Epileptic EEG discharges during burst suppression

Barbiturate anaesthesia is used in the treatment of status epilepticus and severe epilepsy of children. EEG is then used as a measure of the depth of anaesthesia, burst suppression being an easily identified EEG pattern. In this case report we describe epileptiform discharges during EEG suppression in two children undergoing barbiturate anaesthesia for treatment of intractable seizures. One of them had focal, rhythmic discharges of negative spikes on the positive suppression level. Bursts were readily produced by visual stimuli with flashes of red light but this did not increase the frequency of focal spike discharges after bursts. The other patient had generalised, high amplitude spikewave complexes, which were easy to distinguish from the bursts. We emphasise that it is important to make a distinction between electrocerebral silence, or isoelectric EEG as it was previously called, from EEG suppression. It is also important to distinguish epileptiform discharges from bursts, if the intention is to keep the anaesthesia at EEG burst suppression level.