1 Department of Intensive Care, Erasme University Hospital, Université Libre de Bruxelles, Route de Lennik 808, 1070, Brussels, Belgium. jlvincent@intensive.org.
2 Division of Pulmonary, Allergy and Critical Care, Emory University School of Medicine, Grady Memorial Hospital, 615 Michael Street, Suite 205, Atlanta, GA, 30322, USA.
3 Division of Pulmonary, Critical Care and Sleep Medicine, Alpert Medical School at Brown University, 593 Eddy Street, Providence, RI, 02903, USA.