Anesthesiology
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Postoperative delirium has been associated with greater complications, medical cost, and increased mortality during hospitalization. Recent evidence suggests that preoperative executive dysfunction and depression may predict postoperative delirium; however, the combined effect of these risk factors remains unknown. This study examined the association among preoperative executive function, depressive symptoms, and established clinical predictors of postoperative delirium among 998 consecutive patients undergoing major noncardiac surgery. ⋯ Preoperative executive dysfunction and depressive symptoms are predictive of postoperative delirium among noncardiac surgical patients. Executive tasks with greater complexity are more strongly associated with postoperative delirium relative to tests of basic sequencing.
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Millions of neonates undergo anesthesia each year. Certain anesthetic agents cause brain cell death and long-term neurocognitive dysfunction in postnatal day (P)7 rats. Despite its intuitive appeal, a causal link between cell death and neurocognitive decline after anesthesia has not been established. If one existed, the degree of cell death would be expected to correlate with the degree of neurocognitive dysfunction caused by anesthesia. The authors therefore tested if cell death caused by various durations of isoflurane at 1 minimum alveolar concentration causes duration-dependent long-term neurocognitive dysfunction. ⋯ Isoflurane-induced brain cell death may be partly caused by hypercarbia. The inconsistencies between cell death and neurocognitive outcome suggest that additional or alternative mechanisms may mediate anesthesia-induced long-term neurocognitive dysfunction.
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There are no existing data regarding risk factors for impossible mask ventilation and limited data regarding its incidence. The authors sought to determine the incidence, predictors, and outcomes associated with impossible mask ventilation. ⋯ Impossible mask ventilation is an infrequent airway event that is associated with difficult intubation. Neck radiation changes represent the most significant clinical predictor of impossible mask ventilation in the patient dataset.
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Several experimental studies have suggested that early exposure to anesthetic agents, i.e., before completion of synaptogenesis, can result in widespread apoptotic neuronal degeneration and late cognitive impairment, but human data are lacking. The authors performed a retrospective pilot study to test the feasibility and calculate sample sizes for a larger epidemiologic study of disturbed neurobehavioral development as a function of age at the time of first anesthetic exposure. Pediatric urological procedures were selected because the timing of surgery depends mainly on the age at which a diagnosis is made. ⋯ Children undergoing urologic surgery at age less than 24 months showed more behavioral disturbances than children in whom surgery was performed after age 2 yr, although the results were not statistically significant. To confirm or refute an effect of anesthesia on cognitive development, at least 2,268 children need to be studied. With retrospective study designs, residual confounding remains an issue that can only be solved in prospective randomized studies.
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Isoflurane causes long-term hippocampal-dependent learning deficits in rats despite limited isoflurane-induced hippocampal cell death, raising questions about the causality between isoflurane-induced cell death and isoflurane-induced cognitive function. Neurogenesis in the dentate gyrus is required for hippocampal-dependent learning and thus constitutes a potential alternative mechanism by which cognition can be altered after neonatal anesthesia. The authors tested the hypothesis that isoflurane alters proliferation and differentiation of hippocampal neural progenitor cells. ⋯ The authors conclude that isoflurane does not cause cell death, but it does act directly on neural progenitor cells independently of effects on the surrounding brain to decrease proliferation and increase neuronal fate selection. These changes could adversely affect cognition after isoflurane anesthesia.