Senior Research Scientist
- Wellcome Centre for Integrative Neuroimaging
- Nuffield Division of Anaesthesia
Neuroimaging of anaesthesia and altered states of consciousness
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My research interests cover anaesthesia, pain and sleep. I lead a research programme using multimodal neuroimaging to understand the changes in the brain under anaesthesia and during altered states of consciousness. My group is based in the Wellcome Centre for Integrative Neuroimaging at FMRIB. I was recently awarded the 2017 National Institute for Academic Anaesthesia (NIAA) Research award.
One of my current research goals is to identify and develop objective neurophysiological measures of conscious perception under anaesthesia, and translate these findings to the clinical environment. We previously identified a potential electroencephalographic marker of perception loss under anaesthesia (Ni Mhuircheartaigh*, Warnaby* et al., Science Translational Medicine, 2013).
We observed that saturation of slow wave activity (SWAS) signalled a striking change in how each individual’s brain processes incoming sensory stimuli. At SWAS, we observed a disruption in stereotypical thalamocortical processing and stimulus-evoked activity in a brain network previously associated with severe disorders of consciousness.
We extended this work recently to show that SWAS occurs during surgical anaesthesia (Warnaby*, Sleigh* et al., Anesthesiology 2017), and that delayed emergence from SWAS (termed neural inertia) is linked to confused thinking and delirium on waking, particularly in older individuals.
Additionally, we are currently developing a real-time Bayesian prediction model that will allow titration of anaesthesia to SWAS. Through its clinical translation and further investigation of the neural correlates of consciousness as part of the Luminous project, we hope to demonstrate that SWAS truly indicates perception loss, or at the very least a disconnection of the patient from the external world.
More recently, we investigated what is specifically ‘lost’ in the brain under anaesthesia at the earlier loss of behavioural responsiveness, i.e. before SWAS is achieved (Warnaby et al., Anesthesiology, 2016). We identified that anterior insula suppression occurs to incoming multisensory stimuli, and was associated with decreased functional connectivity with decision-making regions at this time.
I am also principal investigator of the Oxford Persisting Post-Operative Pain Study (OxPPOPS). OxPPOPS is a major clinical trial to identify the incidence and predictive factors for development of chronic pain after surgery and its impact on quality of life.
Predictive factors under investigation are psychological, anaesthetic, surgical, genetic and hormonal factors as well as those relating to post-operative analgesic management and sleep. Identification of the variables that predict the development of persistent post-operative pain will allow interventions in ‘at-risk’ patients to be implemented.
Slow-wave activity saturation and thalamocortical isolation during propofol anesthesia in humans.
Ní Mhuircheartaigh R. et al, (2013), Sci Transl Med, 5
Anesthesia-induced Suppression of Human Dorsal Anterior Insula Responsivity at Loss of Volitional Behavioral Response.
Warnaby CE. et al, (2016), Anesthesiology, 124, 766 - 778
Functional brain imaging: gatecrashing the clinical party?
Sleigh J. and Warnaby CE., (2014), Lancet, 384, 476 - 477
Investigation of Slow-wave Activity Saturation during Surgical Anesthesia Reveals a Signature of Neural Inertia in Humans.
Warnaby CE. et al, (2017), Anesthesiology, 127, 645 - 657
Electroencephalographic Response to Sodium Nitrite May Predict Delayed Cerebral Ischemia After Severe Subarachnoid Hemorrhage.
Garry PS. et al, (2016), Crit Care Med, 44, e1067 - e1073
Impact of preoperative pain and psychology during pregnancy before elective Caesarean section
Lee M. et al, (2016), BRITISH JOURNAL OF ANAESTHESIA, 116, E930 - E930