Neuron Specific Enolase and S-100B As Predictors of Outcome After Cardiac Arrest and Induced Hypothermia

Aim: To assess the prognostic value of repetitive serum samples of neuron specific enolase (NSE) and S-100B in cardiac arrest patients treated with hypothermia.

Methods: In a three-centre study, comatose patients after cardiac arrest were treated with hypothermia at 33 degrees C for 24h, regardless of cause or the initial rhythm. Serum samples were collected at 2, 24, 48 and 72h after the arrest and analysed for NSE and S-100B in a non-blinded way. The cerebral performance categories scale (CPC) was used as the outcome measure; a best CPC of 1-2 during 6 months was regarded as a good outcome, a best CPC of 3-5 a poor outcome.

Results: One centre was omitted in the NSE analysis due to missing 24 and 48h samples. Two partially overlapping groups were studied, the NSE group (n=102) and the S-100B group (n=107). NSE at 48h >28microg/l (specificity 100%, sensitivity 67%) and S-100B >0.51microg/l at 24h (specificity 96%, sensitivity 62%) correlated with a poor outcome, and so did a rise in NSE of >2microg/l between 24 and 48h (odds ratio 9.8, CI 3.5-27.7). A majority of missing samples (n=123) were from the 2h sampling time (n=56) due to referral from other hospitals or inter-hospital transfer.

Conclusion: NSE was a better marker than S-100B for predicting outcome after cardiac arrest and induced hypothermia. NSE above 28microg/l at 48h and a rise in NSE of more than 2microg/l between 24 and 48h were markers for a poor outcome.