Abstracts

Rationale: Potentially ictal patterns frequently occur following cardiac arrest. These patterns will be undetected in the absence of early EEG recording. Continuous EEG (CEEG) is used to assess cerebral function during and after therapeutic hypothermia (TH), yet there is not a standard recommendation for timing to initiate recording. Recent studies have indicated that ictal EEG patterns were often found at initiation of EEG. This suggests that earlier onset of EEG recording following cardiac arrest may prompt earlier treatment with antiepileptic drugs(AEDs), which, in turn, may result in improved neurologic prognosis.Methods: We reviewed all CEEGs acquired at Wake Forest Baptist Health in 2010. Fifty patient instances were identified with cardiac arrest and subsequent TH and CEEG for up to 48 hours. We reviewed patient demographics, medical history, presenting cardiac rhythm (in those with witnessed cardiac arrest), time of initiation of TH, and time of initiation of CEEG. In addition, we reviewed initial EEG patterns and timing of subsequent EEG changes, as well as 1 and 6 month survival.Results: The most commonly identified presenting cardiac rhythm was ventricular fibrillation (19/50), followed by pulseless electrical asystole (11/50). The remaining patients were undocumented or unwitnessed arrests. EEG initiation occurred after TH in all cases, with onset between 2 and 12 hours after cardiac arrest (mean 7.6 hrs). Five patients had already established seizures and an additional 13 had potentially ictal patterns at the beginning of recordings. Two additional patients developed seizures more than 24 hours after the cardiac arrest. 29 patients were confirmed dead and 11 survived at 6 months, with the remaining 10 undetermined. No EEG pattern or cardiac rhthym correlated wtih survival.Conclusions: TH has been previously shown to improve outcome following cardiac arrest, but optimal therapeutic use of CEEG in this population had not been determined. Our study documents that ictal changes are seen, on average before 7.6 hours after cardiac arrest despite TH. These data suggest that earlier CEEG recordings may capture the initial, rather than these later ictal changes and thus could avoid delays in treatment of seizures. Further study is needed to determine if earlier CEEGs can positively affect neurologic outcome of post cardiac arrest patients.