Cerebral state index may reflect electrical brain activity during propofol or isoflurane anaesthesia in rabbits.

Approach Eighteen New Zealand white rabbits, undergoing surgical catheterisation of the bilateral carotid and internal jugular vein, were used in this study. In group I (propofol), anaesthesia was maintained with an intravenous (iv) infusion of propofol at a rate of 0.7 mg/kg/min and interval iv fentanyl. In group II (isoflurane), the end-tidal concentration was adjusted to 1.0 minimum alveolar concentration (2.05 per cent), at a fresh gas flow rate of 3 l/min in 100 per cent oxygen for maintenance. The CSI values were collected from a CSM using three electrodes placed according to the manufacturer’s instructions on the shaved and defatted heads of the rabbits. During the procedure, the left femoral artery was cannulated for blood gas analysis. An anaesthetist, blinded to the EEG signals, assessed the animals for behavioural responses to stimuli and for the sedation score.