Secretoneurin as a marker for hypoxic brain injury after cardiopulmonary resuscitation

The neuropeptide secretoneurin (SN) shows widespread distribution in the brain. We evaluated whether SN is elevated after cardiopulmonary resuscitation (CPR) and could serve as a potential new biomarker for hypoxic brain injury after CPR. This was a prospective observational clinical study. All patients admitted to a tertiary medical intensive care unit after successful CPR with expected survival of at least 24 h were consecutively enrolled from September 2008 to April 2013. Serum SN and neuron-specific enolase were determined in 24 h intervals starting with the day of CPR for 7 days. Neurological outcome was assessed with the Cerebral Performance Categories Scale (CPC) at hospital discharge. A total of 134 patients were included with 49 % surviving to good neurological outcome (CPC 1-2). SN serum levels peaked within the first 24 h showing on average a sixfold increase above normal. SN levels were significantly higher in patients with poor (CPC 3-5) than in patients with good neurological outcome [0-24 h: 75 (43-111) vs. 38 (23-68) fmol/ml, p < 0.001; 24-48 h: 45 (24-77) vs. 23 (16-39) fmol/ml, p < 0.001]. SN determined within the first 48 h showed a receiver operating characteristic (ROC) area under the curve (AUC) of 0.753 (0.665-0.841). NSE in the first 72 h had a ROC-AUC of 0.881 (0.815-0.946). When combining the two biomarkers an AUC of 0.925 (0.878-0.972) for outcome prediction could be reached. SN is a promising early biomarker for hypoxic brain injury. Further studies will be required for confirmation of these results.