Cerebral State Index And Bispectral Index For Monitoring The Depth Of Propofol Sedation In ICU Patients

Objective:To investigate the effectiveness of cerebral state index (CSI)and bispectral index(BIS)in measuring the level of sedation during the target controlled infusion(TCI)of propofol in the elderly in the intensive care unit(ICU).Methods:31 ICU patients whose Ramsay score was 1 were divided into two groups:Group A(20～64 years old,n=16)and Group B(＞64 years old,n=15).The electrodes of BIS and CSI were placed according to the instruction manual s before the target controlled infusion of propofol. The level of sedation was assessed using Ramsay score.The target effect-site concentration was set initially at 0.3ug/ml increasing gradually (seeing the text)until the time when the patients lost consciousness and did not respond to pain stimulation(Ramsay score =6).CSI and BIS were monitored and recorded.Ramsay score and each effect-site concentration (Ce)were recorded at every time point during the experiment.The mean artery pressure and heart rate were monitored and recorded too.Spearman correlation coefficient was calculated for each sedation level with CSI and BIS.The differences of BIS and CSI between the two groups were calculated. Result:The BIS and CSI values decreased as Ce increased.CSI and BIS correlates well with Ramsay score.Ramsay score correlates well with Ce.There were significant differences between groups of CSI,but no significant differences between groups of BIS.The mean artery pressure and heart rate decreased significantly as the infusion time of propofol increased.Conclusion:BIS and CSI highly correlates with the effect-site concentration.BIS and CSI can distinguish the level of sedation effectively and promptly.But the CSI of the elderly appeared to be lower than the youth at the same Ramsay score.