Seizures severity during rewarming can predict seizure outcomes of infants with neonatal hypoxic-ischemic encephalopathy following therapeutic hypothermia

Abstract

Background The aim of this study was to examine the predictive value of amplitude-integrated electroencephalography (aEEG) on 12-month seizure outcomes of infants with neonatal hypoxic-ischemic encephalopathy (HIE) treated with therapeutic hypothermia. Methods We conducted this retrospective cohort study in a tertiary neonatal intensive care unit between May 2012 and September 2017. Neonates with HIE who received both therapeutic hypothermia (TH) and aEEG were enrolled. Results A total of 23 infants (14 boys, nine girls) with a mean gestational age of 38.9 weeks were enrolled. Fifteen (65%) infants had moderate HIE and eight (35%) had severe HIE according to modified Sarnat staging. The mean aEEG recording time was 107.5 h. Twenty (86.9%) infants had seizure activity during the first 24 h after cooling and 14 (60.8%) had seizure activity during the first 24 h after rewarming. At 12 months, five (21.7%) infants had poor seizure outcomes. Repetitive seizures or status epilepticus pattern during the first 24 h after rewarming, but not the first 24 h after cooling, were associated with the presence of epilepsy at 12 months ( p = 0.037). Conclusions We identified a high incidence of electrographic seizures in infants with neonatal HIE treated with therapeutic hypothermia, and post-neonatal epilepsy in the children who survived after HIE. Repetitive seizures or status epilepticus pattern during the first 24 h after rewarming, but not in the first 24 h after cooling, were associated with the presence of epilepsy at 12 months.

Association Between Increased Seizures During Rewarming After Hypothermia for Neonatal Hypoxic Ischemic Encephalopathy and Abnormal Neurodevelopmental Outcomes at 2-Year Follow-up

“…Findings underscore the necessity of either continuous EEG or aEEG monitoring during rewarming as most seizures detected were subclinical and would have be missed otherwise. The low-voltage span and discontinuous patterns observed in this cohort at 72 hours reflect the encephalopathy severity . Secondary aEEG analysis showed no significant effect of rewarming on background voltage activity congruent with other studies showing that a temperature above 32 °C does not influence these parameters …”

“…Monitoring for seizures during rewarming can identify infants who have a more severe injury with impaired autoregulation leading to hemodynamic mismatch between oxygen delivery and metabolic demands . A number of small studies using electroencephalography (EEG) or amplitude integrated EEG (aEEG) have described late or rebound seizures during rewarming after 72 hours of hypothermia . To our knowledge, none of the prior large randomized trials of hypothermia for moderate or severe HIE included EEG or aEEG during the rewarming phase .…”

Protecting the blossoming brain – Neurocritical care in children

“…To note, this issue contains additionally two original articles by the author's department, reporting encouraging first results regarding the use of TTM for the treatment of paediatric refractory status epilepticus [ 37 ], as well as the predictive value of seizure patterns during rewarming after TTM in neonates with hypoxic-ischaemic encephalopathy [ 38 ].…”

“…Chen et al. carried out a retrospective cohort study using amplitude-integrated electroencephalography at the moment of TH administration, and comparing the patients for the presence of epilepsy 12 months later [ 38 ].…”

Recent update in pediatric neurocritical care: Preface

“…The third part of this issue includes some challenging issues, such as abusive head trauma related to child abuse [ 7 ], anti-NMDA receptor encephalitis [ 8 ], neurocritical care and surgical management of intraventricular hemorrhage and posthemorrhagic hydrocephalus in premature infants [ 9 , 10 ]. In the third part, we also include two original articles of the studies of seizure outcomes after TTM and one study about the diminished Toll-like receptor response in FIRES [ [11] , [12] , [13] ].…”