Electroencephalographic density spectral array (DSA) is a three dimensional method to display electroencephalogram (EEG) signals consisting of the EEG frequency (y-axis), the power of the EEG signal (colour-coded to be integrated into a two dimensional plot) and the development of the EEG power spectrum over time (x-axis). DSA is routinely used to measure depth of hypnosis (DoH) by a part of the staff members in our department. When DSA is used, dose adjustments of sevoflurane will be made based on monitoring depth of anaesthesia. However, most of our colleague do not use DSA. Dose adjustment is then based on (subjective) clinical surrogate parameters, or in general mostly based on a minimal alveolar concentration of the anaesthetic gas that is used.~Electroencephalographic DSA monitoring provides continuous objective information on DoH and should result in a faster speed of emergence and recovery from general anaesthesia (GA). This will be addressed in a randomised controlled trial.~In patients randomised to the intervention group, the anaesthetic agent sevoflurane will be administered on the basis of objective measures of anaesthetic depth, the typical DSA pattern for GA. We expect a significantly faster speed of emergence and recovery in the intervention group based on clinical experience. The Narcotrend monitor is validated for use in paediatric patients. There are thus no additional risk factors apart from those, which are inherent with general anaesthesia. Patient randomised to the control group will receive standard treatment, that is delivery of sevoflurane based on a MAC of 0.9 respectively an end tidal sevoflurane concentration of 2.3%. A non-invasive therapeutical intervention (DSA based conduct of GA) should result in the advantage of faster recovery, without any additional risk factor.
In this randomised, blinded study, we will investigate the influence of DSA on recovery from general anaesthesia. DSA monitoring provides continuous information on depth of hypnosis. Based on DSA monitoring dose adjustments of sevoflurane can be made. We expect that this will lead to a faster speed of emergence and recovery.