1. Department of Anesthesiology and Critical Care Medicine; Johns Hopkins University School of Medicine; Baltimore Maryland U.S.A
2. Departments of Physical Medicine and Rehabilitation; Uniformed Services University of the Health Sciences; Bethesda Maryland U.S.A
3. Walter Reed National Military Medical Center; Bethesda Maryland U.S.A
4. Departments of Neurology and Physical Medicine & Rehabilitation; Johns Hopkins School of Medicine; Baltimore Maryland U.S.A
5. Department of Anesthesiology; Walter Reed National Military Medical Center; Bethesda Maryland U.S.A