Articles: anesthetics.
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Building on their known ability to influence sleep and arousal, Li and colleagues show that modulating the activity of glutamatergic pedunculopontine tegmental neurones also alters sevoflurane-induced hypnosis. This finding adds support for the shared sleep-anaesthesia circuit hypothesis. However, the expanding recognition of many neuronal clusters capable of modulating anaesthetic hypnosis raises the question of how disparate and anatomically distant sites ultimately interact to coordinate global changes in the state of the brain. Understanding how these individual sites work in concert to disrupt cognition and behaviour is the next challenge for anaesthetic mechanisms research.
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Delayed emergence from general anaesthesia poses a significant perioperative safety hazard. Subanaesthetic doses of ketamine not only deepen anaesthesia but also accelerate recovery from isoflurane anaesthesia; however, the mechanisms underlying this phenomenon remain elusive. Esketamine exhibits a more potent receptor affinity and fewer adverse effects than ketamine and exhibits shorter recovery times after brief periods of anaesthesia. As the paraventricular thalamus (PVT) plays a pivotal role in regulating wakefulness, we studied its role in the emergence process during combined esketamine and isoflurane anaesthesia. ⋯ Our results suggest that esketamine promotes recovery from isoflurane anaesthesia by activating PVTGlu neurones. This mechanism could explain the rapid arousability exhibited upon treatment with a low dose of esketamine.
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Administration of subanaesthetic doses of ketamine during isoflurane anaesthesia has been shown in animals to deepen the anaesthetised state, while accelerating emergence. Duan and colleagues have now shown that the addition of subanaesthetic doses of esketamine to isoflurane has a similar effect of increasing the burst suppression ratio, while accelerating emergence. Using c-Fos expression and fibre photometry, they show that esketamine activates glutamatergic neurones in the paraventricular nucleus of the thalamus, a structure that regulates wakefulness. Chemogenetic inhibition of these neurones attenuates the arousal-promoting effects, suggesting a causal role of the paraventricular nucleus of the thalamus in esketamine-mediated acceleration of recovery from anaesthesia.
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This study aimed to establish a population pharmacokinetic and pharmacodynamic (PK-PD) model to explore the optimal maintenance dose and appropriate starting time of maintenance dose after induction of ciprofol and investigate the efficacy and safety of ciprofol for general anesthesia induction and maintenance in patients undergoing elective surgery. ⋯ A population PK-PD model was successfully developed to describe the ciprofol PK and BIS changes. Efficacy was consistent across the exposure range with a well-tolerated safety profile indicating no maintenance dose adjustment is required for patients undergoing elective surgery.
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Case Reports
Remimazolam and Remifentanil Anesthetics for an Adolescent Patient with Stiff-Person Syndrome: A Case Report.
Stiff-person syndrome (SPS) is a rare autoimmune disease characterized by fluctuating rigidity and stiffness of the axial muscles. There are no reports on the use of remimazolam in a patient with SPS. A 16-year-old Japanese woman with SPS was scheduled to undergo intrathecal baclofen pump exchange. ⋯ Additionally, electroencephalographic signature showed sufficient anesthetic depth. The patient's emergence from general anesthesia was uneventful. In conclusion, remimazolam could be considered an effective anesthetic drug for patients with SPS.