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

Introduction

Cardiac arrest is a medical emergency that, in certain groups of patients, is potentially reversible if treated early enough. Outcome after cardiac arrest is mostly determined by the degree of hypoxic brain damage. Patients recovering from cardiopulmonary resuscitation are at great risk of subsequent death or severe neurological damage, including a persistent vegetative state. The early definition of prognosis for these patients has ethical and economic implications; it is estimated that the cost for the care of severely brain-damaged survivors runs into billions of dollars each year.

Methods

The main purpose of this study was to investigate the value of serum neuron-specific enolase (NSE) in predicting outcomes in patients early after inhospital cardiac arrest. This study was carried on 30 patients who had inhospital cardiac arrest during their admission to the critical care unit and for whom cardiopulmonary resuscitation was performed according to the protocol of the European Resuscitation Guidelines, who survived for at least 12 hours after the event and for whom informed consent was obtained. We excluded patients with neoplastic diseases known to increase NSE levels (small cell lung cancer, melanoma and malignancy of the kidney and testicles, stroke (ischemic and/or hemorrhagic) or traumatic brain injury).

Results

As regards NSE, it was found that the NSE level at 24 hours in patients with good recovery ranged between 0.80 ng/ml and 10.20 ng/ml with a mean of 5.60 ± 3.26 ng/ml, and for those with severe disability the NSE level ranged between 18.30 ng/ml and 20.50 ng/ml with a mean of 19.40 ± 1.56 ng/ml. Vegetative patients had a higher NSE level than others with a mean of 64.38 ± 26.16 ng/ml, and patients who died had a mean NSE level of 22.61 ± 9.93 ng/ml. The difference was statistically significant, showing a higher NSE level in patients with more hypoxic brain insult after arrest who died or remained in a persistent vegetative state. (P significant, P < 0.001.)

Conclusion

The present study demonstrated that the NSE value at 24 hours after return of spontaneous circulation was one of the best predictors for neurological outcome as NSE levels, and it tended to increase in patients with a bad neurological outcome. The NSE level tended to decrease in those with a good neurological outcome. If NSE concentrations increase by >15 ng/ml, prognosis tends to be bad.