EEG monitoring of prolonged thiopentone administration for intractable seizures and status epilepticus in infants and young children

Abstract

Thiopentone anaesthesia was used in the treatment of seizures in 19 infants and young children. Nine had a pre-existing seizure disorder without acute cerebral injury and 10 had status epilepticus secondary to an acute cerebral illness. Clinical details, drug levels and findings from serial multichannel electroencephalograms (EEG) and continuous 1 to 2 channel signal processed EEGs using a Cerebral Function Analysing Monitor (CFAM) were reviewed to evaluate the contribution of these techniques to clinical management. Initial EEGs showed discharges that were not generalised in 16/19 patients. This necessitated the use of 7 different montages for continuous monitoring. Three different CFAM patterns representing particular EEG paroxysmal findings were seen. Acute seizure control was achieved in all 19 patients. All patients with a pre-existing seizure disorder survived, although 4/10 with an acute cerebral illness died. During treatment, patterns of burst-suppression to electrocerebral silence (ECS) were eventually seen in 16/19 patients and repeat EEGs demonstrated concordant multi-channel findings in 8/8. Although increasing thiopentone levels (13 patients) correlated with deeper suppression of cortical electrical activity, there was marked inter-patient variability. Inotropic support was not required during the period of treatment even when ECS was induced. In young children a combination of multi-channel EEG and continuous 1 to 2 channel monitoring has advantages over either method used alone. In individual patients on-line monitoring can be easily incorporated in a protocol of controlled cortical suppression and drug titration for seizure control.