Anesthesiology
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Volatile anesthetics moderately depress respiratory function at clinically relevant concentrations. Phox2b-expressing chemosensitive neurons in the retrotrapezoid nucleus, a respiratory control center, are activated by isoflurane, but the underlying mechanisms remain unclear. The hypothesis of this study was that the sodium leak channel contributes to the volatile anesthetics-induced modulation of retrotrapezoid nucleus neurons and to respiratory output. ⋯ Isoflurane and sevoflurane increase neuronal excitability of chemosensitive retrotrapezoid nucleus neurons partly by enhancing sodium leak channel conductance. Sodium leak channel expression in the retrotrapezoid nucleus is required for the ventilatory response to carbon dioxide during anesthesia by isoflurane and sevoflurane, thus identifying sodium leak channel as a requisite determinant of respiratory output during anesthesia of volatile anesthetics.
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It is a commonly held view that information flow between widely separated regions of the cerebral cortex is a necessary component in the generation of wakefulness (also termed "connected" consciousness). This study therefore hypothesized that loss of wakefulness caused by propofol anesthesia should be associated with loss of information flow, as estimated by the effective connectivity in the scalp electroencephalogram (EEG) signal. ⋯ Propofol-induced unresponsiveness is marked by a global decrease in information flow, greatest from the lateral frontal and prefrontal brain regions in a posterior and medial direction. Loss of information flow may be a useful measure of connected consciousness.
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Obstructive sleep apnea is underdiagnosed in surgical patients. The cost-effectiveness of obstructive sleep apnea screening is unknown. This study's objective was to evaluate the cost-effectiveness of preoperative obstructive sleep apnea screening (1) perioperatively and (2) including patients' remaining lifespans. ⋯ The cost-effectiveness of preoperative obstructive sleep apnea screening differs depending on time horizon. Preoperative screening with STOP-Bang followed by immediate confirmatory testing with polysomnography is cost-effective on the lifetime horizon but not the perioperative horizon. The integration of preoperative screening based on STOP-Bang and polysomnography is a cost-effective means of mitigating the long-term disease burden of obstructive sleep apnea.