Articles: function.
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Anesthesia and analgesia · Oct 2022
Open Reimplementation of the BIS Algorithms for Depth of Anesthesia.
BIS (a brand of processed electroencephalogram [EEG] depth-of-anesthesia monitor) scores have become interwoven into clinical anesthesia care and research. Yet, the algorithms used by such monitors remain proprietary. We do not actually know what we are measuring. If we knew, we could better understand the clinical prognostic significance of deviations in the score and make greater research advances in closed-loop control or avoiding postoperative cognitive dysfunction or juvenile neurological injury. In previous work, an A-2000 BIS monitor was forensically disassembled and its algorithms (the BIS Engine) retrieved as machine code. Development of an emulator allowed BIS scores to be calculated from arbitrary EEG data for the first time. We now address the fundamental questions of how these algorithms function and what they represent physiologically. ⋯ The openibis algorithm finally provides definitive answers about the BIS: the reliance of the most important signal components on the low-gamma waveband and how these components are weighted against each other. Reverse engineering allows these conclusions to be reached with a clarity and precision that cannot be obtained by other means. These results contradict previous review articles that were believed to be authoritative: the BIS score does not appear to depend on a bispectral index at all. These results put clinical anesthesia research using depth-of-anesthesia scores on a firm footing by elucidating their physiological basis and enabling comparison to other animal models for mechanistic research.
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Curr Opin Anaesthesiol · Oct 2022
ReviewBrain death/death by neurologic criteria determination: an update.
Brain death, also known as death by neurologic criteria (DNC), is a well-established concept. In this article, we present a short history of the concept and give an overview of recent changes and a practical update on diagnosis and definitions of brain death/DNC. Unresolved issues will be discussed. ⋯ There are two sets of criteria for declaration of death. First, if there is neither cardiac output nor respiratory effort, then cardiopulmonary criteria are used. Second, if both the cerebrum and brainstem have completely and permanently lost all functions, and there is a persistent coma, absent brainstem reflexes and no spontaneous respiratory effort, death can be declared on the basis of brain death/DNC. Although attempts to formulate uniform criteria are ongoing, consensus has been reached on the minimum criteria. Some inconsistencies and questions remain.
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Curr Opin Anaesthesiol · Oct 2022
ReviewCerebral metabolic derangements following traumatic brain injury.
Outcome following traumatic brain injury (TBI) remains variable, and derangements in cerebral metabolism are a common finding in patients with poor outcome. This review compares our understanding of cerebral metabolism in health with derangements seen following TBI. ⋯ Mitochondrial dysfunction and the use of alternative energy substrates are potential therapeutic targets, but improved understanding of the causes, impact and significance of metabolic derangements in clinical TBI are needed. Maintaining adequate oxygen and glucose delivery across the injured brain may accelerate the recovery of mitochondrial function and cerebral energy metabolism and remain important management targets.
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Asthma is a common disease affecting 350 million people worldwide, which is characterized by airways inflammation and hyperreactivity. Historically diagnosis and treatment have been mainly based on symptoms, which have the potential to result in misdiagnosis and inappropriate treatment. Nitric oxide (NO) is exhaled in human breath and is a marker of airways inflammation. ⋯ The inclusion of FeNO testing can increase diagnostic accuracy of asthma, while high levels in asthmatic patients can help predict response to inhaled corticosteroids (ICS) and suppression of levels with ICS to monitor adherence. FeNO levels are also a predictor of asthma risk with increased exacerbation rates and accelerated decline in lung function associated with high levels as well as having an emerging role in predicting response to some biologic therapies in severe asthma. FeNO testing is cost-effective and has been shown, when combined with clinical assessment, to improve asthma management.
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Youth with sickle cell disease (SCD) and chronic pain, defined in this study as pain on most days for 3 months, experience variability in daily pain and physical and psychosocial functioning. This study aimed to (1) empirically derive chronic pain subgroups based on pain characteristics among youth with chronic SCD pain; and (2) investigate derived subgroups for differences in sociodemographics, clinical characteristics, and psychosocial and functional outcomes. ⋯ Identifying chronic SCD pain subgroups may inform tailored assessment and intervention to mitigate poor pain and functional outcomes.