Outcome prediction by amplitude-integrated EEG in adults with hypoxic ischemic encephalopathy

Introduction: Amplitude-integrated electroencephalography (aEEG) had been widely used in predicting outcome in infants with hypoxic ischemic encephalopathy (HIE). We aimed to evaluate the use of aEEG as a quantitative predictor of outcome in adult patients with HIE.

Methods: aEEG and Glasgow coma scale (GCS) were recorded for patients with HIE within 72 h of onset. aEEG traces were categorized as Grade I (normal amplitude): upper margin of aEEG activity >10 μV, lower margin >5 μV; Grade II (moderately abnormal amplitude): upper margin of aEEG activity >10 μV, lower margin ≤5 μV, or with suppressed amplitude, upper margin ≤10 μV, lower margin >5μV; Grade III (mild abnormality): either upper margin <10 μV, lower margin <5 μV. GCS was graded as I (9-14), grade II (4-8), or grade III (3). Cerebral performance category scores (CPCs) were determined 1 and 3 month after clinical evolution. CPC 1,2 were defined as favorable outcome; CPC 3,4,5 were considered as poor outcome.

Results: 30 cases met inclusion criteria. Both the aEEG grade and GCS scores correlated significantly with short-term outcome, and cases with a worse aEEG grade were more likely to have an unfavorable short-term outcome. Since the number of patients is really too small for long-term outcome analysis, we did not perform the analysis of aEEG, GCS and longer-term outcome. There was significant difference of clinical findings among aEEG classifications, while no statistical difference was found of causes of HIE.

Conclusions: aEEG is a reliable predictor of short-term outcome in HIE, and aEEG results within 72h after onset were associated with neurodevelopmental outcome at 1 mo following clinical evolution.