Background: The influence of sensor dislocation on bispectral index (BIS) values is not clear. We compared the BIS values obtained from dislocated sensors with those from the commercially recommended positions.
Methods: We used two BIS sensors for each patient receiving propofol-based anesthesia; one in the recommended position and one positioned around the lateral corner of the right eye.
Results: Bland and Altman analysis revealed better agreement of two BIS values when the values during induction of and emergence from anesthesia were excluded.
Conclusions: The results indicate that during induction of and emergence from general anesthesia, a dislocated BIS sensor may produce questionable BIS values.