[1] Univ Calif San Diego, Div Pulm Crit Care & Sleep Med, La Jolla, CA 92037 USA
[2] Duke Univ Hosp, Div Pulm Allergy & Crit Care Med, Durham, CA USA
[3] Guangxi Med Univ, Affiliated Hosp 1, Div Pulm & Crit Care Med, Nanning 530021, Peoples R China
[4] Naval Med Ctr San Diego, Dept Pulm & Crit Care, San Diego, CA USA