Abstracts

Rationale: An estimated 450,000 people suffer cardiac arrest in the United States each year (1,2). Mortality amongst patients who are successfully resuscitated remains high around 60% (3). Patients treated with therapeutic hypothermia (TH) after cardiac arrest with shockable rhythms have improved survival rate and improved neurological outcomes (4,5). Continuous EEG (cEEG) recordings are commonly employed in the care of patients during and after hypothermia to detect subclinical seizures, non-convulsive status epilepticus and aid prognosis. Multiple EEG patterns, some with unclear clinical significance are recorded in these patients. At times antiseizure drugs (ASD) are used for a therapeutic trial. This retrospective study analyzed the EEG patterns, efficacy of ASD and clinical outcomes of patients who underwent TH after cardiac arrest at our institution. Methods: We retrospectively reviewed the electronic medical record of successive patients who underwent TH after cardiac arrest from 2015 to 2018. Inclusion criteria: 1) cEEG for more than 24 hours, 2) Documented history of resuscitation post arrest. Exclusion criteria: 1) Age <16 years, 2) Unclear cause of coma. Clinical and demographic variables (age, sex, duration of hospital stay, antiseizure drug use), EEG characteristics (during TH, during re-warming, post-rewarming) and functional outcomes (at discharge and last follow-up) were collected and analyzed using descriptive statistics. Results: Forty-seven patients (66% male) met inclusion criteria. Anoxic ischemic brain injury was found in 30 (63.8%) patients. Patients underwent a median of 44 hours (range 24-132) of cEEG. Five (10.6%) patients exhibited motor symptoms suggestive of clinical seizures (myoclonus, tonic-clonic activity) Three of these five had epileptiform features on EEG. Non-convulsive seizures were recorded in 9 (19.5%) patients. Ten (21.3%) patients were treated with ASD. Seven (70%) patients treated with ASD showed no change in EEG patterns or clinical picture after treatment while EEG normalized in 2 (20%) patients. Twenty patients (42.6%) died in the hospital. Of the 27 patients who survived hospitalization, follow up was available for 24 (88.9%) patients. Median follow up was 50 weeks (range 1-172). Cerebral performance category at last follow up was 1 (normal function) for 19, 2 (disabled but independent) for 4, and 3 (conscious but disabled and dependent) for 1 patient(s).  Conclusions: The mortality of cardiac arrest is high despite the use of TH. ASD are used in a few patients undergoing TH and their use was not associated with clinical improvement in majority of the patients. Most patients who survived hospitalization had a favorable neurological outcome at long term follow up. Funding: No funding