The probability of seizures during continuous EEG monitoring in high‐risk neonates

• Published in: Epilepsia (Copenhagen) 2019-12, Vol.60 (12), p.2508-2518
• Main Authors: Worden, Lila T., Chinappen, Dhinakaran M., Stoyell, Sally M., Gold, Jacquelyn, Paixao, Luis, Krishnamoorthy, Kalpathy, Kramer, Mark A., Westover, Michael B., Chu, Catherine J.
• Format: Article
• Language: English
• Subjects: continuous EEG; continuous electroencephalography; Convulsions & seizures; critical care; EEG; Electroencephalography; Electroencephalography - methods; Electroencephalography - trends; electrographic seizure; Encephalopathy; Epilepsy; Female; Firing pattern; Health risk assessment; Humans; Infant, Newborn; Male; Neonates; NICU; Predictive Value of Tests; Risk Factors; Seizures; Seizures - diagnosis; Seizures - physiopathology
• ISSN: 0013-9580; 1528-1167
• DOI: 10.1111/epi.16387

Objective We evaluated the impact of monitoring indication, early electroencephalography (EEG), and clinical features on seizure risk in all neonates undergoing continuous EEG (cEEG) monitoring following a standardized monitoring protocol. Methods All cEEGs from unique neonates 34‐48 weeks postmenstrual age monitored from 1/2011‐10/2017 (n = 291) were included. We evaluated the impact of cEEG monitoring indication (acute neonatal encephalopathy [ANE], suspicious clinical events [SCEs], or other high‐risk conditions [OHRs]), age, medication status, and early EEG abnormalities (including the presence of epileptiform discharges and abnormal background continuity, amplitude, asymmetry, asynchrony, excessive sharp transients, and burst suppression) on time to first seizure and overall seizure risk using Kaplan‐Meier survival curves and multivariable Cox proportional hazards models. Results Seizures occurred in 28% of high‐risk neonates. Discontinuation of monitoring after 24 hours of seizure‐freedom would have missed 8.5% of neonates with seizures. Overall seizure risk was lower in neonates monitored for ANE compared to OHR (P = .004) and trended lower compared to SCE (P = .097). The time course of seizure presentation varied by group, where the probability of future seizure was less than 1% after 17 hours of seizure‐free monitoring in the SCE group, but required 42 hours in the OHR group, and 73 hours in the ANE group. The presence of early epileptiform discharges increased seizure risk in each group (ANE: adjusted hazard ratio [aHR] 4.32, 95% confidence interval [CI] 1.23‐15.13, P = .022; SCE: aHR 10.95, 95% CI 4.77‐25.14, P