Objective: Bispectral analysis (BIS) is a technology using EEG information from a forehead electrode to calculate an index (0-100; 0 = coma, 90-100 = awake). Our objective was to determine the degree of agreement between sedation scales and BIS values in pediatric patients undergoing sedation.
Methods: Patients ages 2 to 17 years, undergoing procedural sedation, were enrolled. Sedation was performed in the customary manner with the addition of BIS monitoring and assessment of a clinical sedation scale: the Observer's Assessment of Alertness/Sedation (OAA/S), every 5 minutes during the sedation procedure. Clinical scales were performed by an investigator blinded to the BIS index. The association between a clinical scale and BIS scores was analyzed using longitudinal regression analysis.
Results: We enrolled 47 subjects; 55% were sedated with ketamine and midazolam and the remaining 45% received methohexital, propofol or midazolam and a narcotic. The results of the regression analysis demonstrated a highly significant association between the OAA/S score and BIS value (β = 5.0, 95% CI 4.3 to 5.7, P < 0.0001). Patients were divided into 2 groups, those sedated with ketamine and those sedated with nonketamine medications. The association between OAA/S score and BIS value was not statistically significant for the ketamine population (β = 0.809, 95% CI -0.1 to 1.7, P = 0.09), but remained significant for the nonketamine subjects (β = 8.6, 95% CI 7.7 to 9.4, P < 0.0001).
Conclusions: The OAA/S sedation scale predicts the BIS value for pediatric patients undergoing procedural sedation when sedated with certain medications, excluding ketamine.