Hypoxic-Ischemic Encephalopathy (HIE) Clinical Pathway, ICU – Neurological Monitoring

Hypoxic-Ischemic Encephalopathy (HIE) Clinical Pathway — ICU

Neurological Monitoring

HIE accounts for ≥ 50% of all neonatal seizures. Seizures typically occur within the first 48 hrs after insult but can also occur during the re-warming period. Therapeutic hypothermia may reduce seizure burden in neonates with HIE, but the incidence of seizure remains high.

EEG is needed for the diagnosis and management of seizures in the neonate. Clinical seizures are difficult to diagnose. Subtle signs are common and misleading, and many neonatal seizures have no clinical signs. A high percentage of seizures are only noted on EEG (Subclinical or EEG-only seizures), especially after treatment with an antiseizure medication i.e., electroclinical dissociation. If seizures are suspected on aEEG, then cEEG should be obtained for confirmation and management.

Role of Neurologic Monitoring in Establishing Diagnosis of Moderate or Severe HIE

  • Neuromonitoring (cEEG or aEEG) not required to establish eligibility for neuroprotective care
  • Can be used as an additional diagnostic tool
  • Normal cEEG does not exclude an infant from neuroprotective treatment if all other criteria
    are present

Seizure Surveillance During Neuroprotective Care/Active Temperature Management

Continuous EEG (cEEG)
  • Continuous EEG (cEEG) remains the gold standard for seizure detection and quantification, use as possible
  • Monitor for a minimum of 84 hrs
    • 72 hrs hypothermia → 6 hrs rewarming → 6 hrs monitoring
  • Consider 24 hrs of cEEG monitoring during normothermia for neonates with moderate to severely abnormal EEG background (excessive discontinuity with IBI > 30 secs, low voltage or suppressed/flat tracing, burst suppression)
  • If neonate experiences an electrographic seizure, cEEG monitoring should be continued until the neonate is 24 hrs seizure free
Amplitude-integrated EEG (aEEG)
  • aEEG is an alternative and can be useful where cEEG is not available
  • Monitor for a minimum of 84 hrs
    • 72 hrs hypothermia → 6 hrs rewarming → 6 hrs
    • Normothermia for neonates with moderate to severely abnormal EEG background (excessive discontinuity with IBI > 30 secs, low voltage or suppressed/flat tracing, burst suppression)
  • If concern for seizures on aEEG or signs of clinical seizures, recommend connecting to cEEG or transferring to center with cEEG availability
  • Note: In the absence of seizure-like activity, all infants should be screened with a routine EEG lasting a minimum of 1 hr at 12-36 hrs of life to assess for subclinical seizures and EEG background