Anesthesiology
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Multicenter Study Observational Study
Current Ventilator and Oxygen Management during General Anesthesia: A Multicenter, Cross-sectional Observational Study.
Intraoperative oxygen management is poorly understood. It was hypothesized that potentially preventable hyperoxemia and substantial oxygen exposure would be common during general anesthesia. ⋯ Potentially preventable hyperoxemia and substantial oxygen exposure are common during general anesthesia, especially during one-lung ventilation. Future research should explore the safety and feasibility of a more conservative approach for intraoperative oxygen therapy.
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In supine patients with acute respiratory distress syndrome, the lung typically partitions into regions of dorsal atelectasis and ventral aeration ("baby lung"). Positive airway pressure is often used to recruit atelectasis, but often overinflates ventral (already aerated) regions. A novel approach to selective recruitment of dorsal atelectasis is by "continuous negative abdominal pressure." ⋯ Continuous negative abdominal pressure added to PEEP reduces ventilator-induced lung injury in a pig model compared with PEEP alone, despite targeting identical expiratory transpulmonary pressure.
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Historical Article
History of the Development of Anesthesia for the Dolphin: A Quest to Study a Brain as Large as Man's.
It is important for academic-minded human anesthesiologists to have an interdisciplinary perspective when engaging in cutting-edge research as well as the practice of human anesthesiology. This was a philosophy promoted by Dr. Robert Dripps, former pioneering Chairman of the Anesthesiology Department at the University of Pennsylvania (Philadelphia, Pennsylvania). ⋯ The motivation to anesthetize dolphins came from the fact that scientists and physicians wanted to study the brain of the dolphin, a brain as large as man's. Also, investigators wanted to develop anesthesia for the dolphin in order to study the electrophysiology of the dolphin's highly sophisticated auditory system, which facilitates the dolphin's amazing echolocation capability. Dolphin anesthesia involves a complex matter of unique neural control, airway anatomy, neuromuscular control of respiration, and sleep behavior.
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γ-Aminobutyric Acid Type A Receptor Potentiation Inhibits Learning in a Computational Network Model.
Propofol produces memory impairment at concentrations well below those abolishing consciousness. Episodic memory, mediated by the hippocampus, is most sensitive. Two potentially overlapping scenarios may explain how γ-aminobutyric acid receptor type A (GABAA) potentiation by propofol disrupts episodic memory-the first mediated by shifting the balance from excitation to inhibition while the second involves disruption of rhythmic oscillations. We use a hippocampal network model to explore these scenarios. The basis for these experiments is the proposal that the brain represents memories as groups of anatomically dispersed strongly connected neurons. ⋯ Memory formation is widely thought to depend on changes in neuronal connection strengths during learning that enable neuronal groups to respond with greater facility to familiar stimuli. This experiment suggests the ability to form such groups is sensitive to alteration in the balance between excitation and inhibition such as that resulting from administration of a γ-aminobutyric acid-mediated anesthetic agent.
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Potential deleterious effect of multiple anesthesia exposures on the developing brain remains a clinical concern. We hypothesized that multiple neonatal anesthesia exposures are more detrimental to brain maturation than an equivalent single exposure, with more pronounced long-term behavioral consequences. We designed a translational approach using proton magnetic resonance spectroscopy in rodents, noninvasively tracking the neuronal marker N-acetyl-aspartate, in addition to tracking behavioral outcomes. ⋯ Our data demonstrate the feasibility of using the biomarker N-acetyl-aspartate, measured noninvasively using proton magnetic resonance spectroscopy, for longitudinally monitoring anesthesia-induced neurotoxicity. These results also indicate that the neonatal rodent brain is more vulnerable to multiple anesthesia exposures than to a single exposure of the same cumulative duration.