Anesthesiology
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The effect of isoflurane on median nerve somatosensory evoked potentials (MN-SSEPs) was studied in 15 patients. Anesthesia was induced with thiamylal and maintained with oxygen and isoflurane. MN-SSEPs were recorded in awake patients and after achieving 0.5, 1.0, 1.5, and 2.0% stable end-tidal concentrations of isoflurane. ⋯ N20 was not discernible in one out of 14 patients after 1.5% and in three out of ten patients after 2% isoflurane. These results indicate that subcortical potentials are less affected by isoflurane anesthesia than cortical potentials. Amplitude reduction of cortical potentials was more noticeable than either prolongation of peak latency or conduction time.(ABSTRACT TRUNCATED AT 250 WORDS)
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Comparative Study
A comparison of alfentanil pharmacokinetics in children and adults.
The pharmacokinetics of alfentanil have been studied in eight children aged between 4 and 8 yr and five adults during general anesthesia. All patients were given 20 micrograms/kg alfentanil as an intravenous bolus injection. Plasma concentrations were measured at intervals up to 6 h by radioimmunoassay. ⋯ The shorter elimination half-life could be due to the smaller total apparent volume of distribution in children. Plasma protein binding was comparable between children and adults and could not explain the smaller volume of distribution in children. It is suggested that the smaller volume of distribution of alfentanil in children is a result of the decreased percentage of fat tissue in children.