Haemodynamic and electroencephalograph responses to intubation during induction with propofol or propofol/fentanyl

Purpose: To observe the changes in EEG bispectral index (BIS), 95% spectral edge frequency (95% SEF) and median frequency (MF) with haemodynamic changes to intubation during induction with propofol or propofol and 2 mu g . kg(-1) fentanyl iv, Methods: Twenty four ASA I-II patients were randomized to receive either propofol infusion preceded by normal saline (group P: n=12) or propofol preceded by 2 mu g . kg(-1) fentanyl (group PF, n=12), Intubation was performed live minutes after maintenance of BIS within 45 +/- 5, EEG and haemodynamic variables were recorded at before induction, and before and after intubation. Results: Haemodynamic responses to intubation were greater in group P than in group PF (P < 0.05), Postintubation SBP, DBP and HR increased, compared with preinduction values, more in group P than in group PF; Postintubation BIS values increased from 45.5 +/- 3.5 and 44.2 +/- 4.1 to 51.1 +/- 4.1 anti 50.9 +/- 5.3 in groups P and PF, respectively, compared with preintubation values, The BIS values were not different between treatment groups before and after intubation, and 95% SEF and MF values did not increase after intubation, Conclusion: Fentanyl, 2 mu g . kg(-1) iv, blunted the haemodynamic responses to intubation, but failed to attenuate the arousal of cerebral cortical activity, The different haemodynamic responses postintubation but similar BIS and 95% SEF changes in the two groups suggest that BIS or 95% SEF cannot predict the haemodynamic responses to intubation during anaesthesia induction with propofol and fentanyl.