The Influence Of Rocuronium On Bispectral Index And Cerebral State Index Under Different Sedation Levels Of Propofol

Objective: To investigate the influence of non-depolarization muscle relaxant rocuronium on the bispectral index(BIS), cerebral state index(CSI) in patients without surgery stimulation during propofol induced different sedation levels, analyze the relationship between BIS and spectral edge frequency of 95% (SEF95%) and frontal electromyogram (fEMG), approaching for the mechanisms of the influence of non-depolarization muscle relaxants to BIS and CSI.Methods: 70 ASA physical statusⅠ～Ⅱpatients undergoing general anesthesia randomized into two groups, group 1(n=35) and group 2(n=35) with different sedation levels provided by propofol, and then into two subsets, group A(n=20) and group B(n=15) respectively, Group A for experimental group(EG) and group B for blank group(BG). All subjects received a target controlled infusion of propofol. Intubation were done at the effect concentration of 4.0ug/ml. Then the effect site of propofol concentration was set to 2.5ug/ml in group 1A and 1B, and maintained at 4.0ug/ml in group 2A and 2B. When arrived at the setting effect concentration and stabilized for 20 minnutes, the ulnar nerve was stimulated at the wrist with train-of-four provided by TOF-Watch, when T₁ was stabilized at 100% for 10 minutes, a bolus of 2ED₉₅ rocuronium (0.6mg/ml) were received in group 1A and 2A and the experiment was finished when T₁ recoveried to 10%. In group 1B and 2B, 5ml NS were received at the arrive of effect concentration, and 20 minutes later the termination were made. The following variables were recorded: bispectral index (BIS), spectral edge frequency of 95% (SEF95%), frontal electromyogram (fEMG) provided by Aspect A-2000, cerebral state index (CSI) provided by cerebral state monitor (CSM).Results: In deep sedation groups the BIS and CSI were much lower compared with the light sedation groups at loss of consciousness. The administration of non-depolarization muscle relaxant induced a obvious decrease in BIS from 62.22±7.89 to 50.85±7.24 (P＜0.001)and in CSI from 64.50±3.99 to 53.55±5.75 (P＜0.001)in group 1A, while there were not obvious difference between BIS and CSI(P=0.268＞0.05) compared with value measured at loss of consciousness in light sedation groups, nevertheless, the changes were not such significant in group 2A (P=0.92＞0.05), while the CSI were higher than BIS (P=0.001). When BIS was below 70, there was not obvious relationship between BIS and fEMG. which were detected by Aspect A-2000 BIS monitor.Conclusion:1. The administration of rocuronium decreased the value of BIS and CSI in light sedation level which were supported by propofol intravenous anesthesia with the effect concentration of 2.5ug/ml. The mechanism may result from the decrease of excitability from the muscle spindle to the reticular activation system (RAS) by the administration of non-depolarization muscle relaxant.2. During the deeper sedation level provided by propofol with the effect concentration of 4.0ug/ml, there were not such significant changes with the administration of rocuronium, the reason may be that the inhibition of propofol to the reticular activation system (RAS) was much more powerful than the stimulation from the muscle spindle to RAS.3. During intravenous sedation merely depend on propofol, when BIS were below 70, there was not obvious relationship between BIS and fEMG which were detected by Aspect-A2000 BIS monitor.