[1] Louisiana State Univ, Med Ctr, Div Pulm Crit Care, New Orleans, LA 70112 USA
[2] Univ Illinois, Coll Med, Peoria, IL 61656 USA
[3] Maricopa Med Ctr, Phoenix, AZ USA
[4] Univ Washington, Seattle, WA 98195 USA
[5] Univ Washington, Harborview Med Ctr, Seattle, WA 98104 USA
[6] Barberton Citizens Hosp, Barberton, OH USA
[7] Amgen Inc, Thousand Oaks, CA 91320 USA
[8] Texas Tech Univ, El Paso, TX USA
[9] Dalhousie Univ, Halifax, NS, Canada
[10] Victoria Gen Hosp, Halifax, NS B3H 2Y9, Canada
[11] Alfred Univ, Dept Resp Med, Melbourne, Vic, Australia