Document Type : Research Article
Background: Bispectral index is an accepted monitoring to assess the depth of anaesthesia and helps the anaesthesiologist to prevent awareness during surgical procedures under general anaesthesia. The influence of frontal brain tumours on bispectral index (BIS) measurements is unknown. The aim of our study was to determine whether BIS values recorded at loss and return of consciousness (LOC and ROC, respectively) differ between patients with unilateral frontal brain tumours and control patients.
Methods: We enrolled 30 patients with a frontal brain tumour and 30 control patients. Bilateral BIS measurements were done during induction of propofol anaesthesia, during recovery of consciousness, and during a second induction of anaesthesia. The isolated-forearm test was used to determine the moments of LOC1, ROC and LOC2.
Results: The median BIS values recorded at LOC1, ROC and LOC2 did not differ between the groups. There were no significant inter-hemispheric differences in BIS in tumour and control patients.
Conclusions: The presence of a frontal brain tumour did not affect ipsilateral BIS values and so need not influence the placement of unilateral BIS electrodes if BIS monitoring is used to titrate the dose of propofol during anaesthesia.