Blood Biomarkers of Hypoxic-Ischemic Brain Injury after Cardiac Arrest.

Biomarkers are part of the recommended outcome predictors after cardiac arrest. In general, blood biomarkers can easily be performed as routine laboratory tests, and they are unaffected by sedation, but bear the potential risk of laboratory errors. Nonetheless, if used properly, with the potential limitations in mind, they certainly help predict outcome after cardiac arrest. Among the routinely used and available blood biomarkers, neuron-specific enolase (NSE) has the best predictive value for poor outcome if measured serially from 24 to 72 hours. Cutoff values should be taken with caution because there is no 100% specificity (0% false-positive rate) in clinical practice. Rather, the increase over time of high NSE values is predictive of poor outcome. Other biomarkers like protein S100 and inflammatory markers also bear a potential to predict outcome, but they are outperformed by NSE. New blood biomarkers are currently under investigation and might improve the accuracy of outcome prediction. The family of noncoding RNAs, including microRNAs, is probably the most promising as microRNAs are not only associated with outcome, but also have the potential for therapeutic implications through their mechanism of action.