British Journal of Anaesthesia - The Consciousness Library

Dreaming during anaesthesia: a scoping review.

British Journal of Anaesthesia August 1, 2026 Pilleriin Sikka, Sherry Hu, Boris D. Heifets

Dreaming during anaesthesia has been documented for over a century, yet it remains poorly understood. This scoping review synthesises evidence on the frequency, phenomenology, predictors, outcomes, and neural correlates of anaesthesia dreaming. We systematically searched multiple databases for studies examining anaesthesia dreaming, including clinical trials, observational studies, and...

DOI: 10.1016/j.bja.2026.05.002 Full text Ketamine Phenomenology Anaesthesia dreaming Disconnected consciousness +4

Effects of ketamine on postoperative cognition: a scoping review.

British Journal of Anaesthesia July 7, 2025 Connor T A Brenna, Xuan W He, Daheng Liu et al. 8 citations

Postoperative delirium and other forms of perioperative neurocognitive deficits occur commonly in older adult patients. Ketamine, administered either before or during general anaesthesia, may have cognitive-sparing properties owing to its ability to reduce neuroinflammation, increase neurotrophin levels, or allow reductions in the doses of other general anaesthetic drugs. However, the efficacy...

DOI: 10.1016/j.bja.2025.05.035 Full text Arketamine Delayed neurocognitive recovery Perioperative neurocognitive disorders Postoperative delirium +3

Orexin signalling in the nucleus accumbens promotes arousal from isoflurane anaesthesia and restores communication between the nucleus accumbens and frontal cortex.

British Journal of Anaesthesia May 28, 2025 Jia Huo, Huiming Li, Dan Wang et al. 4 citations

Orexin can induce arousal from general anaesthesia; however, the underlying mechanisms are not fully understood. Nucleus accumbens (NAc), a downstream target of orexinergic neurones, plays a role in regulating consciousness. We aimed to clarify whether and how the NAc mediates the arousal effects of orexin. Fibre photometry was used to track changes of orexinergic afferent activity during...

DOI: 10.1016/j.bja.2025.03.042 Full text D1 receptor Coherence General anaesthesia Isoflurane +6

Connectome harmonic decomposition tracks the presence of disconnected consciousness during ketamine-induced unresponsiveness.

British Journal of Anaesthesia April 1, 2025 Milan Van Maldegem, Jakub Vohryzek, Selen Atasoy et al. 3 citations

Ketamine, in doses suitable to induce anaesthesia in humans, gives rise to a unique state of unresponsiveness accompanied by vivid experiences and sensations, making it possible to disentangle the correlated but distinct concepts of conscious awareness and behavioural responsiveness. This distinction is often overlooked in the study of consciousness. The mathematical framework of connectome...

DOI: 10.1016/j.bja.2024.12.036 Full text Consciousness research Psychedelic medicine Brain imaging Ketamine effects +6

The diverse effects of ketamine, jack-of-all-trades: a narrative review.

British Journal of Anaesthesia March 1, 2025 Nicholas D Richards, Simon J Howell, Mark C Bellamy et al. 20 citations

Ketamine, an N-methyl-D-aspartic acid receptor antagonist that was first discovered in 1962, has become established in anaesthesia providing dose-dependent anaesthetic, sedative, and analgesic effects. Ketamine, however, also acts on a wide range of other cellular targets, resulting in interesting and diverse effects on both physiological and pathological processes. Potential beneficial...

DOI: 10.1016/j.bja.2024.11.018 Full text Nmda receptor antagonist Anaesthesia Anti-inflammatory properties Antidepressant effects +7

Acute effects of esketamine on hypoxic ventilatory response, haemodynamics, and brain function in healthy volunteers.

British Journal of Anaesthesia February 1, 2025 Simone C Jansen, Monique van Velzen, Elise Sarton et al. 11 citations

The acute hypoxic ventilatory response is a critical chemoreflex originating at the carotid bodies. This study investigates the impact of low-dose i.v. esketamine on the ventilatory response to 20 min of isocapnic hypoxia to test the hypothesis that esketamine does not affect hypoxic ventilation. In this open-label study, 18 healthy subjects received a 3-h escalating i.v. infusion of...

DOI: 10.1016/j.bja.2024.08.040 Full text Esketamine Haemodynamics Hypoxic ventilatory response Anesthesia +4

Changes in information integration and brain networks during propofol-, dexmedetomidine-, and ketamine-induced unresponsiveness.

British Journal of Anaesthesia March 1, 2024 Zhenhu Liang, Yu Chang, Xiaoge Liu et al. 10 citations

Information integration and network science are important theories for quantifying consciousness. However, whether these theories propose drug- or conscious state-related changes in EEG during anaesthesia-induced unresponsiveness remains unknown. A total of 72 participants were randomised to receive i.v. infusion of propofol, dexmedetomidine, or ketamine at a constant infusion rate until loss...

DOI: 10.1016/j.bja.2023.11.033 Full text Ketamine Brain network Dexmedetomidine Electroencephalography +1

Evaluation of putative signatures of consciousness using specific definitions of responsiveness, connectedness, and consciousness.

British Journal of Anaesthesia February 1, 2024 Cameron P Casey, Sean Tanabe, Zahra Z Farahbakhsh et al.

Understanding the neural correlates of consciousness has important ramifications for the theoretical understanding of consciousness and for clinical anaesthesia. A major limitation of prior studies is the use of responsiveness as an index of consciousness. We identified a collection of measures derived from unresponsive subjects and more specifically their association with consciousness (any...

DOI: 10.1016/j.bja.2023.09.031 Full text Consciousness Electroencephalography Intraoperative responsiveness Sensory awareness +1

Esketamine accelerates emergence from isoflurane general anaesthesia by activating the paraventricular thalamus glutamatergic neurones in mice.

British Journal of Anaesthesia December 1, 2023 Wenying Duan, Kang Peng, Hui-Min Qin et al.

BACKGROUND Delayed emergence from general anaesthesia poses a significant perioperative safety hazard. Subanaesthetic doses of ketamine not only deepen anaesthesia but also accelerate recovery from isoflurane anaesthesia; however, the mechanisms underlying this phenomenon remain elusive. Esketamine exhibits a more potent receptor affinity and fewer adverse effects than ketamine and exhibits...

DOI: 10.1016/j.bja.2023.10.038

Subjective experiences during dexmedetomidine- or propofol-induced unresponsiveness and non-rapid eye movement sleep in healthy male subjects.

British Journal of Anaesthesia August 1, 2023 Katja Valli, Linda Radek, Roosa E Kallionpää et al.

Anaesthetic-induced unresponsiveness and non-rapid eye movement (NREM) sleep share common neural pathways and neurophysiological features. We hypothesised that these states bear resemblance also at the experiential level. We compared, in a within-subject design, the prevalence and content of experiences in reports obtained after anaesthetic-induced unresponsiveness and NREM sleep. Healthy males...

DOI: 10.1016/j.bja.2023.04.026 Full text Dreaming Anaesthesia Awareness Consciousness +4

Dreaming and awareness during dexmedetomidine- and propofol-induced unresponsiveness.

British Journal of Anaesthesia July 1, 2018 Linda Radek, Roosa E Kallionpää, M Karvonen et al.

Experiences during anaesthetic-induced unresponsiveness have previously been investigated by interviews after recovery. To explore whether experiences occur during drug administration, we interviewed participants during target-controlled infusion (TCI) of dexmedetomidine or propofol and after recovery. Healthy participants received dexmedetomidine (n=23) or propofol (n=24) in stepwise...

DOI: 10.1016/j.bja.2018.03.014 Full text Awareness Consciousness Dexmedetomidine Interview +1

Subanaesthetic ketamine and altered states of consciousness in humans

British Journal of Anaesthesia April 13, 2018 Phillip E. Vlisides, Tarik Bel‐bahar, Amanda Nelson et al. 117 citations

BackgroundDespite its designation as a 'dissociative anaesthetic,' the dissociative and psychoactive effects of ketamine remain incompletely understood. The goal of this study was to characterise the subjective experiences and accompanying EEG changes with subanaesthetic doses of ketamine.MethodsHigh-density EEG was recorded in 15 human volunteers before, during, and after subanaesthetic...

DOI: 10.1016/j.bja.2018.03.011 Ketamine Altered state Consciousness Cognitive science

General anaesthesia as fragmentation of selfhood: insights from electroencephalography and neuroimaging

British Journal of Anaesthesia February 4, 2018 Jamie Sleigh, Catherine E. Warnaby, Irene Tracey 35 citations

Selfhood is linked to brain processes that enable the experience of a person as a distinct entity, capable of agency. This framework naturally incorporates a continuum of both non-conscious and conscious self-related information processing, and includes a hierarchy of components, such as awareness of existence (core self), embodied self (sentience), executive self (agency/volition), and various...

DOI: 10.1016/j.bja.2017.12.038 Sentience Consciousness Electroencephalography Cognitive psychology +1

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