Clinical significance of serum S100B levels in neurointensive care

Objective: S100B is viewed as the most promising biomarker for brain damage. It has been proposed that this marker is useful in a Neurointensive Care Unit (NICU) as a monitoring parameter. This study aims to examine the clinical usefulness of daily serum S100B measurements in this setting. Design: Prospective consecutive inclusion of patients. Patients: A total of 79 patients with confirmed or suspected head injury or cerebrovascular insults (CVIs) (based upon patient history, computed tomography (CT) and/or magnetic resonance imaging (MRI) and neurological examination including coma scoring) who required neurointensive care were included in the study. Interventions: Sampling for S100B was performed at admission and daily until patients were discharged from the NICU. S100B measurements were statistically compared to occurrence of secondary complications and outcome according to Glasgow Outcome Scale (GOS), with focus on clinical prediction. Measurements and main results: 17 of 79 patients (22%) had secondary neurological complications. Mean S100B levels were found to be an independent parameter associated with these complications (P ≤ 0.03). Mean S100B levels were higher in patients with complications compared to those without on both the complication day (P ≤ 0.033) and the day after (P ≤ 0.015), but not the day prior to the complication (P ≤ 0.62). S100B did not predict secondary neurological complication. Neither mean (P ≤ 0.182) nor peak (P ≤ 0.370) S100B levels were associated with or predicted outcome according to dichotomised GOS. Conclusion: Daily S100B measurements are associated with secondary complications but not to outcome. However, daily S100B levels do not predict secondary complications, which limit the usefulness of this brain biomarker in this setting.