Prostacyclin Treatment in Severe Traumatic Brain Injury: A Microdialysis and Outcome Study

Prostacyclin ([PGI.sub.2]) is a potent vasodilator, inhibitor of leukocyte adhesion, and platelet aggregation. In trauma the balance between [PGI.sub.2] and thromboxane [A.sub.2] (TX[A.sub.2]) is shifted towards TX[A.sub.2]. Externally provided [PGI.sub.2] would, from a theoretical and experimental point of view, improve the microcirculation in injured brain tissue. This study is a prospective consecutive double-blinded randomized study on the effect of [PGI.sub.2] versus placebo in severe traumatic brain injury (sTBI). All patients with sTBI were eligible. Inclusion criteria: verified sTBI, Glasgow Coma Score (GCS) at intubation and sedation of ≤ 8, age 15-70 years, a first-recorded cerebral perfusion pressure (CPP) of ≥ 10mm Hg, and arrival within 24 h of trauma. All subjects received an intracranial pressure (ICP) measuring device, bilateral intracerebral microdialysis catheters, and a microdialysis catheter in the abdominal subcutaneous adipose tissue. Subjects were treated according to an ICP-targeted therapy based on the Lund concept. 48 patients (mean age of 35.5 years and a median GCS of 6 [3-8]) were included. We found no significant effect of prostacyclin (epoprostenol, Flolan) on either the lactate-pyruvate ratio (L/P) at 24 h or the brain glucose levels. There was no significant difference in clinical outcome between the two groups. The median Glasgow Outcome Score (GOS) at 3 months was 4, and mortality was 12.5%. The favorable outcome (GOS 4-5) was 52%. The initial L/P did not prognosticate for outcome. Thus our results indicate that there is no effect of [PGI.sub.2] at a dose of 0.5ng/kg/min on brain L/P, brain glucose levels, or outcome at 3 months. Key words: lactate-pyruvate ratio; microdialysis; prostacyclin; severe traumatic brain injury