CHARLOTTE, NC – , according to a multicenter study that was presented at the annual meeting of the Child Neurology Society. Delays in initiating EEG monitoring are associated with longer seizure duration in this patient population.
Neurologists are advised to initiate continuous EEG monitoring rapidly for all cases of pediatric refractory status epilepticus. Little information is available, however, about patterns in the timing of EEG placement. In addition, the relationship between delays in the initiation of continuous EEG and outcomes of refractory status epilepticus are unknown.
A retrospective analysis of pSERG data
Dr. Tchapyjnikov and colleagues analyzed data from 11 hospitals participating in the Pediatric Status Epilepticus Research Group (pSERG), a prospective, observational cohort. They focused on pediatric patients who were admitted from 2011 to 2017 with refractory status epilepticus, which they defined as a seizure that persisted after treatment with two or more antiseizure medications (ASMs), one of which had to be a nonbenzodiazepine ASM, or a continuous infusion. Eligible patients were between 1 month and 21 years old and had convulsive seizures at onset. Patients who had EEG placement before seizure onset were excluded.
The investigators included in their study 121 patients who had seizure durations of 3 or more hours. Based on an exploratory analysis of various time-point cutoffs, Dr. Tchapyjnikov and colleagues defined delayed continuous EEG placement as placement at more than 5 hours after seizure onset. They used the Kaplan–Meier estimator to assess time to continuous EEG and used covariate-adjusted proportional hazards models to examine the association between delay in continuous EEG placement and seizure duration.
EEG placement overall was delayed
The median time to continuous EEG placement after seizure onset was 9 hours. Approximately 4% of the children had continuous EEG placed within 1 hour, and 74% had it placed within 24 hours.
The investigators found that seizure onset outside the study hospital was associated with a higher likelihood of delayed time to EEG placement. “Females seemed to be more likely to have timely EEG placement,” said Dr. Tchapyjnikov. “I don’t have a physiological explanation for that.” The researchers saw no difference in treatment between patients who had timely EEG placement and those who had delayed EEG placement.
About 68% of children were having seizures at the time of continuous EEG placement. A presumed seizure etiology of CNS infection was associated with a higher likelihood of being in status epilepticus at the time of EEG placement. A history of epilepsy, developmental delay, or home ASM use, however, was associated with a lower likelihood of being in status epilepticus at time of EEG placement.
Dr. Tchapyjnikov’s group found that the 24-hour cumulative probability of seizure resolution was lower among patients who did not have continuous EEG initiation within 5 hours, compared with those who did (56% vs.70%). The association remained significant after the investigators adjusted the data for covariates that were independently associated with 24-hour seizure resolution (hazard ratio, 0.31).
The investigators included in their analysis patients who had seizure resolution before EEG placement, because restricting the analysis to patients who have persistent status epilepticus would have overemphasized the benefits of EEG, according to Dr. Tchapyjnikov. “Looking at the overall hazard ratios is a more conservative way of looking at these data.”
The study was not supported by external funding. Dr. Tchapyjnikov had no relevant disclosures.