Clinically relevant asymmetry of bispectral index during recovery from anaesthesia for ear-nose-throat surgery in adults and children.

Abstract

This study investigates the incidence of clinically relevant asymmetry in bispectral index readings from different sides of the skull (using two monitors) during ear-nose-throat surgery in 42 adults and 46 children. A unilateral increase or decrease > 10% from baseline was defined as an 'asymmetry'. Asymmetry followed by movement after stimulation was defined as a 'clinically relevant asymmetry'. Asymmetry occurred in 39 out of 42 adults (93%) and in 20 out of 46 children (44%) during surgery and in 24 out of 42 adults (57%) and in 17 out of 46 children (37%) during recovery. Clinically relevant asymmetry was observed in 5 out of 42 adults (12%) and 6 out of 46 children (13%). The incidence of asymmetry was higher in adults during surgery (p = 0.0002). In conclusion, clinically relevant bispectral index asymmetry has been observed in > 10% of paediatric and adult anaesthesia and may have clinical implications. You can respond to this article at http://www.anaesthesiacorrespondence.com.