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To investigate spatial correlation between interictal HFOs and neuroimaging abnormalities, and to determine if complete removal of prospectively identified interictal HFOs correlates with post-surgical seizure-freedom.Interictal fast ripples (FRs: 250-500 Hz) in 19 consecutive children with pharmacoresistant focal epilepsy who underwent extra-operative electrocorticography (ECoG) recording were prospectively analyzed. The interictal FRs were sampled at 2000 Hz and were visually identified during 10 min of slow wave sleep. Interictal FRs, MRI and FDG-PET were delineated on patient-specific reconstructed three-dimensional brain MRI.Interictal FRs were observed in all patients except one. Thirteen out of 18 patients (72%) exhibited FRs beyond the extent of neuroimaging abnormalities. Fifteen of 19 children underwent resective surgery, and survival analysis with log-rank test demonstrated that complete resection of cortical sites showing interictal FRs correlated with longer post-operative seizure-freedom (p 0.01). Complete resection of seizure onset zones (SOZ) also correlated with longer post-operative seizure-freedom (p = 0.01), yet complete resection of neuroimaging abnormalities did not (p = 0.43).Prospective visual analysis of interictal FRs was feasible, and it seemed to accurately localize epileptogenic zones.Topological extent of epileptogenic region may exceed what is discernible by multimodal neuroimaging.

OBJECTIVES To evaluate the risk factors for mortality in pediatric extracorporeal membrane oxygenation patients. DESIGN Retrospective, single-center study. SETTING PICU and Pediatric cardiothoracic ICU in an urban, quaternary care center. PATIENTS All neonatal and pediatric patients requiring extracorporeal membrane oxygenation at our institution between January 2014 and December 2018, who underwent a standardized continuous electroencephalogram neuromonitoring protocol during most of the duration of extracorporeal membrane oxygenation support. We excluded patients who had extracorporeal membrane oxygenation initiated at another institution. INTERVENTION None. MEASUREMENTS AND MAIN RESULTS Sixty-six children required extracorporeal membrane oxygenation support during this period. Four patients were excluded, three due to lack of electroencephalogram data, one with extracorporeal membrane oxygenation initiated at other institution. In the remaining 62, 11 patients (17%) had seizures, of which 5 (45%) had status epilepticus. Eight of 11 patients (72%) had exclusively electrographic seizures. A total of 33 patients (53.2%) died, of which 22 died during extracorporeal membrane oxygenation course, and one died 3 years after hospital discharge. Mean survival from extracorporeal membrane oxygenation initiation was 766.9 days (standard deviation, 691.7; median, 546.5; interquartile range 1-3, 97.7-1255.0). In multivariate analysis, increased risk of mortality was associated with the use of extracorporeal cardiopulmonary resuscitation (hazard ratio, 4.33; 95% CI, 1.75-10.72; p = 0.002), imaging findings of cerebral edema (hazard ratio, 14.31; 95% CI, 5.18-39.54; p 100 mg/dL within 2 hr preextracorporeal membrane oxygenation) (hazard ratio, 1.22; 95% CI, 1.03-1.44; p = 0.022), and prolonged deep hypothermic circulatory arrest (hazard ratio, 3.43; 95% CI, 1.65-7.13; p < 0.001). Presence of seizures was associated with imaging findings of cerebral edema (hazard ratio, 4.16; 95% CI, 1.04-16.58; p = 0.04). CONCLUSIONS Seizures are common in children requiring extracorporeal membrane oxygenation support, with a high rate of electrographic seizures and status epilepticus, as in prior studies. Presence of cerebral edema is both risk factor for mortality and seizures. Other risk factors for mortality include extracorporeal cardiopulmonary resuscitation, high lactate levels, and prolonged deep hypothermic circulatory arrest.

Seizures are common in term infants with hypoxic-ischemic encephalopathy (HIE) undergoing therapeutic hypothermia. Although phenobarbital (PHB) is generally considered first-line therapy, some centers have embraced third-generation antiepileptic drugs (AEDs) such as levetiracetam (LEV) given the impression of comparable efficacy and superior tolerability. We set out to compare the efficacy of PHB and LEV in a large single-center cohort.We retrospectively identified consecutive newborns with HIE who were monitored with continuous video-electroencephalogram (VEEG) for the duration of therapeutic hypothermia. After identification of seizures, infants were treated with PHB or LEV at the discretion of treating physicians. We assessed time to seizure freedom as a function of AED choice, with adjustment for HIE severity and initial seizure frequency using the Kaplan-Meier procedure and multivariate Cox proportional hazards regression.We identified 78 infants with HIE. Among 44 (56%) patients who had VEEG-confirmed seizures, 34 became seizure-free during monitoring, and the remaining 10 died. Initial treatment with LEV, in comparison with PHB, predicted a shorter interval to seizure freedom in a univariate analysis (Hazard ratio (HR) = 2.58, P = 0.007), even after adjustment for initial seizure frequency and an unbiased ad hoc measure of HIE severity (adjusted HR = 2.57, P = 0.010). This effect was recapitulated in an analysis in which patients with treatment crossover were excluded. As expected, severity of HIE was an independent predictor of longer duration to seizure freedom (HR = 0.16, P 0.001) and remained a significant predictor after adjustment for initial seizure burden and treatment agent.Despite a relatively small sample size and retrospective design, this study suggests that LEV is a viable alternative to PHB in the treatment of neonatal seizures associated with HIE. A large-scale randomized controlled trial is needed to confirm these findings.

PURPOSE Extracorporeal membrane oxygenation (ECMO) is a life-saving heart and lung bypass procedure that can cause substantial EEG artifact. Continuous EEG monitoring is nonetheless a helpful neuromonitoring tool for patients receiving ECMO therapy because neurologic complications are frequent, but factors such as sedation, neuromuscular blockade, and hemodynamic instability limit clinical and radiographic evaluation. We examined whether using conductive plastic electrodes in place of conventional gold electrodes reduces artifact in clinical EEG studies of pediatric ECMO patients. METHODS Four masked electroencephalographers assessed artifact and its impact on overall EEG interpretation in samples from 21 consecutive EEGs recorded during ECMO therapy (14 gold and 7 plastic). A spectral power analysis then quantified 50- to 70-Hz artifact in a larger group of 14 gold and 34 plastic electrode studies during ECMO and 4 non-ECMO gold electrode studies. RESULTS The masked electroencephalographers identified less artifact (P < 0.001) and indicated greater confidence in the accuracy of EEG interpretation (P < 0.001) among studies recorded with plastic electrodes. In quantitative analyses, ECMO was associated with greater 50- to 70-Hz power among studies using gold electrodes (P < 0.001) and gold electrodes exhibited greater 50- to 70-Hz power than plastic electrodes (P < 0.001). Contrasting studies in which most of the electroencephalographers believed that interpretation was (n = 12; 7 gold and 5 plastic) or was not (n = 7; all gold) compromised by artifact, 50- to 70-Hz power was similarly higher among the compromised studies (P < 0.001). CONCLUSION Plastic electrodes substantially reduce the burden of electrical artifact in EEG studies performed on pediatric ECMO patients and improve confidence in EEG interpretation.