Publications by authors named "M Bright"

177 Publications

Iatrogenic uvular injury related to airway instrumentation: A report of 13 cases from the webAIRS database and a review of uvular necrosis following inadvertent uvular injury.

Anaesth Intensive Care 2021 Apr 8:310057X20982623. Epub 2021 Apr 8.

Department of Anaesthesia and Perioperative Medicine, Royal Brisbane and Women's Hospital, Brisbane, Australia.

Published reports of uvular necrosis are uncommon and it is possibly an under-reported complication of oropharyngeal manipulation. Uvular necrosis is thought to develop due to ischaemia secondary to mechanical compression of the uvula from oropharyngeal devices. Patients typically present with symptoms of a sore throat within 48 hours postoperatively. It is unclear whether there are any preventable factors, or any specific management strategies that might reduce this complication. Treatment is most commonly conservative management, including observation and simple analgesia. We present 13 cases of uvular injury that were reported to a web-based anaesthesia incident reporting system (webAIRS), a voluntary de-identified anaesthesia incident reporting system in Australia and New Zealand. While the postoperative findings varied, sore throat was the most frequent symptom. Most of the cases resolved spontaneously; the remainder with supportive treatment only. The findings suggest that patients who sustain a uvular injury can be reassured, but they should be advised to seek review early if sore throat persists or any difficulty with breathing develops.
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http://dx.doi.org/10.1177/0310057X20982623DOI Listing
April 2021

Use of therapeutic caffeine in acute care postoperative and critical care settings: a scoping review.

BMC Anesthesiol 2021 Mar 31;21(1):100. Epub 2021 Mar 31.

Department of Intensive Care Services, Royal Brisbane and Women's Hospital and Faculty of Health, Queensland University of Technology (QUT), Brisbane, Queensland, Australia.

Background: Caffeine is the most utilised psychoactive drug worldwide. However, caffeine withdrawal and the therapeutic use of caffeine in intensive care and in the perioperative period have not been well summarised. Our objective was to conduct a scoping review of caffeine withdrawal and use in the intensive care unit (ICU) and postoperative patients.

Methods: PubMed, Embase, CINAHL Complete, Scopus and Web of Science were systematically searched for studies investigating the effects of caffeine withdrawal or administration in ICU patients and in the perioperative period. Areas of recent systematic review such as pain or post-dural puncture headache were not included in this review. Studies were limited to adults.

Results: Of 2268 articles screened, 26 were included and grouped into two themes of caffeine use in in the perioperative period and in the ICU. Caffeine withdrawal in the postoperative period increases the incidence of headache, which can be effectively treated prophylactically with perioperative caffeine. There were no studies investigating caffeine withdrawal or effect on sleep wake cycles, daytime somnolence, or delirium in the intensive care setting. Administration of caffeine results in faster emergence from sedation and anaesthesia, particularly in individuals who are at high risk of post-extubation complications. There has only been one study investigating caffeine administration to facilitate post-anaesthetic emergence in ICU. Caffeine administration appears to be safe in moderate doses in the perioperative period and in the intensive care setting.

Conclusions: Although caffeine is widely used, there is a paucity of studies investigating withdrawal or therapeutic effects in patients admitted to ICU and further novel studies are a priority.
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http://dx.doi.org/10.1186/s12871-021-01320-xDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8011218PMC
March 2021

The role of antibodies in Bacille Calmette Guérin-mediated immune responses and protection against tuberculosis in humans: A systematic review.

Tuberculosis (Edinb) 2020 Jun 9:101947. Epub 2020 Jun 9.

Department of Paediatrics, The University of Melbourne, Parkville, Victoria, Australia; Murdoch Children's Research Institute, Parkville, Victoria, Australia. Electronic address:

Background: The mechanisms underlying Bacille Calmette-Guérin (BCG) vaccine's protective effects against tuberculosis (TB) are incompletely understood but are proposed to involve a predominantly cell-mediated process. However, there is increasing evidence for the involvement of antibodies in the control of Mycobacteria tuberculosis and in the immune response to BCG.

Methods: We did a systematic review of studies investigating anti-BCG antibodies in individuals with active or latent TB, and in the response to BCG vaccination.

Results: Of 1417 articles screened, 70 were relevant, comprising 52 investigating anti-BCG antibodies in TB and 18 investigating the anti-BCG antibody response to BCG-vaccination. Individuals with active TB have higher levels of anti-BCG antibodies compared with individuals with latent TB or healthy individuals. Antibodies to BCG are present after BCG vaccination. There is some evidence for the in utero transfer of maternal anti-BCG antibodies to infants.

Conclusions: BCG vaccination induces a humoral response. Antibodies targeted against BCG and its antigens may play a role in protection against active TB.
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http://dx.doi.org/10.1016/j.tube.2020.101947DOI Listing
June 2020

ICA-based denoising strategies in breath-hold induced cerebrovascular reactivity mapping with multi echo BOLD fMRI.

Neuroimage 2021 06 6;233:117914. Epub 2021 Mar 6.

Basque Center on Cognition, Brain and Language, Donostia, Spain. Electronic address:

Performing a BOLD functional MRI (fMRI) acquisition during breath-hold (BH) tasks is a non-invasive, robust method to estimate cerebrovascular reactivity (CVR). However, movement and breathing-related artefacts caused by the BH can substantially hinder CVR estimates due to their high temporal collinearity with the effect of interest, and attention has to be paid when choosing which analysis model should be applied to the data. In this study, we evaluate the performance of multiple analysis strategies based on lagged general linear models applied on multi-echo BOLD fMRI data, acquired in ten subjects performing a BH task during ten sessions, to obtain subject-specific CVR and haemodynamic lag estimates. The evaluated approaches range from conventional regression models, i.e. including drifts and motion timecourses as nuisance regressors, applied on single-echo or optimally-combined data, to more complex models including regressors obtained from multi-echo independent component analysis with different grades of orthogonalization in order to preserve the effect of interest, i.e. the CVR. We compare these models in terms of their ability to make signal intensity changes independent from motion, as well as the reliability as measured by voxelwise intraclass correlation coefficients of both CVR and lag maps over time. Our results reveal that a conservative independent component analysis model applied on the optimally-combined multi-echo fMRI signal offers the largest reduction of motion-related effects in the signal, while yielding reliable CVR amplitude and lag estimates, although a conventional regression model applied on the optimally-combined data results in similar estimates. This work demonstrates the usefulness of multi-echo based fMRI acquisitions and independent component analysis denoising for precision mapping of CVR in single subjects based on BH paradigms, fostering its potential as a clinically-viable neuroimaging tool for individual patients. It also proves that the way in which data-driven regressors should be incorporated in the analysis model is not straight-forward due to their complex interaction with the BH-induced BOLD response.
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http://dx.doi.org/10.1016/j.neuroimage.2021.117914DOI Listing
June 2021

Cerebrovascular Reactivity Mapping Without Gas Challenges: A Methodological Guide.

Front Physiol 2020 18;11:608475. Epub 2021 Jan 18.

Institute for Systems and Robotics - Lisboa and Department of Bioengineering, Instituto Superior Técnico, Universidade de Lisboa, Lisbon, Portugal.

Cerebrovascular reactivity (CVR) is defined as the ability of vessels to alter their caliber in response to vasoactive factors, by means of dilating or constricting, in order to increase or decrease regional cerebral blood flow (CBF). Importantly, CVR may provide a sensitive biomarker for pathologies where vasculature is compromised. Furthermore, the spatiotemporal dynamics of CVR observed in healthy subjects, reflecting regional differences in cerebral vascular tone and response, may also be important in functional MRI studies based on neurovascular coupling mechanisms. Assessment of CVR is usually based on the use of a vasoactive stimulus combined with a CBF measurement technique. Although transcranial Doppler ultrasound has been frequently used to obtain global flow velocity measurements, MRI techniques are being increasingly employed for obtaining CBF maps. For the vasoactive stimulus, vasodilatory hypercapnia is usually induced through the manipulation of respiratory gases, including the inhalation of increased concentrations of carbon dioxide. However, most of these methods require an additional apparatus and complex setups, which not only may not be well-tolerated by some populations but are also not widely available. For these reasons, strategies based on voluntary breathing fluctuations without the need for external gas challenges have been proposed. These include the task-based methodologies of breath holding and paced deep breathing, as well as a new generation of methods based on spontaneous breathing fluctuations during resting-state. Despite the multitude of alternatives to gas challenges, existing literature lacks definitive conclusions regarding the best practices for the vasoactive modulation and associated analysis protocols. In this work, we perform an extensive review of CVR mapping techniques based on MRI and CO variations without gas challenges, focusing on the methodological aspects of the breathing protocols and corresponding data analysis. Finally, we outline a set of practical guidelines based on generally accepted practices and available data, extending previous reports and encouraging the wider application of CVR mapping methodologies in both clinical and academic MRI settings.
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http://dx.doi.org/10.3389/fphys.2020.608475DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7848198PMC
January 2021