Jugular venous and arterial concentrations of serum S-100B protein in patients with severe head injury: a pilot study

The objective of this study was to analyse the temporal course of the jugular venous-arterial gradient of S-100B protein after severe head injury and the correlation between the absolute concentrations of serum S-100B protein and outcome, CT findings, and clinical variables. Fifteen patients were included in this pilot study. All patients were treated according to a standard therapy protocol targeted to maintain cerebral perfusion pressure. The serum concentration of S-100 protein was measured daily for five consecutive days after injury by a monoclonal two site immunoluminometric assay. Nine patients showed favourable and six unfavourable outcome after 6 months with a mortality rate of 33% (five patients). The mean gradient between jugular venous and arterial blood was 8.2% (p<0.05). Patients showing an unfavourable outcome had significantly higher jugular venous or arterial S-100 values compared with those with a favourable outcome (jugular venous S-100B 2.78 mu g/l v 1.22 mu g/l, p<0.05; arterial S-100B 2.48 mu g/l v 1.19 mu g/l, p<0.05). All patients with an initial or secondary increase in S-100B value of >2 mu g/l were found to have an unfavourable outcome. S-100B was found to be an independent predictor of outcome after severe head injury. The persisting increase of S-100B for three to five days even in patients with favourable outcome and no signs of secondary insults might reflect continuing damage to the blood-brain barrier or ongoing glial cell death.