Hypoxic-ischemic Encephalopathy

Posted On March 8, 2020

Prognosis assessment

  • Prognosis based on history:
    • Out of hospital cardiac arrest
      • 44% survive initially
      • 30% alive at 24 hours
      • 13% at 1 month
      • 6% after 6 months
    • CPR over 15 minutes
    • Other variables for poor prognosis
      • age >70
      • renal failure prior to event
      • fever wihtin first 24 hr
      • recent congestive heart failure
    • Initial rhythm of tachycardia or ventricular fibrillation
      • better prognosis
    • Prognosis based on exam:
      • Exam findings at Day 3 indicate poor outcome
        • Absent or extensor (decerebrate) response
        • Absent pupil or corneal reflex
    • Tests:
      • EEG malignant type has higher mortality
        • complete or near complete suppression – most specific
        • burst suppression
        • generalized periodic complexes
        • low voltage pattern < 10 microvolts
        • intermittent or continuous seizure
        • lack of response to stimuli
        • alpha-theta pattern
      • EEG – nonconvulsive seizures (NCS)
        • be aware that seizure may be suppressed by sedation or NM blockage
        • non convulsive seizure detected 9-30% post CPR
        • Hypothermia may precipitate NCS
        • NCS- associated with poor prognosis, not improved by antiseizure medications
      • Biochemistry
        • neuron-specific enolase (NSE)
        • NSE > 33 mcg/L may be associated with poor outcome
      • Imaging:
        • CT head: Day 1 usually negative
          • Day 3: cerebral edema, inversion of gray-white densities indicate poor prognosis.
        • MRI especially diffusion coefficient mapping useful
          • Most useful when performed at Day 5
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