Performance of BIS in children using the paediatric BIS Quattro sensor

The Bispectral Index (BIS) is one of the most frequently used electroencephalogram-derived depth of anaesthesia monitors. Previous studies in children have suggested BIS performs well in older children, however these studies have used earlier versions of the BIS device. The aim of this study was to compare the performance of BIS over different age groups using the BIS paediatric Quattro sensor (Aspect Medical Systems, Norwood, MA, U.S.A.). One hundred and eighty children between one and 13 years were enrolled. At a predetermined time during emergence from anaesthesia, wakefulness was assessed and BIS recorded. For analysis, children were divided into four groups (one to three, three to six, six to nine and nine to 13 years) and for each age group a receiver operating characteristic curve was generated. Areas under the curve were compared across age groups. Good quality BIS data was available in 161 children. The areas under the curves for each age group were: one to three years 0.80, three to six years 0.88, six to nine years 0.85 and nine to 13 years 0.95. Although the area was least in the youngest age group and greatest in the oldest age group, there was no evidence for a difference when tested with ANOVA (P=0.26). When combining all age groups taking a BIS value of 50 or greater provided 100% sensitivity to detect wakefulness. This study found no evidence for any substantial difference in performance between ages one and 13 years. If BIS is used in children to detect wakefulness occurring with lightening of anaesthesia, then this study suggests that if the BIS is maintained below 50 then wakefulness is unlikely to have occurred.