Accuracy of bispectral index in predicting outcomes in patients with acute cerebral hemorrhage

Objective To evaluate the accuracy of bispectral index (BIS) in predicting outcomes in patients with cerebral hemorrhage. Methods A total of 103 patients of either sex with acute cerebral hemorrhage, aged 18-77 yr, with body mass index of 17-29 kg/m2, of American Society of Anesthesiologists physical status Ⅱ-Ⅳ, undergoing craniotomy for evacuation of hematoma, were enrolled in this prospective study.BIS electrodes were adhered to the forehead of patients, and the BIS value was continuously recorded for 20 min.The maximum BIS value (BISmax) and minimum BIS value (BISmin) were recorded, and the mean BIS value (BISmean) was calculated.The patients were divided into 2 groups according to Glasgow Outcome Scale (GOS) scores assessed at 6 months after surgery: good outcome group (GOS score≥3) and poor outcome group (GOS score 1 or 2). The receiver operating characteristic curve of BIS in predicting outcomes was plotted, and the area under the curve (AUC) and 95% confidential interval (CI) were calculated.The best cut point and sensitivity and specificity were calculated according to the BIS value when Youden index reached the maximal value. Results The AUC (95% CI) for BISmax in predicting outcomes was 0.903 (0.830-0.976), the best cut point 79, the sensitivity 84%, the specificity 86%, and Youden index 0.695.The AUC (95% CI) for BISmin in predicting outcomes was 0.841 (0.760-0.921), the best cut point 43, the sensitivity 86%, the specificity 71%, and Youden index 0.577.The AUC (95% CI) for BISmean in predicting outcomes was 0.883 (0.800-0.958), the best cut point 60, the sensitivity 90%, the specificity 76%, and Youden index 0.662. Conclusion BIS can accurately predict outcomes in patients with acute cerebral hemorrhage, and BISmax provides the highest accuracy. Key words: Electroencephalography; Cerebral hemorrhage; Prognosis