[1] Univ Pittsburgh, Safar Ctr Resuscitat Res, Pittsburgh, PA 15260 USA
[2] Univ Pittsburgh, Brain Trauma Res Ctr, Pittsburgh, PA 15260 USA
[3] Univ Pittsburgh, Dept Anesthesiol & Crit Care Med, Pittsburgh, PA 15260 USA
[4] Univ Pittsburgh, Dept Pediat, Pittsburgh, PA 15260 USA
[5] Univ Pittsburgh, Dept Neurol Surg, Pittsburgh, PA 15260 USA