Application Of Cerebral State Index For Assessment Of Anesthetic Depth

Partâ… :Comparison of accuracy of cerebral state index and bispectral index for assessment of sedation depth during TCI of propofol and remifentanil.Objective To compare the accuracy of cerebral state index(CSI) and bispectral index(BIS) used to measure depth of sedation during target-controlled infusion(TCI) of propofol and remifentanil.Methods Forty-four consenting ASAâ… orâ…¡patients aged 18-60 years undergoing elective surgery under general anesthesia were randomly divided into 4 groups(n=11 each) according to the target effect-site concentration of remifentanil administered by TCI during induction of anesthesia.0,2,4,6 ng.ml^-1.Anesthesia was induced with TCI of remifentanil and propofol.10 minutes after TCI of remifentanil,all patients received graded site concentration of propofol.The initial site concentration of propofol was 1.5μg.ml^-1 and was increased by 0.5μg.ml^-1 every 4 minutes.OAA/S score(5=alert,1=does not respond to prodding) was recorded every 20 seconds.Electric tetanic stimulation was given when OAA/S score was 1.All patients had spontaneous respiration with occasional assistance given when necessary.Standard monitoring(heart rate,noninvasive arterial blood pressure and oxygen saturation) was initiated and a peripheralâ…£line was installed.At this time,the sensors of Datex Ohmeda S/5^TM BIS monitor and the CSM were attached according to the manufacturer's recommendations.The smoothing time period of the BIS monitor was set at 15 s.The data of the CSM and BIS were automatically recorded in intervals of 1s, respectively.BIS values were recorded using Datex-Ohmeda S/5 Collect and transferred to a computer hard disk for off-line analysis.The values of CSI were recorded using the Danmeter A/S CSM capture V2.02 into the computer hard disk.The predicted effect-site concentration of propofol(Ce) in TCI system were recorded when they increased by more than 0.1μg/ml.Values of BIS,CSI and Ce were recorded at loss of eyelash response(LOR eyelash) and loss of response to electric tetanic stimulation(LOR titanic).Spearman correlation coefficient between OAA/S score and BIS and CSI,and their prediction probabilities(Pk) were calculated.CSI₅₀,BIS₅₀,Ce₅₀ at loss of eyelash reflex(LOR eyelash) and at loss of response to electric tetanic stimulation(LOR tetanic) were also calculated by a quantal response model(Probit analysis).Statistical analyses were performed with SPSS 12.0.A P value less than 0.05 was considered statistically significant.Results No significant demographic differences were found between groups.The baseline(awake) values of CSI and BIS were 91.64±4.20 and 95.72±2.30,respectively. Compared with BIS(0.024),CSI(0.046) had larger baseline variability as defined by the coefficient of variation.CSI and BIS correlated well with sedation depth.CSI and BIS decreased after induction of anesthesia.The increase in sedation(OAA/S decreasing from 5 to 0) was associated with decreases in the median values of CSI as well as BIS.CSI and BIS were correlated well with OAA/S in all four groups,but the difference between BIS and CSI was not statistically significant.The coefficients of correlation between OAA/S, and CSI and BIS,were higher than those between OAA/S,and MAP and HR.CSI and BIS showed a high prediction probability(Pk＞0.85) in different OAA/S.Pk was higher for CSI and BIS than for MAP and HR,and there were no significant differences in Pk values between CSI and BIS.Good correlations between BIS and the predicted effect-site concentration of propofol and between CSI and the predicted effect-site concentration of propofol were noted in all four groups.CSI well correlated positively with OAA/S and BIS, but negatively with Ce.CSI and BIS values were higher but Ce value were lower at LOR eyelash and LOR tetanic in patients receiving TCI remifentanil as compared with R₀ group. CSI₅₀,BIS₅₀ value at LOR eyelash and LOR titanic were increased followed the increased target effect-site concentration of remifentanil,Ce₅₀ value were decreased followed the increased target effect-site concentration of remifentanil,BIS₅₀ value were higher than CSI₅₀ value respectively in all four groups.Conclusion CSI can be used to measure sedation depth fairly accurately during TCI of propofol and remifentanil.Partâ…¡:The predictive effect of cerebral state index on consciousness recovery during the emergence of general anesthesia after TCI of propofol and remifentanilObjective To evaluate the predictive effect of cerebral state index(CSI) on consciousness recovery during the emergence of general anesthesia after TCI of propofol and remifentanil.Methods Twenty consenting ASAâ… orâ…¡patients aged 18-60 years undergoing elective abdominal surgery were anesthetized with target controlled infusion of propofol and remifentanil.Standard monitoring(heart rate,noninvasive arterial blood pressure and oxygen saturation) was initiated and a peripheralâ…£line was installed.The target efect-site propofol and remifentanil concentration were 2.5μg/ml(Marsh-model) and 4ng/ml (Minto-model),respectively.During surgery,the target efect-site propofol and remifentanil concentration were 2-4μg/ml and 2-8ng/ml respectively to ensure stable hemodynamic prarmeters.After surgery,the sensors of Datex Ohmeda S/5^TM BIS monitor and the CSM were attached according to the manufacturer's recommendations.The smoothing time period of the BIS monitor was set at 15s.The data of the CSM and BIS were automatically recorded in intervals of 1s,respectively.BIS values were recorded using Datex-Ohmeda S/5 Collect and transferred to a computer hard disk for off-line analysis.The values of CSI were recorded using the Danmeter A/S CSM capture V2.02 into the computer hard disk.CSI, BIS,effect-site propofol concentration(Ce),and hemodynamic parameters(MAP and HR) were recorded during the period of non-reaction to the stimulation,at the time of eyes opening and orientation recovery.The prediction probability(Pk) of each parameters was calculated and compared.Spearman correlation coefficient between OAA/S score and BIS,CSI,Ce,MAP,HR were calculated and compared,and A line regression were analysized between CSI and BIS,Ce.The prediction probabilities(Pk) of BIS,CSI,Ce,MAP,HR were calculated and compared.Statistical analyses were performed with SPSS 12.0.A P value less than 0.05 was considered statistically significant.Results There were significant diffirences for CSI,BIS and Ce at diffirent state of consciousness during anesthesia emergence.CSI well correlated positively with BIS,but negatively with Ce,respectively.Regression equation between CSI and BIS was CSI=0.97BIS+5.6,and regression equation between CSI and Ce was CSI=94-15Ce.Pk value of CSI and BIS in predicting eyes opening and orientation recovery were 0.83±0.09, 0.85±0.04 and 0.91±0.02,0.93±0.06,respectively,and were obviously higher than 0.5 and Pk values of MAP and HR.Conclusion Cerebral state index could be used for predicting patients consciousness recovery effectively during the emergence of general anesthesia after TCI of propofol and remifentanil.