Evidence map›Paper›PMID 39665912›Full record

ArticleBritish journal of anaesthesia2025

The relationship of bispectral index values to conscious state: an analysis of two volunteer cohort studies.

Jordan J Wehrman, Peter J Schuller, Cameron P Casey, Annalotta Scheinin, Roosa E Kallionpää, Katja Valli, Antti Revonsuo, Oskari Kantonen, Sean Tanabe, William Filbey and 4 more

Abstract readMulticenter Study
PubMed Full text at PMC Publisher
In one paragraph

Article in British journal of anaesthesia, 2025. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 3 papers.

0numbers the graph read from it
0cells of the map it votes in
3citing papers in PubMed
–field-weighted citation impact
1 · What the graph read from it

What it found

Each row is one number read from the abstract, on the scale the paper reported it, with its interval. Left of the dashed line favours the treatment, right favours the comparator. Under each row is the sentence it came from. New to these charts? A ten-minute tutorial.

The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.

2 · The registry

The trial behind it

Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.

Neither the registry nor the abstract names a trial number. If this is a trial report, that itself is worth knowing.

3 · Its place in the literature

Who cites it

3 citing papers in PubMed.

  1. Trial
  2. Article
  3. Article
4 · The record

Corrections and comments

PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.

5 · Who and what money

Authors and funding

14 authors.

Jordan J WehrmanCentral Clinical School, Faculty of Medicine and Health, The University of Sydney, Sydney, NSW, Australia; Department of Anaesthetics, Royal Prince Alfred Hospital, Sydney Local Health District, Sydney, NSW, Australia. Electronic address: Jordan.Wehrman@sydney.edu.au.
Peter J SchullerDepartment of Anaesthesia, Cairns Hospital, Cairns, QLD, Australia; James Cook University, Townsville, QLD, Australia.
Cameron P CaseyDepartment of Anesthesiology, School of Medicine and Public Health, University of Wisconsin, Madison, WI, USA.
Annalotta ScheininTurku PET Centre, University of Turku and Turku University Hospital, Turku, Finland; Department of Perioperative Services, Intensive Care and Pain Medicine, Turku University Hospital, Turku, Finland.
Roosa E KallionpääDepartment of Psychology and Speech-Language Pathology, and Turku Brain and Mind Center, University of Turku, Turun yliopisto, Finland.
Katja ValliDepartment of Perioperative Services, Intensive Care and Pain Medicine, Turku University Hospital, Turku, Finland; Department of Psychology and Speech-Language Pathology, and Turku Brain and Mind Center, University of Turku, Turun yliopisto, Finland; Department of Cognitive Neuroscience and Philosophy, School of Bioscience, University of Skövde, Skövde, Sweden.
Antti RevonsuoDepartment of Psychology and Speech-Language Pathology, and Turku Brain and Mind Center, University of Turku, Turun yliopisto, Finland; Department of Cognitive Neuroscience and Philosophy, School of Bioscience, University of Skövde, Skövde, Sweden.
Oskari KantonenTurku PET Centre, University of Turku and Turku University Hospital, Turku, Finland; Department of Perioperative Services, Intensive Care and Pain Medicine, Turku University Hospital, Turku, Finland.
Sean TanabeDepartment of Neuroscience, Canadian Centre for Behavioural Research, University of Lethbridge, Lethbridge, AB, Canada.
William FilbeyDepartment of Anesthesiology, School of Medicine and Public Health, University of Wisconsin, Madison, WI, USA.
Robert A PearceDepartment of Anesthesiology, School of Medicine and Public Health, University of Wisconsin, Madison, WI, USA.
Jamie W SleighDepartment of Anaesthesia, Waikato Hospital, Hamilton, New Zealand; Department of Anaesthesiology, Waikato Clinical School, Waikato Clinical Campus, University of Auckland, New Zealand.
Harry ScheininTurku PET Centre, University of Turku and Turku University Hospital, Turku, Finland; Department of Perioperative Services, Intensive Care and Pain Medicine, Turku University Hospital, Turku, Finland.
Robert D SandersCentral Clinical School, Faculty of Medicine and Health, The University of Sydney, Sydney, NSW, Australia; Department of Anaesthetics, Royal Prince Alfred Hospital, Sydney Local Health District, Sydney, NSW, Australia; Institute of Academic Surgery, Royal Prince Alfred Hospital, Sydney Local Health District, Sydney, NSW, Australia; NHMRC Clinical Trials Centre, The University of Sydney, Sydney, NSW, Australia.

Funding

No grant is acknowledged in the PubMed record.

6 · The paper itself

Abstract

backgroundThe ability of current depth-of-anaesthesia monitors to differentiate subtle changes in the conscious state has not been well characterised. We examine the variability in bispectral index (BIS) scores associated with disconnected conscious and unconscious states as confirmed by a novel serial awakening paradigm.

methodsSeventy adult participants, given propofol or dexmedetomidine, had a cumulative 1381 electroencephalographic (EEG) recordings across two centres. Participants were awakened periodically, and their recent conscious experience interrogated by structured questioning. BIS were reconstructed from EEG using openibis, and the distribution of BIS scores were compared using linear mixed effects modelling. The predictive capacity of BIS across states of consciousness was also examined.

resultsReconstructed BIS scores correlated significantly with blood concentrations of propofol and dexmedetomidine (all P<0.001). However, while the average BIS was different between baseline wakefulness (mean BIS=95.1 [standard deviation=3.5]); connected consciousness with drug present (84.0 [10.9]); disconnected consciousness (70.0 [16.9]); and unconsciousness (68.1 [16.1]), the interquartile range of these states (3.6, 15.1, 23.3 and 26.8, respectively) indicated high degrees of overlap and individual variability. Connected consciousness could be differentiated from either disconnected consciousness or unconsciousness with 86% accuracy (i.e. 14% error rate), and disconnected consciousness differentiated from unconsciousness with 74% accuracy.

conclusionsThese results agree with previous studies that BIS scores fail to reliably differentiate between states of consciousness, exacerbated by segregating connected, disconnected, and unconscious states. To develop a method that reliably identifies the conscious state of an individual (not an average), work is needed to establish the causal mechanisms of disconnection and unconsciousness.

Indexed as

ConsciousnessConsciousness MonitorsAdultAgedAnesthetics, IntravenousCohort StudiesDexmedetomidineElectroencephalographyFemaleHumansHypnotics and SedativesMaleMiddle AgedPropofolUnconsciousnessWakefulnessAnesthetics, IntravenousDexmedetomidineHypnotics and SedativesPropofolBISbispectral indexconsciousness assessmentdexmedetomidineopenibispropofolserial awakening

Identifiers

PMID39665912
PMCPMC11867084

What OpenQuestion holds

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Registered trials

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Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.