Correlation of the bispectral index monitor with the COMFORT scale in the pediatric intensive care unit

Objective: The COMFORT scale is a commonly used observational scoring system to assess the level of sedation in ventilated children in pediatric intensive care units (PICUs). The bispectral index (BIS) monitor is a processed electroencephalographic parameter that noninvasively measures the hypnotic effect of anesthetic and sedative drugs on the brain. The objective of this study was to assess the degree of correlation between the COMFORT scale and the BIS monitor. Design: A prospective study in a tertiary level PICU. Results: A total of 75 children were enrolled in the study, resulting in 869 valid paired observations of BIS values and COMFORT scores. The median age was 10 months, with a range of 1 month to 12 yrs. The median COMFORT score was 11 (range, 8-40). The median BIS value was 52 (range, 0-98). In a repeated-measures analysis, the correlation coefficient between COMFORT scores and BIS values averaged over time was 0.61 (p < .0001). Conclusions: The BIS monitor may be a valid and useful monitor of the level of sedation of children in the PICU. We cannot expect perfect correlation between BIS values and observational scales because they measure different variables. The BIS monitor may be the best objective monitor currently available for children receiving neuromuscular blockade because it does not rely on subjective measures such as those used in the COMFORT scale. The ability of the BIS monitor to distinguish between very deep levels of sedation may be useful to prevent oversedation of children in PICUs and to help clarify the appropriate target level of sedation for each child.