Anesthesia and analgesia
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Anesthesia and analgesia · Oct 2022
Observational StudyKetamine Associated Intraoperative Electroencephalographic Signatures of Elderly Patients With and Without Preoperative Cognitive Impairment.
Ketamine is typically used by anesthesiologists as an adjunct for general anesthesia and as a nonopioid analgesic. It has been explored for prevention of postoperative delirium, although results have been contradictory. In this study, we investigated the association of ketamine with postoperative delirium and specific encephalographic signatures. Furthermore, we examined these associations in the context of baseline neurocognition as measured by a validated assessment. ⋯ Ketamine-related changes in EEG are observed in a heterogeneous group of patients receiving spine surgery. This result was driven primarily by the effect of ketamine on cognitively normal patients and not observed in patients that were cognitively impaired at baseline. Furthermore, patients who were cognitively impaired at baseline and who had received ketamine were more likely to develop postoperative delirium, suggesting that cognitive vulnerability might be predicted by the lack of a neurophysiologic response to ketamine.
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Anesthesia and analgesia · Oct 2022
Randomized Controlled TrialSingle-Shot Lumbar Erector Spinae Plane Block in Total Hip Replacement: A Randomized Clinical Trial.
Lumbar erector spinae plane block (ESPB) has been proposed to relieve pain after total hip replacement (THR), but high-quality evidence is scarce. ⋯ This trial did not demonstrate that ESPB at L1 improved analgesia following THR.
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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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Anesthesia and analgesia · Oct 2022
Biography Historical ArticleThomas Drysdale Buchanan, MD, and the Birth of Academic Anesthesiology.
Thomas Drysdale Buchanan, MD (1876-1940), founding president of the American Board of Anesthesiology, was the first person in the United States to hold the title "Professor of Anesthesiology" in a medical school faculty position dedicated exclusively to the specialty. An 1897 graduate of New York Medical College, Dr Buchanan joined the faculty of his alma mater in 1902 in response to demands by medical students and recent graduates for a dedicated instructor in anesthesia. Within a decade, the instructorship had become a professorship, and Dr Buchanan was on his way to distinction as one of the founders of academic anesthesiology. This chapter in Dr Buchanan's early career illustrates how anesthesiology took shape as a distinct body of knowledge during the formative decades of modern medical education at the turn of the century, laying the groundwork for its recognition 30 years later as a specialty in its own right.