Anesthesiology
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Randomized Controlled Trial Clinical Trial
Surgical stimulation induces changes in brain electrical activity during isoflurane/nitrous oxide anesthesia. A topographic electroencephalographic analysis.
The aim of this study was to investigate topographic changes in electroencephalographic (EEG) power and frequency induced by abdominal surgery during anesthesia with 0.6% or 1.2% isoflurane in 66% nitrous oxide. ⋯ The current data demonstrate graded EEG responses induced by abdominal surgery during anesthesia with 0.6% or 1.2% isoflurane in 66% nitrous oxide. Spatial heterogeneities in absolute spectral power densities were reflected by color changes in the EEG maps. The topographic EEG analysis indicates that these changes were most dominant at frontal areas. The increases in delta and decreases in alpha activities may be related to intraoperative "paradoxical" electrophysiologic arousal phenomena.
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Randomized Controlled Trial Comparative Study Clinical Trial
Rapid increase in desflurane concentration is associated with greater transient cardiovascular stimulation than with rapid increase in isoflurane concentration in humans.
Increases in desflurane and isoflurane concentrations can transiently increase arterial blood pressure or heart rate or both during induction of anesthesia. The current study tested the hypothesis that a rapid increase of desflurane concentration in humans increases sympathetic activity and hormonal variables and heart rate and arterial blood pressure more than does an equivalent increase in isoflurane concentration. ⋯ In healthy male volunteers, rapid increases of desflurane or isoflurane from 0.55 to 1.66 MAC increase sympathetic and renin-angiotensin system activity, and cause transient increases in arterial blood pressure and heart rate. Desflurane causes significantly greater increases than isoflurane, and also causes a transient increase in plasma AVP concentration. The temporal relationships suggest that the increased sympathetic activity increases mean arterial blood pressure and heart rate, with mean arterial blood pressure also increased by increased plasma AVP concentration, whereas the delayed, increased plasma renin activity is likely a response to the ensuing hypotension, or earlier inhibition by AVP, or both.