with a higher probability but slower response times than NFSC in patients waking after TIVA.
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Affiliation(s)
- T Ledowski
- Department of Anaesthesia and Pain Medicine, Royal Perth Hospital Wellington Street Campus, Perth WA 6000, Australia.
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Ledowski T, Paech MJ, Storm H, Jones R, Schug SA. Skin conductance monitoring compared with bispectral index ® monitoring to assess emergence from general anaesthesia using sevoflurane and remifentanil. Br J Anaesth 2006; 97:187-91. [PMID: 16720673 DOI: 10.1093/bja/ael119] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
BACKGROUND Changes in skin conductance have previously been reported to correlate well with plasma levels of stress hormones and awakening stimuli. In this study, monitoring of skin conductance during emergence from general anaesthesia was compared with the monitoring of bispectral index (BIS). METHODS Twenty-five patients undergoing minor elective surgery were investigated. The number of fluctuations in mean skin conductance (NFSC), BIS and haemodynamic parameters were recorded simultaneously. The performance of the monitoring devices to predict and distinguish between the clinical states 'steady-state anaesthesia', 'first reaction' and 'extubation' were compared using the method of prediction probability (P(K)) calculation. RESULTS Both monitors showed similar performance in distinguishing between 'steady-state anaesthesia' vs 'first reaction' (P(K) NFSC 0.89; BIS 0.94) and 'steady-state anaesthesia' vs 'extubation' (P(K) NFSC 0.96; BIS 0.96). The response times of the monitors, to indicate the likelihood of 'first reaction', were not significantly different. CONCLUSIONS NFSC, as a parameter of skin conductance, performed similarly to BIS in patients waking after a general anaesthetic.
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Affiliation(s)
- T Ledowski
- Department of Anaesthesia and Pain Medicine, Royal Perth Hospital, Perth, Australia.
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Conti A, Iacopino DG, Fodale V, Micalizzi S, Penna O, Santamaria LB. Cerebral haemodynamic changes during propofol-remifentanil or sevoflurane anaesthesia: transcranial Doppler study under bispectral index monitoring. Br J Anaesth 2006; 97:333-9. [PMID: 16829673 DOI: 10.1093/bja/ael169] [Citation(s) in RCA: 92] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND Sevoflurane or propofol-remifentanil-based anaesthetic regimens represent modern techniques for neurosurgical anaesthesia. Nevertheless, there are potential differences related to their activity on the cerebrovascular system. The magnitude of such difference is not completely known. METHODS In total 40 patients, treated for spinal or maxillo-facial disorders, were randomly allocated to either i.v. propofol-remifentanil or inhalational sevoflurane anaesthesia. Transcranial Doppler was used to assess changes in cerebral blood flow velocity, carbon dioxide reactivity, cerebral autoregulation and the bispectral index to assess the depth of anaesthesia. RESULTS Time-averaged mean flow velocity (MFV) was significantly reduced after induction of anaesthesia in both sevoflurane and propofol-remifentanil groups (P<0.001). At deeper levels of anaesthesia, MFV increased in the sevoflurane group, suggesting an uncoupling flow/metabolism, whereas it was further reduced in the propofol-remifentanil group (P<0.001). Indices of cerebral autoregulation were reduced in patients with high-dose sevoflurane whereas autoregulation was preserved in patients anaesthetized with propofol-remifentanil (P<0.001). Higher CO(2) concentrations impaired cerebral autoregulation in the sevoflurane group but not in patients anaesthetized with propofol-remifentanil. CONCLUSIONS Propofol-remifentanil anaesthesia induced a dose-dependent low-flow state with preserved cerebral autoregulation, whereas sevoflurane at high doses provided a certain degree of luxury perfusion.
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Affiliation(s)
- A Conti
- Department of Neurosciences, Psychiatric and Anaesthesiological Sciences, University of Messina, School of Medicine, Policlinico Universitario "G. Martino", via C.Valeria 98125, Messina, Italy
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Zikov T, Bibian S, Dumont GA, Huzmezan M, Ries CR. Quantifying cortical activity during general anesthesia using wavelet analysis. IEEE Trans Biomed Eng 2006; 53:617-32. [PMID: 16602568 DOI: 10.1109/tbme.2006.870255] [Citation(s) in RCA: 75] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
This paper reports on a novel method for quantifying the cortical activity of a patient during general anesthesia as a surrogate measure of the patient's level of consciousness. The proposed technique is based on the analysis of a single-channel (frontal) electroencephalogram (EEG) signal using stationary wavelet transform (SWT). The wavelet coefficients calculated from the EEG are pooled into a statistical representation, which is then compared to two well-defined states: the awake state with normal EEG activity, and the isoelectric state with maximal cortical depression. The resulting index, referred to as the wavelet-based anesthetic value for central nervous system monitoring (WAV(CNS)), quantifies the depth of consciousness between these two extremes. To validate the proposed technique, we present a clinical study which explores the advantages of the WAV(CNS) in comparison with the BIS monitor (Aspect Medical Systems, MA), currently a reference in consciousness monitoring. Results show that the WAV(CNS) and BIS are well correlated (r = 0.969) during periods of steady-state despite fundamental algorithmic differences. However, in terms of dynamic behavior, the WAV(CNS) offers faster tracking of transitory changes at induction and emergence, with an average lead of 15-30 s. Furthermore, and conversely to the BIS, the WAV(CNS) regains its preinduction baseline value when patients are responding to verbal command after emergence from anesthesia. We conclude that the proposed analysis technique is an attractive alternative to BIS monitoring. In addition, we show that the WAV(CNS) dynamics can be modeled as a linear time invariant transfer function. This index is, therefore, well suited for use as a feedback sensor in advisory systems, closed-loop control schemes, and for the identification of the pharmacodynamic models of anesthetic drugs.
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Affiliation(s)
- Tatjana Zikov
- Department of Electrical and Computer Engineering, The University of British Columbia, Vancouver, BC V6T 1Z4, Canada
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Duncan D, Kelly KP, Andrews PJD. A comparison of bispectral index and entropy monitoring, in patients undergoing embolization of cerebral artery aneurysms after subarachnoid haemorrhage. Br J Anaesth 2006; 96:590-6. [PMID: 16565229 DOI: 10.1093/bja/ael064] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
BACKGROUND Processed EEG monitoring of anaesthetic depth could be useful in patients receiving general anaesthesia following subarachnoid haemorrhage. We conducted an observational study comparing performance characteristics of bispectral index (BIS) and entropy monitoring systems in these patients. METHODS Thirty-one patients of the World Federation of Neurosurgeons grades 1 and 2, undergoing embolization of cerebral artery aneurysms following acute subarachnoid haemorrhage, were recruited to have both BIS and entropy monitoring during general anaesthesia. BIS and entropy indices were matched to clinical indicators of anaesthetic depth. Anaesthetists were blinded to the anaesthetic depth monitoring indices. Analysis of data from monitoring devices allowed calculation of prediction probability (P(K)) constants, and receiver operating characteristic (ROC) analysis to be performed. RESULTS BIS and entropy [response entropy (RE), state entropy (SE)] performed well in their ability to show concordance with clinically observed anaesthetic depth. P(K) values were generally high (BIS 0.966-0.784, RE 0.934-0.663, SE 0.857-0.701) for both forms of monitoring. ROC curve analysis shows a high sensitivity and specificity for all monitoring indices when used to detect the presence or absence of eyelash reflex. Area under curve for BIS, RE and SE to detect the absence or presence of eyelash reflex was 0.932, 0.888 and 0.887, respectively. RE provides earlier warning of return of eyelash reflex than BIS. CONCLUSION BIS and entropy monitoring perform well in patients who receive general anaesthesia after good grade subarachnoid haemorrhage.
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Affiliation(s)
- D Duncan
- Department of Anaesthesia, Critical Care and Pain Medicine, Western General Hospital Crewe Road, Edinburgh EH4 2XU, Scotland, UK.
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Abstract
The Narcotrend (MonitorTechnik, Bad Bramstedt, Germany) is an EEG monitor designed to measure the depth of anaesthesia. It has been developed at the University Medical School of Hannover, Germany, has been commercially available for 5 years and has meanwhile received US Food and Drug Administration approval. The Narcotrend algorithm is based on pattern recognition of the raw electroencephalogram (EEG) and classifies the EEG traces into different stages from A (awake) to F (increasing burst suppression down to electrical silence). The newest Narcotrend software version includes a dimensionless Narcotrend index from 100 (awake) to 0 (electrical silence). The raw EEG signal can be recorded by standard electrocardiogram electrodes for single- and double-channel registration. The Narcotrend monitor provides a vast amount of information: the actual Narcotrend stage and index, the trend ('cerebrogram'), the raw EEG signal and a power spectrum and several derived EEG parameters. Multiple clinical and validation studies are available for the Narcotrend monitor, including comparisons with the BIS monitor (Aspect Medical Systems, Natick, USA).
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Affiliation(s)
- S Kreuer
- Department of Anaesthesiology and Intensive Care Medicine, University of Saarland, 66421 Homburg/Saar, Germany.
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Freye E, Levy JV. Cerebral monitoring in the operating room and the intensive care unit: an introductory for the clinician and a guide for the novice wanting to open a window to the brain. Part I: The electroencephalogram. J Clin Monit Comput 2006; 19:1-76. [PMID: 16167222 DOI: 10.1007/s10877-005-0712-z] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
While there is an increasing body of knowledge in regard to central nervous system function and/or the mode of action of centrally active agents on neuronal function, little is done to develop new techniques on how to measure such changes. Also, monitoring of the cardiovascular system in the past has made extensive progress especially when it comes to evaluate the failing heart. In contrast monitoring of the central nervous system is only done in rare cases where operative procedures likely impede nervous function integrity. Since in the past decade the aging population undergoing operation has rise considerably, the risk of cerebral malperfusion or minute signs of degradation of the aging central nervous system (CNS) to anesthetics and agents being used in the operation room (OR) or the intensive care unit (ICU), needs continuous monitoring of an organ which presents the highest vulnerability and is likely to deteriorate faster than the cardiovascular system. In spite the rapid improvement in technology regarding the electroencephalogram (EEG) and evoked potential monitoring, physicians still are reluctant to use a technology on a routine base, which will give them insight information into brain function and activity. Such "windows to the brain" now not just are reserved to specialists working in the area of neurology and/or psychiatry. More so, cerebral monitoring is getting an integrated part in the overall therapy in patients undergoing operation or who need ventilatory support in the ICU as it effects the well-being and the outcome. The present book therefore, is intended for the practitioners who work with the patient, guide the clinician in his decision making and outlining those situations where cerebral monitoring presents an integrated part in the diagnosis and therapy of patient care. Without going too much into the technical details, representative cases underline the potential use of cerebral monitoring in the underlying clinical situation where either the patient presents borderline perfusion of the CNS, undergoes vascular surgery, or where monitoring of cerebral function in the intensive care in a head trauma patients is an integrated part in therapy. The book therefore is meant for all those clinicians who have to deal with the CNS in a day-to-day situation. This may be the anesthesiologist, the surgeon, the intensive care therapist, the nurse anesthetist as well as all other medical personal involved in intensive care therapy. The aim of the book therefore is to outline the possibilities, the limitations, and the options for therapy when the windows to the brain are opened, how to interpret the data in the light of other physiological parameters and aid the user in the technical details of how to avoid artifacts in recording which may have an impact on final decision making. Therefore, emphasis is placed on the electrode placement, artifact and electrical noise reduction, as well as data interpretation so that cerebral function diagnosis can be made on reliable grounds. The following serves as an introduction to and as a reference guide for Cerebral Monitoring in the OR and the ICU: Gives complete coverage of EEG power spectra analysis. Describes in detail the EEG machines available to be used in the OR and ICU setting. Describes in detail the major features of EEG power spectra and evoked potential measurements, including amplifiers, filter setting and microprocessor algorithm for data reduction. Gives suggestions for assessing and improving signal quality, including noise and artifact rejection, which usually are encountered in the operation room and the intensive care unit, both of which can be considered as electrically contaminated. Gives examples of EEG power spectra and evoked potential monitoring related to different types of anesthesia, in coma, after head trauma, and for the detection of ischemic events. In addition, gives complete coverage of those machines being available for the OR and the ICU, including a list of parameters regarding latency and amplitude in evoked potential As an introductory, recommendations are given for the novice to start cerebral monitoring and guide the beginner in setting up cerebral monitoring in the clinical environment.
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Affiliation(s)
- Enno Freye
- Clinics of Vascular Surgery and Renal Transplantation, Heinrich-Heine-University-Düsseldorf, Deichstrasse 3a, 41468 Neuss-Uedesheim, Germany.
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Kreuer S, Bruhn J, Stracke C, Aniset L, Silomon M, Larsen R, Wilhelm W. Narcotrend or Bispectral Index Monitoring During Desflurane-Remifentanil Anesthesia: A Comparison with a Standard Practice Protocol. Anesth Analg 2005; 101:427-434. [PMID: 16037157 DOI: 10.1213/01.ane.0000157565.00359.e2] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
UNLABELLED Bispectral Index (BIS) (Aspect Medical Systems, Newton, MA) and Narcotrend (MonitorTechnik, Bad Bramstedt, Germany) are monitoring devices that were, as others, designed to assess the depth of anesthesia. Meanwhile, a number of studies indicate that with total IV anesthesia, BIS and Narcotrend have comparable effects on drug consumption and recovery times whereas comparative clinical data for volatile anesthetics are still missing. Therefore, we designed the present prospective, randomized, and double-blinded study to compare the effects of BIS and Narcotrend monitoring during desflurane-remifentanil anesthesia and versus a standard anesthetic practice protocol. One-hundred-twenty adult patients scheduled for minor orthopedic surgery were randomized to receive a desflurane-remifentanil anesthetic controlled either by Narcotrend or by BIS or solely by clinical variables. Anesthesia was induced with 0.4 microg x kg(-1) x min(-1) remifentanil and 2 mg/kg propofol. After tracheal intubation, remifentanil was infused at a constant rate of 0.2 microg x kg(-1) x min(-1) whereas desflurane in 1.5 L/min O(2)/air was adjusted according to clinical variables or the following target values: during maintenance of anesthesia to a value of "D(0)" (Narcotrend) or "50" (BIS), 15 min before the end of surgery to "C(1)" (Narcotrend) or "60" (BIS), whereas in the standard protocol group, desflurane was controlled according to clinical variables, e.g., heart rate, arterial blood pressure, movements. Recovery times and desflurane consumption were recorded by a blinded investigator. The desflurane vaporizer was weighed before and after anesthesia and consumption per minute was calculated. Data are mean +/- sd. The groups were comparable for demographic data, duration of anesthesia, and mean remifentanil dosages. Compared with standard practice, patients with Narcotrend or BIS monitoring needed significantly less desflurane (standard practice 443 +/- 71 mg/min, Narcotrend 374 +/- 124 mg/min, BIS monitoring 416 +/- 99 mg/min desflurane [both P < 0.05]). However, recovery times were not significantly different between the groups, e.g., opening of eyes 4.7 +/- 2.2 versus 3.7 +/- 2.0 versus 4.2 +/- 2.1 min. During desflurane-remifentanil anesthesia, Narcotrend and BIS monitoring seem to be equally effective compared with standard anesthetic practice: BIS and Narcotrend allow for a small reduction of desflurane consumption whereas recovery times are only slightly reduced. IMPLICATIONS Monitoring the electroencephalogram with Narcotrend or Bispectral Index during desflurane-remifentanil anesthesia only slightly reduces recovery times when compared with a standard practice protocol.
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Affiliation(s)
- Sascha Kreuer
- Department of Anesthesiology and Intensive Care Medicine, *University of Saarland, Homburg/Saar; †University of Bonn, Bonn; and ‡St.-Marien-Hospital, Lünen, Germany
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Weber F, Gruber M, Taeger K. The correlation of the Narcotrend Index and classical electroencephalographic parameters with endtidal desflurane concentrations and hemodynamic parameters in different age groups. Paediatr Anaesth 2005; 15:378-84. [PMID: 15828988 DOI: 10.1111/j.1460-9592.2005.01465.x] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
BACKGROUND The Narcotrend Index (NI) for assessment of depth of anesthesia by analysis of the electroencephalogram (EEG), is potentially a pharmacodynamic measure of the effects of desflurane on the brain. METHODS In this prospective study of 30 pediatric and adult patients (group 1: 3-6 years, n = 10; group 2: > 6 < 12 years; group 3: 12-40 years), undergoing ophthalmological surgery, we investigated the pharmacodynamic relationship between nonsteady state endtidal desflurane concentrations (eT(Des)), NI, classical EEG parameters (cEEG), heart rate (HR) and mean arterial pressure (MAP). The performance of the Narcotrend for differentiation between consciousness and unconsciousness was evaluated using prediction probability (P(K)). RESULTS Spearman correlation analysis showed significant negative correlations (P < 0.001) between eT(Des) and NI (group 1: r = -0.93, group 2: r = -0.86, group 3: r = -0.66). Correlations between eT(Des) and MAP or HR were either only weak negative (r < -0.5) or not significant. Desflurane EC(50) (eT(Des) with half maximal effect on NI) was 7.18% for group 1, 7.34% for group 2, and 4.15% for group 3 (P < 0.001 Vs groups 1 and 2). Overall awake NI values (96.7 +/- 1.4) were significantly higher (P < 0.001) than at the moment of loss of consciousness (58.3 +/- 17.5), with no overlap (P(K) 1.0), whereas P(K) values for cEEG, MAP and HR were all <0.85. CONCLUSIONS The pharmacodynamic relationship between eT(Des) and NI is age dependent with a significantly higher EC(50) in children than in adolescents and adults. The NI appears to be superior to cEEG, MAP and HR in differentiating consciousness from unconsciousness.
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Affiliation(s)
- Frank Weber
- Department of Anaesthesia, University of Regensburg, D-93042 Regensburg, Germany.
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Schmidt GN, Bischoff P, Standl T, Lankenau G, Hellstern A, Hipp C, Schulte am Esch J. SNAP index and Bispectral index during different states of propofol/remifentanil anaesthesia. Anaesthesia 2005; 60:228-34. [PMID: 15710006 DOI: 10.1111/j.1365-2044.2004.04120.x] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
The accuracy of the new SNAP index with the Bispectral index (BIS) to distinguish different states of propofol/remifentanil anaesthesia was compared in 19 female patients who were undergoing minor gynaecological surgery. Comparisons of the SNAP index, BIS, spectral edge frequency, mean arterial blood pressure and heart rate were performed. The ability of all parameters to distinguish between the steps of anaesthesia -awake vs. loss of response, awake vs. anaesthesia, anaesthesia vs. first reaction and anaesthesia vs. extubation - were analysed with the prediction probability. The prediction probability to differentiate between two interesting nuances of anaesthetic states -loss of response vs. first reaction - was calculated. Only the BIS showed no overlap between the investigated steps of anaesthesia. Both the SNAP index and BIS failed to differentiate the nuances of anaesthesia. The SNAP index and BIS were superior to mean arterial blood pressure and heart rate and spectral edge frequency in distinguishing between different steps of anaesthesia with propofol and remifentanil and provided useful additional information.
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Affiliation(s)
- G N Schmidt
- Department of Anaesthesiology, University Hospital Eppendorf, Hamburg, Germany.
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Joint Esctaic – Sfimar Meeting. J Clin Monit Comput 2004. [PMCID: PMC7101990 DOI: 10.1007/s10877-005-0703-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Kreuer S, Bruhn J, Larsen R, Bialas P, Wilhelm W. Comparability of Narcotrend index and bispectral index during propofol anaesthesia. Br J Anaesth 2004; 93:235-40. [PMID: 15194623 DOI: 10.1093/bja/aeh182] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND The dimensionless Narcotrend (NCT) index (MonitorTechnik, Germany, version 4.0), from 100 (awake) to 0, is a new index based on electroencephalogram pattern recognition. Transferring guidelines for titrating the Bispectral Index (BIS, Aspect Medical Systems, USA, version XP) to the NCT index depends on their comparability. We compared the relationship between BIS and NCT values during propofol anaesthesia. METHODS Eighteen adult patients about to have radical prostatectomy were investigated. An epidural catheter was placed in the lumbar space and electrodes for BIS and NCT were applied as recommended by the manufacturers. After i.v. fentanyl 0.1 mg, anaesthesia was induced with a propofol infusion. After intubation, patients received bupivacaine 0.5% 15 ml via the epidural catheter. Forty-five minutes after induction, the propofol concentration was increased to substantial burst suppression pattern and then decreased. This was done twice in each patient, and BIS and Narcotrend values were recorded at intervals of 5 s. The efficacy of NCT and BIS in predicting consciousness vs unconsciousness was evaluated using the prediction probability (P(K)). RESULTS We collected 38 629 artefact-free data pairs of BIS and NCT values from the respective 5-s epochs. Because of artefacts, another 5008 epochs had been excluded from data analysis (3855 epochs for the NCT index alone, 245 epochs for the BIS alone and 908 epochs for both indices). Mean (sd) values in awake patients were 94 (6) for Narcotrend and 91 (8) for BIS. With loss of the eyelash reflex, both values were significantly reduced, to 72 (9) for NCT (P<0.001) and to 77 (11) for the BIS index (P<0.001). The PK value for loss of eyelash reflex was similar for BIS (0.95) and NCT (0.93). Decreasing BIS values coincided with decreasing NCT values. A sigmoid model [NCT index=52.8+26.8/(1+exp(-(BIS-78.3)/4.8))(0.4); r=0.52] described the correlation between BIS and NCT index in a BIS range between 100 and 50. For BIS values lower than 50, a second sigmoid model with a correlation of r=0.83 was applied [NCT index=6.6+45.3/(1+exp(-(BIS-29.8)/2.4)) (0.6) r=0.83]. The relationship between burst suppression ratio (BSR) and NCT index was best described by the following sigmoid model: NCT index=265/(1+exp((-BSR+108)/-49); r=0.73. CONCLUSIONS We found a sufficient correlation between BIS and NCT index, but deviations from the line of identity in some ranges require attention. Therefore, a simple 1:1 transfer from BIS to NCT values is not adequate. Our results might serve as a blueprint for the rational translation of BIS into NCT values.
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Affiliation(s)
- S Kreuer
- Department of Anaesthesiology and Intensive Care Medicine, University of Saarland, Homburg/Saar, Germany.
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Schmidt GN, Bischoff P, Standl T, Lankenau G, Hilbert M, Schulte Am Esch J. Comparative evaluation of Narcotrend, Bispectral Index, and classical electroencephalographic variables during induction, maintenance, and emergence of a propofol/remifentanil anesthesia. Anesth Analg 2004; 98:1346-53, table of contents. [PMID: 15105213 DOI: 10.1213/01.ane.0000111209.44119.30] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
UNLABELLED In the present study, we sought to compare the abilities of Narcotrend (NT) with the Bispectral Index (BIS) electroencephalographic system to monitor depth of consciousness immediately before induction of anesthesia until extubation during a standardized anesthetic. We investigated 26 patients undergoing laminectomy. Investigated states of anesthesia were: awake, loss of response, loss of eyelash reflex, steady-state anesthesia, first reaction, and extubation during emergence. NT, BIS, spectral edge frequency, median frequency, relative power in delta, theta, alpha, beta, and hemodynamics were recorded simultaneously. The ability of all variables to distinguish between awake versus loss of response, awake versus loss of eyelash reflex, awake versus steady-state anesthesia, steady-state anesthesia versus first reaction and extubation were analyzed with the prediction probability. Effects of remifentanil during propofol infusion were investigated with Friedman's and post hoc with Wilcoxon's test. Only NT and BIS were able to distinguish all investigated states accurately with a prediction probability >0.95. After start of remifentanil infusion, only hemodynamics changed statistically significantly (P < 0.05). NT and BIS are more reliable indicators for the assessment of anesthetic states than classical electroencephalographic variables and hemodynamics, whereas the analgesic potency of depth of anesthesia could not be detected by NT and BIS. IMPLICATIONS The modern electroencephalographic monitoring systems Narcotrend and Bispectral Index are more reliable indicators for the assessment of anesthetic states than classical electroencephalographic and hemodynamic variables to predict anesthetic conditions from before induction of anesthesia until extubation during a standardized anesthetic regime with propofol and remifentanil. The analgesic potency of depth of anesthesia could not be detected by Narcotrend and Bispectral Index.
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Affiliation(s)
- Gunter N Schmidt
- Department of Anesthesiology, University Hospital Eppendorf, Hamburg, Germany.
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Mantz J. Évaluation de la profondeur de la sédation en neuroréanimation : les scores cliniques, les méthodes électrophysiologiques et le BIS. ACTA ACUST UNITED AC 2004; 23:535-40. [PMID: 15158249 DOI: 10.1016/j.annfar.2004.03.003] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The primary goal of sedation is to achieve security and comfort of mechanically ventilated ICU patients. Delivery of pharmacologic agents must avoid over sedation, which increases morbidity by prolongation of the duration of mechanical ventilation. Similarly, under sedation may favour life-threatening events such as accidental extubation. Many clinical scales have been generated to regularly measure the level of sedation (consciousness and tolerance to the ICU environment). No electrophysiological monitor (BIS) has proved reliability for measuring the depth of sedation or analgesia yet. The presence of brain damage in ICU patients makes the level of sedation impossible to interpret. Glasgow coma scale, which is exclusively devoted to the consciousness domain, is the only recommendation that can be made in neurocritical care at the present time.
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Affiliation(s)
- J Mantz
- Service d'anesthésie-réanimation, faculté de médecine Xavier-Bichat, hôpital Xavier-Bichat, 46, rue Henri-Huchard, 75018 Paris, France.
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Schultz A, Grouven U, Beger FA, Schultz B. The Narcotrend Index: Classification Algorithm, Correlation with Propofol Effect-Site Concentrations, and Comparison with Spectral Parameters / Der Narcotrend-Index: Klassifikationsalgorithmus, Korrelation mit Propofol-Effekt-Site-Konzentrationen und Vergleich mit Spektralparametern. BIOMED ENG-BIOMED TE 2004; 49:38-42. [PMID: 15106896 DOI: 10.1515/bmt.2004.008] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
A reliable assessment of the depth of hypnosis during sedation and general anaesthesia using the EEG is a subject of current interest. The Narcotrend Index implemented in the latest version 4.0 of the EEG monitor Narcotrend provides an automatic classification of the EEG on a scale ranging from 100 (awake) to 0 (very deep hypnosis, EEG suppression). The classification algorithms implemented in the EEG monitor Narcotrend are described. In a study the correlation of the propofol effect-site concentration with the Narcotrend Index and with the traditional spectral parameters total power, relative power in the standard frequency bands delta, theta, alpha, and beta, median frequency, 95% spectral edge frequency, burst-compensated spectral edge frequency, and spectral entropy was investigated. The Narcotrend Index had the highest average correlation with the propofol effect-site concentration and the smallest variability of the individual correlation values. Moreover, the Narcotrend Index was the only parameter which showed a monophasic trend over the whole investigated time period. The Narcotrend monitor can make a significant contribution to the improvement of the quality of anaesthesia by adjusting the dosage of hypnotics to individual patient needs.
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Affiliation(s)
- A Schultz
- Arbeitsgruppe Informatik/Biometrie der Anästhesie, Klinikum Hannover Oststadt, Medizinische Hochschule Hannover, Germany.
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