Agreement of Cerebral State Index and Glasgow Coma Scale in Brain-Injured Patients

Background: Variables derived from electroencephalogram like cerebral state index (CSI) have been used to monitor the anesthesia depth during general anesthesia. Observed evidences show such variables have also been used as a detector of brain death or outcome predictor in traumatic brain-injured (TBI) patients. Objectives: The current study was designed to determine the correlation between Glasgow coma score (GCS) and CSI among TBI patients. Patients and Methods: In 60 brain-injured patients who did not need and receive sedatives, GCS and CSI were daily measured during the first ten days of their hospital stay. Correlation between GCS and CSI was studied using the Pearson's correlation test. The Gamma agreement coefficient was also calculated between the two variables for the first day of hospitalization. Results: A significant correlation coefficient of 0.611-0.796 was observed between CSI and GCS in a ten-day period of the study (P < 0.001). Gamma agreement coefficient was 0.79 (P < 0.001) for CSI and GCS for the first day of hospitalization. An increased daily correlation was observed in both CSI and GCS values. However, this increase was less significant in CSI compared with the GCS. Conclusions: A statistically significant correlation and agreement was found between GCS and CSI in the brain-injured patients and GCS was also found to be more consistent and reliable compared with CSI.