The Utility of Bispectral Index Scores for Sedative Intoxication in the Emergency Department

Sung, Hyen Kyeng; Hong, Sung Youp; Lee, Jang Young; Yang, Young Mo; Park, Gyeong Nam; Yang, Hee Bum; Park, Jung Kyu; Yi, Hwa Yeon

Abstract

PURPOSE
This study was designed to determine the utility of bispectral index scores (BIS) compared to Glasgow coma scale (GCS) or Observer's Assessment of Alertness/Sedation Scale (OAA/S), in measuring changes in consciousness, prognosis and management of sedative-intoxication patients.
METHODS
Sedative intoxication patients, who came to the emergency department with a severe deficit in consciousness, or a GCS less than 12, were analyzed. Patients' consciousness states were evaluated using OAA/S and GCS and compared with BIS scores. Patients' consciousness recovery time and hospitalization were recorded to see if these could be predicted by BIS using regression analysis. BIS, OAS/S and GCS were compared with regard to intubation, admission and ICU admission. Furthermore, usefulness and cut-off values of BIS were evaluated for those intubated.
RESULTS
Of 128 sedative intoxication patients, 32 were enrolled for this study. Mean age was 50.94+/-18.01. They took 20.76+/-16.95 times over the average recommended dose. OAA/S and GCS ranged between 1~4 and 4~12, respectively; BIS was 39~88. The Spearman bivariate correlation coefficient was 0.619 between OAA/S and BIS and 0.651 between GCS and BIS, both showing a positive correlation (p<0.001). The coefficient of determination between BIS and recovery time was 0.182 and was statistically significant (Recovery time = -0.321xBIS+34.806) (p=0.015). However, admission, ICU admission and hospitalization were not significant (p>0.05). BIS was an effective index for intubation (p=0.012) showing a sensitivity of 91% and a specificity of 50% when the boundary value was set to 65.5. When set to 77.5, sensitivity and specificity were 59%, 100%, respectively.
CONCLUSION
In sedative intoxication patients, BIS is useful in determining the degree of sedation, predicting time to recovery of consciousness and as an objective index of intubation.