Modeling serum level of s100β and bispectral index to predict outcome after cardiac arrest

Abstract

Objectives: This study was designed to evaluate multimodal prognostication in patients after cardiac arrest (CA).

Background: Accurate methods to predict outcome after CA are lacking.

Methods: Seventy-five patients with CA treated with therapeutic hypothermia after cardiac resuscitation were enrolled in this prospective observational study. Serum levels of neuron-specific enolase (NSE) and neuron-enriched S100 beta (S100β) were measured 48 h after CA. Bispectral index (BIS) was continuously monitored during the first 48 h after CA. The primary endpoint was neurological outcome, as defined by the cerebral performance category (CPC) at 6-month follow-up: scores 1 or 2 indicated good outcome, and scores 3 to 5, poor outcome. The secondary endpoint was survival.

Results: A total of 46 (61%) patients survived at 6 months and 41 (55%) patients had CPC 1 or 2. Levels of NSE and S100β were higher in patients with poor outcomes compared with patients with good outcomes (4-fold and 10-fold, respectively; p < 0.001). BIS was lower in patients with poor outcomes (10-fold; p < 0.001). NSE, S100β, or BIS alone predicted neurological outcome, with areas under the receiver-operating characteristic curve (AUC) above 0.80. Combined determination of S100β and BIS had an incremental predictive value (AUC: 0.95). S100β improved discriminations based on BIS (p = 0.0008), and BIS improved discriminations based on S100β (p < 10(-5)). Patients with S100β level above 0.03 μg/l and BIS below 5.5 had a 3.6-fold higher risk of poor neurological outcome (p < 0.0001). S100β and BIS predicted 6-month mortality (log-rank statistic: 50.41; p < 0.001).

Conclusions: Combined determination of serum level of S100β and BIS monitoring accurately predicts outcome after CA.

Keywords: BIS; CA; CPC; EEG; ICU; IDI; NSE; ROSC; S100β; SAPS; biomarkers; bispectral index; brain injury; cardiac arrest; cerebral performance category; electroencephalogram; electroencephalography; integrated discrimination improvement; intensive care unit; neuron-enriched S100 beta; neuron-specific enolase; prognosis; return of spontaneous circulation; simplified acute physiology score; survival.