Late-Onset Findings During Extended EEG Monitoring Are Rare in Critically Ill Children.

PURPOSE: Electrographic seizures (ES) are common in critically ill children undergoing continuous EEG (CEEG) monitoring, and previous studies have aimed to target limited CEEG resources to children at highest risk of ES. However, previous studies have relied on observational data in which the duration of CEEG was clinically determined. Thus, the incidence of late occurring ES is unknown. The authors aimed to assess the incidence of ES for 24 hours after discontinuation of clinically indicated CEEG. METHODS: This was a single-center prospective study of nonconsecutive children with acute encephalopathy in the pediatric intensive care unit who underwent 24 hours of extended research EEG after the end of clinical CEEG. The authors assessed whether there were new findings that affected clinical management during the extended research EEG, including new-onset ES. RESULTS: Sixty-three subjects underwent extended research EEG. The median duration of the extended research EEG was 24.3 hours (interquartile range 24.0-25.3). Three subjects (5%) had an EEG change during the extended research EEG that resulted in a change in clinical management, including an increase in ES frequency, differential diagnosis of an event, and new interictal epileptiform discharges. No subjects had new-onset ES during the extended research EEG. CONCLUSIONS: No subjects experienced new-onset ES during the 24-hour extended research EEG period. This finding supports observational data that patients with late-onset ES are rare and suggests that ES prediction models derived from observational data are likely not substantially underrepresenting the incidence of late-onset ES after discontinuation of clinically indicated CEEG.

Relationship of Neonatal Seizure Burden Before Treatment and Response to Initial Antiseizure Medication.

OBJECTIVE: To assess among a cohort of neonates with hypoxic-ischemic encephalopathy (HIE) the association of pretreatment maximal hourly seizure burden and total seizure duration with successful response to initial antiseizure medication (ASM). STUDY DESIGN: This was a retrospective review of data collected from infants enrolled in the HEAL Trial (NCT02811263) between January 25, 2017, and October 9, 2019. We evaluated a cohort of neonates born at ≥36 weeks of gestation with moderate-to-severe HIE who underwent continuous electroencephalogram monitoring and had acute symptomatic seizures. Poisson regression analyzed associations between (1) pretreatment maximal hourly seizure burden, (2) pretreatment total seizure duration, (3) time from first seizure to initial ASM, and (4) successful response to initial ASM. RESULTS: Among 39 neonates meeting inclusion criteria, greater pretreatment maximal hourly seizure burden was associated with lower chance of successful response to initial ASM (adjusted relative risk for each 5-minute increase in seizure burden 0.83, 95% CI 0.69-0.99). There was no association between pretreatment total seizure duration and chance of successful response. Shorter time-to-treatment was paradoxically associated with lower chance of successful response to treatment, although this difference was small in magnitude (relative risk 1.007, 95% CI 1.003-1.010). CONCLUSIONS: Maximal seizure burden may be more important than other, more commonly used measures in predicting response to acute seizure treatments.

Prenatal Brain Maturation is Delayed in Neonates with Congenital Diaphragmatic Hernia.

OBJECTIVE: To assess brain development in fetuses with congenital diaphragmatic hernia (CDH) using a fetal Total Maturation Score (fTMS). STUDY DESIGN: This is a retrospective cohort study using data from a single-center clinical registry. Neonates with an antenatal diagnosis of CDH between 2014 and 2020 and prenatal brain magnetic resonance imaging (MRI) (n = 48) were included. We compared our study sample with historical healthy controls (n = 48). The relationship between fTMS and gestational age (GA), as well as the association between fTMS and key prenatal variables and placental pathologic findings, were evaluated. RESULTS: Compared with healthy controls, neonates with CDH had a significant delay in fTMS (P value <.001). Within the CDH cohort, there was no significant difference in fTMS based on CDH severity, intrathoracic liver position, right vs left CDH, sex, presence of abnormal echocardiogram findings, treatment with extracorporeal membrane oxygenation (ECMO), or in-hospital mortality. Placentas of neonates with CDH had a high proportion of fetal vascular malperfusion (56%) and chronic inflammation (67%), and relatively large placentas had a protective effect on prenatal brain maturation (P value = .025). CONCLUSIONS: Prenatal brain maturation in neonates with CDH is delayed. Placental pathology may influence fetal brain development. The etiology and clinical impact of prenatal brain immaturity in neonates with CDH warrant further investigation.

Extracorporeal Membrane Oxygenation for Neonates With Congenital Diaphragmatic Hernia: Prevalence of Seizures and Outcomes.

OBJECTIVES: We aimed to determine the prevalence of electrographic seizures and associated odds of adverse outcomes of electrographic seizures in neonates with congenital diaphragmatic hernia (CDH) receiving extracorporeal membrane oxygenation (ECMO). DESIGN: Retrospective, descriptive case series. SETTING: Neonatal ICU (NICU) in a quaternary care institution. PATIENTS: All neonates with CDH receiving ECMO undergoing continuous electroencephalographic monitoring (CEEG) and follow-up between January 2012 and December 2019. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: All eligible neonates with CDH receiving ECMO underwent CEEG (n = 75). Electrographic seizures occurred in 14 of 75 (19%): they were exclusively electrographic-only in nine of 14, both electrographic-only and electroclinical in three of 14, and electroclinical only in two of 14. Two neonates developed status epilepticus. We identified an association between presence of seizures, rather than not, and longer duration of initial session of CEEG monitoring (55.7 hr [48.2-87.3 hr] vs 48.0 hr [43.0-48.3 hr]; p = 0.001). We also found an association between presence of seizures, rather than not, and greater odds of use of a second CEEG monitoring (12/14 vs 21/61; odds ratio [OR], 11.43 [95% CI, 2.34-55.90; p = 0.0026). Most neonates with seizures (10/14), experienced their onset of seizures more than 96 hours after the start of ECMO. Overall, the presence of electrographic seizures, compared with not, was associated with lower odds of survival to NICU discharge (4/14 vs 49/61; OR 0.10 [95% CI 0.03 to 0.37], p = 0.0006). Also, the presence of seizures-rather than not-was associated with greater odds of a composite of death and all abnormal outcomes on follow-up (13/14 vs 26/61; OR, 17.5; 95% CI, 2.15-142.39; p = 0.0074). CONCLUSIONS: Nearly one in five neonates with CDH receiving ECMO developed seizures during the ECMO course. Seizures were predominantly electrographic-only and when present were associated with great odds of adverse outcomes. The current study provides evidence to support standardized CEEG in this population.

Electroencephalography as a tool to predict cerebral oxygen metabolism during deep-hypothermic circulatory arrest in neonates with critical congenital heart disease.

Objectives: Recent research suggests that increased cerebral oxygen use during surgical intervention for neonates with congenital heart disease may play a role in the development of postoperative white matter injury. The objective of this study is to determine whether increased cerebral electrical activity correlates with greater decrease of cerebral oxygen saturation during deep hypothermic circulatory arrest. Methods: Neonates with critical congenital heart disease requiring surgical intervention during the first week of life were studied. All subjects had continuous neuromonitoring with electroencephalography and an optical probe (to quantify cerebral oxygen saturation) during cardiac surgical repair that involved the use of cardiopulmonary bypass and deep hypothermic circulatory arrest. A simple linear regression was used to investigate the association between electroencephalography metrics before the deep hypothermic circulatory arrest period and the change in cerebral oxygen saturation during the deep hypothermic circulatory arrest period. Results: Sixteen neonates had both neuromonitoring modalities attached during surgical repair. Cerebral oxygen saturation data from 5 subjects were excluded due to poor data quality, yielding a total sample of 11 neonates. A simple linear regression model found that the presence of electroencephalography activity at the end of cooling is positively associated with the decrease in cerebral oxygen saturation that occurs during deep hypothermic circulatory arrest (P < .05). Conclusions: Electroencephalography characteristics within 5 minutes before the initiation of deep hypothermic circulatory arrest may be useful in predicting the decrease in cerebral oxygen saturation that occurs during deep hypothermic circulatory arrest. Electroencephalography may be an important tool for guiding cooling and the initiation of circulatory arrest to potentially decrease the prevalence of new white matter injury in neonates with critical congenital heart disease.

Incidence of postoperative seizures in neonates following cardiac surgery with regional cerebral perfusion and deep hypothermic circulatory arrest.

Objectives: Historically, our center has primarily used deep hypothermic circulatory arrest, but in recent years some surgeons have selectively used regional cerebral perfusion as an alternative. We aimed to compare the incidence of postoperative electroencephalographic seizure incidence in neonates undergoing surgery with regional cerebral perfusion and deep hypothermic circulatory arrest. Methods: A retrospective analysis was performed in neonates who underwent surgery between 2012 and 2022 with either deep hypothermic circulatory arrest or regional cerebral perfusion with routine postoperative continuous electroencephalography monitoring for 48 hours. Propensity matching was performed to compare postoperative seizure risk between the 2 groups. Results: Among 1136 neonates undergoing cardiac surgery with cardiopulmonary bypass, regional cerebral perfusion was performed in 99 (8.7%) and deep hypothermic circulatory arrest in 604 (53%). The median duration of regional cerebral perfusion was 49 minutes (interquartile range, 38-68) and deep hypothermic circulatory arrest was 41 minutes (interquartile range, 31-49). The regional cerebral perfusion group had significantly longer total support, cardiopulmonary bypass, and aortic crossclamp times. Overall seizure incidence was 11% (N = 76) and 13% (N = 35) in the most recent era (2019-2022). The unadjusted seizure incidence was similar in neonates undergoing regional cerebral perfusion (N = 12, 12%) and deep hypothermic circulatory arrest (N = 64, 11%). After propensity matching, the seizure incidence was similar in neonates undergoing regional cerebral perfusion (N = 12, 12%) and deep hypothermic circulatory arrest (N = 37, 12%) (odds ratio, 0.97; 95% CI, 0.55-1.71; P = .92). Conclusions: In this contemporary single-center experience, the incorporation of regional cerebral perfusion did not result in a change in seizure incidence in comparison with deep hypothermic circulatory arrest. However, unmeasured confounders may have impacted these findings. Further studies are needed to determine the impact, if any, of regional cerebral perfusion on postoperative seizure incidence.

Seizure Severity and Treatment Response in Newborn Infants with Seizures Attributed to Intracranial Hemorrhage.

OBJECTIVE: We sought to characterize intracranial hemorrhage (ICH) as a seizure etiology in infants born term and preterm. For infants born term, we sought to compare seizure severity and treatment response for multisite vs single-site ICH and hypoxic-ischemic encephalopathy (HIE) with vs without ICH. STUDY DESIGN: We studied 112 newborn infants with seizures attributed to ICH and 201 infants born at term with seizures attributed to HIE, using a cohort of consecutive infants with clinically diagnosed and/or electrographic seizures prospectively enrolled in the multicenter Neonatal Seizure Registry. We compared seizure severity and treatment response among infants with complicated ICH, defined as multisite vs single-site ICH and HIE with vs without ICH. RESULTS: ICH was a more common seizure etiology in infants born preterm vs term (27% vs 10%, P < .001). Most infants had subclinical seizures (74%) and an incomplete response to initial antiseizure medication (ASM) (68%). In infants born term, multisite ICH was associated with more subclinical seizures than single-site ICH (93% vs 66%, P = .05) and an incomplete response to the initial ASM (100% vs 66%, P = .02). Status epilepticus was more common in HIE with ICH vs HIE alone (38% vs 17%, P = .05). CONCLUSIONS: Seizure severity was greater and treatment response was lower among infants born term with complicated ICH. These data support the use of continuous video electroencephalogram monitoring to accurately detect seizures and a multistep treatment plan that considers early use of multiple ASMs, particularly with parenchymal and high-grade intraventricular hemorrhage and complicated ICH.

Characteristics of Neonates with Cardiopulmonary Disease Who Experience Seizures: A Multicenter Study.

OBJECTIVE: To compare key seizure and outcome characteristics between neonates with and without cardiopulmonary disease. STUDY DESIGN: The Neonatal Seizure Registry is a multicenter, prospectively acquired cohort of neonates with clinical or electroencephalographic (EEG)-confirmed seizures. Cardiopulmonary disease was defined as congenital heart disease, congenital diaphragmatic hernia, and exposure to extracorporeal membrane oxygenation. We assessed continuous EEG monitoring strategy, seizure characteristics, seizure management, and outcomes for neonates with and without cardiopulmonary disease. RESULTS: We evaluated 83 neonates with cardiopulmonary disease and 271 neonates without cardiopulmonary disease. Neonates with cardiopulmonary disease were more likely to have EEG-only seizures (40% vs 21%, P < .001) and experience their first seizure later than those without cardiopulmonary disease (174 vs 21 hours of age, P < .001), but they had similar seizure exposure (many-recurrent electrographic seizures 39% vs 43%, P = .27). Phenobarbital was the primary initial antiseizure medication for both groups (90%), and both groups had similarly high rates of incomplete response to initial antiseizure medication administration (66% vs 68%, P = .75). Neonates with cardiopulmonary disease were discharged from the hospital later (hazard ratio 0.34, 95% CI 0.25-0.45, P < .001), although rates of in-hospital mortality were similar between the groups (hazard ratio 1.13, 95% CI 0.66-1.94, P = .64). CONCLUSION: Neonates with and without cardiopulmonary disease had a similarly high seizure exposure, but neonates with cardiopulmonary disease were more likely to experience EEG-only seizures and had seizure onset later in the clinical course. Phenobarbital was the most common seizure treatment, but seizures were often refractory to initial antiseizure medication. These data support guidelines recommending continuous EEG in neonates with cardiopulmonary disease and indicate a need for optimized therapeutic strategies.

Associations between Infant and Parent Characteristics and Measures of Family Well-Being in Neonates with Seizures: A Cohort Study.

OBJECTIVE: To characterize and determine risk factors for key dimensions of well-being at hospital discharge in families of neonates with acute symptomatic seizures. STUDY DESIGN: This prospective, observational cohort study enrolled 144 parent-infant dyads among neonates with acute symptomatic seizures from 9 pediatric hospitals in the Neonatal Seizure Registry. One parent per family completed a discharge survey, which included measures of anxiety and depression, health-related quality of life, and impact on the family. Multivariable regression analyses adjusted for site were constructed to examine parent and infant characteristics associated with well-being. RESULTS: At discharge, 54% of parents reported symptoms of anxiety and 32% reported symptoms of depression. Parents of infants with hypoxic-ischemic encephalopathy reported more depression and worse quality of life than parents of infants with other seizure etiologies. Parental quality of life was also lower with greater infant age at discharge. A higher level of maternal education was associated with greater impact on the family. All these differences were medium to large effect sizes, ranging from 0.52 to 0.78. CONCLUSIONS: Symptoms of anxiety and depression are common in parents of infants with neonatal seizures, and several parent and infant characteristics are associated with poorer parental quality of life and family well-being. These findings are a call to action to improve mental health screening and services for parents of infants with neonatal seizures.

Population Pharmacokinetics of IV Phenobarbital in Neonates After Congenital Heart Surgery.

OBJECTIVES: To develop a population pharmacokinetic model for IV phenobarbital in neonates following cardiac surgery and perform simulations to identify optimal dosing regimens. DESIGN: Retrospective single-center pharmacokinetic study. SETTING: Cardiac ICU at Children's Hospital of Philadelphia. PATIENTS: Consecutive neonates who received greater than or equal to one dose of IV phenobarbital and had greater than or equal to one phenobarbital concentration drawn per standard of care from June 15, 2012, to October 15, 2018. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: A population pharmacokinetic model was developed using nonlinear mixed-effects modeling. Simulations were performed using the final model variables. Optimal phenobarbital loading doses were determined based on attainment of peak and maintenance concentrations between 20 and 40 mg/L. A total of 37 neonates contributed 159 pharmacokinetic samples. The median (range) weight, postmenstrual age, and postnatal age were 3.2 kg (1.3-3.8), 39 2/7 weeks (28 2/7 to 42 6/7), and 5 days (0-26 d), respectively. Twelve patients (32%) were on extracorporeal membrane oxygenation. An one-compartment model best described the data. The final population pharmacokinetic model included (1) weight and postnatal age for clearance and (2) weight, extracorporeal membrane oxygenation, and albumin for volume of distribution. In neonates not on extracorporeal membrane oxygenation, loading doses of 30 and 20 mg/kg reached goal concentration with albumin values less than or equal to 3 and 3.5 mg/dL, respectively. Loading doses of 30 mg/kg reached goal concentration on extracorporeal membrane oxygenation regardless of albumin values. Maintenance doses of 4-5 mg/kg/d reached goal concentration in all neonates. CONCLUSIONS: In neonates following cardiac surgery, phenobarbital clearance increased with postnatal age. Volume of distribution increased with extracorporeal membrane oxygenation and lower albumin values. Loading doses of 30 mg/kg on extracorporeal membrane oxygenation and 20-30 mg/kg without extracorporeal membrane oxygenation were needed to reach goal concentration based on simulations.

Treatment Duration After Acute Symptomatic Seizures in Neonates: A Multicenter Cohort Study.

We aimed to define determinants of duration of treatment for acute symptomatic neonatal seizures in a contemporary multicenter observational cohort study. After adjustment for potential confounders, only study site and seizure etiology remained significantly associated with the chance of continuing antiseizure medication after discharge to home.