Successful Wean Despite Emergence of Ictal-Interictal EEG Patterns During the Weaning of Prolonged Burst-Suppression Therapy for Super-Refractory Status Epilepticus.

Abstract

Management of refractory status epilepticus (SE) commonly involves the induction of burst suppression using intravenous anesthetic agents. However, the endpoints of these therapies are not well defined. Weaning anesthetic agents are complicated by the emergence of electroencephalogram (EEG) patterns along the ictal-interictal continuum (IIC), which have uncertain significance given that IIC patterns may worsen cerebral metabolism and oxygenation, have a dissociation between scalp and depth EEG recordings, or may indicate a late stage of SE itself. Determining the significance of IIC patterns in the unique context of anesthetic weaning is important to prevent the potential for unnecessarily prolonging anesthetic coma. Among 118 individuals with SE, we retrospectively identified a series of patients who underwent at least 24h of burst-suppression therapy, experienced two or more weaning trials, and developed IIC patterns during anesthetic weaning. Anesthetic titration strategies during the emergence of these patterns were examined. Each of the six individuals who met inclusion criteria experienced aggressive weaning despite the emergence of IIC patterns. The IIC patterns that were encountered during anesthetic weaning (including generalized and lateralized periodic discharges) are described in detail. Favorable outcomes were reported in each subject. IIC patterns encountered during anesthetic weaning may be transitional and warrant observation, allowing for the emergence of more definitive clinical or electrographic results. The metabolic impact of these IIC patterns on brain activity is uncertain, but weaning strategies that treat IIC as a surrogate of recurrent SE risk further prolonging anesthetic management and its known toxicity. We speculate that these patterns may have a context-specific association with SE relapse, with less-risk conferred when these patterns are observed during the weaning of anesthetic agents after prolonged burst-suppression therapy. Other electrographic features aside from this clinical context may discriminate the risk of SE relapse, such as EEG background activity.