Nicholas S. Abend

The American clinical neurophysiology society's guideline on continuous electroencephalography monitoring in neonates

This article offers the preferred methods and indications for longterm, conventional electroencephalography (EEG) monitoring for selected, high-risk neonates of postmenstrual age less than 48 weeks. The authors recognize that there may be significant practical barriers to the implementation of these recommendations for many caregivers and institutions, particularly with regard to the availability of equipment, and technical and interpretive personnel. A wide range of clinical circumstances dictates the implementation of EEG monitoring, frequency of EEG review, and the subsequent treatment of seizures or EEG background abnormalities detected by neonatal EEG. Consequently, this article should be considered as an expression of idealized goals and not as a mandated standard of care.

ELECTROENCEPHALOGRAPHIC MONITORING DURING HYPOTHERMIA AFTER PEDIATRIC CARDIAC ARREST

Background: Hypoxic ischemic brain injury secondary to pediatric cardiac arrest (CA) may result in acute symptomatic seizures. A high proportion of seizures may be nonconvulsive, so accurate diagnosis requires continuous EEG monitoring. We aimed to determine the safety and feasibility of long-term EEG monitoring, to describe electroencephalographic background and seizure characteristics, and to identify background features predictive of seizures in children undergoing therapeutic hypothermia (TH) after CA. Methods: Nineteen children underwent TH after CA. Continuous EEG monitoring was performed during hypothermia (24 hours), rewarming (12–24 hours), and then an additional 24 hours of normothermia. The tolerability of these prolonged studies and the EEG background classification and seizure characteristics were described in a standardized manner. Results: No complications of EEG monitoring were reported or observed. Electrographic seizures occurred in 47% (9/19), and 32% (6/19) developed status epilepticus. Seizures were nonconvulsive in 67% (6/9) and electrographically generalized in 78% (7/9). Seizures commenced during the late hypothermic or rewarming periods (8/9). Factors predictive of electrographic seizures were burst suppression or excessively discontinuous EEG background patterns, interictal epileptiform discharges, or an absence of the expected pharmacologically induced beta activity. Background features evolved over time. Patients with slowing and attenuation tended to improve, whereas those with burst suppression tended to worsen. Conclusions: EEG monitoring in children undergoing therapeutic hypothermia after cardiac arrest is safe and feasible. Electrographic seizures and status epilepticus are common in this setting but are often not detectable by clinical observation alone. The EEG background often evolves over time, with milder abnormalities improving and more severe abnormalities worsening. BS = burst suppression; CA = cardiac arrest; CPR = cardiopulmonary resuscitation; DD = developmental delay; FEN = fentanyl; FOS = fosphenytoin; HIE = hypoxic ischemic encephalopathy; LEV = levetiracetam; LZP = lorazepam; MDZ = midazolam; NCS = nonconvulsive seizures; NCSE = nonconvulsive status epilepticus; NPV = negative predictive value; PB = phenobarbital; PED = periodic epileptiform discharge; PICU = pediatric intensive care unit; PPV = positive predictive value; SE = status epilepticus; SIDS = sudden infant death syndrome; sz = seizures; TH = therapeutic hypothermia; VEC = vecuronium; VPA = valproic acid; VT = ventricular tachycardia.

Treatment of Refractory Status Epilepticus: Literature Review and a Proposed Protocol

Refractory status epilepticus describes continuing seizures despite adequate initial pharmacologic treatment. This situation is common in children, but few data are available to guide management. We review the literature related to the pharmacologic treatment and overall management of refractory status epilepticus, including midazolam, pentobarbital, phenobarbital, propofol, inhaled anesthetics, ketamine, valproic acid, topiramate, levetiracetam, pyridoxine, corticosteroids, the ketogenic diet, and electroconvulsive therapy. Based on the available data, we present a sample treatment algorithm that emphasizes the need for rapid therapeutic intervention, employs consecutive medications with different mechanisms of action, and attempts to minimize the risk of hypotension. The initial steps suggest using benzodiazepines and phenytoin. Second steps suggest using levetiracetam or valproic acid, which exert few hemodynamic adverse effects and have multiple mechanisms of action. Additional management strategies that could be employed in tertiary-care settings, such as coma induction guided by continuous electroencephalogram monitoring and surgical options, are also discussed.

Nonconvulsive seizures are common in critically ill children

Background: Retrospective studies have reported the occurrence of nonconvulsive seizures in critically ill children. We aimed to prospectively determine the incidence and risk factors of nonconvulsive seizures in critically ill children using predetermined EEG monitoring indications and EEG interpretation terminology. Methods: Critically ill children (non-neonates) with acute encephalopathy underwent continuous EEG monitoring if they met institutional clinical practice criteria. Study enrollment and data collection were prospective. Logistic regression analysis was utilized to identify risk factors for seizure occurrence. Results: One hundred children were evaluated. Electrographic seizures occurred in 46 and electrographic status epilepticus occurred in 19. Seizures were exclusively nonconvulsive in 32. The only clinical risk factor for seizure occurrence was younger age (p = 0.03). Of patients with seizures, only 52% had seizures detected in the first hour of monitoring, while 87% were detected within 24 hours. Conclusions: Seizures were common in critically ill children with acute encephalopathy. Most were nonconvulsive. Clinical features had little predictive value for seizure occurrence. Further study is needed to confirm these data in independent high-risk populations, to clarify which children are at highest risk for seizures so limited monitoring resources can be allocated optimally, and to determine whether seizure detection and management improves outcome.

Consensus Statement on Continuous EEG in Critically Ill Adults and Children, Part I: Indications

Introduction: Critical Care Continuous EEG (CCEEG) is a common procedure to monitor brain function in patients with altered mental status in intensive care units. There is significant variability in patient populations undergoing CCEEG and in technical specifications for CCEEG performance. Methods: The Critical Care Continuous EEG Task Force of the American Clinical Neurophysiology Society developed expert consensus recommendations on the use of CCEEG in critically ill adults and children. Recommendations: The consensus panel recommends CCEEG for diagnosis of nonconvulsive seizures, nonconvulsive status epilepticus, and other paroxysmal events, and for assessment of the efficacy of therapy for seizures and status epilepticus. The consensus panel suggests CCEEG for identification of ischemia in patients at high risk for cerebral ischemia; for assessment of level of consciousness in patients receiving intravenous sedation or pharmacologically induced coma; and for prognostication in patients after cardiac arrest. For each indication, the consensus panel describes the patient populations for which CCEEG is indicated, evidence supporting use of CCEEG, utility of video and quantitative EEG trends, suggested timing and duration of CCEEG, and suggested frequency of review and interpretation. Conclusion: CCEEG has an important role in detection of secondary injuries such as seizures and ischemia in critically ill adults and children with altered mental status.

American clinical neurophysiology society standardized EEG terminology and categorization for the description of continuous EEG monitoring in neonates: report of the American Clinical Neurophysiology Society critical care monitoring committee.

BACKGROUNDCritically ill neonates are at high risk for adverse neurologic sequelae, but the bedside evaluation of a neonates neurologic status, especially cortical functioning, is extremely limited. In such circumstances, continuous video EEG provides particularly useful information about brain

Electrographic status epilepticus is associated with mortality and worse short-term outcome in critically ill children.

Objectives:Electrographic seizures and electrographic status epilepticus are common in critically ill children. We aimed to determine whether electrographic seizures and electrographic status epilepticus are associated with higher mortality or worse short-term neurologic outcome. Design:Prospective observational study. Setting:PICU of a tertiary children’s hospital. Patients:Non-neonatal children admitted to a PICU with acute encephalopathy underwent continuous electroencephalographic monitoring. Electroencephalographs were scored as 1) no seizures, 2) electrographic seizures, or 3) electrographic status epilepticus. Covariates included age, acute neurologic disorder category, prior neurodevelopmental status, sex, and electroencephalographic background category. Outcomes were mortality and worsening of pediatric cerebral performance category from preadmission to PICU discharge. Chi-square analysis, Fisher’s exact test, and multivariable logistic regression were used to evaluate the associations between electrographic seizures or electrographic status epilepticus and mortality or short-term neurologic outcome, using odds ratios and 95% confidence intervals. Interventions:None. Main Results:Two hundred children underwent continuous electroencephalographic monitoring. Eighty-four (42%) had seizures, which were categorized as electrographic seizures in 41 (20.5%) and electrographic status epilepticus in 43 (21.5%). Thirty-six subjects (18%) died, and 88 subjects (44%) had pediatric cerebral performance category worsening. In multivariable analysis, electrographic status epilepticus was associated with an increased risk of mortality (odds ratio 5.1; 95% confidence interval 1.4, 18; p = 0.01) and pediatric cerebral performance category worsening (odds ratio 17.3; 95% confidence interval 3.7, 80; p < 0.001), whereas electrographic seizures were not associated with an increased risk of mortality (odds ratio 1.3; 95% confidence interval 0.3, 5.1; p = 0.74) or pediatric cerebral performance category worsening (odds ratio 1.2; 95% confidence interval 0.4, 3.9; p = 0.77). Conclusions:Electrographic status epilepticus, but not electrographic seizures, is associated with mortality and worse short-term neurologic outcome in critically ill children with acute encephalopathy.

Electrographic Seizures During Therapeutic Hypothermia for Neonatal Hypoxic-Ischemic Encephalopathy:

Electrographic seizures are common in neonates with hypoxic-ischemic encephalopathy, but detailed data are not available regarding seizure incidence during therapeutic hypothermia. The objective of this prospective study was to determine the incidence and timing of electrographic seizures in term neonates undergoing whole-body therapeutic hypothermia for hypoxic-ischemic encephalopathy as detected by conventional full-array electroencephalography for 72 hours of therapeutic hypothermia and 24 hours of normothermia. Clinical and electroencephalography data were collected from 26 consecutive neonates. Electroencephalograms were reviewed by 2 pediatric neurophysiologists. Electrographic seizures occurred in 17 of 26 (65%) patients. Seizures were entirely nonconvulsive in 8 of 17 (47%), status epilepticus occurred in 4 of 17 (23%), and seizure onset was in the first 48 hours in 13 of 17 (76%) patients. Electrographic seizures were common, were often nonconvulsive, and had onset over a broad range of times in the first days of life.

Electrographic seizures in pediatric ICU patients Cohort study of risk factors and mortality

Objectives: We aimed to determine the incidence of electrographic seizures in children in the pediatric intensive care unit who underwent EEG monitoring, risk factors for electrographic seizures, and whether electrographic seizures were associated with increased odds of mortality. Methods: Eleven sites in North America retrospectively reviewed a total of 550 consecutive children in pediatric intensive care units who underwent EEG monitoring. We collected data on demographics, diagnoses, clinical seizures, mental status at EEG onset, EEG background, interictal epileptiform discharges, electrographic seizures, intensive care unit length of stay, and in-hospital mortality. Results: Electrographic seizures occurred in 162 of 550 subjects (30%), of which 61 subjects (38%) had electrographic status epilepticus. Electrographic seizures were exclusively subclinical in 59 of 162 subjects (36%). A multivariable logistic regression model showed that independent risk factors for electrographic seizures included younger age, clinical seizures prior to EEG monitoring, an abnormal initial EEG background, interictal epileptiform discharges, and a diagnosis of epilepsy. Subjects with electrographic status epilepticus had greater odds of in-hospital death, even after adjusting for EEG background and neurologic diagnosis category. Conclusions: Electrographic seizures are common among children in the pediatric intensive care unit, particularly those with specific risk factors. Electrographic status epilepticus occurs in more than one-third of children with electrographic seizures and is associated with higher in-hospital mortality.

Levetiracetam for treatment of neonatal seizures.

Neonatal seizures are often refractory to treatment with initial antiseizure medications. Consequently, clinicians turn to alternatives such as levetiracetam, despite the lack of published data regarding its safety, tolerability, or efficacy in the neonatal population. We report a retrospectively identified cohort of 23 neonates with electroencephalographically confirmed seizures who received levetiracetam. Levetiracetam was considered effective if administration was associated with a greater than 50% seizure reduction within 24 hours. Levetiracetam was initiated at a mean conceptional age of 41 weeks. The mean initial dose was 16 ± 6 mg/kg and the mean maximum dose was 45 ± 19 mg/kg/day. No respiratory or cardiovascular adverse effects were reported or detected. Levetiracetam was associated with a greater than 50% seizure reduction in 35% (8 of 23), including seizure termination in 7. Further study is warranted to determine optimal levetiracetam dosing in neonates and to compare efficacy with other antiseizure medications.