1 Departments of Anesthesiology & Critical Care Medicine.
2 Neurology, Johns Hopkins School of Medicine, Baltimore, Maryland.
3 Physical Medicine & Rehabilitation, Johns Hopkins School of Medicine, Baltimore, Maryland.
4 Department of Anesthesiology and Physical Medicine & Rehabilitation, Walter Reed National Military Medical Center, Uniformed Services University of the Health Sciences, Bethesda, Maryland.
5 Department of Anesthesiology, Critical Care and Pain Medicine Service, VA Boston Healthcare System, Boston, Massachusetts.
6 Department of Edith Nourse Rogers Memorial Veterans Hospital, Harvard Medical School, Bedford, Massachusetts, USA.