Cerebral State Index during Propofol Anesthesia

Abstract

Background The objective of this study was to prospectively test the Cerebral State Index designed for measuring the depth of anesthesia. The Cerebral State Index is calculated using a fuzzy logic combination of four subparameters of the electroencephalographic signal. The performance of the Cerebral State Index was compared with that of the Bispectral Index and the A-Line ARX Index. Methods This study applied raw data from two previously published clinical protocols. The patients in protocol 1 were given a continuous propofol infusion, 300 ml/h, until 80% of burst suppression occurred. In protocol 2, a stepwise increased target-controlled infusion of propofol was administered to patients until loss of response to noxious stimuli while the Observer's Assessment of Alertness and Sedation was registered every 4 min. The Cerebral State Index was calculated off-line from the recorded electroencephalographic data. The Spearman rank correlation coefficient between electronic indices and the effect site concentration of propofol was calculated along with the prediction probability of each index to predict the Observer's Assessment of Alertness and Sedation level. Results The Spearman rank correlation coefficients between the Cerebral State Index, Bispectral Index, and A-Line ARX Index and the propofol effect site concentration were -0.94, -0.89, and -0.82, respectively, in protocol 1, whereas the prediction probability values between the Cerebral State Index, Bispectral Index, and A-Line ARX Index and the Observer's Assessment of Alertness and Sedation score in protocol 2 were 0.92, 0.93, and 0.91, respectively. Conclusion The Cerebral State Index detects well the graduated levels of propofol anesthesia when compared with the propofol effect site concentration and the Observer's Assessment of Alertness and Sedation score.

The effect of intrathecal fentanyl on Cerebral State Index‐guided sedation during spinal anaesthesia*

“…The level of sedation can be monitored using the Observer's Assessment of Alertness ⁄ Sedation scale (OAA ⁄ S) and other commercially available monitors such as BIS, entropy and the Cerebral State Index (CSI), which uses the spontaneous EEG to calculate a numerical index between 100 and 0. The CSI has been reported to distinguish between graduated levels of propofol anaesthesia [1,10].…”

“…The CSI resembles the BIS index, which displays a numerical value from 0 to 100 using the spontaneous EEG signal. However, the CSI uses four parameters from the EEG combined into a fuzzy logic classifier, while the BIS basically applies a double spectral analysis (hence the word bispectral) of the EEG activity [10]. By applying a fuzzy logic-based system, the CSI achieves a faster response; hence the value displayed on the screen is closer to the real time value.…”

“…In addition, CSI monitoring uses a handheld monitor with electrodes that do not take much space in the front of the patient. Although CSI was reported to produce a highly significant correlation with the propofol effect-site concentration [10], anaesthetic depth was also evaluated with a clinical observation scale (OAA ⁄ S) to ensure adequate sedation in this study. The OAA ⁄ S scores were in accordance with the graded CSI value.…”

“…The level of sedation can be monitored using the Observer's Assessment of Alertness ⁄ Sedation scale (OAA ⁄ S) and other commercially available monitors such as BIS, entropy and the Cerebral State Index (CSI), which uses the spontaneous EEG to calculate a numerical index between 100 and 0. The CSI has been reported to distinguish between graduated levels of propofol anaesthesia [1,10].The purpose of this study was to investigate the effect of intrathecal fentanyl on the dose of propofol required for sedation guided by CSI monitoring and the OAA ⁄ S scale in patients undergoing lower extremity surgery. We hypothesised that the addition of intrathecal fentanyl would decrease the propofol dose for an adequate level of sedation during spinal anaesthesia.…”

Comparison between clinical tests and the Cerebral State Index or brain death determination

“…Confirmatory tests have been used to corroborate brain death, but they are expensive, nonattainable in all ICUs and in some instances have no correlation with clinical tests [1]. The Cerebral State Index (CSI) (Danmeter, Odense, Denmark) is a portable apparatus that has been made for determination of the depth of anesthesia based on brain waves determination and analysis [2]. …”