The bispectral index, a useful adjunct for the timely diagnosis of brain death in the comatose trauma patient.
BACKGROUND
The bispectral index (BIS) is a processed electroencephalographic value (awake = 100, isoelectric = 0). The relationship of BIS and brain death (BD) is assessed.


METHODS
BIS was evaluated in GCS 3 head-injured patients with BD (no brain function including apnea) or near BD (no apnea or negative ancillary test [cerebral perfusion and electroencephalogram]).


RESULTS
In 27 patients, there were 37 BD evaluations (apnea assessment or ancillary test). BD was confirmed in 62% (n = 23). However, 38% (n = 14) showed near BD. BD BIS is 3 + or - 5 and near BD BIS is 36 + or - 31 (P = .002). In the 23 BD patients, BIS was <20 for 7 hours + or - 6 hours before a BD evaluation was performed. Of 14 near BD evaluations, 9 (64%) had BIS > or = 20. BIS <20 for predicting BD had a sensitivity of 100% (23/23), a positive predictive value of 84% (23/28), and a negative predictive value of 100% (9/9).


CONCLUSIONS
Distinguishing brain death and near brain death in severely comatose trauma patients is complex. By indicating the likelihood of brain death, BIS is an adjunct for efficient evaluation.
Dunham
C Michael
CM
Trauma/Critical Care Services, St. Elizabeth Health Center, 1044 Belmont Avenue, Youngstown, OH 44501, USA.
Katradis
D Alisa
DA
Williams
Mark D
MD
D001926:Brain Death / Q000175:diagnosis*; D001930:Brain Injuries / Q000150:complications; D003128:Coma / Q000150:complications; D004569:Electroencephalography; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D012720:Severity of Illness Index