Bispectral index monitoring: A comparison between normal children and children with quadriplegic cerebral palsy

We performed this study to compare the correlation of bispectral index (BIS) values with different sevoflurane concentrations between normal children and those with quadriplegic cerebral palsy with mental retardation (CPMR). Twenty children with CPMR (Group 1) and 21 normal children (Group 11) between 2 and 14 yr of age were studied. Anesthesia was induced and maintained with sevoflurane and 66% N2O/O-2. Bispectral values were recorded on an Aspect Medical Systems (Natick, MA) monitor, and sevoflurane concentrations were measured with an Ohmeda (Hanover, MA) inhaled anesthetic monitor. The BIS values were recorded after midazolam premedication; after the induction of anesthesia; at end-tidal sevoflurane concentrations of 1%, 3%, and again at 1%; and after emergence from the anesthetic. Both groups were similar in age and sex distribution, but children in Group I weighed less than those in Group II (P < 0.05). The BIS values were significantly lower in Group I compared with Group II after sedation, at 1% sevoflurane concentrations, and after emergence. No difference was observed between the two groups at anesthesia induction (8%) and at 3% sevoflurane concentration. We conclude that, in children with CPMR, BIS values exhibit a pattern of change similar to that observed in normal children. However, absolute BIS values obtained in such children are lower than those in normal children while awake and at different sevoflurane concentrations.