Abstracts

Rationale: Mild hypothermia induced after resuscitation from cardiac arrest (CA) has been reported to decrease mortality and improves neurological outcome. However, therapeutic hypothermia (TH) delays the recovery of motor responses and thus, makes clinical evaluation often unreliable. The aim of this study was to investigate the occurrence of various EEG patterns during hypothermia after cardiac arrest and their prognostic value.Methods: Twenty- six consecutive patients treated with TH for 36 hrs after CA in our institution from 2010 to 2011 were retrospectively collected. Twenty- two of those who had either continuous EEG or 1 hour EEG after cardiac arrest were included. All patients who were found to have electrographic activity other than generalized slowing and attenuation on 1 hour EEG were continuously monitored. Most EEGs were initiated during TH. Academic center epileptologists analyzed these EEGs for background activity. Variables included in the review where age, cause of arrest, initial cardiac rhythm, estimated time from collapse to return of spontaneous circulation (ROSC), time of TH initiation, pre-morbid functional state, and presence of myoclonic jerks. We correlated EEG findings with neurological outcome by employing Cerebral Performance Category Scale at the time of discharge or death. Results: Hypothermia was induced in all patients within 4 hrs after ROSC. Age of patients ranged from 22 to 86 years with mean age of 59 years. Average time from collapse to ROSC was 18.6 min. Of patients status post cardiac arrest, theta and/or delta rhythm was found in 63%, electrographic status epilepticus (ESE) was found in 27%, alpha coma was found in 5%, and isoelectic rhythm was found in 5%. Ten (45%) of the total 22 patients were discharged alive. The mean CPS score for patient who were discharged alive with theta and /or delta rhythm was 1.4. Only one patient out of 6 with ESE and myoclonic jerks survived with CPC score of 2 and pre-hospitalization CPC score of 1. There was also one patient in alpha coma with no myoclonic jerks who survived with CPC score of 2 and the same pre-hospitalization score. See following table. All patients with ESE were aggressively treated with ?3 anti-epileptic drugs (AED). One out of 6 patients with ESE was successfully treated with 3 AEDS. The other 5 patients had ESE refractory to optimal doses of 2-3 AEDs and intravenous sedation. Conclusions: Post anoxic status epilepticus (SE) was not uniformly associated with poor outcome. Thus, it is important to utilize continues EEG recording on patients with hypothermia protocol as soon as possible after CA to detect seizure activity. This activity is often not observed clinically, especially in setting of neuromuscular blockade. Larger studies are needed to investigate how often early detection and treatment of electrographic seizures or SE leads to a favorable outcome.