Bispectral Analysis of Eeg May Predict Anesthetic Depth During Narcotic Induction

Kearse, Lee A.; Saini, Vikas; deBros, F.; Chamoun, Nassib G.

doi:10.1097/00000542-199109001-00175

Cited by 19 publications

(5 citation statements)

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“…Kearse et al 10 found a statistically significant difference between patients who mounted a haemodynamic response (BIS 67±10) compared with those who did not (BIS45±14). In this study, power spectral edge and median frequency did not distinguish those subjects who responded from those who did not.…”

Section: Discussionmentioning

confidence: 98%

Bispectral index analysis in general anesthesia: An observational study

Rao¹,

N²,

Murthy³

et al. 2020

IJCA

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Introduction: Bispectral index monitoring (BIS) is one of the major techniques used in monitoring depth of anesthesia. The present study was carried out to observe the changes in BIS values vis-a-vis the changes in hemodynamic parameters during the standard general anaesthesia practices in our institute. Materials and Methods: This prospective observational study was carried out in 50 ASA I/II elective surgeries in adults under general anesthesia. Conditions and drugs likely to interfere with BIS values were excluded. Anesthesia protocol was kept uniform. Patients were induced with IV propofol 2mg/kg, IV pentazocine 0.5mg /kg and IV vecuronium 0.1mg/kg. Patients were intubated with appropopriate size endotracheal tube and oxygen, nitrous oxide, halothane and vecuronium were used for maintanence of anesthesia. Patients were reversed with IV neostigmine 0.05mg/kg and I V Atropine 20mcg/kg. The BIS values, hemodymanic changes, recovery characteristics (including awareness) were noted. Correlation between BIS scores and hemodynamic parameters was assessed. Results: There were predictable changes in BIS scores with the standard anesthesia technique followed in the present study. Similarly, hemodynamic changes were also on the expected lines during the course of anesthesia. However, the correlation between BIS score and hemodynamics could not be established. Conclusion:Bispectral Index Monitor is a useful tool to assess the depth of anesthesia in standard anesthetic management. Alterations in anesthetic management and drug dosages can be guided by BIS scores. Cost factor and the need to use updated and refined versions of the software are the possible limitations.

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Section: Discussionmentioning

confidence: 98%

Bispectral index analysis in general anesthesia: An observational study

Rao¹,

N²,

Murthy³

et al. 2020

IJCA

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“…Bispectral analysis trends these changes as well, but also provides a measure of synchronization via the degree of phase coupling. Bispectral analysis is still subject of active research, and several investigators have demonstrated that it provides useful information concerning the patient's cerebral state during the administration of anesthesia [100][101][102]. Aspect Medical Systems has reduced the complex data arrays generated from bispectral analysis using a sophisticated algorithm to generate a composite, numerical Bispectral Index which tracks changes in the cerebral state.…”

Section: The Bispectral Index (Bis) -Monitoring the Level Of Consciou...mentioning

confidence: 99%

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

Freye

Levy²

2005

J Clin Monit Comput

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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...

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“…A thorough explanation of how the bicoherence changes across the whole bifrequency plane with anaesthetic depth, and how these changes actually relate to the patterns seen in the EEG, is currently unavailable. Earlier studies applying bispectral analysis to the monitoring of depth of anaesthesia [ 13 - 18 ] have shown an increase in the bicoherence values in the lower frequency regions (below 5Hz) at pre-incision (sedated) compared to pre-induction (awake) EEG. More recently Hagahira et al [ 19 - 21 ], Morimoto et al [ 22 ] and Hayashi et al [ 23 , 24 ], have completed work describing the influences anaesthesia has on bicoherence of the spontaneous EEG.…”

Section: Introductionmentioning

confidence: 99%

Peak and averaged bicoherence for different EEG patterns during general anaesthesia

Pritchett

Zilberg

et al. 2010

BioMedical Engineering OnLine

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BackgroundChanges in nonlinear neuronal mechanisms of EEG generation in the course of general anaesthesia have been extensively investigated in research literature. A number of EEG signal properties capable of tracking these changes have been reported and employed in anaesthetic depth monitors. The degree of phase coupling between different spectral components is a marker of nonlinear EEG generators and is claimed to be an important aspect of BIS. While bicoherence is the most direct measure of phase coupling, according to published research it is not directly used in the calculation of BIS, and only limited studies of its association with anaesthetic depth and level of consciousness have been published. This paper investigates bicoherence parameters across equal band and unequal band bifrequency regions, during different states of anaesthetic depth relating to routine clinical anaesthesia, as determined by visual inspection of EEG.Methods41 subjects scheduled for day surgery under general anaesthesia were recruited into this study. EEG bicoherence was analysed using average and smoothed-peak estimates calculated over different regions on the bifrequency plane. Statistical analysis of associations between anaesthetic depth/state of consciousness and bicoherence estimates included linear regression using generalised linear mixed effects models (GLMs), ROC curves and prediction probability (Pk).ResultsBicoherence estimates for the δ_θ region on the bifrequency plane were more sensitive to anaesthetic depth changes compared to other bifrequency regions. Smoothed-peak bicoherence displayed stronger associations than average bicoherence. Excluding burst suppression and large transients, the δ_θ peak bicoherence was significantly associated with level of anaesthetic depth (z = 25.74, p < 0.001 and R2 = 0.191). Estimates of Pk for this parameter were 0.889(0.867-0.911) and 0.709(0.689-0.729) respectively for conscious states and anaesthetic depth levels (comparable BIS estimates were 0.928(0.905-0.950) and 0.801(0.786-0.816)). Estimates of linear regression and areas under ROC curves supported Pk findings. Bicoherence for eye movement artifacts were the most distinctive with respect to other EEG patterns (average |z| value 13.233).ConclusionsThis study quantified associations between deepening anaesthesia and increase in bicoherence for different frequency components and bicoherence estimates. Increase in bicoherence was also established for eye movement artifacts. While identified associations extend earlier findings of bicoherence changes with increases in anaesthetic drug concentration, results indicate that the unequal band bifrequency region, δ_θ, provides better predictive capabilities than equal band bifrequency regions.

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Bispectral Analysis of Eeg May Predict Anesthetic Depth During Narcotic Induction

Cited by 19 publications

References 0 publications

Bispectral index analysis in general anesthesia: An observational study

Bispectral index analysis in general anesthesia: An observational study

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

Peak and averaged bicoherence for different EEG patterns during general anaesthesia

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