Value of electroencephalographic monitoring in newborns with hypoxic-ischemic encephalopathy treated with hypothermia

Abstract

Background:The values of electroencephalography (EEG) in neonatal hypoxic-ischemic encephalopathy (HIE) during therapeutic hypothermia (TH) are still uncertain.Aims:The aim of this study is to detect EEG background, the prevalence of seizures during cooling, and to determine different EEG patterns that can predict brain injury in magnetic resonance imaging (MRI).Patients and Methods:Thirty-nine newborns with HIE were subjected to TH. Continuous monitoring by video-EEG was carried out throughout cooling and during rewarming. MRI was done for all newborns after rewarming. The predictive value of EEG background for MRI brain injury was evaluated at 6-h intervals during cooling and rewarming.Results:At all-time intervals, normal EEG was associated with no or mild MRI brain injury. At the beginning of cooling, normal background was more predictive of a favorable MRI outcome than at later time points. After 24 h of monitoring, diffuse burst suppression and depressed patterns had the greatest prognostic value. In most patients, a discontinuous pattern was not associated with poor prognosis. Thirty-one percent developed electrical seizures, and 8% developed status epilepticus. Seizures were subclinical in 42%. There is a significant association between duration of seizure patterns detected on the EEG and severity of brain injury on MRI.Conclusions:Continuous EEG monitoring in newborns with HIE under cooling has a prognostic value about early MRI brain injury and identifies electrographic seizures, approximately 50% of which are subclinical. Treatment of clinical and subclinical seizure results in a reduction of the total duration of seizure pattern supports the hypothesis that subclinical seizures should be treated.

Predictive value of early EEG for seizures in neonates with hypoxic–ischemic encephalopathy undergoing therapeutic hypothermia

“…The present data are in line with previous studies showing that 100% of neonates with an early normal background and 73-75% of those with an excessively discontinuous pattern after rewarming had no or only mild MRI injury. 3,27 This association between a normal/mildly abnormal initial EEG and none or mild MRI brain injury supports the observation that an excessively discontinuous background in the setting of TH is usually not associated with a poor outcome.…”

“…In the context of TH for presumed HIE, EEG background appears to have the greatest prognostic value at 24 h of monitoring for later seizure occurrence. 3,27,32 In our large cohort, the vast majority of neonates with a normal/ excessively discontinuous EEG background (97%) had no or mild MRI brain injury. The present data are in line with previous studies showing that 100% of neonates with an early normal background and 73-75% of those with an excessively discontinuous pattern after rewarming had no or only mild MRI injury.…”

“…This proportion of neonates with normal or mildly abnormal EEG is higher than previously reported in neonates treated with TH. 5,27 Possible explanations include a drift toward cooling neonates with milder encephalopathy as described in other cohorts, 28,29 earlier recognition of encephalopathy, and faster implementation of cooling leading to the possibility that, by the time EEG is started, the brain activity has already improved in some neonates. Furthermore, our definition of excessively discontinuous background encompasses a wide range of interburst intervals (up to 15 s).…”

Association of Hospital Resource Utilization With Neurodevelopmental Outcomes in Neonates With Hypoxic-Ischemic Encephalopathy

“… 19 , 28 Continuous EEG monitoring allows earlier detection of electrographic seizures, reduces the time to ASM therapy and decreases seizure burden. 19 , 28 , 29 , 30 , 31 A recent study by Hunt et al 32 in contrast did not reveal such utility or benefit to using aEEG monitoring to direct treatment of electrographic seizures with regards to death or disability at 2 years of age. However, the analyses did not account for differences in ASM use or seizure severity and/or burden.…”

“…However, neonatal seizures are often subclinical and difficult to identify even for experienced clinicians . Continuous EEG monitoring allows earlier detection of electrographic seizures, reduces the time to ASM therapy and decreases seizure burden . A recent study by Hunt et al in contrast did not reveal such utility or benefit to using aEEG monitoring to direct treatment of electrographic seizures with regards to death or disability at 2 years of age.…”