This is a substudy of the Targeted Temperature Management for 24 vs 48h trial. NSE and S-100b levels were analysed retrospectively in serum samples collected upon admission, at 24, 48, and 72h after reaching the target temperature of 33±1°C. The primary outcome was biomarker serum concentrations and secondary outcome was the cerebral performance category score after 6 months.
115 patients from two centres were analysed. NSE and S-100b levels did not differ between TTM groups at any single time-point. Poor outcome patients had higher biomarker levels at 24, 48, and 72h: NSE: 9.73 (7.2; 10.9) versus 20.40 (12.7; 27.2), 8.86 (6.6; 9.6) versus 17.47 (11.1; 37.3) and 6.23 (5.3; 8.5) versus 31.05 (12.8; 52.5) respectively and S-100b: 0.09 (0.07; 0.11) versus 0.23 (0.19; 0.39), 0.08 (0.07; 0.09) versus 0.18 (0.15; 0.33) and 0.07 (0.06; 0.08) versus 0.13 (0.09; 0.23). The daily changes in NSE from admission to Day 2 after the cardiac arrest (CA) were also related to the outcome (p=0.003 and p=0.02). The best prediction of outcome was found at 72h for NSE and at 24h as well as 48h for S100b.
No clinically relevant differences were found in the levels of NSE or S-100b between standard and prolonged TTM. Prognostic reliability of NSE and S-100b was unaltered by prolonged TTM.