Early EEG correlates of neuronal injury after brain anoxia.
OBJECTIVE
EEG and serum neuron-specific enolase (NSE) are used for outcome prognostication in patients with postanoxic coma; however, it is unclear if EEG abnormalities reflect transient neuronal dysfunction or neuronal death. To assess this question, EEG abnormalities were correlated with NSE. Moreover, NSE cutoff values and hypothermic EEG features related with poor outcome were explored.


METHODS
In a prospective cohort of 61 adults treated with therapeutic hypothermia (TH) after cardiac arrest (CA), multichannel EEG recorded during TH was assessed for background reactivity and continuity, presence of epileptiform transients, and correlated with serum NSE collected at 24-48 hours after CA. Demographic, clinical, and functional outcome data (at 3 months) were collected and integrated in the analyses.


RESULTS
In-hospital mortality was 41%, and 82% of survivors had good neurologic outcome at 3 months. Serum NSE and EEG findings were strongly correlated (Spearman rho = 0.45; p < 0.001). Median NSE peak values were higher in patients with unreactive EEG background (p < 0.001) and discontinuous patterns (p = 0.001). While all subjects with nonreactive EEG died, 5 survivors (3 with good outcome) had NSE levels >33 μg/L.


CONCLUSIONS
The correlation between EEG during TH and serum NSE levels supports the hypothesis that early EEG alterations reflect permanent neuronal damage. Furthermore, this study confirms that absent EEG background reactivity and presence of epileptiform transients are robust predictors of poor outcome after CA, and that survival with good neurologic recovery is possible despite serum NSE levels> 33 μg/L. This underscores the importance of multimodal assessments in this setting.
Department of Clinical Neurosciences, University Hospital and Faculty of Biologyand Medicine, Lausanne, Switzerland. andrea.rossetti@chuv.ch
Andrea O
AO
Rossetti
Emmanuel
E
Carrera
Mauro
M
Oddo
D000368:Aged; D000927:Anticonvulsants / Q000627:therapeutic use; D015331:Cohort Studies; D003128:Coma / Q000209:etiology; D003627:Data Interpretation, Statistical; D004569:Electroencephalography; D005260:Female; D006323:Heart Arrest; D017052:Hospital Mortality; D006801:Humans; D007036:Hypothermia, Induced; D002534:Hypoxia, Brain / Q000473:pathology* / Q000503:physiopathology* / Q000628:therapy; D008297:Male; D008875:Middle Aged; D009460:Neurologic Examination; D009474:Neurons / Q000473:pathology*; D010751:Phosphopyruvate Hydratase / Q000097:blood*; D011379:Prognosis; D011446:Prospective Studies; D016896:Treatment Outcome
D000927:Anticonvulsants; D010751:Phosphopyruvate Hydratase