1. Department of Physical Medicine and Rehabilitation, University of Pittsburgh, Pittsburgh, Pennsylvania.
2. Safar Center for Resuscitation Research, University of Pittsburgh, Pittsburgh, Pennsylvania.
3. Department Obstetrics and Gynecology, Emory University, Atlanta, Georgia.
4. Department of Neurological Surgery, University of Pittsburgh, Pittsburgh, Pennsylvania.
5. Department of Epidemiology, University of Pittsburgh, Pittsburgh, Pennsylvania.