[1] Univ Pittsburgh, Sch Med, Dept Crit Care Med, Safar Ctr Resuscitat Res, Pittsburgh, PA 15260 USA
[2] Univ Pittsburgh, Sch Med, Dept Surg, Safar Ctr Resuscitat Res, Pittsburgh, PA USA
[3] Univ Pittsburgh, Sch Med, Dept Anesthesiol, Safar Ctr Resuscitat Res, Pittsburgh, PA 15261 USA