Bispectral index in predicting the prognosis of patients with coma in intensive care unit

Abstract

Background: The bispectral (BIS) index is a processed electroencephalogram (EEG) parameter with extensive validation and demonstrated clinical utility. The study aimed to investigate the correlation between the BIS index and the prognosis of patients with coma in the ICU.

Methods: A total of 208 patients with coma in the ICU were enrolled in this study. According to the BIS value, the patients were divided into four groups: group I, BIS value 0 to 20; group II, BIS value 21 to 40; group III, BIS value 41 to 60; and group IV, BIS value greater than 60. The difference in BIS values with the differences in prognosis of patients with coma was compared between the four groups, and the prognosis of patients with coma was stratified into consciousness, coma, vegetative state, and brain death. Subsequently, the best cut-off score of BIS values calculated for determining the correlation between BIS value and mental state was proposed.

Results: There are no significant differences in the age and APACHE II scores between the four groups (P>0.05). An inverse correlation was observed between BIS value and mental state (r= -0.749, P=0.00). According to the ROC curve, as BIS value was greater than 42.5, there were higher sensitivity and specificity in conscious-coma patients.

Conclusion: BIS value is correlated with the prognosis of patients with coma in ICU, and BIS value can be a useful marker for estimating the prognosis of comatose patients.

Keywords: Bispectral index; Coma; Prognosis.

Figure 1

ROC curve analysis of BIS values on conscious coma, vegetative state, and brain death.