Correlation between BIS and GCS in patients suffering from head injury

Abstract

Glasgow coma scale (GCS) is considered an important parameter to predict the clinical outcome in head injury; however, in some cases such as the use of sedative drugs the estimate of GCS would not be precise. Bispectral index (BIS) is an electrophysiological parameter to determine the clinical state of anesthesia. The aim of the present study is to evaluate correlation between GCS and BIS in patients suffering from head injury and to see if we can use BIS values as a prognostic factor in head trauma. In this analytic study 61 consecutive patients with traumatic head injury admitted to the intensive care unit from January till June 2010 were examined. In each case the GCS and BIS values were measured and compared regarding different degrees of head injuries. Mean BIS in mild injury group was 96.20 ± 3.27 and in moderate injury group was 45.57 ± 1.28 and in severe injury group was 31.37 ± 2.08. There was a significant correlation between GCS and mean BIS (r = 0.88; P < 0.05). Mean BIS values were significantly different between mild, moderate and severe head injuries (96.2 ± 3.2, 45.5 ± 1.2, and 31.3 ± 2.08, respectively; P < 0.05). We found significant correlation between GCS and BIS in patients with traumatic head injury, so BIS can be used in addition to GCS for prediction of outcome in these patients specially in patients who are sedated or are intubated or in other case in whom GCS values cannot be determined accurately.