1. From Critical Care Medicine Department, Clinical Center, National Institutes of Health, Bethesda, Maryland; National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, Maryland; Critical Care Medicine Department, Clinical Center, National Institutes of Health, Bethesda, Maryland; National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, Maryland; National Eye Institute, National Institutes of Health, Bethesda, Maryland;
2. National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, Maryland; Hospital Epidemiology Service, Clinical Center, National Institutes of Health, Bethesda, Maryland; National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland.