1. Department of Critical Care Medicine, University of Pittsburgh School of Medicine, Children's Hospital of Pittsburgh, Pittsburgh, Pennsylvania.
2. Safar Center for Resuscitation Research, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania.
3. Division of Pediatric Critical Care Medicine, Pennsylvania State University College of Medicine, Penn State Children's Hospital, Hershey, Pennsylvania.
4. Department of Neurosurgery, University of Pittsburgh School of Medicine, Children's Hospital of Pittsburgh, Pittsburgh, Pennsylvania.
5. Department of Epidemiology, Graduate School of Public Health, University of Pittsburgh School of Medicine, Pittsburgh,Pennsylvania.
6. Department of Pharmacology and Medicine, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania.