Anesthesiology
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Noncardiac surgery conveys a substantial risk of secondary organ dysfunction and injury. Neurocognitive dysfunction and covert stroke are emerging as major forms of perioperative organ dysfunction, but a better understanding of perioperative neurobiology is required to identify effective treatment strategies. ⋯ Translation of these imaging methods into the perioperative setting has highlighted several potential avenues to optimize tissue perfusion and deliver neuroprotection. This review introduces the methods, metrics, and evidence underlying emerging optical and magnetic resonance neuroimaging methods and discusses their potential experimental and clinical utility in the setting of noncardiac surgery.
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Observational Study
Intraoperative Hypotension and Acute Kidney Injury, Stroke and Mortality during and outside Cardiopulmonary Bypass: A Retrospective Observational Cohort Study.
In cardiac surgery, the association between hypotension during specific intraoperative phases or vasopressor-inotropes with adverse outcomes remains unclear. This study's hypothesis was that intraoperative hypotension duration throughout the surgery or when separated into hypotension during and outside cardiopulmonary bypass may be associated with postoperative major adverse events. ⋯ This study confirms previous single-center findings that intraoperative hypotension throughout cardiac surgery is associated with an increased risk of acute kidney injury, mortality, or stroke.
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Residual neuromuscular blockade can be avoided with quantitative neuromuscular monitoring. The authors embarked on a professional practice initiative to attain documented train-of-four ratios greater than or equal to 0.90 in all patients for improved patient outcomes through reducing residual paralysis. ⋯ In this professional practice initiative, documentation of train-of-four ratios greater than or equal to 0.90 occurred for 93% of patients in a busy clinical practice. Return-of-strength documentation is an intermediate outcome, and only one of many factors contributing to patient outcomes.
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Midazolam amplifies synaptic inhibition via different γ-aminobutyric acid type A (GABAA) receptor subtypes defined by the presence of α1-, α2-, α3-, or α5-subunits in the channel complex. Midazolam blocks long-term potentiation and produces postoperative amnesia. The aims of this study were to identify the GABAA receptor subtypes targeted by midazolam responsible for affecting CA1 long-term potentiation and synaptic inhibition in neocortical neurons. ⋯ These results demonstrate a predominant role of α1-GABAA receptors in the actions of midazolam at low nanomolar concentrations. At higher concentrations, midazolam also enhances other GABAA receptor subtypes. α1-GABAA receptors may already contribute at sedative doses to the phenomenon of postoperative amnesia that has been reported after midazolam administration.
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In this first memorial lecture after John Severinghaus's death in 2021, the author traces his journey as a physician-scientist, using the framework of the hero's journey as described by the author Joseph Campbell 40 to 50 yr ago, and parallels that journey to his own. The author discusses how each were gadgeteers: Severinghaus in a creative engineering way, while the author's approach was asking simple questions translating basic research in pain from animals to humans. The classic hero's journey of departure to achieve a goal, then trials, transformation, and finally, returning with benefits to the individual and others is translated to the common physician-scientist career with motivations progressing from "I will show" to "I wonder if" to "I wonder why." Critical to this journey is self-questioning, openness to new ideas, and realizing that progress occurs through failure as much as success.