Kristina Crothers, MD 
Division of Pulmonary and Critical Care Medicine, Department of Medicine, Harborview Medical Center, University of Washington School of Medicine, University of Washington, 325 Ninth Avenue, Box 359762, Seattle, WA 98104, USA
Laurence Huang, MD 
Division of Pulmonary and Critical Care Medicine and HIV/AIDS Division, Department of Medicine, San Francisco General Hospital, University of California San Francisco, 995 Potrero Avenue, San Francisco, CA 94110, USA
Alison Morris, MD, MS 
Division of Pulmonary, Allergy, and Critical Care Medicine, Departments of Medicine and Immunology, University of Pittsburgh School of Medicine, 3459 Fifth Avenue, 628 NW MUH, Pittsburgh, PA 15213, USA