Journal of neurosurgical anesthesiology
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J Neurosurg Anesthesiol · Jan 1996
Comparative StudyA comparison of the electrophysiologic characteristics of EEG burst-suppression as produced by isoflurane, thiopental, etomidate, and propofol.
Electroencephalogram (EEG) burst-suppression can be produced with several anesthetic agents. Discussions of burst-suppression suggest that it has been viewed by many as a relatively uniform physiologic state independent of the agent used to produce it. This view may be an oversimplification. ⋯ The cortical versus subcortical comparison revealed, for all agents, greater peak-to-peak voltage and area under the curve in the subcortex. The data indicate that the electrophysiologic characteristics of burst-suppression vary among the four agents, with the possible exception of etomidate and propofol. The data suggest that the neurophysiologic states associated with burst-suppression produced by various anesthetics should not be assumed to be uniform.
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J Neurosurg Anesthesiol · Jan 1996
Comparative Study Clinical Trial Controlled Clinical TrialThe bispectral index during induction of anesthesia with midazolam and propofol.
This study evaluated the bispectral index as an indicator of anesthetic depth in relation to the cardiovascular response to intubation. Two treatments were compared: group 1 (n = 8) received propofol for induction of anesthesia (2 mg/kg bolus followed by an infusion of 0.20 mg/kg-1/min-1, group 2 (n = 8) was given 90 micrograms/kg midazolam 2 min before, followed by anesthesia with half-strength propofol (1 mg/kg bolus with infusion of 0.10 mg/kg-1/min-1). The bispectral index of the electroencephalogram, blood pressure, and heart rate were measured under unanesthetized conditions, during anesthetic induction, intubation, and a 15-min period after intubation. ⋯ Throughout the rest of the surgery, more propofol was used in group 1 (77 +/- 14 micrograms/kg-1/min-1) than in group 2 (42 +/- 14 micrograms/kg-1/min-1). These results show that the decrease in bispectral index provides an indication of the blood pressure increase to intubation during propofol anesthesia. Midazolam pretreatment did not attenuate the cardiovascular response to intubation but did decrease propofol use during surgery.
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J Neurosurg Anesthesiol · Jan 1996
Case ReportsLimitations of jugular bulb oxyhemoglobin saturation without intracranial pressure monitoring in subarachnoid hemorrhage.
We report a case of subarachnoid hemorrhage in which, even after having obtained a normal jugular bulb oxyhemoglobin saturation, cerebrovenous desaturation developed, and brain death occurred. The limitations of jugular bulb oxyhemoglobin saturation without intracranial pressure monitoring are discussed. We conclude that if increased intracranial pressure is suspected, use of jugular bulb oxyhemoglobin saturation monitoring alone would appear to be substantially limited.
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J Neurosurg Anesthesiol · Jan 1996
Comparative Study Clinical TrialRecovery from mivacurium-induced neuromuscular blockade is not affected by anticonvulsant therapy.
Long-term chronic anticonvulsant therapy produces a resistance to the effects of all nondepolarizing neuromuscular blocking agents studied to date. Since the metabolism of mivacurium is unique among the nondepolarizing neuromuscular blocking agents, the effect of anticonvulsants on its recovery parameters was examined. Forty-five patients were separated into three groups based on the number of chronic anticonvulsant medications the subjects were taking: subjects in group 1, the control group, took no anticonvulsant medication; group 2 subjects took one medication; and group 3 subjects took two medications. ⋯ T-1 at 25% was 18.2 +/- 1.8, 20.7 +/- 1.9, and 21.5 +/- 1.4 min for groups 1, 2, and 3, respectively, with TR at 25% being 23.7 +/- 2.3, 26.9 +/- 2.4, and 27.3 +/- 2.3 min. No significant differences were noted in neuromuscular recovery between groups at any time point. These results fail to demonstrate the resistance to the nondepolarizing neuromuscular blockade of mivacurium that has been observed with other nondepolarizing agents.
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J Neurosurg Anesthesiol · Jan 1996
Effect of desflurane anesthesia on transcortical motor evoked potentials.
The effect of the volatile anesthetic desflurane on motor evoked potentials was examined in male rats. Animals underwent cortical stimulation using small platinum ball stimulating electrodes secured on the motor cortex. To record evoked compound muscle action potentials (CMAPs), single-shock electrical stimulation was delivered to the forelimb representation of the motor cortex. ⋯ Although there was a decrease in heart rate, the results were not statistically significant (p = 0.03). No significant difference in the onset latency or the duration of the CMAP was noted at different concentrations of the anesthetic. We conclude that desflurane anesthesia significantly alters the amplitude of the muscle response evoked by motor cortex stimulation in experimental animals.