Anesthesiology
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Comparative Study
Xenon neurotoxicity in rat hippocampal slice cultures is similar to isoflurane and sevoflurane.
Anesthetic neurotoxicity in the developing brain of rodents and primates has raised concern. Xenon may be a nonneurotoxic alternative to halogenated anesthetics, but its toxicity has only been studied at low concentrations, where neuroprotective effects predominate in animal models. An equipotent comparison of xenon and halogenated anesthetics with respect to neurotoxicity in developing neurons has not been made. ⋯ Xenon causes neuronal cell death in an in vitro model of the developing rodent brain at 1 MAC, as does isoflurane and sevoflurane at similarly potent concentrations. Preconditioning with a subtoxic dose of isoflurane eliminates this toxicity.
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The authors examined in vivo the effects of general anesthetics on evoked substance P release (primary afferent excitability) and c-Fos expression (neuronal activation) in superficial dorsal horn. ⋯ General anesthetics at anesthetic concentrations block spinal neuron activation through a mechanism that is independent of an effect on small primary afferent peptide release. The effect of fentanyl alone and the synergistic effect of isoflurane and nitrous oxide on substance P release suggest a correlative rationale for the therapeutic use of these anesthetic protocols by blocking nociceptive afferent transmitter release and preventing the initiation of cascade, which is immediately postsynaptic to the primary afferent.
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Allogeneic erythrocyte transfusion in cardiac surgical patients is associated with a fourfold increase in pulmonary complications. Our understanding of the processes underlying these observations is poor and there is no experimental model of transfusion-related acute lung injury that shows homology to cardiac surgical patients. Our objective was to develop a novel swine recovery model to determine how two clinical risk factors, allogenic erythrocyte transfusion and cardiopulmonary bypass, interact in the genesis of postcardiac surgery acute lung injury. ⋯ In this novel large animal model of allogeneic erythrocyte transfusion, pulmonary dysfunction occurs in the absence of any priming event, is increased when combined with other inflammatory stimuli, and is mediated by monocyte activation and T-lymphocyte depletion.
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High-frequency oscillatory ventilation (HFOV) at higher frequencies minimizes the tidal volume. However, whether increased frequencies during HFOV can reduce ventilator-induced lung injury remains unknown. ⋯ The use of HFOV at 9 Hz minimizes lung stress and tidal volumes, resulting in less lung injury and reduced levels of inflammatory mediators compared with the HFOV-3 Hz and CMV conditions.