<p><strong>OBJECTIVE: </strong>To compare key seizure and outcome characteristics between neonates with and without cardiopulmonary disease.</p>

<p><strong>STUDY DESIGN: </strong>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.</p>

<p><strong>RESULTS: </strong>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&nbsp;&lt;&nbsp;.001) and experience their first seizure later than those without cardiopulmonary disease (174 vs 21&nbsp;hours of age, P&nbsp;&lt;&nbsp;.001), but they had similar seizure exposure (many-recurrent electrographic seizures 39% vs 43%, P&nbsp;=&nbsp;.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&nbsp;=&nbsp;.75). Neonates with cardiopulmonary disease were discharged from the hospital later (hazard ratio 0.34, 95% CI 0.25-0.45, P&nbsp;&lt;&nbsp;.001), although rates of in-hospital mortality were similar between the groups (hazard ratio 1.13, 95% CI 0.66-1.94, P&nbsp;=&nbsp;.64).</p>

<p><strong>CONCLUSION: </strong>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.</p>

<p><strong>OBJECTIVE: </strong>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.</p>

<p><strong>STUDY DESIGN: </strong>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.</p>

<p><strong>RESULTS: </strong>ICH was a more common seizure etiology in infants born preterm vs term (27% vs 10%, P&nbsp;&lt;&nbsp;.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&nbsp;=&nbsp;.05) and an incomplete response to the initial ASM (100% vs 66%, P&nbsp;=&nbsp;.02). Status epilepticus was more common in HIE with ICH vs HIE alone (38% vs 17%, P&nbsp;=&nbsp;.05).</p>

<p><strong>CONCLUSIONS: </strong>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.</p>