Andrea O Rossetti, Luis A Urbano, Frederik Delodder, Peter W Kaplan, Mauro Oddo; Critical Care 2010, 14:R173
Introduction: Continuous EEG (cEEG) is increasingly used to monitor brain function in neuro-ICU patients. However its value in patients with coma after cardiac arrest (CA), particularly in the setting of therapeutic hypothermia (TH), is only beginning to be elucidated. The aim of this study was to examine whether cEEG performed during TH may predict outcome.
Methods: From April 2009 to April 2010, we prospectively studied 34 consecutive comatose patients treated with TH after CA who were monitored with cEEG, initiated during hypothermia and maintained after rewarming. EEG background reactivity to painful stimulation was tested. We analyzed the association between cEEG findings and neurological outcome, assessed at 2 months with the Glasgow-Pittsburgh Cerebral Performance Categories (CPC).
Results: Continuous EEG recording was started 12 +/- 6 hours following CA and lasted 30 11 hours. Non-reactive cEEG background (12/15 [75%] among non-survivors vs. 0/19 [0%] survivors, P<0.001) and prolonged discontinuous "burst-suppression" activity (11/15 [73%] vs. 0/19 [0%], P<0.001) were significantly associated with mortality. EEG seizures with absent background reactivity also differed significantly (7/15 [47%] vs. 0/12 [0%], P=0.001). In patients with non-reactive background or seizures/epileptiform discharges on cEEG, no improvement was seen after TH. Non-reactive cEEG background during TH had a positive predictive value of 100% (95% confidence interval 74 to 100 %) and a false positive rate of 0% (95% CI: 0% to 18%) for mortality. All survivors had cEEG background reactivity, and the majority of them (14/19 [74%]) had a favorable outcome (CPC 1 or 2).
Conclusions: Continuous EEG monitoring showing a non-reactive or discontinuous background during TH is strongly associated with unfavorable outcome in patients with coma after CA. These data warrant larger studies to confirm the value of continuous EEG monitoring in predicting prognosis after CA and TH.
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