Anesthesiology
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Randomized Controlled Trial Comparative Study Clinical Trial
Desflurane-mediated sympathetic activation occurs in humans despite preventing hypotension and baroreceptor unloading.
Increasing concentrations of desflurane result in progressive decreases in blood pressure (BP) and, unlike other currently marketed, potent volatile anesthetics, heightened sympathetic nervous system activity. This study aimed to determine whether baroreflex mechanisms are involved in desflurane-mediated sympathetic excitation. ⋯ The increase in basal levels of SNA with increasing concentrations of desflurane persisted despite "fixing" BP and thus is probably not due to hypotension and unloading of the baroreceptors. Further, the preservation of reflex increases in SNA to nitroprusside during desflurane indicates that desflurane preserves one component of the baroreflex in humans when BP is "fixed."
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Nonsteroidal anti-inflammatory drugs (NSAIDs) may interfere with hemostasis during the perioperative period, and the combination of NSAID and enoxaparin could increase this effect. The aim of this prospective, blinded experimental study was to assess these effects using a model of arterial thrombosis and bleeding in the rabbit. ⋯ Ketorolac had an important antithrombotic activity. The association of enoxaparin with ketorolac seemed to lengthen the bleeding time observed with ketorolac.
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Comparative Study
Acetylcholinesterase and butyrylcholinesterase are expressed in the spinal meninges of monkeys and pigs.
Acetylcholinesterase inhibition at the spinal level has been shown to produce a potent antinociceptive effect. However, the site of cholinesterase inhibition is unknown. To determine whether the spinal meninges participate in acetylcholine metabolism, the spinal meninges of monkeys and pigs were assayed for cholinesterase activity. ⋯ These data show that the spinal meninges express acetylcholinesterase and butyrylcholinesterase; for monkeys, although not pigs, the level of cholinesterase activity is comparable with that found in the spinal cord. This finding suggests that the meninges may be an important site for acetylcholine metabolism and may play a role in the analgesic effect produced by intrathecally administered cholinesterase inhibitors.
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Comparative Study
Interaction of isoflurane and sevoflurane with alpha- and beta-adrenoceptor stimulations in rat myocardium.
Halothane potentiates the positive inotropic effects of alpha- and beta-adrenoceptor stimulations but impairs the positive lusitropic effect of beta-adrenoceptor stimulations. However, the interactions of isoflurane and sevoflurane with alpha- and beta-adrenoceptor stimulation have not been entirely defined. ⋯ Although isoflurane and sevoflurane have moderate negative inotropic effects, they potentiated the positive inotropic effects of alpha- and beta-adrenoceptor stimulations but did not modify the positive lusitropic effects of beta-adrenoceptor stimulation.
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Etomidate is an anesthetic agent that reduces the cerebral metabolic rate and causes minimal cardiovascular depression. Its ability to improve recovery after anoxia or ischemia is equivocal. An in vitro neuronal preparation was used to examine the action of etomidate on electrophysiologic and biochemical parameters during and after anoxia. ⋯ A range of etomidate concentrations did not significantly alter recovery of the evoked population spike after anoxia in rat hippocampal slices. A high concentration of etomidate did attenuate the increase in sodium and the decrease in potassium during anoxia.