Journal of clinical monitoring and computing
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J Clin Monit Comput · Aug 2002
Randomized Controlled Trial Clinical TrialBiasing effect of the electromyogram on BIS: a controlled study during high-dose fentanyl induction.
A biasing effect of the electromyogram (EMG) on the Bispectral Index (BIS) may explain discrepancies in previous studies assessing BIS in the presence of neuromuscular activity. Our aims were: to evaluate variations of BIS in the presence of high EMG activity associated with muscular rigidity after administration of high-dose fentanyl; to compare muscular rigidity, as measured by the EMG variable of the BIS monitor, in patients who were administered two different dosages of fentanyl at induction of cardiac anaesthesia. ⋯ During fentanyl-induced muscular rigidity BIS recordings reflect EMG variations. When assessing BIS in the absence of neuromuscular blockade, it is necessary to evaluate the effect of EMG on BIS before making conclusions about depth of sedation. Fentanyl-induced rigidity appears to be a dose-related phenomenon which the EMG variable of BIS 3.4 is able to quantify.
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J Clin Monit Comput · Aug 2002
Clinical TrialCorrelation beween AAI-index and the BIS-index during propofol hypnosis: a clinical study.
To determine the degree of linearity and correlation between the anaesthetic depth indices BIS and AAI over a wide range of hypnotic depth using propofol. ⋯ The AAI-index correlates with the BIS-index during propofol hypnosis in the absence of surgical stimulation. Neither the BIS-index, heart rate, nor systemic blood pressure were influenced by the acoustical stimulation from the A-line monitor. Both indices decreased in relation to increasing doses of propofol, but the AAI-index was lower both before becoming unconscious, during transition to unconsciousness, and during the deeper levels of sedation. The AAI-index lacks linearity at both very low and higher levels of propofol sedation with a nearly on-off behaviour for wakefulness vs hypnosis.
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J Clin Monit Comput · Aug 2002
Clinical TrialA preliminary evaluation of a new derived EEG index monitor in anesthetized patients.
An electroencephalogram (EEG) monitoring device, recently developed by Nicolet Biomedical, analyzes both high and low EEG frequencies. A processed derivative is obtained and displayed graphically and numerically on a monitor and may be used during anesthesia to indicate anesthetic "depth." However, radio-frequency interference from electrical equipment typically used in the operating room has the potential to interfere with the analysis of the high frequency components of the EEG. ⋯ The derived EEG Index monitoring system evaluated in this study functioned satisfactorily in the operating room setting in patients undergoing general anesthesia. Interference from ESU, facial nerve stimulation, and movement of the electrode wires caused brief interruptions of the derived EEG Index display and did not affect its utility in monitoring brain activity during anesthesia.