Bispectral index value correlates with Glasgow Coma Scale in traumatic brain injury patients

Tjokorda Gde Agung Senapathi, Made Wiryana, I Gusti Ngurah Mahaalit Aribawa, Christopher Ryalino Department of Anesthesiology and Intensive Care, Udayana University, Sanglah General Hospital, Denpasar, Bali, Indonesia Background: Accuracy of consciousness level assessment is very important. It may determine and influence further clinical decisions, thus influences patients’ outcomes. The widest method in determining the level of awareness is the Glasgow Coma Scale (GCS). Despite its common use, GCS scores obtained by one clinician may differ from others depending on their interpretations and past experience. One of the tools used to assess the level of consciousness objectively is bispectral index (BIS). The aim of this study was to identify the correlation between BIS and GCS score in patients with traumatic brain injury. Patients and Methods: A total of 78 patients who were admitted to emergency room for traumatic brain injury were included in this study. One observer evaluated the GCS of all patients to minimize subjectivity. Another investigator then obtained the BIS values for each patient. Spearman’s rank correlation coefficient was used to determine whether GCS correlated with BIS value. Results: In 78 patients, the BIS was found to be significantly correlated with GCS (r=0.744, p<0.01). The BIS values increased with an increasing GCS. Mean BIS values of mild, moderate, and severe head injury were 88.1±5.6, 72.1±11.1, and 60.4±11.7, respectively. Conclusion: In this study, a significant correlation existed between GCS and BIS. This finding suggests that BIS may be used for assessing GCS in patients with traumatic brain injury. However, the scatters of BIS values for any GCS level may limit the BIS in predicting GCS accurately. Keywords: decreased consciousness, head injury, BIS monitor, consciousness level, anesthesia depth, prediction, associatio