Anesthesiology
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Clinical Trial
Use of dynamic negative airway pressure (DNAP) to assess sedative-induced upper airway obstruction.
Traditional methods of assessing ventilatory effects of sedative agents do not measure their propensity to cause upper airway obstruction (UAO). The primary objective of this study was to develop a method, using dynamic negative airway pressure (DNAP), for replicating UAO during deep sedation. ⋯ Dynamic Negative Airway Pressure is a useful method for provoking midazolam-induced UAO, and may potentially be used to compare the potential for different sedatives and patient factors to cause UAO. Flumazenil was completely effective in reversing the potential for midazolam to cause UAO.
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Clinical Trial Controlled Clinical Trial
Sympathetic neural activation evoked by mu-receptor blockade in patients addicted to opioids is abolished by intravenous clonidine.
Mu-opioid receptor blockade by naloxone administered for acute detoxification in patients addicted to opioids markedly increases catecholamine plasma concentrations, muscle sympathetic activity (MSA), and is associated with cardiovascular stimulation despite general anesthesia. The current authors tested the hypothesis that the alpha2-adrenoceptor agonist clonidine (1) attenuates increased MSA during mu-opioid receptor blockade for detoxification, and (2) prevents cardiovascular activation when given before detoxification. ⋯ Administration of the alpha2-adrenoceptor agonist clonidine decreases both increased MSA and catecholamine plasma concentrations observed after mu-opioid receptor blockade for detoxification. Furthermore, clonidine pretreatment prevents the increase in catecholamine plasma concentration that otherwise occurs during mu-opioid receptor blockade.
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Clinical Trial
Can assessment for obstructive sleep apnea help predict postadenotonsillectomy respiratory complications?
The aim of this study was to determine the frequency and type of respiratory complications after adenotonsillectomy in children. A second aim was to assess the ability of preoperative sleep studies to identify children at risk for respiratory complications. ⋯ The data suggest, but do not prove, that preoperative nocturnal oximetry could be a useful preoperative test to identify children who are at increased risk for postoperative respiratory complications.
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Mannitol and furosemide are used to reduce increased intracranial pressure (ICP) and to reduce brain bulk during neurosurgery. One mechanism by which these changes might occur is via a reduction in brain water content. Although mannitol and furosemide are commonly used in combination, there has been no formal evaluation of the interactive effects of these two drugs on brain water. The effect of mannitol and furosemide alone and in combination on water content of normal rat brain was examined. ⋯ The doses of mannitol and furosemide utilized were much larger than clinically applicable doses and were selected to maximize the ability to detect effect on brain water. The combination of mannitol and furosemide resulted in greater reduction of brain water content than did mannitol alone. Furosemide enhanced the effect of mannitol on plasma osmolality, resulting in a greater reduction of brain water content. Potential interaction (if any) of smaller, clinically used doses of mannitol and furosemide cannot be surmised from the current study.
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There is a belief that clonidine may be effective in reducing perioperative myocardial ischemic events, although the results of several trials are conflicting. The aim of the current study was to provide a systematic review of randomized controlled trials that tested the efficacy of clonidine in this regard. ⋯ The meta-analysis suggests that perioperative clonidine reduces cardiac ischemic episodes in patients with known, or at risk of, coronary arterial disease without increasing the incidence of bradycardia. Therefore, these findings strongly justify planning and execution of a definitive study seeking the benefits of clonidine.