1. Critical Care Medicine Department, National Institutes of Health Clinical Center, and National Heart, Lung, and Blood Institute, Bethesda, Maryland (M.N., S.W., A.M., J.S., C.Y., R.A., M.R., M.W., B.J.S., C.Y.D., S.S.K.)
2. Critical Care Medicine Department, National Institutes of Health Clinical Center, Bethesda, Maryland (S.H.S., E.C.)
3. Harborview Medical Center, Seattle, Washington (S.H.M.)
4. University of Minnesota and Hennepin Healthcare, Minneapolis, Minnesota (J.H.)
5. Department of Health Research Methods, Evidence and Impact, McMaster University, Hamilton, Ontario, Canada (B.R.)
6. Interdepartmental Division of Critical Care Medicine, University of Toronto, Toronto, Ontario, Canada (E.F.).