Correlation between bispectral index values and the Glasgow Coma Scale in traumatic brain injury patients: a prospective observational study.

Abstract

Purpose: Traumatic brain injury (TBI) severity is typically assessed using the Glasgow Coma Scale (GCS). In contrast, the bispectral index (BIS) objectively evaluates a patient's level of consciousness in an intensive care unit. The primary objective of this study was to evaluate the correlation between GCS and BIS values in TBI patients. Secondary objectives included determining the range of BIS scores corresponding to different levels of consciousness and assessing the correlation among mild, moderate, and severe TBI.

Methods: Sixty patients participated in a prospective observational study conducted at a government tertiary care facility. After obtaining a detailed history and performing a physical examination, each patient's age, sex, intubation status, computed tomography brain findings, and vital signs were recorded. Subsequently, the patients' GCS and BIS values were measured at 0, 6, 12, 18, and 24 hours. Quantitative data are presented as mean±standard deviation, while qualitative data are illustrated using frequency and percentage tables. Spearman correlation analysis was employed to evaluate the association.

Results: Spearman correlation analysis demonstrated a strong positive relationship between BIS and GCS at 0 hours (r=0.655, P<0.05), 6 hours (r=0.647, P<0.05), 12 hours (r=0.652, P<0.05), 18 hours (r=0.659, P<0.05), and 24 hours (r=0.648, P<0.05). Moreover, the mean BIS value decreased significantly with increasing severity of head injury.

Conclusions: Similar to the GCS, the BIS correlates with head injury severity and may serve as a complementary tool for predicting outcomes in TBI patients.