1. Department of Physical Medicine & Rehabilitation, University of Pittsburgh School of Medicine, Pittsburgh, PA 15213, USA
2. Safar Center for Resuscitation Research, University of Pittsburgh School of Medicine, Pittsburgh, PA 15213, USA
3. Department of Health Promotion & Development, University of Pittsburgh School of Nursing, Pittsburgh, PA 15213, USA
4. Department of Critical Care Medicine, University of Pittsburgh School of Medicine, Pittsburgh, PA 15213, USA