21 Feasibility of a Multicomponent Protocol to Promote Dreaming during Surgical AnesthesiaImage: A. Johnson, Vivo Visuals Studio.Implementation of a treatment bundle consisting of verbal priming, propofol infusion, electroencephalography-guided titration, 10 min or longer of minimization of stimulation, and immediate dream interviews resulted in a high incidence of reported dreaming. Apart from...
ON THE COVER: Dreaming during anesthesia is common and may have mental health benefits. However, systematic research on its incidence and outcomes in clinical settings remains limited. In this issue of Anesthesiology, Sikka et al. implemented a standardized propofol-based, electroencephalography-guided emergence bundle to facilitate a preemergence state conducive to dreaming, integrating it...
BACKGROUND: Dreaming during anesthesia is common and may have mental health benefits. However, systematic research on its incidence and outcomes in clinical settings remains limited. This study implemented a standardized propofol-based, electroencephalography (EEG)-guided emergence bundle to facilitate a preemergence state conducive to dreaming, integrating it into routine care to assess...
AnesthesiologyOctober 1, 2025Jia-Yan Li, Ye-Hui Wu, Yi-Han Wang et al.
Glutamatergic neurons in the supramammillary nucleus (SuM) have previously been shown to be pivotal parts of the wakefulness-sleep regulation system. However, whether they play a role in propofol-mediated modulation of consciousness remains unclear. This study hypothesized that glutamatergic neurons in the SuM contribute to the regulation of altered states of consciousness under propofol...
During the last 100 years, the role of anesthesiologists in psychiatry has focused primarily on facilitating electroconvulsive therapy and mitigating postoperative delirium and other perioperative neurocognitive disorders. The discovery of the rapid and sustained antidepressant properties of ketamine, and early results suggesting that other general anesthetic drugs (including nitrous oxide,...
The near-death experience has been reported since antiquity and is often characterized by the perception of light, interactions with other entities, and life recall. Near-death experiences can occur in a variety of situations, but they have been studied systematically after in-hospital cardiac arrest, with an incidence of 10 to 20%. Long attributed to metaphysical or supernatural causes, there...
Identifying the state-related "neural correlates of consciousness" for anesthetics-induced unconsciousness is challenging. Spatiotemporal complexity is a promising tool for investigating consciousness. The authors hypothesized that spatiotemporal complexity may serve as a state-related but not drug-related electroencephalography (EEG) indicator during an unconscious state induced by different...
Chronic pain is a public health concern that affects approximately 1.5 billion people globally. Conventional therapeutic agents including opioid and non-opioid analgesics have been associated with adverse side effects, issues with addiction, and ineffective analgesia. Novel agents repurposed to treat pain via different mechanisms are needed to fill the therapeutic gap in chronic pain...
We read with interest the study of ketamine psychedelic and analgesic effects by Olofsen et al.1 and the accompanying editorial by Mashour.2 In both articles, the authors refer to the “dissociative” effects of ketamine. Corssen and Domino3 originally used the term “dissociative” in 1966 to describe “patients and subjects who, during recovery from CI-581 [ketamine], felt as though they were in...
We thank Bowdle et al.1 for their interest in our article,2 and for the important issue they raise, paraphrased as follows: what is the best anthropocentric description of the "mind-altering" effects of a heterogeneous group of compounds and drugs that act at the brain and cause significant changes in mental state. The group of drugs that we are referring to includes N-methyl-d-aspartate (NMDA)...
Editorial| May 2022 Ketamine Analgesia and Psychedelia: Can We Dissociate Dissociation? George A. Mashour, M.D., Ph.D. George A. Mashour, M.D., Ph.D. Department of Anesthesiology, University of Michigan Medical School, Ann Arbor, Michigan. Search for other works by this author on: This Site PubMed Google Scholar Author and Article Information Accepted for publication February 11, 2022....
BACKGROUND: Ketamine produces potent analgesia combined with psychedelic effects. It has been suggested that these two effects are associated and possibly that analgesia is generated by ketamine-induced dissociation. The authors performed a post hoc analysis of previously published data to quantify the pharmacodynamic properties of ketamine-induced antinociception and psychedelic symptoms. The...
Although the precise neural correlates of consciousness have not yet been identified, there is one neurochemical marker that appears to track with our capacity to experience something: acetylcholine concentration in the cerebral cortex. Cortical acetylcholine concentration is high during wakefulness, decreases during slow-wave sleep, and increases again during rapid eye movement sleep, when we...
IF ketamine were an animal, it would have to be an octopus: unique, endlessly mutable, potentially dangerous, devilishly complicated to study, and seeming to extend its grasp into every corner of medicine. In the 50 years ketamine has been commercially available in the United States, practitioners and researchers have called it an analgesic, antidepressant, anti-inflammatory agent, dissociative...
Background: Ketamine is a dissociative anesthetic with analgesic properties. Ketamine’s analgesic properties have been suggested to result from its dissociative properties. To the authors’ knowledge, this postulate is unsubstantiated. The authors hypothesize that the dissociative and analgesic properties of ketamine are independent. Methods: The authors conducted a single-site, open-label study...
AnesthesiologyApril 2020Jesus J Ballesteros, Pamela Huang, Shaun R Patel et al.
Ketamine is a noncompetitive N-methyl-D-aspartate antagonist and is known for unique electrophysiologic profiles in electroencephalography. However, the mechanisms of ketamine-induced unconsciousness are not clearly understood. The authors have investigated neuronal dynamics of ketamine-induced loss and return of consciousness and how multisensory processing is modified in the primate...
BACKGROUND: Investigations of the electrophysiology of gaseous anesthetics xenon and nitrous oxide are limited revealing inconsistent frequency-dependent alterations in spectral power and functional connectivity. Here, the authors describe the effects of sedative, equivalent, stepwise levels of xenon and nitrous oxide administration on oscillatory source power using a crossover design to...
Anesthesiology, V 129 • No 2 228 August 2018 A NESTHETIC gases block consciousness selectively, sparing nonconscious brain activities, and thus their specific action could unravel the age-old mystery of how the brain generates, or mediates, consciousness. In this issue, Li et al.1 make a significant contribution to our understanding of both anesthesia and consciousness, showing that an isotope...
Oh Excellent Air Bag presents a curated collection of 12 scientific and popular works about nitrous oxide, spanning 1799 to 1920. Voyeuristic readers will enjoy reading the frequently explicit experiences of inhaling nobles. Readers who prefer a coherent history with a focus on characters, causes, and effects may be less satisfied. That reader will savor the historian Mike Jay’s engaging...
BACKGROUND: Esketamine is traditionally administered via intravenous or intramuscular routes. In this study we developed a pharmacokinetic model of inhalation of nebulized esketamine with special emphasis on pulmonary absorption and bioavailability. METHODS: Three increasing doses of inhaled esketamine (dose escalation from 25 to 100 mg) were applied followed by a single intravenous dose (20...
The article by Icaza and Mashour1 is a very interesting article because it presents a topic of investigation that is currently attracting the attention of pharmacologists, neuroscientists, and biological psychiatrists around the globe: human research with psychedelic compounds. The text brings important information regarding the history and pharmacology of psychedelics but presents important...
Abstract The psychedelic experience has been reported since antiquity, but there is relatively little known about the underlying neural mechanisms. A recent neuroimaging study on psilocybin revealed a pattern of decreased cerebral blood flow and functional disconnections that is surprisingly similar to that caused by various anesthetics. In this article, the authors review historical examples...
INTRODUCTION: General anesthesia induces unconsciousness along with functional changes in brain networks. Considering the essential role of hub structures for efficient information transmission, the authors hypothesized that anesthetics have an effect on the hub structure of functional brain networks. METHODS: Graph theoretical network analysis was carried out to study the network properties of...
INTRODUCTION: Directional connectivity from anterior to posterior brain regions (or "feedback" connectivity) has been shown to be inhibited by propofol and sevoflurane. In this study the authors tested the hypothesis that ketamine would also inhibit cortical feedback connectivity in frontoparietal networks. METHODS: Surgical patients (n = 30) were recruited for induction of anesthesia with...