The purpose of this study is to estimate the effect of medical treatment of electro-encephalographic status epilepticus on neurological outcome of patients with postanoxic encephalopathy after cardiac arrest.

Rationale: Electroencephalographic status epilepticus is described in 9-35% of patients with postanoxic encephalopathy after cardiac arrest and is associated with case fatality rates of 90-100%. It is unclear whether (some) electroencephalographic seizure patterns in these patients represent a condition which can be treated with antiepileptic drugs to improve outcome, or have to be regarded as an expression of severe ischemic damage, in which treatment with antiepileptic would be futile. Therefore, both treatment with and treatment without antiepileptic drugs are considered standard modalities in these patients. We aim to compare these standard strategies and hypothesize that aggressive and early treatment of electro-encephalographic status epilepticus with antiepileptic drugs improves outcome as compared to treatment without these drugs.

Objective: To estimate the effect of medical treatment of electro-encephalographic status epilepticus on neurological outcome of patients with postanoxic encephalopathy after cardiac arrest

Study design: We will perform a multicenter clinical trial with randomized treatment allocation, open label treatment and blinded endpoint evaluation (PROBE design). The intervention contrast will be aggressive medical treatment vs. no treatment of electroencephalographic status epilepticus, in addition to standard best medical management of comatose patients after cardiac arrest, including mild therapeutic hypothermia.

Study population: The study population will consist of adult patients with postanoxic encephalopathy after cardiac arrest, admitted to the intensive care unit, with electroencephalographic status epilepticus on continuous EEG, who are eligile for inclusion in this trial.

Intervention: Treatment of electroencephalographic status epilepticus will be based on guidelines for treatment of overt status epilepticus. The objective of this treatment will be to suppress all epileptiform activity in the EEG. If the electroencephalographic status epilepticus will return after tapering sedative treatment at 24 hours, the procedure will be repeated. If the status will return after 2 x 24 hours, it will be considered refractory.

Main study parameters/endpoints: The primary outcome measure will be neurological outcome defined as the score on the Cerebral Performance Category (CPC) at 3 months dichotomized as good (CPC 1-2 = no or moderate neurological disability) and poor (CPC 3-5 = severe disability, coma, or death).

Sample size: With a presumed reduction of poor outcome of 7%, from 99% - 92%, alpha of 5%, power of 80%, one tailed testing, and one interim analysis by an independent data safety and monitoring board, the objected number of inclusions is 172. With an estimation of an incidence of electroencephalographic status epilepticus of 20% in patients with postanoxic coma, the total number of patients to be monitored will be 860.

Nature and extent of the burden and risks associated with participation: Medical treatment of electroencephalographic status epilepticus may modify the high risk of death. Otherwise, this treatment of electroencephalographic status epilepticus may lead to prolonged hospitalization of several days of comatose patients that otherwise would have died. The risk of an increase of morbidity or mortality on the longer term is considered negligible.

Inclusion Criteria:

• Patients after cardiac arrest with suspected postanoxic encephalopathy
• Age 18 years or older
• Continuous EEG with at least eight electrodes started within 24 hours after cardiac arrest
• Electroencephalographic status epilepticus on continuous EEG
• Possibility to start treatment within three hours after detection of electroencephalographic status epilepticus.

Exclusion Criteria:

• A known history of another medical condition with limited life expectancy (<6 months)
• Any progressive brain illness, such as a brain tumor or neurodegenerative disease
• Pre-admission Glasgow Outcome Scale score of 3 or lower
• Reason other than neurological condition to withdraw treatment
• Follow-up impossible due to logistic reasons