1 Los Angeles, CA; Department of Emergency Medicine, University of South Carolina School of Medicine, Piedmont Hospital, Newnan, Georgia; Department of Critical Care Medicine, National and & Gulf Center for evidence based health practice, King Saud Bin Abdulaziz University for Health Sciences, Riyadh, Saudi Arabia, Department of Clinical Epidemiology and Biostatistics, McMaster University, Hamilton, ON, Canada; Foothills Medical Centre, University of Calgary, Calgary, AB, Canada; Division of Pulmonary and Critical Care Medicine, Eastern Virginia Medical School, Norfolk, VA.