1. From Duke Clinical Research Institute, Duke University Medical Center, Durham, NC (E.L.F., C.B.G., J.G.J., L.M., L.L., B.L.L., Y.X., E.D.P., S.W.G.); the Department of Emergency Medicine, Carolinas Medical Center, Charlotte, NC (J.L.G.); the Department of Emergency Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC (G.M., S.W.G.); and the New Hanover Regional Medical Center, Wilmington, NC (C.C.C.).