Anesthesiology
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Preexisting factors such as age and cognitive performance can influence the electroencephalogram (EEG) during general anesthesia. Specifically, spectral EEG power is lower in elderly, compared to younger, subjects. Here, the authors investigate age-related changes in EEG architecture in patients undergoing general anesthesia through a detailed examination of spectral and entropic measures. ⋯ Like the sleep literature, spectral and entropic EEG features under general anesthesia change with age revealing a shift toward a faster, more irregular, oscillatory composition of the EEG in older patients. Age-related changes in neurophysiological activity may underlie these findings however the contribution of age-related changes in filtering properties or the signal to noise ratio must also be considered. Regardless, most current EEG technology used to guide anesthetic management focus on spectral features, and improvements to these devices might involve integration of entropic features of the raw EEG.
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Investigations of the electrophysiology of gaseous anesthetics xenon and nitrous oxide are limited revealing inconsistent frequency-dependent alterations in spectral power and functional connectivity. Here, the authors describe the effects of sedative, equivalent, stepwise levels of xenon and nitrous oxide administration on oscillatory source power using a crossover design to investigate shared and disparate mechanisms of gaseous xenon and nitrous oxide anesthesia. ⋯ Electromagnetic source-level imaging revealed widespread power changes in xenon and nitrous oxide anesthesia, but failed to reveal clear universal features of action for these two gaseous anesthetics. Magnetoencephalographic and electroencephalographic power changes showed notable differences which will need to be taken into account to ensure the accurate monitoring of brain state during anaesthesia.
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Zygapophyseal (facet) joint interventions are the second most common interventional procedure in pain medicine. Opioid exposure after surgery is a significant risk factor for chronic opioid use. The aim of this study was to determine the incidence of new persistent use of opioids after lumbar facet radiofrequency ablation and to assess the effect of postprocedural opioid prescribing on the development of new persistent opioid use. ⋯ Periprocedural opioid use after lumbar radiofrequency ablation was associated with new persistent use in previously opioid-naïve patients, suggesting that new exposure to opioids is an independent risk factor for persistent use in patients having radiofrequency ablation for chronic back pain. Opioid prescribing after radiofrequency ablation should be reevaluated and likely discontinued in this population.
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Overactivation of ryanodine receptors and the resulting impaired calcium homeostasis contribute to Alzheimer's disease-related pathophysiology. This study hypothesized that exposing neuronal progenitors derived from induced pluripotent stems cells of patients with Alzheimer's disease to dantrolene will increase survival, proliferation, neurogenesis, and synaptogenesis. ⋯ Dantrolene ameliorated the impairment of neurogenesis and synaptogenesis, in association with restoring intracellular Ca homeostasis and physiologic autophagy, cell survival, and proliferation in induced pluripotent stem cells and their derived neurons from sporadic and familial Alzheimer's disease patients.