A5051927501- Optical Imaging and Spectroscopy Techniques
- Traumatic Brain Injury and Neurovascular Disturbances
- Non-Invasive Vital Sign Monitoring
- Cardiac, Anesthesia and Surgical Outcomes
- Hemodynamic Monitoring and Therapy
- Spectroscopy Techniques in Biomedical and Chemical Research
- Photoacoustic and Ultrasonic Imaging
- Long-Term Effects of COVID-19
- Blood Pressure and Hypertension Studies
- Neurosurgical Procedures and Complications
- Cardiac Arrest and Resuscitation
- Photoreceptor and optogenetics research
- Intracranial Aneurysms: Treatment and Complications
- COVID-19 Clinical Research Studies
- Heart Rate Variability and Autonomic Control
- Vehicle emissions and performance
- Thermoregulation and physiological responses
- Airway Management and Intubation Techniques
- Anesthesia and Sedative Agents
- Anesthesia and Neurotoxicity Research
- Fluid Dynamics and Turbulent Flows
- COVID-19 and healthcare impacts
- Cerebrovascular and Carotid Artery Diseases
- Enhanced Recovery After Surgery
- Delphi Technique in Research
University College London
2010-2024
National Hospital for Neurology and Neurosurgery
2010-2024
Princess Alexandra Hospital
2018-2024
The University of Queensland
2018-2024
Royal London Hospital
2013-2024
Population Health Research Institute
2023
Committee on Publication Ethics
2022
Princess Alexandra Hospital
2022
Prince Charles Hospital
2021
University of Plymouth
2020
The pandemic of coronavirus disease 2019 (COVID-19) has several implications relevant to neuroanesthesiologists, including neurological manifestations the disease, impact anesthesia provision for specific neurosurgical procedures and electroconvulsive therapy, health care provider wellness. Society Neuroscience in Anesthesiology Critical Care appointed a task force provide timely, consensus-based expert guidance neuroanesthesiologists during COVID-19 pandemic. aim this document is focused...
The redox state of cerebral mitochondrial cytochrome c oxidase monitored with near-infrared spectroscopy (Δ[oxCCO]) is a signal strong potential as non-invasive, bedside biomarker metabolic status. We hypothesised that the higher density brain compared to skin and skull would lead evidence brain-specificity Δ[oxCCO] when measured multi-distance (NIRS) system. Measurements well concentration changes in oxygenated (Δ[HbO2]) deoxygenated haemoglobin (Δ[HHb]) were taken at multiple...
We present the first three-dimensional, functional images of human brain to be obtained using a fibre-less, high-density diffuse optical tomography system. Our technology consists independent, miniaturized, silicone-encapsulated DOT modules that can placed directly on scalp. Four these were arranged provide up 128, dual-wavelength measurement channels over scalp area approximately 60 × 65 mm2. Using series motor-cortex stimulation experiments, we demonstrate this system obtain high-quality,...
Continuous monitoring of cerebral autoregulation might provide novel treatment targets and identify therapeutic windows after acute brain injury. Slow oscillations hemodynamics (0.05-0.003 Hz) are visible in multimodal neuromonitoring may be analyzed to novel, surrogate measures autoregulation. Near-infrared spectroscopy (NIRS) is an optical technique, which shows promise for widespread clinical applicability because it noninvasive easily delivered across a wide range scenarios. The aim this...
The first wearable multi-wavelength technology for functional near-infrared spectroscopy has been developed, based on a custom-built 8-wavelength light emitting diode (LED) source. A lightweight fibreless probe is designed to monitor changes in the concentrations of multiple absorbers (chromophores) biological tissue, most dominant which at wavelengths are oxyhemoglobin and deoxyhemoglobin. use enables signals due less chromophores be more easily distinguished from those hemoglobin thus...
Intra-operative hypotension frequently complicates anaesthesia in older patients and is implicated peri-operative organ hypoperfusion injury. The prevalence corresponding treatment thresholds of are incompletely described the UK. This study aimed to identify intra-operative its UK practice. Patients aged ≥ 65 years were studied prospectively from 196 hospitals within a 48-hour timeframe. primary outcome was incidence (mean arterial pressure <65 mmHg; systolic blood reduction >20%; <100...
Acute brain injury is associated with depressed aerobic metabolism. Below a critical mitochondrial pO 2 cytochrome c oxidase, the terminal electron acceptor in respiratory chain, fails to sustain oxidative phosphorylation. After acute injury, this ischaemic threshold might be shifted into apparently normal levels of tissue oxygenation. We investigated oxygen dependency metabolism 16 acutely brain-injured patients using 120-min normobaric hyperoxia challenge phase (24–72 h) post-injury and...
Hypoxic ischemic encephalopathy (HIE) leads to significant morbidity and mortality. Impaired autoregulation after hypoxia-ischaemia has been suggested contribute further injury. Thalamic lactate/N-Acetylasperate (Lac/NAA) peak area ratio of > 0.3 on proton (1H) magnetic resonance spectroscopy (MRS) is associated with poor neurodevelopment outcome following HIE. Cytochrome-c-oxidase (CCO) plays a central role in mitochondrial oxidative metabolism ATP synthesis. Using novel broadband NIRS...
We present a multi-channel, multi-distance broadband near-infrared spectroscopy (NIRS) system with the capability of measuring changes in haemoglobin concentrations (Δ[HbO2], Δ[HHb]), oxidation state cytochrome-c-oxidase (Δ[oxCCO]) and tissue oxygen saturation (TOI) adult human brain. The main components instrument are two customized spectrographs light sources. Each spectrograph is lens-based to improve throughput, has grating enhanced optimise reflection (NIR) spectral region uses front...
Functional Near-Infrared Spectroscopy (fNIRS) is a non-invasive optical technique that measures cerebral hemodynamics across multiple regions of interest, and thereby characterises brain functional activation. Since its first description in 1993, fNIRS has undergone substantial developments hardware, analysis techniques, applications. Thirty years later, this significantly enchancing our understanding diverse areas neuroscience research such as neurodevelopment, cognitive neuroscience,...
In diffuse optical tomography (DOT), overlapping and multidistance measurements are required to reconstruct depth-resolved images of oxy- ([Formula: see text]) deoxy- (HHb) hemoglobin concentration changes occurring in the brain. These can be considered an indirect measure brain activity, under assumption intact neurovascular coupling. Broadband systems also allow redox state cytochrome c oxidase (oxCCO) measured, which important biomarker when coupling is impaired. We used DOT [Formula:...
Multimodal monitoring of brain state is important both for the investigation healthy cerebral physiology and to inform clinical decision making in conditions injury disease. Near-infrared spectroscopy an instrument modality that allows non-invasive measurement several physiological variables interest, notably haemoglobin oxygenation redox metabolic enzyme cytochrome c oxidase. Interpreting such measurements requires integration multiple signals from different sources try understand states...
Transcranial near-infrared spectroscopy (NIRS) provides an assessment of cerebral oxygen metabolism by monitoring concentration changes in oxidised cytochrome c oxidase Δ[oxCCO]. We investigated the response Δ[oxCCO] to global delivery at different source-detector separations 16 healthy adults. Hypoxaemia was induced a hypoxic inspired gas mix and hypercapnia addition 6 % CO2 gases. A hybrid optical spectrometer used measure frontal cortex light absorption scattering discrete wavelengths...
Anaesthesia is frequently complicated by intraoperative hypotension (IOH) in the elderly, and this associated with adverse outcome. The definition of IOH controversial, although management guidelines for elderly exist, frequency typical clinically applied treatment thresholds are largely unknown UK. We audited blood pressure against national patients undergoing surgery. Depth anaesthesia (DOA) monitoring was also due to association between low DOA values increased mortality (as part "double"...
Hypercapnia increases cerebral blood flow. The effects on metabolism remain incompletely understood although studies show an oxidation of cytochrome c oxidase, Complex IV the mitochondrial respiratory chain. Systems modelling was combined with previously published non-invasive measurements tissue oxygenation, flow, and oxidase redox state to evaluate any metabolic hypercapnia. Cerebral oxygen saturation were measured broadband near infrared spectroscopy flow velocity transcranial Doppler...
Functional hyperaemia, characterised as an increase in concentration of oxyhaemoglobin [HbO2] and a decrease deoxyhaemoglobin [HHb] response to neuronal activity, can be precisely mapped using diffuse optical spectroscopy. However, such techniques do not directly measure changes metabolic activity during activation. Changes the redox state cerebral oxidised cytochrome c oxidase Δ[oxCCO] measured by broadband spectroscopy may more specific marker activity. This study aims investigate spatial...
Acute brain injury (ABI) is associated with changes in near infrared light absorption reflecting haemodynamic and metabolic status via cerebral oxygenation (haemoglobin cytochrome-c-oxidase oxidation). Light scattering has not been comprehensively investigated following ABI may be an important confounding factor the assessment of chromophore concentration changes, and/or a novel non-invasive optical marker tissue morphology, cytostructure, hence status. The aim this study to characterize...
Aneurysmal subarachnoid haemorrhage (SAH) is a devastating disease associated with high mortality and poor outcome in many survivors. Aggressive treatment by comprehensive multidisciplinary team improved outcome, but the intensive care management of SAH presents significant challenges. Multimodal neuromonitoring may detect secondary insults before irreversible neuronal damage has occurred, increasingly being used to guide treatment. This article reviews current trends from aspects initial...