Secretoneurin as a marker for hypoxic brain injury after cardiopulmonary resuscitation

PURPOSE: 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.

METHODS: 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.

RESULTS: 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.

CONCLUSIONS: SN is a promising early biomarker for hypoxic brain injury. Further studies will be required for confirmation of these results.