Background: Cortical high-frequency activation immediately before death has been reported, raising questions about an enhanced conscious state at this critical time. Here, we analyzed an electroencephalogram (EEG) from a comatose patient during the dying process with a standard bedside monitor and spectral parameterization techniques.
Methods: We report neurophysiologic features of a dying patient without major cortical injury.
Background: Aperiodic (nonoscillatory) electroencephalogram (EEG) activity can be characterised by its power spectral density, which decays according to an inverse power law. Previous studies reported a shift in the spectral exponent α from consciousness to unconsciousness. We investigated the impact of aperiodic EEG activity on parameters used for anaesthesia monitoring to test the hypothesis that aperiodic EEG activity carries information about the hypnotic component of general anaesthesia.
View Article and Find Full Text PDFBackground: Postoperative delirium is a common complication in older adults, associated with poor outcomes, morbidity, mortality, and higher health care costs. Older age is a strong predictor of delirium. Intraoperative burst suppression on the electroencephalogram (EEG) has also been linked to postoperative delirium and poor neurocognitive outcomes.
View Article and Find Full Text PDFBackground: Numerous, sometimes conflicting, changes in brain functional connectivity have been associated with the transition from wakefulness to unresponsiveness at induction of general anesthesia. However, relatively few studies have looked at the detailed time evolution of the transition, for different electroencephalogram (EEG) frequency bands, and in the clinical scenario of surgical patients undergoing general anesthesia.
Methods: The authors investigated the changes in the frontal and frontoparietal directed and undirected functional connectivity to multichannel EEG data recorded from 29 adult male surgical patients undergoing propofol-induced loss of consciousness during induction of anesthesia.
Background: The electroencephalographic (EEG) provides the anesthesiologist with information regarding the level of anesthesia. Processed EEG indices are available that reflect the level of anesthesia as a single number. Strong oscillatory EEG activity in the alpha-band may be associated with an adequate level of anesthesia and a lower incidence of cognitive sequelae.
View Article and Find Full Text PDFIntroduction: During general anesthesia, frontal electroencephalogram (EEG) activity in the alpha frequency band (8-12 Hz) correlates with the adequacy of analgesia. Transcranial direct current stimulation (tDCS) and auditory stimulation, two noninvasive neuromodulation techniques, can entrain alpha activity in awake or sleeping patients. This study evaluates their effects on alpha oscillations in patients under general anesthesia.
View Article and Find Full Text PDFBackground: Frontal electroencephalography (EEG) monitoring can be useful in guiding the titration of anesthetics, but it is not always feasible to place electrodes in the standard configuration in some circumstances, including during neurosurgery. This study compares 5 alternate configurations of the Masimo Sedline Sensor.
Methods: Ten stably sedated patients in the intensive care unit were recruited.
Background: Intraoperative alpha-band power in frontal electrodes may provide helpful information about the balance of hypnosis and analgesia and has been associated with reduced occurrence of delirium in the postanesthesia care unit. Recent studies suggest that narrow-band power computations from neural power spectra can benefit from separating periodic and aperiodic components of the electroencephalogram. This study investigates whether such techniques are more useful in separating patients with and without delirium in the postanesthesia care unit at the group level as opposed to conventional power spectra.
View Article and Find Full Text PDFBackground: Monitoring the electroencephalogram (EEG) during general anesthesia can help to safely navigate the patient through the procedure by avoiding too deep or light anesthetic levels. In daily clinical practice, the EEG is recorded from the forehead and available neuromonitoring systems translate the EEG information into an index inversely correlating with the anesthetic level. Electrode placement on the forehead can lead to an influence of electromyographic (EMG) activity on the recorded signal in patients without neuromuscular blockade (NMB).
View Article and Find Full Text PDFBackground: Processed electroencephalography (EEG) is used to monitor the level of anesthesia, and it has shown the potential to predict the occurrence of delirium. While emergence trajectories of relative EEG band power identified post hoc show promising results in predicting a risk for a delirium, they are not easily transferable into an online predictive application. This article describes a low-resource and easily applicable method to differentiate between patients at high risk and low risk for delirium, with patients at low risk expected to show decreasing EEG power during emergence.
View Article and Find Full Text PDFMonitoring brain activity and associated physiology during the administration of general anesthesia (GA) in mice is pivotal to guarantee postanesthetic health. Clinically, electroencephalogram (EEG) monitoring is a well-established method to guide GA. There are no established methods available for monitoring EEG in mice (Mus musculus) during surgery.
View Article and Find Full Text PDFTelemetric electroencephalography (EEG) recording, using subdermal needle electrodes, is a minimally-invasive method to investigate mammalian neurophysiology during anesthesia. These inexpensive systems may streamline experiments examining global brain phenomena during surgical anesthesia or disease. We utilized the OpenBCI™ Cyton board with subdermal needle electrodes to extract EEG features in six C57BL/6J mice undergoing isoflurane anesthesia.
View Article and Find Full Text PDFBackground: An optimized anesthesia monitoring using electroencephalographic (EEG) information in the elderly could help to reduce the incidence of postoperative complications. Processed EEG information that is available to the anesthesiologist is affected by the age-induced changes of the raw EEG. While most of these methods indicate a "more awake" patient with age, the permutation entropy (PeEn) has been proposed as an age-independent measure.
View Article and Find Full Text PDFBackground: Devices monitoring the hypnotic component of general anesthesia can help to guide anesthetic management. The main purposes of these devices are the titration of anesthesia dose. While anesthesia at low doses can result in awareness with intraoperative memory formation, excessive administration of anesthetics may be associated with an increased risk of postoperative neurocognitive disorder.
View Article and Find Full Text PDFAdvanced age, American Society of Anesthesiologists physical status (ASA) classification and the presence of cognitive impairment are associated with an elevated risk of postoperative morbidity and mortality. The visual paired comparison (VPC) task, which relies on recognition of novel images, examines declarative memory. VPC scores have demonstrated the ability to detect mild cognitive impairment and track progression of neurodegenerative disease.
View Article and Find Full Text PDFHaving a healthy sleep pattern plays a vital role in one's overall health. Sleep in the elderly is characterized by decreased slow-wave sleep and an increase of REM sleep. Furthermore, quantitative electroencephalographic (qEEG) studies have shown an age-related attenuation of total EEG power in sleep.
View Article and Find Full Text PDFThe course of neuro-cognitive recovery following anaesthesia and surgery is distinctive and poorly understood. Our objective was to identify patterns of neuro-cognitive recovery of the domains routinely assessed for delirium diagnosis in the post anaesthesia care unit (PACU) and to compare them to the cognitive recovery patterns observed in other studies; thereby aiding in the identification of pathological (high risk) patterns of recovery in the PACU. We also compared which of the currently available tests (3D-CAM, CAM-ICU, and NuDESC) is the best to use in PACU.
View Article and Find Full Text PDFConsiderable evidence from mouse models and human postmortem brain suggests loss of Muscleblind-like protein 2 (MBNL2) function in brain is a major driver of CNS symptoms in Myotonic dystrophy type 1 (DM1). Increased hypersomnia, fatigue, and surgical complications associated with general anesthesia suggest possible sensitivity to GABAergic inhibition in DM1. To test the hypothesis that MBNL2 depletion leads to behavioral sensitivity to GABA receptor (GABA-R) modulation, knock-out (KO) and wild-type (WT) littermates were treated with the anesthetic sevoflurane, the benzodiazepine diazepam, the imidazopyridine zolpidem, and the benzodiazepine rescue agent, flumazenil (Ro 15-1788), and assessed for various behavioral metrics.
View Article and Find Full Text PDFStudy Objective: Postoperative neurocognitive disorders (PND) are common complications after surgery under general anesthesia. In our aging society the incidence of PND will increase. Hence, interdisciplinary efforts should be taken to minimize the occurrence of PND.
View Article and Find Full Text PDFJ Neurosurg Anesthesiol
July 2023
Background: Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) negatively impacts the central nervous system, and studies using a full montage of electroencephalogram (EEG) electrodes have reported nonspecific EEG patterns associated with coronavirus disease 2019 (COVID-19) infection. The use of this technology is resource-intensive and limited in its implementation. In this descriptive pilot study, we report neurophysiological patterns and the potential prognostic capability of an abbreviated frontal EEG electrode montage in critically ill COVID-19 patients.
View Article and Find Full Text PDFBackground: Ketamine is typically used by anesthesiologists as an adjunct for general anesthesia and as a nonopioid analgesic. It has been explored for prevention of postoperative delirium, although results have been contradictory. In this study, we investigated the association of ketamine with postoperative delirium and specific encephalographic signatures.
View Article and Find Full Text PDFBackground: Intraoperative neuromonitoring can help to navigate anesthesia. Pronounced alpha oscillations in the frontal electroencephalogram (EEG) appear to predict favorable perioperative neurocognitive outcomes and may also provide a measure of intraoperative antinociception. Monitoring the presence and strength of these alpha oscillations can be challenging, especially in elderly patients, because the EEG in these patients may be dominated by oscillations in other frequencies.
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