Bispectral electroencephalographic analysis of head-injured patients in the emergency department.

OBJECTIVES

Bispectral analysis of single-lead electroencephalographs (BIS) has proven valuable in assessing the level of awareness in sedated patients. In this study, the authors sought to determine if BIS values had a predictive value in patients with traumatic brain injuries (TBIs). Therefore, the objective was to determine in emergency department (ED) patients presenting with head trauma whether BIS and Glasgow Coma Scale score (GCS) prior to sedation would be sensitive and specific in predicting TBI.

METHODS

A convenience sample of patients with known or suspected head trauma presenting between June and August of both 2001 and 2002 were entered into the study by having a BIS monitor placed immediately on presentation to the ED. BIS and GCS scores were collected every 2 minutes. Head computed tomography (CT) results and discharge dictations were then evaluated to determine the presence of TBI.

RESULTS

Fifty-two patients were entered into the study; 13 were excluded due to receiving sedatives prior to enrollment. Of the remaining 39 patients, 14 had intracranial hemorrhage on initial head CT. Of these 14, two had BIS scores over 95. Both of these were neurologically intact at discharge. Eleven of the 12 remaining patients died or left the hospital neurologically impaired. Of the patients with no abnormalities on initial head CT, 19 of 25 had initial BIS scores >95 and all left the hospital neurologically intact. Of the patients with normal initial head CT and initial BIS scores < 95, four of six died or were neurologically impaired at discharge. Twenty of 39 patients presented with an initial GCS of 15; four of 20 had an initial BIS score < 95, three of whom were neurologically impaired at discharge. The 16 of 20 with BIS >95 left the hospital neurologically intact. All patients with a GCS of 14 had BIS scores >95 and left the hospital neurologically intact. All patients with a GCS of 13 had initial BIS scores < 95 and were neurologically impaired at discharge. One patient with a GCS of 11 and a BIS score of 67 left the hospital neurologically intact; all other patients with a GCS < 12 had a BIS < 95 and left the hospital with a neurologic deficit.

CONCLUSIONS

BIS scores obtained prior to sedative medicines in the face of trauma are predictive of TBI and neurologic outcome at discharge.