This study is a prospective consecutive double-blinded randomized study on the effect of PGI2, prostacyclin (epoprostenol, Flolan®) versus placebo (saline)in patients with severe traumatic brain injury. All patients with severe traumatic brain injury were eligible for inclusion. Inclusion criteria: verified traumatic brain injury, Glasgow Coma Score (GCS) at intubation and sedation of ≤ 8, age 15-70 years, a first-recorded cerebral perfusion pressure (CPP) of > 10 mm Hg, and arrival within 24 hours after trauma.

Tne primary aim was to evaluate whether treatment with epoprostenol would reduce a lactate/pyruvate ratio,as measured by cerebral microdialysis after 24 hours of treatment.

A secondary aim was to evaluate the effect of epoprostenol on systemic inflammatory markers, measured by different cytokines.

Inclusion Criteria:

• traumatic brain injury, Glasgow coma scale ≤ 8

Exclusion Criteria:

• pregnant or lactating women