Serum levels of the brain-derived proteins S-100 and NSE predict long-term outcome after cardiac arrest

Background and purpose: patients with cardiac arrest have a high mortality and the long-term outcome is doubtful. The prognosis is mainly dependent on clinical parameters. S-100 and neurone specific enolase (NSE) are established biochemical markers of central nervous system (CNS) injury. The purpose of this study was to validate the use of serum determinations of S-100 and NSE with neurological investigations in regard to brain damage and long-term outcome after cardiac arrest. Methods: neurological examinations were performed on 66 patients after cardiac arrest. Serum levels of S-100 and NSE were determined during the first 3 days of post arrest, using commercial luminescent immunoassays (LIAs). The main outcome variable was the Glasgow Outcome Scale (GOS), while secondary variables were the activity of daily living (ADL) index and mini mental state examination (MMSE). Outcome was determined at 1 year. Results: the serum levels of S-100 and NSE were increased during the first 3 days after the arrest and were related to coma depth, time of anoxia and abnormal brain stem reflexes. High levels predicted a poor outcome, according to the GOS (death, vegetative state and severe disability). The prognostic value of the brain damage markers was comparable with that of traditional clinical parameters. None of the secondary outcome variables (ADL and MMSE) was strongly associated with S-100 or NSE. Discussion: the serum levels of S-100 and NSE increased after cardiac arrest due to the anoxic brain damage. The determination of S-100 and NSE can be used as an adjunct to predict long-term outcome after cardiac arrest.