Serum neuron-specific enolase as early predictor of outcome after cardiac arrest

Objective: To examine the prognostic value of serum neuron-specific enolase for early prediction of outcome in patients at risk for anoxic encephalopathy after cardiac arrest. Design: Prospective study. Setting: Coronary intensive care unit of the University of Heidelberg. Patients: Forty-three patients (66.8 +/- 12.7 [SD] yrs, range 33 to 85) who had had either primary or secondary cardiac arrest, followed by cardiopulmonary resuscitation (CPR). Interventions: Serial blood samples and clinical examinations. Measurements and Main Results: Serum neuron-specific enolase concentrations were determined after CPR on 7 consecutive days. Twenty five patients remained comatose and subsequently died; 18 patients survived the first 3 months and had no relevant functional deficit at 3-month follow-up. Neuron-specific enolase concentrations were correlated with neurologic outcome, Concentrations of >33 ng/mL predicted persistent coma with a high specificity (100%) and a positive predictive Value of 100%. Overall sensitivity was 80%, with a negative predictive value of 78%. Serum concentrations of neuron specific enolase exceeded this cutoff value no more than 3 days after cardiac arrest in 95% of patients in whom these concentrations had exceeded 33 ng/mL, Conclusions: In patients who have been resuscitated after cardiac arrest, serum neuron-specific enolase concentrations of >33 ng/mL predict persistent coma with a high specificity. Values below this cutoff level do not necessarily indicate complete recovery, because this method has a sensitivity of 80%.