Bispectral index monitoring quantifies depth of sedation during emergency department procedural sedation and analgesia in children

Abstract

Study objective The bispectral index monitor uses processed electroencephalogram signals to measure sedation depth on a unitless scale from 0 to 100 (0, coma; 40 to 60, general anesthesia; 60 to 90, sedated; 100, awake). It has been validated in the operating room as an objective measure of sedation depth with nondissociative general anesthesia; however, its usefulness in the pediatric emergency department (ED) for procedural sedation and analgesia has not been established. We determine the ability of the bispectral index to monitor depth of nondissociative procedural sedation and analgesia in children. Methods This was an observational study conducted in a children's hospital ED. Procedural sedation and analgesia was performed in the standard manner, with the addition of bispectral index monitoring and simultaneous clinical sedation scoring (modified Ramsay Sedation Scale [range 1 to 8; 1=alert, 8=unresponsive]). Paired bispectral index and Ramsay Sedation Scale scores were assigned every 5 minutes during the sedation. Ramsay Sedation Scale scores were assigned by a single study investigator blinded to the bispectral index score. An emergency physician independently administered all medications for procedural sedation and analgesia. The correlation between the paired bispectral index/Ramsay Sedation Scale scores was determined by using a repeated-measures regression analysis. Receiver operator characteristic (ROC) curves were constructed to determine the ability of the bispectral index to discriminate various thresholds of sedation depth. Results A convenience sample of 20 patients was enrolled, providing 217 paired bispectral index/Ramsay Sedation Scale measurements. Median age was 4.6 years (range 0.4 to 16.7 years). Fourteen patients received midazolam with fentanyl; the remainder received pentobarbital. Bispectral index scores ranged from 40 to 98 (mean 81.6±16.1). Ramsay Sedation Scale scores ranged from 1 to 8 (median 3; interquartile range 2 to 4). The simple Pearson correlation between paired bispectral index and Ramsay Sedation Scale scores was −0.78 (95% confidence interval [CI] −0.83 to −0.72; P<.001). After adjustment for the nonindependence of intrapatient data with bivariate repeated-measures analysis, the correlation was −0.67 (95% CI −0.90 to −0.43; P<.001). The linear regression coefficient between bispectral index and Ramsay Sedation Scale scores was estimated to be between −5.7 and −12.7. ROC curve analysis demonstrated moderate to high discriminatory power of bispectral index scores in predicting level of sedation throughout the sedation continuum, with areas under the curve at least 0.87 for all Ramsay Sedation Scale score thresholds. Bispectral index scores between 60 and 90 predicted with moderate accuracy traditional clinical levels of sedation typically encountered during procedural sedation and analgesia in the pediatric ED. Conclusion Bispectral index monitoring correlated with clinical sedation scores and may serve as a useful, objective adjunct in quantifying depth of nondissociative procedural sedation and analgesia in children.