1. Safar Center for Resuscitation Research, University of Pittsburgh, Pittsburgh, Pennsylvania.
2. Department of Anesthesiology, University of Pittsburgh, Pittsburgh, Pennsylvania.
3. Department of Pathology, University of Pittsburgh, Pittsburgh, Pennsylvania.
4. Department of Surgery, RA Cowley Shock Trauma Center, University of Maryland, Baltimore, Maryland.
5. Department of Critical Care Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania.