Anesthesiology
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Randomized Controlled Trial
Event-related functional magnetic resonance imaging of a low dose of dexmedetomidine that impairs long-term memory.
Work suggests the amnesia from dexmedetomidine (an α2-adrenergic agonist) is caused by a failure of information to be encoded into long-term memory and that dexmedetomidine might differentially affect memory for emotionally arousing material. We investigated these issues in humans using event-related neuroimaging to reveal alterations in brain activity and subsequent memory effects associated with drug exposure. ⋯ Dexmedetomidine impaired long-term picture memory, but did not disproportionately block memory for emotionally arousing items. The memory impairment on dexmedetomidine corresponds with a weakened hippocampal subsequent memory effect.
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Randomized Controlled Trial
Metabolomic profiling of children's brains undergoing general anesthesia with sevoflurane and propofol.
We recently applied proton magnetic resonance spectroscopy (HMRS) to investigate metabolic consequences of general anesthesia in the rodent brain, and discovered that isoflurane anesthesia was characterized by higher concentrations of lactate, glutamate, and glucose in comparison with propofol. We hypothesized that the metabolomic differences between an inhalant and intravenous anesthetic observed in the rodent brain could be reproduced in the human brain. ⋯ Our results demonstrating higher glucose and lactate with sevoflurane in the human brain compared with propofol could reflect greater neuronal activity with sevofluane resulting in enhanced glutamate-neurotransmitter cycling, increased glycolysis, and lactate shuttling from astrocytes to neurons or mitochondrial dysfunction. Further, the association between emergence delirium and lactate suggests that anesthesia-induced enhanced cortical activity in the unconscious state may interfere with rapid return to "coherent" brain connectivity patterns required for normal cognition upon emergence of anesthesia.