Journal of neurosurgical anesthesiology
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J Neurosurg Anesthesiol · Apr 2012
The potential of quantified lower cranial nerve EMG for monitoring of anesthetic depth.
During surgery, lower cranial nerve (CN) electromyography (EMG) may show spontaneous activity without surgical correlate. These episodes have been observed in association with sudden patient movement. In the study presented, this activity was quantified and correlated to the Bispectral Index (BIS) to evaluate the potential of lower CN-EMG for monitoring the depth of anesthesia. ⋯ Spontaneous EMG of muscles targeted by lower CNs seems to correlate well with arousal reactions at the end of anesthesia. In many cases, this effect preceded BIS changes. Thus, lower CN EMG monitoring may be a valuable tool in monitoring adequate depth of anesthesia.
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J Neurosurg Anesthesiol · Apr 2012
Letter Case ReportsAwake craniotomy under xenon anesthesia: first experience.
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J Neurosurg Anesthesiol · Apr 2012
Randomized Controlled Trial Comparative StudyComparison of the effects of etomidate and propofol combined with remifentanil and guided by comparable BIS on transcranial electrical motor-evoked potentials during spinal surgery.
Transcranial electrical motor-evoked potentials (TceMEPs) can provide early warning of possible motor compromise during surgery. There are fewer reports comparing the effects of etomidate and propofol infusion on TceMEPs when used for the maintenance of anesthesia and guided by comparable values of bispectral index (BIS) during spinal surgery. ⋯ Etomidate has more favorable effects than propofol during the monitoring of TceMEPs under comparable BIS levels.
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J Neurosurg Anesthesiol · Apr 2012
High-frequency stimulation restored motor-evoked potentials to the baseline level in the upper extremities but not in the lower extremities under sevoflurane anesthesia in spine surgery.
Volatile anesthetics attenuate medium-frequency (250 to 500 Hz) pulse train transcranial electrical stimulation (TES) motor-evoked potentials (MEPs) better than propofol. High-frequency (1000 Hz) TES may restore hand MEP amplitude under volatile anesthesia, but its effect on leg MEPs critical for spine surgery monitoring is unknown. ⋯ Sevoflurane is inadvisable for MEP monitoring in the legs during spine surgery as modulation of the TES frequency did not eliminate the suppressive effect of sevoflurane on the MEPs in the legs. Clinicians should be forewarned of the greater risk of unmonitorable MEPs, especially in the legs, under sevoflurane anesthesia.