We evaluated the minimum alveolar concentration of sevoflurane required to maintain the bispectral index below 50 in children. We studied 55 children, divided into 1-year-old, 2- to 4-year-old and 5- to 9-year-old groups and used Dixon's up-and-down method and probit analysis. In the 1-year-old group, the bispectral index values remained above 50, with the end-tidal sevoflurane concentration reaching 4.0% or higher. The minimum alveolar concentration of sevoflurane for maintaining the bispectral index below 50 was significantly higher in the 2- to 4-year-old group (2.33%, 95% CI 2.25-2.57) than in the 5- to 9-year-old group (2.10%, 95% CI 1.94-2.25; p = 0.005). We conclude that assessing the depth of anaesthesia using bispectral index is unreliable in children aged < 2 years anaesthetised with sevoflurane.
© 2014 The Association of Anaesthetists of Great Britain and Ireland.