Serum levels of S100B from jugular bulb as a biomarker of poor prognosis in patients with severe acute brain injury.

Aims/background: To evaluate the correlation between protein S100B concentrations measured in the jugular bulb as well as at peripheral level and the prognostic usefulness of this marker.

Methods: A prospective study of all patients admitted to the intensive care unit with acute brain damage was carried out. Peripheral and jugular bulb blood samples were collected upon admission and every 24h for three days. The endpoints were brain death diagnosis and the Glasgow Outcome Scale score after 6months.

Results: A total of 83 patients were included. Jugular protein S100B levels were greater than systemic levels upon admission and also after 24 and 72h (mean difference>0). Jugular protein S100B levels showed acceptable precision in predicting brain death both upon admission [AUC 0.67 (95% CI 0.53-0.80)] and after 48h [AUC 0.73 (95% CI 0.57-0.89)]. Similar results were obtained regarding the capacity of jugular protein S100B levels upon admission to predict an unfavourable outcome (AUC 0.69 (95% CI 0.56-0.79)). The gradient upon admission (jugular-peripheral levels) showed its capacity to predict the development of brain death [AUC 0.74 (95% CI 0.62-0.86)] and together with the Glasgow Coma Scale constituted the independent factors associated with the development of brain death.

Conclusion: Regional protein S100B determinations are higher than systemic determinations, thus confirming the cerebral origin of protein S100B. The transcranial protein S100B gradient is correlated to the development of brain death.